mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 01:41:39 +00:00
![Julia Lawall](/assets/img/avatar_default.png)
These structures are only used to copy into other structures, so declare them as const. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r disable optional_qualifier@ identifier i; position p; @@ static struct gpio_chip i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p; @bad@ position p != {r.p,ok.p}; identifier r.i; struct gpio_chip e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct gpio_chip i = { ... }; // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Acked-by: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
183 lines
4.4 KiB
C
183 lines
4.4 KiB
C
/*
|
|
* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
|
|
* Andrew F. Davis <afd@ti.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
|
|
* kind, whether expressed or implied; without even the implied warranty
|
|
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License version 2 for more details.
|
|
*/
|
|
|
|
#include <linux/delay.h>
|
|
#include <linux/gpio/consumer.h>
|
|
#include <linux/gpio/driver.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/spi/spi.h>
|
|
|
|
#define DEFAULT_NGPIO 8
|
|
|
|
/**
|
|
* struct pisosr_gpio - GPIO driver data
|
|
* @chip: GPIO controller chip
|
|
* @spi: SPI device pointer
|
|
* @buffer: Buffer for device reads
|
|
* @buffer_size: Size of buffer
|
|
* @load_gpio: GPIO pin used to load input into device
|
|
* @lock: Protects read sequences
|
|
*/
|
|
struct pisosr_gpio {
|
|
struct gpio_chip chip;
|
|
struct spi_device *spi;
|
|
u8 *buffer;
|
|
size_t buffer_size;
|
|
struct gpio_desc *load_gpio;
|
|
struct mutex lock;
|
|
};
|
|
|
|
static int pisosr_gpio_refresh(struct pisosr_gpio *gpio)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&gpio->lock);
|
|
|
|
if (gpio->load_gpio) {
|
|
gpiod_set_value_cansleep(gpio->load_gpio, 1);
|
|
udelay(1); /* registers load time (~10ns) */
|
|
gpiod_set_value_cansleep(gpio->load_gpio, 0);
|
|
udelay(1); /* registers recovery time (~5ns) */
|
|
}
|
|
|
|
ret = spi_read(gpio->spi, gpio->buffer, gpio->buffer_size);
|
|
|
|
mutex_unlock(&gpio->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int pisosr_gpio_get_direction(struct gpio_chip *chip,
|
|
unsigned offset)
|
|
{
|
|
/* This device always input */
|
|
return 1;
|
|
}
|
|
|
|
static int pisosr_gpio_direction_input(struct gpio_chip *chip,
|
|
unsigned offset)
|
|
{
|
|
/* This device always input */
|
|
return 0;
|
|
}
|
|
|
|
static int pisosr_gpio_direction_output(struct gpio_chip *chip,
|
|
unsigned offset, int value)
|
|
{
|
|
/* This device is input only */
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int pisosr_gpio_get(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct pisosr_gpio *gpio = gpiochip_get_data(chip);
|
|
|
|
/* Refresh may not always be needed */
|
|
pisosr_gpio_refresh(gpio);
|
|
|
|
return (gpio->buffer[offset / 8] >> (offset % 8)) & 0x1;
|
|
}
|
|
|
|
static const struct gpio_chip template_chip = {
|
|
.label = "pisosr-gpio",
|
|
.owner = THIS_MODULE,
|
|
.get_direction = pisosr_gpio_get_direction,
|
|
.direction_input = pisosr_gpio_direction_input,
|
|
.direction_output = pisosr_gpio_direction_output,
|
|
.get = pisosr_gpio_get,
|
|
.base = -1,
|
|
.ngpio = DEFAULT_NGPIO,
|
|
.can_sleep = true,
|
|
};
|
|
|
|
static int pisosr_gpio_probe(struct spi_device *spi)
|
|
{
|
|
struct device *dev = &spi->dev;
|
|
struct pisosr_gpio *gpio;
|
|
int ret;
|
|
|
|
gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
|
|
if (!gpio)
|
|
return -ENOMEM;
|
|
|
|
spi_set_drvdata(spi, gpio);
|
|
|
|
gpio->chip = template_chip;
|
|
gpio->chip.parent = dev;
|
|
of_property_read_u16(dev->of_node, "ngpios", &gpio->chip.ngpio);
|
|
|
|
gpio->spi = spi;
|
|
|
|
gpio->buffer_size = DIV_ROUND_UP(gpio->chip.ngpio, 8);
|
|
gpio->buffer = devm_kzalloc(dev, gpio->buffer_size, GFP_KERNEL);
|
|
if (!gpio->buffer)
|
|
return -ENOMEM;
|
|
|
|
gpio->load_gpio = devm_gpiod_get_optional(dev, "load", GPIOD_OUT_LOW);
|
|
if (IS_ERR(gpio->load_gpio)) {
|
|
ret = PTR_ERR(gpio->load_gpio);
|
|
if (ret != -EPROBE_DEFER)
|
|
dev_err(dev, "Unable to allocate load GPIO\n");
|
|
return ret;
|
|
}
|
|
|
|
mutex_init(&gpio->lock);
|
|
|
|
ret = gpiochip_add_data(&gpio->chip, gpio);
|
|
if (ret < 0) {
|
|
dev_err(dev, "Unable to register gpiochip\n");
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pisosr_gpio_remove(struct spi_device *spi)
|
|
{
|
|
struct pisosr_gpio *gpio = spi_get_drvdata(spi);
|
|
|
|
gpiochip_remove(&gpio->chip);
|
|
|
|
mutex_destroy(&gpio->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct spi_device_id pisosr_gpio_id_table[] = {
|
|
{ "pisosr-gpio", },
|
|
{ /* sentinel */ }
|
|
};
|
|
MODULE_DEVICE_TABLE(spi, pisosr_gpio_id_table);
|
|
|
|
static const struct of_device_id pisosr_gpio_of_match_table[] = {
|
|
{ .compatible = "pisosr-gpio", },
|
|
{ /* sentinel */ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, pisosr_gpio_of_match_table);
|
|
|
|
static struct spi_driver pisosr_gpio_driver = {
|
|
.driver = {
|
|
.name = "pisosr-gpio",
|
|
.of_match_table = pisosr_gpio_of_match_table,
|
|
},
|
|
.probe = pisosr_gpio_probe,
|
|
.remove = pisosr_gpio_remove,
|
|
.id_table = pisosr_gpio_id_table,
|
|
};
|
|
module_spi_driver(pisosr_gpio_driver);
|
|
|
|
MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
|
|
MODULE_DESCRIPTION("SPI Compatible PISO Shift Register GPIO Driver");
|
|
MODULE_LICENSE("GPL v2");
|