linux/drivers/gpio/gpio-arizona.c
Charles Keepax 27a49ed17e gpio: arizona: Add support for GPIOs that need to be maintained
The Arizona devices only maintain the state of output GPIOs whilst the
CODEC is active, this can cause issues if the CODEC suspends whilst
something is relying on the state of one of its GPIOs. However, in
many systems the CODEC GPIOs are used for audio related features
and thus the state of the GPIOs is unimportant whilst the CODEC is
suspended. Often keeping the CODEC resumed in such a system would
incur a power impact that is unacceptable.

Allow the user to select whether a GPIO output should keep the
CODEC resumed, by adding a flag through the second cell of the GPIO
specifier in device tree.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-05-29 11:09:01 +02:00

214 lines
5.3 KiB
C

/*
* gpiolib support for Wolfson Arizona class devices
*
* Copyright 2012 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include <linux/mfd/arizona/core.h>
#include <linux/mfd/arizona/pdata.h>
#include <linux/mfd/arizona/registers.h>
struct arizona_gpio {
struct arizona *arizona;
struct gpio_chip gpio_chip;
};
static int arizona_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
struct arizona *arizona = arizona_gpio->arizona;
bool persistent = gpiochip_line_is_persistent(chip, offset);
bool change;
int ret;
ret = regmap_update_bits_check(arizona->regmap,
ARIZONA_GPIO1_CTRL + offset,
ARIZONA_GPN_DIR, ARIZONA_GPN_DIR,
&change);
if (ret < 0)
return ret;
if (change && persistent) {
pm_runtime_mark_last_busy(chip->parent);
pm_runtime_put_autosuspend(chip->parent);
}
return 0;
}
static int arizona_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
struct arizona *arizona = arizona_gpio->arizona;
unsigned int reg, val;
int ret;
reg = ARIZONA_GPIO1_CTRL + offset;
ret = regmap_read(arizona->regmap, reg, &val);
if (ret < 0)
return ret;
/* Resume to read actual registers for input pins */
if (val & ARIZONA_GPN_DIR) {
ret = pm_runtime_get_sync(chip->parent);
if (ret < 0) {
dev_err(chip->parent, "Failed to resume: %d\n", ret);
return ret;
}
/* Register is cached, drop it to ensure a physical read */
ret = regcache_drop_region(arizona->regmap, reg, reg);
if (ret < 0) {
dev_err(chip->parent, "Failed to drop cache: %d\n",
ret);
return ret;
}
ret = regmap_read(arizona->regmap, reg, &val);
if (ret < 0)
return ret;
pm_runtime_mark_last_busy(chip->parent);
pm_runtime_put_autosuspend(chip->parent);
}
if (val & ARIZONA_GPN_LVL)
return 1;
else
return 0;
}
static int arizona_gpio_direction_out(struct gpio_chip *chip,
unsigned offset, int value)
{
struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
struct arizona *arizona = arizona_gpio->arizona;
bool persistent = gpiochip_line_is_persistent(chip, offset);
unsigned int val;
int ret;
ret = regmap_read(arizona->regmap, ARIZONA_GPIO1_CTRL + offset, &val);
if (ret < 0)
return ret;
if ((val & ARIZONA_GPN_DIR) && persistent) {
ret = pm_runtime_get_sync(chip->parent);
if (ret < 0) {
dev_err(chip->parent, "Failed to resume: %d\n", ret);
return ret;
}
}
if (value)
value = ARIZONA_GPN_LVL;
return regmap_update_bits(arizona->regmap, ARIZONA_GPIO1_CTRL + offset,
ARIZONA_GPN_DIR | ARIZONA_GPN_LVL, value);
}
static void arizona_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
struct arizona *arizona = arizona_gpio->arizona;
if (value)
value = ARIZONA_GPN_LVL;
regmap_update_bits(arizona->regmap, ARIZONA_GPIO1_CTRL + offset,
ARIZONA_GPN_LVL, value);
}
static const struct gpio_chip template_chip = {
.label = "arizona",
.owner = THIS_MODULE,
.direction_input = arizona_gpio_direction_in,
.get = arizona_gpio_get,
.direction_output = arizona_gpio_direction_out,
.set = arizona_gpio_set,
.can_sleep = true,
};
static int arizona_gpio_probe(struct platform_device *pdev)
{
struct arizona *arizona = dev_get_drvdata(pdev->dev.parent);
struct arizona_pdata *pdata = dev_get_platdata(arizona->dev);
struct arizona_gpio *arizona_gpio;
int ret;
arizona_gpio = devm_kzalloc(&pdev->dev, sizeof(*arizona_gpio),
GFP_KERNEL);
if (!arizona_gpio)
return -ENOMEM;
arizona_gpio->arizona = arizona;
arizona_gpio->gpio_chip = template_chip;
arizona_gpio->gpio_chip.parent = &pdev->dev;
#ifdef CONFIG_OF_GPIO
arizona_gpio->gpio_chip.of_node = arizona->dev->of_node;
#endif
switch (arizona->type) {
case WM5102:
case WM5110:
case WM8280:
case WM8997:
case WM8998:
case WM1814:
arizona_gpio->gpio_chip.ngpio = 5;
break;
case WM1831:
case CS47L24:
arizona_gpio->gpio_chip.ngpio = 2;
break;
default:
dev_err(&pdev->dev, "Unknown chip variant %d\n",
arizona->type);
return -EINVAL;
}
if (pdata && pdata->gpio_base)
arizona_gpio->gpio_chip.base = pdata->gpio_base;
else
arizona_gpio->gpio_chip.base = -1;
pm_runtime_enable(&pdev->dev);
ret = devm_gpiochip_add_data(&pdev->dev, &arizona_gpio->gpio_chip,
arizona_gpio);
if (ret < 0) {
dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
ret);
return ret;
}
return 0;
}
static struct platform_driver arizona_gpio_driver = {
.driver.name = "arizona-gpio",
.probe = arizona_gpio_probe,
};
module_platform_driver(arizona_gpio_driver);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("GPIO interface for Arizona devices");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:arizona-gpio");