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/*
* Arche Platform driver to control APB.
*
* Copyright 2014-2015 Google Inc.
* Copyright 2014-2015 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/of_gpio.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"
struct arche_apb_ctrl_drvdata {
/* Control GPIO signals to and from AP <=> AP Bridges */
int resetn_gpio;
int boot_ret_gpio;
int pwroff_gpio;
int wake_in_gpio;
int wake_out_gpio;
int pwrdn_gpio;
enum arche_platform_state state;
bool init_disabled;
struct regulator *vcore;
struct regulator *vio;
int clk_en_gpio;
struct clk *clk;
struct pinctrl *pinctrl;
struct pinctrl_state *pin_default;
};
/*
* Note that these low level api's are active high
*/
static inline void deassert_reset(unsigned int gpio)
{
gpio_set_value(gpio, 1);
}
static inline void assert_reset(unsigned int gpio)
{
gpio_set_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_gpio);
/* 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 (gpio_is_valid(apb->clk_en_gpio))
gpio_set_value(apb->clk_en_gpio, 1);
usleep_range(100, 200);
/* deassert reset to APB : Active-low signal */
deassert_reset(apb->resetn_gpio);
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;
}
/* for flashing device should be in reset state */
assert_reset(apb->resetn_gpio);
apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
return 0;
}
static int standby_boot_seq(struct platform_device *pdev)
{
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;
/*
* 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 arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
if (apb->init_disabled || apb->state == ARCHE_PLATFORM_STATE_OFF)
return;
/* disable the clock */
if (gpio_is_valid(apb->clk_en_gpio))
gpio_set_value(apb->clk_en_gpio, 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_gpio);
apb->state = ARCHE_PLATFORM_STATE_OFF;
/* TODO: May have to send an event to SVC about this exit */
}
void apb_bootret_assert(struct device *dev)
{
struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
gpio_set_value(apb->boot_ret_gpio, 1);
}
void apb_bootret_deassert(struct device *dev)
{
struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
gpio_set_value(apb->boot_ret_gpio, 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
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