blob: aa6f266b62a1417408e11b68f2f624b4c40bec7d [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Arche Platform driver to control APB.
*
* Copyright 2014-2015 Google Inc.
* Copyright 2014-2015 Linaro Ltd.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>
#include <linux/spinlock.h>
#include "arche_platform.h"
static void apb_bootret_deassert(struct device *dev);
struct arche_apb_ctrl_drvdata {
/* Control GPIO signals to and from AP <=> AP Bridges */
struct gpio_desc *resetn;
struct gpio_desc *boot_ret;
struct gpio_desc *pwroff;
struct gpio_desc *wake_in;
struct gpio_desc *wake_out;
struct gpio_desc *pwrdn;
enum arche_platform_state state;
bool init_disabled;
struct regulator *vcore;
struct regulator *vio;
struct gpio_desc *clk_en;
struct clk *clk;
struct pinctrl *pinctrl;
struct pinctrl_state *pin_default;
/* V2: SPI Bus control */
struct gpio_desc *spi_en;
bool spi_en_polarity_high;
};
/*
* Note that these low level api's are active high
*/
static inline void deassert_reset(struct gpio_desc *gpio)
{
gpiod_set_raw_value(gpio, 1);
}
static inline void assert_reset(struct gpio_desc *gpio)
{
gpiod_set_raw_value(gpio, 0);
}
/*
* Note: Please do not modify the below sequence, as it is as per the spec
*/
static int coldboot_seq(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
int ret;
if (apb->init_disabled ||
apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
return 0;
/* Hold APB in reset state */
assert_reset(apb->resetn);
if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
devm_gpiod_put(dev, apb->spi_en);
/* Enable power to APB */
if (!IS_ERR(apb->vcore)) {
ret = regulator_enable(apb->vcore);
if (ret) {
dev_err(dev, "failed to enable core regulator\n");
return ret;
}
}
if (!IS_ERR(apb->vio)) {
ret = regulator_enable(apb->vio);
if (ret) {
dev_err(dev, "failed to enable IO regulator\n");
return ret;
}
}
apb_bootret_deassert(dev);
/* On DB3 clock was not mandatory */
if (apb->clk_en)
gpiod_set_value(apb->clk_en, 1);
usleep_range(100, 200);
/* deassert reset to APB : Active-low signal */
deassert_reset(apb->resetn);
apb->state = ARCHE_PLATFORM_STATE_ACTIVE;
return 0;
}
static int fw_flashing_seq(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
int ret;
if (apb->init_disabled ||
apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
return 0;
ret = regulator_enable(apb->vcore);
if (ret) {
dev_err(dev, "failed to enable core regulator\n");
return ret;
}
ret = regulator_enable(apb->vio);
if (ret) {
dev_err(dev, "failed to enable IO regulator\n");
return ret;
}
if (apb->spi_en) {
unsigned long flags;
if (apb->spi_en_polarity_high)
flags = GPIOD_OUT_HIGH;
else
flags = GPIOD_OUT_LOW;
apb->spi_en = devm_gpiod_get(dev, "spi-en", flags);
if (IS_ERR(apb->spi_en)) {
ret = PTR_ERR(apb->spi_en);
dev_err(dev, "Failed requesting SPI bus en GPIO: %d\n",
ret);
return ret;
}
}
/* for flashing device should be in reset state */
assert_reset(apb->resetn);
apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
return 0;
}
static int standby_boot_seq(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
if (apb->init_disabled)
return 0;
/*
* Even if it is in OFF state,
* then we do not want to change the state
*/
if (apb->state == ARCHE_PLATFORM_STATE_STANDBY ||
apb->state == ARCHE_PLATFORM_STATE_OFF)
return 0;
if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
devm_gpiod_put(dev, apb->spi_en);
/*
* As per WDM spec, do nothing
*
* Pasted from WDM spec,
* - A falling edge on POWEROFF_L is detected (a)
* - WDM enters standby mode, but no output signals are changed
*/
/* TODO: POWEROFF_L is input to WDM module */
apb->state = ARCHE_PLATFORM_STATE_STANDBY;
return 0;
}
static void poweroff_seq(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
if (apb->init_disabled || apb->state == ARCHE_PLATFORM_STATE_OFF)
return;
if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
devm_gpiod_put(dev, apb->spi_en);
/* disable the clock */
if (apb->clk_en)
gpiod_set_value(apb->clk_en, 0);
if (!IS_ERR(apb->vcore) && regulator_is_enabled(apb->vcore) > 0)
regulator_disable(apb->vcore);
if (!IS_ERR(apb->vio) && regulator_is_enabled(apb->vio) > 0)
regulator_disable(apb->vio);
/* As part of exit, put APB back in reset state */
assert_reset(apb->resetn);
apb->state = ARCHE_PLATFORM_STATE_OFF;
/* TODO: May have to send an event to SVC about this exit */
}
static void apb_bootret_deassert(struct device *dev)
{
struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
gpiod_set_value(apb->boot_ret, 0);
}
int apb_ctrl_coldboot(struct device *dev)
{
return coldboot_seq(to_platform_device(dev));
}
int apb_ctrl_fw_flashing(struct device *dev)
{
return fw_flashing_seq(to_platform_device(dev));
}
int apb_ctrl_standby_boot(struct device *dev)
{
return standby_boot_seq(to_platform_device(dev));
}
void apb_ctrl_poweroff(struct device *dev)
{
poweroff_seq(to_platform_device(dev));
}
static ssize_t state_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct platform_device *pdev = to_platform_device(dev);
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
int ret = 0;
bool is_disabled;
if (sysfs_streq(buf, "off")) {
if (apb->state == ARCHE_PLATFORM_STATE_OFF)
return count;
poweroff_seq(pdev);
} else if (sysfs_streq(buf, "active")) {
if (apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
return count;
poweroff_seq(pdev);
is_disabled = apb->init_disabled;
apb->init_disabled = false;
ret = coldboot_seq(pdev);
if (ret)
apb->init_disabled = is_disabled;
} else if (sysfs_streq(buf, "standby")) {
if (apb->state == ARCHE_PLATFORM_STATE_STANDBY)
return count;
ret = standby_boot_seq(pdev);
} else if (sysfs_streq(buf, "fw_flashing")) {
if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
return count;
/*
* First we want to make sure we power off everything
* and then enter FW flashing state
*/
poweroff_seq(pdev);
ret = fw_flashing_seq(pdev);
} else {
dev_err(dev, "unknown state\n");
ret = -EINVAL;
}
return ret ? ret : count;
}
static ssize_t state_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
switch (apb->state) {
case ARCHE_PLATFORM_STATE_OFF:
return sprintf(buf, "off%s\n",
apb->init_disabled ? ",disabled" : "");
case ARCHE_PLATFORM_STATE_ACTIVE:
return sprintf(buf, "active\n");
case ARCHE_PLATFORM_STATE_STANDBY:
return sprintf(buf, "standby\n");
case ARCHE_PLATFORM_STATE_FW_FLASHING:
return sprintf(buf, "fw_flashing\n");
default:
return sprintf(buf, "unknown state\n");
}
}
static DEVICE_ATTR_RW(state);
static int apb_ctrl_get_devtree_data(struct platform_device *pdev,
struct arche_apb_ctrl_drvdata *apb)
{
struct device *dev = &pdev->dev;
int ret;
apb->resetn = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(apb->resetn)) {
ret = PTR_ERR(apb->resetn);
dev_err(dev, "Failed requesting reset GPIO: %d\n", ret);
return ret;
}
apb->boot_ret = devm_gpiod_get(dev, "boot-ret", GPIOD_OUT_LOW);
if (IS_ERR(apb->boot_ret)) {
ret = PTR_ERR(apb->boot_ret);
dev_err(dev, "Failed requesting bootret GPIO: %d\n", ret);
return ret;
}
/* It's not mandatory to support power management interface */
apb->pwroff = devm_gpiod_get_optional(dev, "pwr-off", GPIOD_IN);
if (IS_ERR(apb->pwroff)) {
ret = PTR_ERR(apb->pwroff);
dev_err(dev, "Failed requesting pwroff_n GPIO: %d\n", ret);
return ret;
}
/* Do not make clock mandatory as of now (for DB3) */
apb->clk_en = devm_gpiod_get_optional(dev, "clock-en", GPIOD_OUT_LOW);
if (IS_ERR(apb->clk_en)) {
ret = PTR_ERR(apb->clk_en);
dev_err(dev, "Failed requesting APB clock en GPIO: %d\n", ret);
return ret;
}
apb->pwrdn = devm_gpiod_get(dev, "pwr-down", GPIOD_OUT_LOW);
if (IS_ERR(apb->pwrdn)) {
ret = PTR_ERR(apb->pwrdn);
dev_warn(dev, "Failed requesting power down GPIO: %d\n", ret);
return ret;
}
/* Regulators are optional, as we may have fixed supply coming in */
apb->vcore = devm_regulator_get(dev, "vcore");
if (IS_ERR(apb->vcore))
dev_warn(dev, "no core regulator found\n");
apb->vio = devm_regulator_get(dev, "vio");
if (IS_ERR(apb->vio))
dev_warn(dev, "no IO regulator found\n");
apb->pinctrl = devm_pinctrl_get(&pdev->dev);
if (IS_ERR(apb->pinctrl)) {
dev_err(&pdev->dev, "could not get pinctrl handle\n");
return PTR_ERR(apb->pinctrl);
}
apb->pin_default = pinctrl_lookup_state(apb->pinctrl, "default");
if (IS_ERR(apb->pin_default)) {
dev_err(&pdev->dev, "could not get default pin state\n");
return PTR_ERR(apb->pin_default);
}
/* Only applicable for platform >= V2 */
if (of_property_read_bool(pdev->dev.of_node, "gb,spi-en-active-high"))
apb->spi_en_polarity_high = true;
return 0;
}
static int arche_apb_ctrl_probe(struct platform_device *pdev)
{
int ret;
struct arche_apb_ctrl_drvdata *apb;
struct device *dev = &pdev->dev;
apb = devm_kzalloc(&pdev->dev, sizeof(*apb), GFP_KERNEL);
if (!apb)
return -ENOMEM;
ret = apb_ctrl_get_devtree_data(pdev, apb);
if (ret) {
dev_err(dev, "failed to get apb devicetree data %d\n", ret);
return ret;
}
/* Initially set APB to OFF state */
apb->state = ARCHE_PLATFORM_STATE_OFF;
/* Check whether device needs to be enabled on boot */
if (of_property_read_bool(pdev->dev.of_node, "arche,init-disable"))
apb->init_disabled = true;
platform_set_drvdata(pdev, apb);
/* Create sysfs interface to allow user to change state dynamically */
ret = device_create_file(dev, &dev_attr_state);
if (ret) {
dev_err(dev, "failed to create state file in sysfs\n");
return ret;
}
dev_info(&pdev->dev, "Device registered successfully\n");
return 0;
}
static void arche_apb_ctrl_remove(struct platform_device *pdev)
{
device_remove_file(&pdev->dev, &dev_attr_state);
poweroff_seq(pdev);
platform_set_drvdata(pdev, NULL);
}
static int __maybe_unused arche_apb_ctrl_suspend(struct device *dev)
{
/*
* If timing profile permits, we may shutdown bridge
* completely
*
* TODO: sequence ??
*
* Also, need to make sure we meet precondition for unipro suspend
* Precondition: Definition ???
*/
return 0;
}
static int __maybe_unused arche_apb_ctrl_resume(struct device *dev)
{
/*
* At least for ES2 we have to meet the delay requirement between
* unipro switch and AP bridge init, depending on whether bridge is in
* OFF state or standby state.
*
* Based on whether bridge is in standby or OFF state we may have to
* assert multiple signals. Please refer to WDM spec, for more info.
*
*/
return 0;
}
static void arche_apb_ctrl_shutdown(struct platform_device *pdev)
{
apb_ctrl_poweroff(&pdev->dev);
}
static SIMPLE_DEV_PM_OPS(arche_apb_ctrl_pm_ops, arche_apb_ctrl_suspend,
arche_apb_ctrl_resume);
static const struct of_device_id arche_apb_ctrl_of_match[] = {
{ .compatible = "usbffff,2", },
{ },
};
MODULE_DEVICE_TABLE(of, arche_apb_ctrl_of_match);
static struct platform_driver arche_apb_ctrl_device_driver = {
.probe = arche_apb_ctrl_probe,
.remove_new = arche_apb_ctrl_remove,
.shutdown = arche_apb_ctrl_shutdown,
.driver = {
.name = "arche-apb-ctrl",
.pm = &arche_apb_ctrl_pm_ops,
.of_match_table = arche_apb_ctrl_of_match,
}
};
int __init arche_apb_init(void)
{
return platform_driver_register(&arche_apb_ctrl_device_driver);
}
void __exit arche_apb_exit(void)
{
platform_driver_unregister(&arche_apb_ctrl_device_driver);
}