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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"
enum apb_state {
APB_STATE_OFF,
APB_STATE_ACTIVE,
APB_STATE_STANDBY,
};
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 apb_state state;
struct regulator *vcore;
struct regulator *vio;
unsigned 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);
}
/* Export gpio's to user space */
static void export_gpios(struct arche_apb_ctrl_drvdata *apb)
{
gpio_export(apb->resetn_gpio, false);
}
static void unexport_gpios(struct arche_apb_ctrl_drvdata *apb)
{
gpio_unexport(apb->resetn_gpio);
}
/*
* Note: Please do not modify the below sequence, as it is as per the spec
*/
static int apb_ctrl_init_seq(struct platform_device *pdev,
struct arche_apb_ctrl_drvdata *apb)
{
struct device *dev = &pdev->dev;
int ret;
/* Hold APB in reset state */
ret = devm_gpio_request(dev, apb->resetn_gpio, "apb-reset");
if (ret) {
dev_err(dev, "Failed requesting reset gpio %d\n",
apb->resetn_gpio);
return ret;
}
ret = gpio_direction_output(apb->resetn_gpio, 0);
if (ret) {
dev_err(dev, "failed to set reset gpio dir:%d\n", ret);
return ret;
}
ret = devm_gpio_request(dev, apb->pwroff_gpio, "pwroff_n");
if (ret) {
dev_err(dev, "Failed requesting pwroff_n gpio %d\n",
apb->pwroff_gpio);
return ret;
}
ret = gpio_direction_input(apb->pwroff_gpio);
if (ret) {
dev_err(dev, "failed to set pwroff gpio dir:%d\n", ret);
return ret;
}
/* 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");
goto out_vcore_disable;
}
}
ret = devm_gpio_request_one(dev, apb->boot_ret_gpio,
GPIOF_OUT_INIT_LOW, "boot retention");
if (ret) {
dev_err(dev, "Failed requesting bootret gpio %d\n",
apb->boot_ret_gpio);
goto out_vio_disable;
}
gpio_set_value(apb->boot_ret_gpio, 0);
/* On DB3 clock was not mandatory */
if (gpio_is_valid(apb->clk_en_gpio)) {
ret = devm_gpio_request(dev, apb->clk_en_gpio, "apb_clk_en");
if (ret) {
dev_warn(dev, "Failed requesting APB clock en gpio %d\n",
apb->clk_en_gpio);
} else {
ret = gpio_direction_output(apb->clk_en_gpio, 1);
if (ret)
dev_warn(dev, "failed to set APB clock en gpio dir:%d\n",
ret);
}
}
usleep_range(100, 200);
return 0;
out_vio_disable:
if (!IS_ERR(apb->vio))
regulator_disable(apb->vio);
out_vcore_disable:
if (!IS_ERR(apb->vcore))
regulator_disable(apb->vcore);
return ret;
}
static int apb_ctrl_get_devtree_data(struct platform_device *pdev,
struct arche_apb_ctrl_drvdata *apb)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
apb->resetn_gpio = of_get_named_gpio(np, "reset-gpios", 0);
if (apb->resetn_gpio < 0) {
dev_err(dev, "failed to get reset gpio\n");
return apb->resetn_gpio;
}
apb->boot_ret_gpio = of_get_named_gpio(np, "boot-ret-gpios", 0);
if (apb->boot_ret_gpio < 0) {
dev_err(dev, "failed to get boot retention gpio\n");
return apb->boot_ret_gpio;
}
/* It's not mandatory to support power management interface */
apb->pwroff_gpio = of_get_named_gpio(np, "pwr-off-gpios", 0);
if (apb->pwroff_gpio < 0) {
dev_err(dev, "failed to get power off gpio\n");
return apb->pwroff_gpio;
}
/* Do not make clock mandatory as of now (for DB3) */
apb->clk_en_gpio = of_get_named_gpio(np, "clock-en-gpio", 0);
if (apb->clk_en_gpio < 0)
dev_warn(dev, "failed to get clock en gpio\n");
apb->pwrdn_gpio = of_get_named_gpio(np, "pwr-down-gpios", 0);
if (apb->pwrdn_gpio < 0)
dev_warn(dev, "failed to get power down gpio\n");
/* 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);
}
return 0;
}
static void apb_ctrl_cleanup(struct arche_apb_ctrl_drvdata *apb)
{
/* 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 = APB_STATE_OFF;
/* TODO: May have to send an event to SVC about this exit */
}
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;
}
ret = apb_ctrl_init_seq(pdev, apb);
if (ret) {
dev_err(dev, "failed to set init state of control signal %d\n",
ret);
return ret;
}
/* deassert reset to APB : Active-low signal */
deassert_reset(apb->resetn_gpio);
apb->state = APB_STATE_ACTIVE;
platform_set_drvdata(pdev, apb);
export_gpios(apb);
dev_info(&pdev->dev, "Device registered successfully\n");
return 0;
}
int arche_apb_ctrl_remove(struct platform_device *pdev)
{
struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
apb_ctrl_cleanup(apb);
platform_set_drvdata(pdev, NULL);
unexport_gpios(apb);
return 0;
}
static int 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 ???
*/
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