linux/drivers/gpio/gpio-axp209.c
Maxime Ripard 81d3753d9e gpio: axp209: Implement get_direction
Implement the get_direction callback for the GPIOs found in the AXP209
PMIC.

Due to the way they are implemented, in the same register you have the
muxing options, GPIO directions and GPIO values. Since you have no control
over what value is there at reset, simply use output as the default.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-09-23 15:13:04 +02:00

193 lines
4.4 KiB
C

/*
* AXP20x GPIO driver
*
* Copyright (C) 2016 Maxime Ripard <maxime.ripard@free-electrons.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/bitops.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/axp20x.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#define AXP20X_GPIO_FUNCTIONS 0x7
#define AXP20X_GPIO_FUNCTION_OUT_LOW 0
#define AXP20X_GPIO_FUNCTION_OUT_HIGH 1
#define AXP20X_GPIO_FUNCTION_INPUT 2
struct axp20x_gpio {
struct gpio_chip chip;
struct regmap *regmap;
};
static int axp20x_gpio_get_reg(unsigned offset)
{
switch (offset) {
case 0:
return AXP20X_GPIO0_CTRL;
case 1:
return AXP20X_GPIO1_CTRL;
case 2:
return AXP20X_GPIO2_CTRL;
}
return -EINVAL;
}
static int axp20x_gpio_input(struct gpio_chip *chip, unsigned offset)
{
struct axp20x_gpio *gpio = gpiochip_get_data(chip);
int reg;
reg = axp20x_gpio_get_reg(offset);
if (reg < 0)
return reg;
return regmap_update_bits(gpio->regmap, reg,
AXP20X_GPIO_FUNCTIONS,
AXP20X_GPIO_FUNCTION_INPUT);
}
static int axp20x_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct axp20x_gpio *gpio = gpiochip_get_data(chip);
unsigned int val;
int reg, ret;
reg = axp20x_gpio_get_reg(offset);
if (reg < 0)
return reg;
ret = regmap_read(gpio->regmap, reg, &val);
if (ret)
return ret;
return !!(val & BIT(offset + 4));
}
static int axp20x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
struct axp20x_gpio *gpio = gpiochip_get_data(chip);
unsigned int val;
int reg, ret;
reg = axp20x_gpio_get_reg(offset);
if (reg < 0)
return reg;
ret = regmap_read(gpio->regmap, reg, &val);
if (ret)
return ret;
/*
* This shouldn't really happen if the pin is in use already,
* or if it's not in use yet, it doesn't matter since we're
* going to change the value soon anyway. Default to output.
*/
if ((val & AXP20X_GPIO_FUNCTIONS) > 2)
return 0;
/*
* The GPIO directions are the three lowest values.
* 2 is input, 0 and 1 are output
*/
return val & 2;
}
static int axp20x_gpio_output(struct gpio_chip *chip, unsigned offset,
int value)
{
struct axp20x_gpio *gpio = gpiochip_get_data(chip);
int reg;
reg = axp20x_gpio_get_reg(offset);
if (reg < 0)
return reg;
return regmap_update_bits(gpio->regmap, reg,
AXP20X_GPIO_FUNCTIONS,
value ? AXP20X_GPIO_FUNCTION_OUT_HIGH
: AXP20X_GPIO_FUNCTION_OUT_LOW);
}
static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
int value)
{
axp20x_gpio_output(chip, offset, value);
}
static int axp20x_gpio_probe(struct platform_device *pdev)
{
struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
struct axp20x_gpio *gpio;
int ret;
if (!of_device_is_available(pdev->dev.of_node))
return -ENODEV;
if (!axp20x) {
dev_err(&pdev->dev, "Parent drvdata not set\n");
return -EINVAL;
}
gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
gpio->chip.base = -1;
gpio->chip.can_sleep = true;
gpio->chip.parent = &pdev->dev;
gpio->chip.label = dev_name(&pdev->dev);
gpio->chip.owner = THIS_MODULE;
gpio->chip.get = axp20x_gpio_get;
gpio->chip.get_direction = axp20x_gpio_get_direction;
gpio->chip.set = axp20x_gpio_set;
gpio->chip.direction_input = axp20x_gpio_input;
gpio->chip.direction_output = axp20x_gpio_output;
gpio->chip.ngpio = 3;
gpio->regmap = axp20x->regmap;
ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
if (ret) {
dev_err(&pdev->dev, "Failed to register GPIO chip\n");
return ret;
}
dev_info(&pdev->dev, "AXP209 GPIO driver loaded\n");
return 0;
}
static const struct of_device_id axp20x_gpio_match[] = {
{ .compatible = "x-powers,axp209-gpio" },
{ }
};
MODULE_DEVICE_TABLE(of, axp20x_gpio_match);
static struct platform_driver axp20x_gpio_driver = {
.probe = axp20x_gpio_probe,
.driver = {
.name = "axp20x-gpio",
.of_match_table = axp20x_gpio_match,
},
};
module_platform_driver(axp20x_gpio_driver);
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_DESCRIPTION("AXP20x PMIC GPIO driver");
MODULE_LICENSE("GPL");