linux/drivers/gpio/gpio-arizona.c
Charles Keepax 11598d1740 gpio: arizona: Correct handling for reading input GPIOs
The GPIO register is cached since all the configuration resides within
it, however, this means for input GPIOs the driver will not return the
actual state but the last value written to the register cache.

To correct this in the case of reading an input GPIO resume the CODEC
and drop the cache for the input register to ensure an actual hardware
read takes place.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-04-07 12:14:04 +02:00

183 lines
4.6 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;
return regmap_update_bits(arizona->regmap, ARIZONA_GPIO1_CTRL + offset,
ARIZONA_GPN_DIR, ARIZONA_GPN_DIR);
}
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;
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;
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");