Google Git
Sign in
android-kvm / linux / refs/heads/for-upstream/guestmem / . / drivers / tty / serial / sc16is7xx.c
blob: a3093e09309ffe6999eeee8be97e5adbe74c18b5 [file] [log] [blame] [edit]
// SPDX-License-Identifier: GPL-2.0+
/*
* SC16IS7xx tty serial driver - common code
*
* Copyright (C) 2014 GridPoint
* Author: Jon Ringle <jringle@gridpoint.com>
* Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru>
*/
#undef DEFAULT_SYMBOL_NAMESPACE
#define DEFAULT_SYMBOL_NAMESPACE "SERIAL_NXP_SC16IS7XX"
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/idr.h>
#include <linux/kthread.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/sched.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/string.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/uaccess.h>
#include <linux/units.h>
#include "sc16is7xx.h"
#define SC16IS7XX_MAX_DEVS 8
/* SC16IS7XX register definitions */
#define SC16IS7XX_RHR_REG (0x00) /* RX FIFO */
#define SC16IS7XX_THR_REG (0x00) /* TX FIFO */
#define SC16IS7XX_IER_REG (0x01) /* Interrupt enable */
#define SC16IS7XX_IIR_REG (0x02) /* Interrupt Identification */
#define SC16IS7XX_FCR_REG (0x02) /* FIFO control */
#define SC16IS7XX_LCR_REG (0x03) /* Line Control */
#define SC16IS7XX_MCR_REG (0x04) /* Modem Control */
#define SC16IS7XX_LSR_REG (0x05) /* Line Status */
#define SC16IS7XX_MSR_REG (0x06) /* Modem Status */
#define SC16IS7XX_SPR_REG (0x07) /* Scratch Pad */
#define SC16IS7XX_TXLVL_REG (0x08) /* TX FIFO level */
#define SC16IS7XX_RXLVL_REG (0x09) /* RX FIFO level */
#define SC16IS7XX_IODIR_REG (0x0a) /* I/O Direction
* - only on 75x/76x
*/
#define SC16IS7XX_IOSTATE_REG (0x0b) /* I/O State
* - only on 75x/76x
*/
#define SC16IS7XX_IOINTENA_REG (0x0c) /* I/O Interrupt Enable
* - only on 75x/76x
*/
#define SC16IS7XX_IOCONTROL_REG (0x0e) /* I/O Control
* - only on 75x/76x
*/
#define SC16IS7XX_EFCR_REG (0x0f) /* Extra Features Control */
/* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */
#define SC16IS7XX_TCR_REG (0x06) /* Transmit control */
#define SC16IS7XX_TLR_REG (0x07) /* Trigger level */
/* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
#define SC16IS7XX_DLL_REG (0x00) /* Divisor Latch Low */
#define SC16IS7XX_DLH_REG (0x01) /* Divisor Latch High */
/* Enhanced Register set: Only if (LCR == 0xBF) */
#define SC16IS7XX_EFR_REG (0x02) /* Enhanced Features */
#define SC16IS7XX_XON1_REG (0x04) /* Xon1 word */
#define SC16IS7XX_XON2_REG (0x05) /* Xon2 word */
#define SC16IS7XX_XOFF1_REG (0x06) /* Xoff1 word */
#define SC16IS7XX_XOFF2_REG (0x07) /* Xoff2 word */
/* IER register bits */
#define SC16IS7XX_IER_RDI_BIT BIT(0) /* Enable RX data interrupt */
#define SC16IS7XX_IER_THRI_BIT BIT(1) /* Enable TX holding register
* interrupt */
#define SC16IS7XX_IER_RLSI_BIT BIT(2) /* Enable RX line status
* interrupt */
#define SC16IS7XX_IER_MSI_BIT BIT(3) /* Enable Modem status
* interrupt */
/* IER register bits - write only if (EFR[4] == 1) */
#define SC16IS7XX_IER_SLEEP_BIT BIT(4) /* Enable Sleep mode */
#define SC16IS7XX_IER_XOFFI_BIT BIT(5) /* Enable Xoff interrupt */
#define SC16IS7XX_IER_RTSI_BIT BIT(6) /* Enable nRTS interrupt */
#define SC16IS7XX_IER_CTSI_BIT BIT(7) /* Enable nCTS interrupt */
/* FCR register bits */
#define SC16IS7XX_FCR_FIFO_BIT BIT(0) /* Enable FIFO */
#define SC16IS7XX_FCR_RXRESET_BIT BIT(1) /* Reset RX FIFO */
#define SC16IS7XX_FCR_TXRESET_BIT BIT(2) /* Reset TX FIFO */
#define SC16IS7XX_FCR_RXLVLL_BIT BIT(6) /* RX Trigger level LSB */
#define SC16IS7XX_FCR_RXLVLH_BIT BIT(7) /* RX Trigger level MSB */
/* FCR register bits - write only if (EFR[4] == 1) */
#define SC16IS7XX_FCR_TXLVLL_BIT BIT(4) /* TX Trigger level LSB */
#define SC16IS7XX_FCR_TXLVLH_BIT BIT(5) /* TX Trigger level MSB */
/* IIR register bits */
#define SC16IS7XX_IIR_NO_INT_BIT 0x01 /* No interrupts pending */
#define SC16IS7XX_IIR_ID_MASK GENMASK(5, 1) /* Mask for the interrupt ID */
#define SC16IS7XX_IIR_THRI_SRC 0x02 /* TX holding register empty */
#define SC16IS7XX_IIR_RDI_SRC 0x04 /* RX data interrupt */
#define SC16IS7XX_IIR_RLSE_SRC 0x06 /* RX line status error */
#define SC16IS7XX_IIR_RTOI_SRC 0x0c /* RX time-out interrupt */
#define SC16IS7XX_IIR_MSI_SRC 0x00 /* Modem status interrupt
* - only on 75x/76x
*/
#define SC16IS7XX_IIR_INPIN_SRC 0x30 /* Input pin change of state
* - only on 75x/76x
*/
#define SC16IS7XX_IIR_XOFFI_SRC 0x10 /* Received Xoff */
#define SC16IS7XX_IIR_CTSRTS_SRC 0x20 /* nCTS,nRTS change of state
* from active (LOW)
* to inactive (HIGH)
*/
/* LCR register bits */
#define SC16IS7XX_LCR_LENGTH0_BIT BIT(0) /* Word length bit 0 */
#define SC16IS7XX_LCR_LENGTH1_BIT BIT(1) /* Word length bit 1
*
* Word length bits table:
* 00 -> 5 bit words
* 01 -> 6 bit words
* 10 -> 7 bit words
* 11 -> 8 bit words
*/
#define SC16IS7XX_LCR_STOPLEN_BIT BIT(2) /* STOP length bit
*
* STOP length bit table:
* 0 -> 1 stop bit
* 1 -> 1-1.5 stop bits if
* word length is 5,
* 2 stop bits otherwise
*/
#define SC16IS7XX_LCR_PARITY_BIT BIT(3) /* Parity bit enable */
#define SC16IS7XX_LCR_EVENPARITY_BIT BIT(4) /* Even parity bit enable */
#define SC16IS7XX_LCR_FORCEPARITY_BIT BIT(5) /* 9-bit multidrop parity */
#define SC16IS7XX_LCR_TXBREAK_BIT BIT(6) /* TX break enable */
#define SC16IS7XX_LCR_DLAB_BIT BIT(7) /* Divisor Latch enable */
#define SC16IS7XX_LCR_WORD_LEN_5 (0x00)
#define SC16IS7XX_LCR_WORD_LEN_6 (0x01)
#define SC16IS7XX_LCR_WORD_LEN_7 (0x02)
#define SC16IS7XX_LCR_WORD_LEN_8 (0x03)
#define SC16IS7XX_LCR_CONF_MODE_A SC16IS7XX_LCR_DLAB_BIT /* Special
* reg set */
#define SC16IS7XX_LCR_CONF_MODE_B 0xBF /* Enhanced
* reg set */
/* MCR register bits */
#define SC16IS7XX_MCR_DTR_BIT BIT(0) /* DTR complement
* - only on 75x/76x
*/
#define SC16IS7XX_MCR_RTS_BIT BIT(1) /* RTS complement */
#define SC16IS7XX_MCR_TCRTLR_BIT BIT(2) /* TCR/TLR register enable */
#define SC16IS7XX_MCR_LOOP_BIT BIT(4) /* Enable loopback test mode */
#define SC16IS7XX_MCR_XONANY_BIT BIT(5) /* Enable Xon Any
* - write enabled
* if (EFR[4] == 1)
*/
#define SC16IS7XX_MCR_IRDA_BIT BIT(6) /* Enable IrDA mode
* - write enabled
* if (EFR[4] == 1)
*/
#define SC16IS7XX_MCR_CLKSEL_BIT BIT(7) /* Divide clock by 4
* - write enabled
* if (EFR[4] == 1)
*/
/* LSR register bits */
#define SC16IS7XX_LSR_DR_BIT BIT(0) /* Receiver data ready */
#define SC16IS7XX_LSR_OE_BIT BIT(1) /* Overrun Error */
#define SC16IS7XX_LSR_PE_BIT BIT(2) /* Parity Error */
#define SC16IS7XX_LSR_FE_BIT BIT(3) /* Frame Error */
#define SC16IS7XX_LSR_BI_BIT BIT(4) /* Break Interrupt */
#define SC16IS7XX_LSR_BRK_ERROR_MASK \
(SC16IS7XX_LSR_OE_BIT | \
SC16IS7XX_LSR_PE_BIT | \
SC16IS7XX_LSR_FE_BIT | \
SC16IS7XX_LSR_BI_BIT)
#define SC16IS7XX_LSR_THRE_BIT BIT(5) /* TX holding register empty */
#define SC16IS7XX_LSR_TEMT_BIT BIT(6) /* Transmitter empty */
#define SC16IS7XX_LSR_FIFOE_BIT BIT(7) /* Fifo Error */
/* MSR register bits */
#define SC16IS7XX_MSR_DCTS_BIT BIT(0) /* Delta CTS Clear To Send */
#define SC16IS7XX_MSR_DDSR_BIT BIT(1) /* Delta DSR Data Set Ready
* or (IO4)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_DRI_BIT BIT(2) /* Delta RI Ring Indicator
* or (IO7)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_DCD_BIT BIT(3) /* Delta CD Carrier Detect
* or (IO6)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_CTS_BIT BIT(4) /* CTS */
#define SC16IS7XX_MSR_DSR_BIT BIT(5) /* DSR (IO4)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_RI_BIT BIT(6) /* RI (IO7)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_CD_BIT BIT(7) /* CD (IO6)
* - only on 75x/76x
*/
/*
* TCR register bits
* TCR trigger levels are available from 0 to 60 characters with a granularity
* of four.
* The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is
* no built-in hardware check to make sure this condition is met. Also, the TCR
* must be programmed with this condition before auto RTS or software flow
* control is enabled to avoid spurious operation of the device.
*/
#define SC16IS7XX_TCR_RX_HALT(words) ((((words) / 4) & 0x0f) << 0)
#define SC16IS7XX_TCR_RX_RESUME(words) ((((words) / 4) & 0x0f) << 4)
/*
* TLR register bits
* If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
* FIFO Control Register (FCR) are used for the transmit and receive FIFO
* trigger levels. Trigger levels from 4 characters to 60 characters are
* available with a granularity of four.
*
* When the trigger level setting in TLR is zero, the SC16IS74x/75x/76x uses the
* trigger level setting defined in FCR. If TLR has non-zero trigger level value
* the trigger level defined in FCR is discarded. This applies to both transmit
* FIFO and receive FIFO trigger level setting.
*
* When TLR is used for RX trigger level control, FCR[7:6] should be left at the
* default state, that is, '00'.
*/
#define SC16IS7XX_TLR_TX_TRIGGER(words) ((((words) / 4) & 0x0f) << 0)
#define SC16IS7XX_TLR_RX_TRIGGER(words) ((((words) / 4) & 0x0f) << 4)
/* IOControl register bits (Only 75x/76x) */
#define SC16IS7XX_IOCONTROL_LATCH_BIT BIT(0) /* Enable input latching */
#define SC16IS7XX_IOCONTROL_MODEM_A_BIT BIT(1) /* Enable GPIO[7:4] as modem A pins */
#define SC16IS7XX_IOCONTROL_MODEM_B_BIT BIT(2) /* Enable GPIO[3:0] as modem B pins */
#define SC16IS7XX_IOCONTROL_SRESET_BIT BIT(3) /* Software Reset */
/* EFCR register bits */
#define SC16IS7XX_EFCR_9BIT_MODE_BIT BIT(0) /* Enable 9-bit or Multidrop
* mode (RS485) */
#define SC16IS7XX_EFCR_RXDISABLE_BIT BIT(1) /* Disable receiver */
#define SC16IS7XX_EFCR_TXDISABLE_BIT BIT(2) /* Disable transmitter */
#define SC16IS7XX_EFCR_AUTO_RS485_BIT BIT(4) /* Auto RS485 RTS direction */
#define SC16IS7XX_EFCR_RTS_INVERT_BIT BIT(5) /* RTS output inversion */
#define SC16IS7XX_EFCR_IRDA_MODE_BIT BIT(7) /* IrDA mode
* 0 = rate upto 115.2 kbit/s
* - Only 75x/76x
* 1 = rate upto 1.152 Mbit/s
* - Only 76x
*/
/* EFR register bits */
#define SC16IS7XX_EFR_AUTORTS_BIT BIT(6) /* Auto RTS flow ctrl enable */
#define SC16IS7XX_EFR_AUTOCTS_BIT BIT(7) /* Auto CTS flow ctrl enable */
#define SC16IS7XX_EFR_XOFF2_DETECT_BIT BIT(5) /* Enable Xoff2 detection */
#define SC16IS7XX_EFR_ENABLE_BIT BIT(4) /* Enable enhanced functions
* and writing to IER[7:4],
* FCR[5:4], MCR[7:5]
*/
#define SC16IS7XX_EFR_SWFLOW3_BIT BIT(3)
#define SC16IS7XX_EFR_SWFLOW2_BIT BIT(2)
/*
* SWFLOW bits 3 & 2 table:
* 00 -> no transmitter flow
* control
* 01 -> transmitter generates
* XON2 and XOFF2
* 10 -> transmitter generates
* XON1 and XOFF1
* 11 -> transmitter generates
* XON1, XON2, XOFF1 and
* XOFF2
*/
#define SC16IS7XX_EFR_SWFLOW1_BIT BIT(1)
#define SC16IS7XX_EFR_SWFLOW0_BIT BIT(0)
/*
* SWFLOW bits 1 & 0 table:
* 00 -> no received flow
* control
* 01 -> receiver compares
* XON2 and XOFF2
* 10 -> receiver compares
* XON1 and XOFF1
* 11 -> receiver compares
* XON1, XON2, XOFF1 and
* XOFF2
*/
#define SC16IS7XX_EFR_FLOWCTRL_BITS (SC16IS7XX_EFR_AUTORTS_BIT | \
SC16IS7XX_EFR_AUTOCTS_BIT | \
SC16IS7XX_EFR_XOFF2_DETECT_BIT | \
SC16IS7XX_EFR_SWFLOW3_BIT | \
SC16IS7XX_EFR_SWFLOW2_BIT | \
SC16IS7XX_EFR_SWFLOW1_BIT | \
SC16IS7XX_EFR_SWFLOW0_BIT)
/* Misc definitions */
#define SC16IS7XX_FIFO_SIZE (64)
#define SC16IS7XX_GPIOS_PER_BANK 4
#define SC16IS7XX_RECONF_MD BIT(0)
#define SC16IS7XX_RECONF_IER BIT(1)
#define SC16IS7XX_RECONF_RS485 BIT(2)
struct sc16is7xx_one_config {
unsigned int flags;
u8 ier_mask;
u8 ier_val;
};
struct sc16is7xx_one {
struct uart_port port;
struct regmap *regmap;
struct mutex efr_lock; /* EFR registers access */
struct kthread_work tx_work;
struct kthread_work reg_work;
struct kthread_delayed_work ms_work;
struct sc16is7xx_one_config config;
unsigned char buf[SC16IS7XX_FIFO_SIZE]; /* Rx buffer. */
unsigned int old_mctrl;
u8 old_lcr; /* Value before EFR access. */
bool irda_mode;
};
struct sc16is7xx_port {
const struct sc16is7xx_devtype *devtype;
struct clk *clk;
#ifdef CONFIG_GPIOLIB
struct gpio_chip gpio;
unsigned long gpio_valid_mask;
#endif
u8 mctrl_mask;
struct kthread_worker kworker;
struct task_struct *kworker_task;
struct sc16is7xx_one p[];
};
static DEFINE_IDA(sc16is7xx_lines);
static struct uart_driver sc16is7xx_uart = {
.owner = THIS_MODULE,
.driver_name = SC16IS7XX_NAME,
.dev_name = "ttySC",
.nr = SC16IS7XX_MAX_DEVS,
};
#define to_sc16is7xx_one(p,e) ((container_of((p), struct sc16is7xx_one, e)))
static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
unsigned int val = 0;
regmap_read(one->regmap, reg, &val);
return val;
}
static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
regmap_write(one->regmap, reg, val);
}
static void sc16is7xx_fifo_read(struct uart_port *port, u8 *rxbuf, unsigned int rxlen)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, rxbuf, rxlen);
}
static void sc16is7xx_fifo_write(struct uart_port *port, u8 *txbuf, u8 to_send)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
/*
* Don't send zero-length data, at least on SPI it confuses the chip
* delivering wrong TXLVL data.
*/
if (unlikely(!to_send))
return;
regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, txbuf, to_send);
}
static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
u8 mask, u8 val)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
regmap_update_bits(one->regmap, reg, mask, val);
}
static void sc16is7xx_power(struct uart_port *port, int on)
{
sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
SC16IS7XX_IER_SLEEP_BIT,
on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
}
/*
* In an amazing feat of design, the Enhanced Features Register (EFR)
* shares the address of the Interrupt Identification Register (IIR).
* Access to EFR is switched on by writing a magic value (0xbf) to the
* Line Control Register (LCR). Any interrupt firing during this time will
* see the EFR where it expects the IIR to be, leading to
* "Unexpected interrupt" messages.
*
* Prevent this possibility by claiming a mutex while accessing the EFR,
* and claiming the same mutex from within the interrupt handler. This is
* similar to disabling the interrupt, but that doesn't work because the
* bulk of the interrupt processing is run as a workqueue job in thread
* context.
*/
static void sc16is7xx_efr_lock(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
mutex_lock(&one->efr_lock);
/* Backup content of LCR. */
one->old_lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
/* Enable access to Enhanced register set */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_CONF_MODE_B);
/* Disable cache updates when writing to EFR registers */
regcache_cache_bypass(one->regmap, true);
}
static void sc16is7xx_efr_unlock(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
/* Re-enable cache updates when writing to normal registers */
regcache_cache_bypass(one->regmap, false);
/* Restore original content of LCR */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, one->old_lcr);
mutex_unlock(&one->efr_lock);
}
static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
lockdep_assert_held_once(&port->lock);
one->config.flags |= SC16IS7XX_RECONF_IER;
one->config.ier_mask |= bit;
one->config.ier_val &= ~bit;
kthread_queue_work(&s->kworker, &one->reg_work);
}
static void sc16is7xx_ier_set(struct uart_port *port, u8 bit)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
lockdep_assert_held_once(&port->lock);
one->config.flags |= SC16IS7XX_RECONF_IER;
one->config.ier_mask |= bit;
one->config.ier_val |= bit;
kthread_queue_work(&s->kworker, &one->reg_work);
}
static void sc16is7xx_stop_tx(struct uart_port *port)
{
sc16is7xx_ier_clear(port, SC16IS7XX_IER_THRI_BIT);
}
static void sc16is7xx_stop_rx(struct uart_port *port)
{
sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
}
const struct sc16is7xx_devtype sc16is74x_devtype = {
.name = "SC16IS74X",
.nr_gpio = 0,
.nr_uart = 1,
};
EXPORT_SYMBOL_GPL(sc16is74x_devtype);
const struct sc16is7xx_devtype sc16is750_devtype = {
.name = "SC16IS750",
.nr_gpio = 8,
.nr_uart = 1,
};
EXPORT_SYMBOL_GPL(sc16is750_devtype);
const struct sc16is7xx_devtype sc16is752_devtype = {
.name = "SC16IS752",
.nr_gpio = 8,
.nr_uart = 2,
};
EXPORT_SYMBOL_GPL(sc16is752_devtype);
const struct sc16is7xx_devtype sc16is760_devtype = {
.name = "SC16IS760",
.nr_gpio = 8,
.nr_uart = 1,
};
EXPORT_SYMBOL_GPL(sc16is760_devtype);
const struct sc16is7xx_devtype sc16is762_devtype = {
.name = "SC16IS762",
.nr_gpio = 8,
.nr_uart = 2,
};
EXPORT_SYMBOL_GPL(sc16is762_devtype);
static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
{
switch (reg) {
case SC16IS7XX_RHR_REG:
case SC16IS7XX_IIR_REG:
case SC16IS7XX_LSR_REG:
case SC16IS7XX_MSR_REG:
case SC16IS7XX_TXLVL_REG:
case SC16IS7XX_RXLVL_REG:
case SC16IS7XX_IOSTATE_REG:
case SC16IS7XX_IOCONTROL_REG:
return true;
default:
return false;
}
}
static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
{
switch (reg) {
case SC16IS7XX_RHR_REG:
return true;
default:
return false;
}
}
static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg)
{
return reg == SC16IS7XX_RHR_REG;
}
/*
* Configure programmable baud rate generator (divisor) according to the
* desired baud rate.
*
* From the datasheet, the divisor is computed according to:
*
* XTAL1 input frequency
* -----------------------
* prescaler
* divisor = ---------------------------
* baud-rate x sampling-rate
*/
static int sc16is7xx_set_baud(struct uart_port *port, int baud)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
u8 lcr;
unsigned int prescaler = 1;
unsigned long clk = port->uartclk, div = clk / 16 / baud;
if (div >= BIT(16)) {
prescaler = 4;
div /= prescaler;
}
/* Enable enhanced features */
sc16is7xx_efr_lock(port);
sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_ENABLE_BIT,
SC16IS7XX_EFR_ENABLE_BIT);
sc16is7xx_efr_unlock(port);
/* If bit MCR_CLKSEL is set, the divide by 4 prescaler is activated. */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_CLKSEL_BIT,
prescaler == 1 ? 0 : SC16IS7XX_MCR_CLKSEL_BIT);
mutex_lock(&one->efr_lock);
/* Backup LCR and access special register set (DLL/DLH) */
lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_A);
/* Write the new divisor */
regcache_cache_bypass(one->regmap, true);
sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
regcache_cache_bypass(one->regmap, false);
/* Restore LCR and access to general register set */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
mutex_unlock(&one->efr_lock);
return DIV_ROUND_CLOSEST((clk / prescaler) / 16, div);
}
static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
unsigned int iir)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
unsigned int lsr = 0, bytes_read, i;
bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
u8 ch, flag;
if (unlikely(rxlen >= sizeof(one->buf))) {
dev_warn_ratelimited(port->dev,
"ttySC%i: Possible RX FIFO overrun: %d\n",
port->line, rxlen);
port->icount.buf_overrun++;
/* Ensure sanity of RX level */
rxlen = sizeof(one->buf);
}
while (rxlen) {
/* Only read lsr if there are possible errors in FIFO */
if (read_lsr) {
lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
read_lsr = false; /* No errors left in FIFO */
} else
lsr = 0;
if (read_lsr) {
one->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
bytes_read = 1;
} else {
sc16is7xx_fifo_read(port, one->buf, rxlen);
bytes_read = rxlen;
}
lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
port->icount.rx++;
flag = TTY_NORMAL;
if (unlikely(lsr)) {
if (lsr & SC16IS7XX_LSR_BI_BIT) {
port->icount.brk++;
if (uart_handle_break(port))
continue;
} else if (lsr & SC16IS7XX_LSR_PE_BIT)
port->icount.parity++;
else if (lsr & SC16IS7XX_LSR_FE_BIT)
port->icount.frame++;
else if (lsr & SC16IS7XX_LSR_OE_BIT)
port->icount.overrun++;
lsr &= port->read_status_mask;
if (lsr & SC16IS7XX_LSR_BI_BIT)
flag = TTY_BREAK;
else if (lsr & SC16IS7XX_LSR_PE_BIT)
flag = TTY_PARITY;
else if (lsr & SC16IS7XX_LSR_FE_BIT)
flag = TTY_FRAME;
else if (lsr & SC16IS7XX_LSR_OE_BIT)
flag = TTY_OVERRUN;
}
for (i = 0; i < bytes_read; ++i) {
ch = one->buf[i];
if (uart_handle_sysrq_char(port, ch))
continue;
if (lsr & port->ignore_status_mask)
continue;
uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
flag);
}
rxlen -= bytes_read;
}
tty_flip_buffer_push(&port->state->port);
}
static void sc16is7xx_handle_tx(struct uart_port *port)
{
struct tty_port *tport = &port->state->port;
unsigned long flags;
unsigned int txlen;
unsigned char *tail;
if (unlikely(port->x_char)) {
sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
port->icount.tx++;
port->x_char = 0;
return;
}
if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) {
uart_port_lock_irqsave(port, &flags);
sc16is7xx_stop_tx(port);
uart_port_unlock_irqrestore(port, flags);
return;
}
/* Limit to space available in TX FIFO */
txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
if (txlen > SC16IS7XX_FIFO_SIZE) {
dev_err_ratelimited(port->dev,
"chip reports %d free bytes in TX fifo, but it only has %d",
txlen, SC16IS7XX_FIFO_SIZE);
txlen = 0;
}
txlen = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, txlen);
sc16is7xx_fifo_write(port, tail, txlen);
uart_xmit_advance(port, txlen);
uart_port_lock_irqsave(port, &flags);
if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (kfifo_is_empty(&tport->xmit_fifo))
sc16is7xx_stop_tx(port);
else
sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT);
uart_port_unlock_irqrestore(port, flags);
}
static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port)
{
u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
unsigned int mctrl = 0;
mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
mctrl |= (msr & SC16IS7XX_MSR_DSR_BIT) ? TIOCM_DSR : 0;
mctrl |= (msr & SC16IS7XX_MSR_CD_BIT) ? TIOCM_CAR : 0;
mctrl |= (msr & SC16IS7XX_MSR_RI_BIT) ? TIOCM_RNG : 0;
return mctrl;
}
static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
{
struct uart_port *port = &one->port;
unsigned long flags;
unsigned int status, changed;
lockdep_assert_held_once(&one->efr_lock);
status = sc16is7xx_get_hwmctrl(port);
changed = status ^ one->old_mctrl;
if (changed == 0)
return;
one->old_mctrl = status;
uart_port_lock_irqsave(port, &flags);
if ((changed & TIOCM_RNG) && (status & TIOCM_RNG))
port->icount.rng++;
if (changed & TIOCM_DSR)
port->icount.dsr++;
if (changed & TIOCM_CAR)
uart_handle_dcd_change(port, status & TIOCM_CAR);
if (changed & TIOCM_CTS)
uart_handle_cts_change(port, status & TIOCM_CTS);
wake_up_interruptible(&port->state->port.delta_msr_wait);
uart_port_unlock_irqrestore(port, flags);
}
static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
{
bool rc = true;
unsigned int iir, rxlen;
struct uart_port *port = &s->p[portno].port;
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
mutex_lock(&one->efr_lock);
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
rc = false;
goto out_port_irq;
}
iir &= SC16IS7XX_IIR_ID_MASK;
switch (iir) {
case SC16IS7XX_IIR_RDI_SRC:
case SC16IS7XX_IIR_RLSE_SRC:
case SC16IS7XX_IIR_RTOI_SRC:
case SC16IS7XX_IIR_XOFFI_SRC:
rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
/*
* There is a silicon bug that makes the chip report a
* time-out interrupt but no data in the FIFO. This is
* described in errata section 18.1.4.
*
* When this happens, read one byte from the FIFO to
* clear the interrupt.
*/
if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen)
rxlen = 1;
if (rxlen)
sc16is7xx_handle_rx(port, rxlen, iir);
break;
/* CTSRTS interrupt comes only when CTS goes inactive */
case SC16IS7XX_IIR_CTSRTS_SRC:
case SC16IS7XX_IIR_MSI_SRC:
sc16is7xx_update_mlines(one);
break;
case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port);
break;
default:
dev_err_ratelimited(port->dev,
"ttySC%i: Unexpected interrupt: %x",
port->line, iir);
break;
}
out_port_irq:
mutex_unlock(&one->efr_lock);
return rc;
}
static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
{
bool keep_polling;
struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
do {
int i;
keep_polling = false;
for (i = 0; i < s->devtype->nr_uart; ++i)
keep_polling |= sc16is7xx_port_irq(s, i);
} while (keep_polling);
return IRQ_HANDLED;
}
static void sc16is7xx_tx_proc(struct kthread_work *ws)
{
struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
if ((port->rs485.flags & SER_RS485_ENABLED) &&
(port->rs485.delay_rts_before_send > 0))
msleep(port->rs485.delay_rts_before_send);
mutex_lock(&one->efr_lock);
sc16is7xx_handle_tx(port);
mutex_unlock(&one->efr_lock);
}
static void sc16is7xx_reconf_rs485(struct uart_port *port)
{
const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
SC16IS7XX_EFCR_RTS_INVERT_BIT;
u32 efcr = 0;
struct serial_rs485 *rs485 = &port->rs485;
unsigned long irqflags;
uart_port_lock_irqsave(port, &irqflags);
if (rs485->flags & SER_RS485_ENABLED) {
efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT;
if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
}
uart_port_unlock_irqrestore(port, irqflags);
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
}
static void sc16is7xx_reg_proc(struct kthread_work *ws)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(ws, reg_work);
struct sc16is7xx_one_config config;
unsigned long irqflags;
uart_port_lock_irqsave(&one->port, &irqflags);
config = one->config;
memset(&one->config, 0, sizeof(one->config));
uart_port_unlock_irqrestore(&one->port, irqflags);
if (config.flags & SC16IS7XX_RECONF_MD) {
u8 mcr = 0;
/* Device ignores RTS setting when hardware flow is enabled */
if (one->port.mctrl & TIOCM_RTS)
mcr |= SC16IS7XX_MCR_RTS_BIT;
if (one->port.mctrl & TIOCM_DTR)
mcr |= SC16IS7XX_MCR_DTR_BIT;
if (one->port.mctrl & TIOCM_LOOP)
mcr |= SC16IS7XX_MCR_LOOP_BIT;
sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_RTS_BIT |
SC16IS7XX_MCR_DTR_BIT |
SC16IS7XX_MCR_LOOP_BIT,
mcr);
}
if (config.flags & SC16IS7XX_RECONF_IER)
sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG,
config.ier_mask, config.ier_val);
if (config.flags & SC16IS7XX_RECONF_RS485)
sc16is7xx_reconf_rs485(&one->port);
}
static void sc16is7xx_ms_proc(struct kthread_work *ws)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(ws, ms_work.work);
struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
if (one->port.state) {
mutex_lock(&one->efr_lock);
sc16is7xx_update_mlines(one);
mutex_unlock(&one->efr_lock);
kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
}
}
static void sc16is7xx_enable_ms(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
lockdep_assert_held_once(&port->lock);
kthread_queue_delayed_work(&s->kworker, &one->ms_work, 0);
}
static void sc16is7xx_start_tx(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
kthread_queue_work(&s->kworker, &one->tx_work);
}
static void sc16is7xx_throttle(struct uart_port *port)
{
unsigned long flags;
/*
* Hardware flow control is enabled and thus the device ignores RTS
* value set in MCR register. Stop reading data from RX FIFO so the
* AutoRTS feature will de-activate RTS output.
*/
uart_port_lock_irqsave(port, &flags);
sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
uart_port_unlock_irqrestore(port, flags);
}
static void sc16is7xx_unthrottle(struct uart_port *port)
{
unsigned long flags;
uart_port_lock_irqsave(port, &flags);
sc16is7xx_ier_set(port, SC16IS7XX_IER_RDI_BIT);
uart_port_unlock_irqrestore(port, flags);
}
static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
{
unsigned int lsr;
lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
return (lsr & SC16IS7XX_LSR_TEMT_BIT) ? TIOCSER_TEMT : 0;
}
static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
/* Called with port lock taken so we can only return cached value */
return one->old_mctrl;
}
static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
one->config.flags |= SC16IS7XX_RECONF_MD;
kthread_queue_work(&s->kworker, &one->reg_work);
}
static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
{
sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_TXBREAK_BIT,
break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
}
static void sc16is7xx_set_termios(struct uart_port *port,
struct ktermios *termios,
const struct ktermios *old)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
unsigned int lcr, flow = 0;
int baud;
unsigned long flags;
kthread_cancel_delayed_work_sync(&one->ms_work);
/* Mask termios capabilities we don't support */
termios->c_cflag &= ~CMSPAR;
/* Word size */
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr = SC16IS7XX_LCR_WORD_LEN_5;
break;
case CS6:
lcr = SC16IS7XX_LCR_WORD_LEN_6;
break;
case CS7:
lcr = SC16IS7XX_LCR_WORD_LEN_7;
break;
case CS8:
lcr = SC16IS7XX_LCR_WORD_LEN_8;
break;
default:
lcr = SC16IS7XX_LCR_WORD_LEN_8;
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= CS8;
break;
}
/* Parity */
if (termios->c_cflag & PARENB) {
lcr |= SC16IS7XX_LCR_PARITY_BIT;
if (!(termios->c_cflag & PARODD))
lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
}
/* Stop bits */
if (termios->c_cflag & CSTOPB)
lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
/* Set read status mask */
port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
if (termios->c_iflag & INPCK)
port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
SC16IS7XX_LSR_FE_BIT;
if (termios->c_iflag & (BRKINT | PARMRK))
port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
/* Set status ignore mask */
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNBRK)
port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
if (!(termios->c_cflag & CREAD))
port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
/* Configure flow control */
port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
if (termios->c_cflag & CRTSCTS) {
flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
SC16IS7XX_EFR_AUTORTS_BIT;
port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
}
if (termios->c_iflag & IXON)
flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
if (termios->c_iflag & IXOFF)
flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
/* Update LCR register */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
/* Update EFR registers */
sc16is7xx_efr_lock(port);
sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_FLOWCTRL_BITS, flow);
sc16is7xx_efr_unlock(port);
/* Get baud rate generator configuration */
baud = uart_get_baud_rate(port, termios, old,
port->uartclk / 16 / 4 / 0xffff,
port->uartclk / 16);
/* Setup baudrate generator */
baud = sc16is7xx_set_baud(port, baud);
uart_port_lock_irqsave(port, &flags);
/* Update timeout according to new baud rate */
uart_update_timeout(port, termios->c_cflag, baud);
if (UART_ENABLE_MS(port, termios->c_cflag))
sc16is7xx_enable_ms(port);
uart_port_unlock_irqrestore(port, flags);
}
static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termios,
struct serial_rs485 *rs485)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
if (rs485->flags & SER_RS485_ENABLED) {
/*
* RTS signal is handled by HW, it's timing can't be influenced.
* However, it's sometimes useful to delay TX even without RTS
* control therefore we try to handle .delay_rts_before_send.
*/
if (rs485->delay_rts_after_send)
return -EINVAL;
}
one->config.flags |= SC16IS7XX_RECONF_RS485;
kthread_queue_work(&s->kworker, &one->reg_work);
return 0;
}
static int sc16is7xx_startup(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
unsigned int val;
unsigned long flags;
sc16is7xx_power(port, 1);
/* Reset FIFOs*/
val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
udelay(5);
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
SC16IS7XX_FCR_FIFO_BIT);
/* Enable EFR */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_B);
regcache_cache_bypass(one->regmap, true);
/* Enable write access to enhanced features and internal clock div */
sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_ENABLE_BIT,
SC16IS7XX_EFR_ENABLE_BIT);
/* Enable TCR/TLR */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_TCRTLR_BIT,
SC16IS7XX_MCR_TCRTLR_BIT);
/* Configure flow control levels */
/* Flow control halt level 48, resume level 24 */
sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
SC16IS7XX_TCR_RX_RESUME(24) |
SC16IS7XX_TCR_RX_HALT(48));
regcache_cache_bypass(one->regmap, false);
/* Now, initialize the UART */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
/* Enable IrDA mode if requested in DT */
/* This bit must be written with LCR[7] = 0 */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_IRDA_BIT,
one->irda_mode ?
SC16IS7XX_MCR_IRDA_BIT : 0);
/* Enable the Rx and Tx FIFO */
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT,
0);
/* Enable RX, CTS change and modem lines interrupts */
val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_CTSI_BIT |
SC16IS7XX_IER_MSI_BIT;
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
/* Enable modem status polling */
uart_port_lock_irqsave(port, &flags);
sc16is7xx_enable_ms(port);
uart_port_unlock_irqrestore(port, flags);
return 0;
}
static void sc16is7xx_shutdown(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
kthread_cancel_delayed_work_sync(&one->ms_work);
/* Disable all interrupts */
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
/* Disable TX/RX */
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
sc16is7xx_power(port, 0);
kthread_flush_worker(&s->kworker);
}
static const char *sc16is7xx_type(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
}
static int sc16is7xx_request_port(struct uart_port *port)
{
/* Do nothing */
return 0;
}
static void sc16is7xx_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_SC16IS7XX;
}
static int sc16is7xx_verify_port(struct uart_port *port,
struct serial_struct *s)
{
if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
return -EINVAL;
if (s->irq != port->irq)
return -EINVAL;
return 0;
}
static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
}
static void sc16is7xx_null_void(struct uart_port *port)
{
/* Do nothing */
}
static const struct uart_ops sc16is7xx_ops = {
.tx_empty = sc16is7xx_tx_empty,
.set_mctrl = sc16is7xx_set_mctrl,
.get_mctrl = sc16is7xx_get_mctrl,
.stop_tx = sc16is7xx_stop_tx,
.start_tx = sc16is7xx_start_tx,
.throttle = sc16is7xx_throttle,
.unthrottle = sc16is7xx_unthrottle,
.stop_rx = sc16is7xx_stop_rx,
.enable_ms = sc16is7xx_enable_ms,
.break_ctl = sc16is7xx_break_ctl,
.startup = sc16is7xx_startup,
.shutdown = sc16is7xx_shutdown,
.set_termios = sc16is7xx_set_termios,
.type = sc16is7xx_type,
.request_port = sc16is7xx_request_port,
.release_port = sc16is7xx_null_void,
.config_port = sc16is7xx_config_port,
.verify_port = sc16is7xx_verify_port,
.pm = sc16is7xx_pm,
};
#ifdef CONFIG_GPIOLIB
static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
{
unsigned int val;
struct sc16is7xx_port *s = gpiochip_get_data(chip);
struct uart_port *port = &s->p[0].port;
val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
return !!(val & BIT(offset));
}
static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
struct sc16is7xx_port *s = gpiochip_get_data(chip);
struct uart_port *port = &s->p[0].port;
sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
val ? BIT(offset) : 0);
}
static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
unsigned offset)
{
struct sc16is7xx_port *s = gpiochip_get_data(chip);
struct uart_port *port = &s->p[0].port;
sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
return 0;
}
static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int val)
{
struct sc16is7xx_port *s = gpiochip_get_data(chip);
struct uart_port *port = &s->p[0].port;
u8 state = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
if (val)
state |= BIT(offset);
else
state &= ~BIT(offset);
/*
* If we write IOSTATE first, and then IODIR, the output value is not
* transferred to the corresponding I/O pin.
* The datasheet states that each register bit will be transferred to
* the corresponding I/O pin programmed as output when writing to
* IOSTATE. Therefore, configure direction first with IODIR, and then
* set value after with IOSTATE.
*/
sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
BIT(offset));
sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
return 0;
}
static int sc16is7xx_gpio_init_valid_mask(struct gpio_chip *chip,
unsigned long *valid_mask,
unsigned int ngpios)
{
struct sc16is7xx_port *s = gpiochip_get_data(chip);
*valid_mask = s->gpio_valid_mask;
return 0;
}
static int sc16is7xx_setup_gpio_chip(struct sc16is7xx_port *s)
{
struct device *dev = s->p[0].port.dev;
if (!s->devtype->nr_gpio)
return 0;
switch (s->mctrl_mask) {
case 0:
s->gpio_valid_mask = GENMASK(7, 0);
break;
case SC16IS7XX_IOCONTROL_MODEM_A_BIT:
s->gpio_valid_mask = GENMASK(3, 0);
break;
case SC16IS7XX_IOCONTROL_MODEM_B_BIT:
s->gpio_valid_mask = GENMASK(7, 4);
break;
default:
break;
}
if (s->gpio_valid_mask == 0)
return 0;
s->gpio.owner = THIS_MODULE;
s->gpio.parent = dev;
s->gpio.label = dev_name(dev);
s->gpio.init_valid_mask = sc16is7xx_gpio_init_valid_mask;
s->gpio.direction_input = sc16is7xx_gpio_direction_input;
s->gpio.get = sc16is7xx_gpio_get;
s->gpio.direction_output = sc16is7xx_gpio_direction_output;
s->gpio.set = sc16is7xx_gpio_set;
s->gpio.base = -1;
s->gpio.ngpio = s->devtype->nr_gpio;
s->gpio.can_sleep = 1;
return gpiochip_add_data(&s->gpio, s);
}
#endif
static void sc16is7xx_setup_irda_ports(struct sc16is7xx_port *s)
{
int i;
int ret;
int count;
u32 irda_port[SC16IS7XX_MAX_PORTS];
struct device *dev = s->p[0].port.dev;
count = device_property_count_u32(dev, "irda-mode-ports");
if (count < 0 || count > ARRAY_SIZE(irda_port))
return;
ret = device_property_read_u32_array(dev, "irda-mode-ports",
irda_port, count);
if (ret)
return;
for (i = 0; i < count; i++) {
if (irda_port[i] < s->devtype->nr_uart)
s->p[irda_port[i]].irda_mode = true;
}
}
/*
* Configure ports designated to operate as modem control lines.
*/
static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s,
struct regmap *regmap)
{
int i;
int ret;
int count;
u32 mctrl_port[SC16IS7XX_MAX_PORTS];
struct device *dev = s->p[0].port.dev;
count = device_property_count_u32(dev, "nxp,modem-control-line-ports");
if (count < 0 || count > ARRAY_SIZE(mctrl_port))
return 0;
ret = device_property_read_u32_array(dev, "nxp,modem-control-line-ports",
mctrl_port, count);
if (ret)
return ret;
s->mctrl_mask = 0;
for (i = 0; i < count; i++) {
/* Use GPIO lines as modem control lines */
if (mctrl_port[i] == 0)
s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_A_BIT;
else if (mctrl_port[i] == 1)
s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_B_BIT;
}
if (s->mctrl_mask)
regmap_update_bits(
regmap,
SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_MODEM_A_BIT |
SC16IS7XX_IOCONTROL_MODEM_B_BIT, s->mctrl_mask);
return 0;
}
static const struct serial_rs485 sc16is7xx_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1, /* Not supported but keep returning -EINVAL */
};
/* Reset device, purging any pending irq / data */
static int sc16is7xx_reset(struct device *dev, struct regmap *regmap)
{
struct gpio_desc *reset_gpio;
/* Assert reset GPIO if defined and valid. */
reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(reset_gpio))
return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset GPIO\n");
if (reset_gpio) {
/* The minimum reset pulse width is 3 us. */
fsleep(5);
gpiod_set_value_cansleep(reset_gpio, 0); /* Deassert GPIO */
} else {
/* Software reset */
regmap_write(regmap, SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_SRESET_BIT);
}
return 0;
}
int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
struct regmap *regmaps[], int irq)
{
unsigned long freq = 0, *pfreq = dev_get_platdata(dev);
unsigned int val;
u32 uartclk = 0;
int i, ret;
struct sc16is7xx_port *s;
bool port_registered[SC16IS7XX_MAX_PORTS];
for (i = 0; i < devtype->nr_uart; i++)
if (IS_ERR(regmaps[i]))
return PTR_ERR(regmaps[i]);
/*
* This device does not have an identification register that would
* tell us if we are really connected to the correct device.
* The best we can do is to check if communication is at all possible.
*
* Note: regmap[0] is used in the probe function to access registers
* common to all channels/ports, as it is guaranteed to be present on
* all variants.
*/
ret = regmap_read(regmaps[0], SC16IS7XX_LSR_REG, &val);
if (ret < 0)
return -EPROBE_DEFER;
/* Alloc port structure */
s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL);
if (!s) {
dev_err(dev, "Error allocating port structure\n");
return -ENOMEM;
}
/* Always ask for fixed clock rate from a property. */
device_property_read_u32(dev, "clock-frequency", &uartclk);
s->clk = devm_clk_get_optional(dev, NULL);
if (IS_ERR(s->clk))
return PTR_ERR(s->clk);
ret = clk_prepare_enable(s->clk);
if (ret)
return ret;
freq = clk_get_rate(s->clk);
if (freq == 0) {
if (uartclk)
freq = uartclk;
if (pfreq)
freq = *pfreq;
if (freq)
dev_dbg(dev, "Clock frequency: %luHz\n", freq);
else
return -EINVAL;
}
s->devtype = devtype;
dev_set_drvdata(dev, s);
kthread_init_worker(&s->kworker);
s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
"sc16is7xx");
if (IS_ERR(s->kworker_task)) {
ret = PTR_ERR(s->kworker_task);
goto out_clk;
}
sched_set_fifo(s->kworker_task);
ret = sc16is7xx_reset(dev, regmaps[0]);
if (ret)
goto out_kthread;
/* Mark each port line and status as uninitialised. */
for (i = 0; i < devtype->nr_uart; ++i) {
s->p[i].port.line = SC16IS7XX_MAX_DEVS;
port_registered[i] = false;
}
for (i = 0; i < devtype->nr_uart; ++i) {
ret = ida_alloc_max(&sc16is7xx_lines,
SC16IS7XX_MAX_DEVS - 1, GFP_KERNEL);
if (ret < 0)
goto out_ports;
s->p[i].port.line = ret;
/* Initialize port data */
s->p[i].port.dev = dev;
s->p[i].port.irq = irq;
s->p[i].port.type = PORT_SC16IS7XX;
s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE;
s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY;
s->p[i].port.iobase = i;
/*
* Use all ones as membase to make sure uart_configure_port() in
* serial_core.c does not abort for SPI/I2C devices where the
* membase address is not applicable.
*/
s->p[i].port.membase = (void __iomem *)~0;
s->p[i].port.iotype = UPIO_PORT;
s->p[i].port.uartclk = freq;
s->p[i].port.rs485_config = sc16is7xx_config_rs485;
s->p[i].port.rs485_supported = sc16is7xx_rs485_supported;
s->p[i].port.ops = &sc16is7xx_ops;
s->p[i].old_mctrl = 0;
s->p[i].regmap = regmaps[i];
mutex_init(&s->p[i].efr_lock);
ret = uart_get_rs485_mode(&s->p[i].port);
if (ret)
goto out_ports;
/* Disable all interrupts */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
/* Disable TX/RX */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
/* Initialize kthread work structs */
kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc);
/* Register port */
ret = uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
if (ret)
goto out_ports;
port_registered[i] = true;
/* Enable EFR */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_B);
regcache_cache_bypass(regmaps[i], true);
/* Enable write access to enhanced features */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_ENABLE_BIT);
regcache_cache_bypass(regmaps[i], false);
/* Restore access to general registers */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, 0x00);
/* Go to suspend mode */
sc16is7xx_power(&s->p[i].port, 0);
}
sc16is7xx_setup_irda_ports(s);
ret = sc16is7xx_setup_mctrl_ports(s, regmaps[0]);
if (ret)
goto out_ports;
#ifdef CONFIG_GPIOLIB
ret = sc16is7xx_setup_gpio_chip(s);
if (ret)
goto out_ports;
#endif
/*
* Setup interrupt. We first try to acquire the IRQ line as level IRQ.
* If that succeeds, we can allow sharing the interrupt as well.
* In case the interrupt controller doesn't support that, we fall
* back to a non-shared falling-edge trigger.
*/
ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
IRQF_TRIGGER_LOW | IRQF_SHARED |
IRQF_ONESHOT,
dev_name(dev), s);
if (!ret)
return 0;
ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
dev_name(dev), s);
if (!ret)
return 0;
#ifdef CONFIG_GPIOLIB
if (s->gpio_valid_mask)
gpiochip_remove(&s->gpio);
#endif
out_ports:
for (i = 0; i < devtype->nr_uart; i++) {
if (s->p[i].port.line < SC16IS7XX_MAX_DEVS)
ida_free(&sc16is7xx_lines, s->p[i].port.line);
if (port_registered[i])
uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
}
out_kthread:
kthread_stop(s->kworker_task);
out_clk:
clk_disable_unprepare(s->clk);
return ret;
}
EXPORT_SYMBOL_GPL(sc16is7xx_probe);
void sc16is7xx_remove(struct device *dev)
{
struct sc16is7xx_port *s = dev_get_drvdata(dev);
int i;
#ifdef CONFIG_GPIOLIB
if (s->gpio_valid_mask)
gpiochip_remove(&s->gpio);
#endif
for (i = 0; i < s->devtype->nr_uart; i++) {
kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
ida_free(&sc16is7xx_lines, s->p[i].port.line);
uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
sc16is7xx_power(&s->p[i].port, 0);
}
kthread_flush_worker(&s->kworker);
kthread_stop(s->kworker_task);
clk_disable_unprepare(s->clk);
}
EXPORT_SYMBOL_GPL(sc16is7xx_remove);
const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
{ .compatible = "nxp,sc16is740", .data = &sc16is74x_devtype, },
{ .compatible = "nxp,sc16is741", .data = &sc16is74x_devtype, },
{ .compatible = "nxp,sc16is750", .data = &sc16is750_devtype, },
{ .compatible = "nxp,sc16is752", .data = &sc16is752_devtype, },
{ .compatible = "nxp,sc16is760", .data = &sc16is760_devtype, },
{ .compatible = "nxp,sc16is762", .data = &sc16is762_devtype, },
{ }
};
EXPORT_SYMBOL_GPL(sc16is7xx_dt_ids);
MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
const struct regmap_config sc16is7xx_regcfg = {
.reg_bits = 5,
.pad_bits = 3,
.val_bits = 8,
.cache_type = REGCACHE_MAPLE,
.volatile_reg = sc16is7xx_regmap_volatile,
.precious_reg = sc16is7xx_regmap_precious,
.writeable_noinc_reg = sc16is7xx_regmap_noinc,
.readable_noinc_reg = sc16is7xx_regmap_noinc,
.max_raw_read = SC16IS7XX_FIFO_SIZE,
.max_raw_write = SC16IS7XX_FIFO_SIZE,
.max_register = SC16IS7XX_EFCR_REG,
};
EXPORT_SYMBOL_GPL(sc16is7xx_regcfg);
const char *sc16is7xx_regmap_name(u8 port_id)
{
switch (port_id) {
case 0: return "port0";
case 1: return "port1";
default:
WARN_ON(true);
return NULL;
}
}
EXPORT_SYMBOL_GPL(sc16is7xx_regmap_name);
unsigned int sc16is7xx_regmap_port_mask(unsigned int port_id)
{
/* CH1,CH0 are at bits 2:1. */
return port_id << 1;
}
EXPORT_SYMBOL_GPL(sc16is7xx_regmap_port_mask);
static int __init sc16is7xx_init(void)
{
return uart_register_driver(&sc16is7xx_uart);
}
module_init(sc16is7xx_init);
static void __exit sc16is7xx_exit(void)
{
uart_unregister_driver(&sc16is7xx_uart);
}
module_exit(sc16is7xx_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
MODULE_DESCRIPTION("SC16IS7xx tty serial core driver");