| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Synopsys DesignWare I2C adapter driver. |
| * |
| * Based on the TI DAVINCI I2C adapter driver. |
| * |
| * Copyright (C) 2006 Texas Instruments. |
| * Copyright (C) 2007 MontaVista Software Inc. |
| * Copyright (C) 2009 Provigent Ltd. |
| */ |
| #include <linux/clk.h> |
| #include <linux/delay.h> |
| #include <linux/export.h> |
| #include <linux/errno.h> |
| #include <linux/err.h> |
| #include <linux/i2c.h> |
| #include <linux/interrupt.h> |
| #include <linux/io.h> |
| #include <linux/module.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/swab.h> |
| |
| #include "i2c-designware-core.h" |
| |
| static char *abort_sources[] = { |
| [ABRT_7B_ADDR_NOACK] = |
| "slave address not acknowledged (7bit mode)", |
| [ABRT_10ADDR1_NOACK] = |
| "first address byte not acknowledged (10bit mode)", |
| [ABRT_10ADDR2_NOACK] = |
| "second address byte not acknowledged (10bit mode)", |
| [ABRT_TXDATA_NOACK] = |
| "data not acknowledged", |
| [ABRT_GCALL_NOACK] = |
| "no acknowledgement for a general call", |
| [ABRT_GCALL_READ] = |
| "read after general call", |
| [ABRT_SBYTE_ACKDET] = |
| "start byte acknowledged", |
| [ABRT_SBYTE_NORSTRT] = |
| "trying to send start byte when restart is disabled", |
| [ABRT_10B_RD_NORSTRT] = |
| "trying to read when restart is disabled (10bit mode)", |
| [ABRT_MASTER_DIS] = |
| "trying to use disabled adapter", |
| [ARB_LOST] = |
| "lost arbitration", |
| [ABRT_SLAVE_FLUSH_TXFIFO] = |
| "read command so flush old data in the TX FIFO", |
| [ABRT_SLAVE_ARBLOST] = |
| "slave lost the bus while transmitting data to a remote master", |
| [ABRT_SLAVE_RD_INTX] = |
| "incorrect slave-transmitter mode configuration", |
| }; |
| |
| u32 dw_readl(struct dw_i2c_dev *dev, int offset) |
| { |
| u32 value; |
| |
| if (dev->flags & ACCESS_16BIT) |
| value = readw_relaxed(dev->base + offset) | |
| (readw_relaxed(dev->base + offset + 2) << 16); |
| else |
| value = readl_relaxed(dev->base + offset); |
| |
| if (dev->flags & ACCESS_SWAP) |
| return swab32(value); |
| else |
| return value; |
| } |
| |
| void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) |
| { |
| if (dev->flags & ACCESS_SWAP) |
| b = swab32(b); |
| |
| if (dev->flags & ACCESS_16BIT) { |
| writew_relaxed((u16)b, dev->base + offset); |
| writew_relaxed((u16)(b >> 16), dev->base + offset + 2); |
| } else { |
| writel_relaxed(b, dev->base + offset); |
| } |
| } |
| |
| /** |
| * i2c_dw_set_reg_access() - Set register access flags |
| * @dev: device private data |
| * |
| * Autodetects needed register access mode and sets access flags accordingly. |
| * This must be called before doing any other register access. |
| */ |
| int i2c_dw_set_reg_access(struct dw_i2c_dev *dev) |
| { |
| u32 reg; |
| int ret; |
| |
| ret = i2c_dw_acquire_lock(dev); |
| if (ret) |
| return ret; |
| |
| reg = dw_readl(dev, DW_IC_COMP_TYPE); |
| i2c_dw_release_lock(dev); |
| |
| if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) { |
| /* Configure register endianess access */ |
| dev->flags |= ACCESS_SWAP; |
| } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { |
| /* Configure register access mode 16bit */ |
| dev->flags |= ACCESS_16BIT; |
| } else if (reg != DW_IC_COMP_TYPE_VALUE) { |
| dev_err(dev->dev, |
| "Unknown Synopsys component type: 0x%08x\n", reg); |
| return -ENODEV; |
| } |
| |
| return 0; |
| } |
| |
| u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) |
| { |
| /* |
| * DesignWare I2C core doesn't seem to have solid strategy to meet |
| * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec |
| * will result in violation of the tHD;STA spec. |
| */ |
| if (cond) |
| /* |
| * Conditional expression: |
| * |
| * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH |
| * |
| * This is based on the DW manuals, and represents an ideal |
| * configuration. The resulting I2C bus speed will be |
| * faster than any of the others. |
| * |
| * If your hardware is free from tHD;STA issue, try this one. |
| */ |
| return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset; |
| else |
| /* |
| * Conditional expression: |
| * |
| * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) |
| * |
| * This is just experimental rule; the tHD;STA period turned |
| * out to be proportinal to (_HCNT + 3). With this setting, |
| * we could meet both tHIGH and tHD;STA timing specs. |
| * |
| * If unsure, you'd better to take this alternative. |
| * |
| * The reason why we need to take into account "tf" here, |
| * is the same as described in i2c_dw_scl_lcnt(). |
| */ |
| return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000 |
| - 3 + offset; |
| } |
| |
| u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) |
| { |
| /* |
| * Conditional expression: |
| * |
| * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) |
| * |
| * DW I2C core starts counting the SCL CNTs for the LOW period |
| * of the SCL clock (tLOW) as soon as it pulls the SCL line. |
| * In order to meet the tLOW timing spec, we need to take into |
| * account the fall time of SCL signal (tf). Default tf value |
| * should be 0.3 us, for safety. |
| */ |
| return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset; |
| } |
| |
| int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev) |
| { |
| u32 reg; |
| int ret; |
| |
| ret = i2c_dw_acquire_lock(dev); |
| if (ret) |
| return ret; |
| |
| /* Configure SDA Hold Time if required */ |
| reg = dw_readl(dev, DW_IC_COMP_VERSION); |
| if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { |
| if (!dev->sda_hold_time) { |
| /* Keep previous hold time setting if no one set it */ |
| dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); |
| } |
| |
| /* |
| * Workaround for avoiding TX arbitration lost in case I2C |
| * slave pulls SDA down "too quickly" after falling egde of |
| * SCL by enabling non-zero SDA RX hold. Specification says it |
| * extends incoming SDA low to high transition while SCL is |
| * high but it apprears to help also above issue. |
| */ |
| if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) |
| dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; |
| |
| dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n", |
| dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK, |
| dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT); |
| } else if (dev->set_sda_hold_time) { |
| dev->set_sda_hold_time(dev); |
| } else if (dev->sda_hold_time) { |
| dev_warn(dev->dev, |
| "Hardware too old to adjust SDA hold time.\n"); |
| dev->sda_hold_time = 0; |
| } |
| |
| i2c_dw_release_lock(dev); |
| |
| return 0; |
| } |
| |
| void __i2c_dw_disable(struct dw_i2c_dev *dev) |
| { |
| int timeout = 100; |
| |
| do { |
| __i2c_dw_disable_nowait(dev); |
| /* |
| * The enable status register may be unimplemented, but |
| * in that case this test reads zero and exits the loop. |
| */ |
| if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == 0) |
| return; |
| |
| /* |
| * Wait 10 times the signaling period of the highest I2C |
| * transfer supported by the driver (for 400KHz this is |
| * 25us) as described in the DesignWare I2C databook. |
| */ |
| usleep_range(25, 250); |
| } while (timeout--); |
| |
| dev_warn(dev->dev, "timeout in disabling adapter\n"); |
| } |
| |
| unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) |
| { |
| /* |
| * Clock is not necessary if we got LCNT/HCNT values directly from |
| * the platform code. |
| */ |
| if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) |
| return 0; |
| return dev->get_clk_rate_khz(dev); |
| } |
| |
| int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare) |
| { |
| if (IS_ERR(dev->clk)) |
| return PTR_ERR(dev->clk); |
| |
| if (prepare) |
| return clk_prepare_enable(dev->clk); |
| |
| clk_disable_unprepare(dev->clk); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk); |
| |
| int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) |
| { |
| int ret; |
| |
| if (!dev->acquire_lock) |
| return 0; |
| |
| ret = dev->acquire_lock(); |
| if (!ret) |
| return 0; |
| |
| dev_err(dev->dev, "couldn't acquire bus ownership\n"); |
| |
| return ret; |
| } |
| |
| void i2c_dw_release_lock(struct dw_i2c_dev *dev) |
| { |
| if (dev->release_lock) |
| dev->release_lock(); |
| } |
| |
| /* |
| * Waiting for bus not busy |
| */ |
| int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) |
| { |
| int timeout = TIMEOUT; |
| |
| while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { |
| if (timeout <= 0) { |
| dev_warn(dev->dev, "timeout waiting for bus ready\n"); |
| i2c_recover_bus(&dev->adapter); |
| |
| if (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) |
| return -ETIMEDOUT; |
| return 0; |
| } |
| timeout--; |
| usleep_range(1000, 1100); |
| } |
| |
| return 0; |
| } |
| |
| int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) |
| { |
| unsigned long abort_source = dev->abort_source; |
| int i; |
| |
| if (abort_source & DW_IC_TX_ABRT_NOACK) { |
| for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) |
| dev_dbg(dev->dev, |
| "%s: %s\n", __func__, abort_sources[i]); |
| return -EREMOTEIO; |
| } |
| |
| for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) |
| dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); |
| |
| if (abort_source & DW_IC_TX_ARB_LOST) |
| return -EAGAIN; |
| else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) |
| return -EINVAL; /* wrong msgs[] data */ |
| else |
| return -EIO; |
| } |
| |
| u32 i2c_dw_func(struct i2c_adapter *adap) |
| { |
| struct dw_i2c_dev *dev = i2c_get_adapdata(adap); |
| |
| return dev->functionality; |
| } |
| |
| void i2c_dw_disable(struct dw_i2c_dev *dev) |
| { |
| /* Disable controller */ |
| __i2c_dw_disable(dev); |
| |
| /* Disable all interupts */ |
| dw_writel(dev, 0, DW_IC_INTR_MASK); |
| dw_readl(dev, DW_IC_CLR_INTR); |
| } |
| |
| void i2c_dw_disable_int(struct dw_i2c_dev *dev) |
| { |
| dw_writel(dev, 0, DW_IC_INTR_MASK); |
| } |
| |
| u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev) |
| { |
| return dw_readl(dev, DW_IC_COMP_PARAM_1); |
| } |
| EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param); |
| |
| MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); |
| MODULE_LICENSE("GPL"); |