mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Linus Walleij](/assets/img/avatar_default.png)
This driver is a pure GPIO driver and should only include <linux/gpio/driver.h>. Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
205 lines
5.4 KiB
C
205 lines
5.4 KiB
C
/*
|
|
* Kontron PLD GPIO driver
|
|
*
|
|
* Copyright (c) 2010-2013 Kontron Europe GmbH
|
|
* Author: Michael Brunner <michael.brunner@kontron.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License 2 as published
|
|
* by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/gpio/driver.h>
|
|
#include <linux/mfd/kempld.h>
|
|
|
|
#define KEMPLD_GPIO_MAX_NUM 16
|
|
#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8))
|
|
#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
|
|
#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
|
|
#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
|
|
#define KEMPLD_GPIO_IEN 0x4A
|
|
|
|
struct kempld_gpio_data {
|
|
struct gpio_chip chip;
|
|
struct kempld_device_data *pld;
|
|
};
|
|
|
|
/*
|
|
* Set or clear GPIO bit
|
|
* kempld_get_mutex must be called prior to calling this function.
|
|
*/
|
|
static void kempld_gpio_bitop(struct kempld_device_data *pld,
|
|
u8 reg, u8 bit, u8 val)
|
|
{
|
|
u8 status;
|
|
|
|
status = kempld_read8(pld, reg);
|
|
if (val)
|
|
status |= KEMPLD_GPIO_MASK(bit);
|
|
else
|
|
status &= ~KEMPLD_GPIO_MASK(bit);
|
|
kempld_write8(pld, reg, status);
|
|
}
|
|
|
|
static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
|
|
{
|
|
u8 status;
|
|
|
|
kempld_get_mutex(pld);
|
|
status = kempld_read8(pld, reg);
|
|
kempld_release_mutex(pld);
|
|
|
|
return !!(status & KEMPLD_GPIO_MASK(bit));
|
|
}
|
|
|
|
static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
|
|
struct kempld_device_data *pld = gpio->pld;
|
|
|
|
return !!kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);
|
|
}
|
|
|
|
static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
|
|
{
|
|
struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
|
|
struct kempld_device_data *pld = gpio->pld;
|
|
|
|
kempld_get_mutex(pld);
|
|
kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
|
|
kempld_release_mutex(pld);
|
|
}
|
|
|
|
static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
|
|
struct kempld_device_data *pld = gpio->pld;
|
|
|
|
kempld_get_mutex(pld);
|
|
kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);
|
|
kempld_release_mutex(pld);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
|
|
int value)
|
|
{
|
|
struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
|
|
struct kempld_device_data *pld = gpio->pld;
|
|
|
|
kempld_get_mutex(pld);
|
|
kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
|
|
kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);
|
|
kempld_release_mutex(pld);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
|
|
struct kempld_device_data *pld = gpio->pld;
|
|
|
|
return !kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset);
|
|
}
|
|
|
|
static int kempld_gpio_pincount(struct kempld_device_data *pld)
|
|
{
|
|
u16 evt, evt_back;
|
|
|
|
kempld_get_mutex(pld);
|
|
|
|
/* Backup event register as it might be already initialized */
|
|
evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
|
|
/* Clear event register */
|
|
kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
|
|
/* Read back event register */
|
|
evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
|
|
/* Restore event register */
|
|
kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
|
|
|
|
kempld_release_mutex(pld);
|
|
|
|
return evt ? __ffs(evt) : 16;
|
|
}
|
|
|
|
static int kempld_gpio_probe(struct platform_device *pdev)
|
|
{
|
|
struct device *dev = &pdev->dev;
|
|
struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
|
|
struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
|
|
struct kempld_gpio_data *gpio;
|
|
struct gpio_chip *chip;
|
|
int ret;
|
|
|
|
if (pld->info.spec_major < 2) {
|
|
dev_err(dev,
|
|
"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
|
|
if (!gpio)
|
|
return -ENOMEM;
|
|
|
|
gpio->pld = pld;
|
|
|
|
platform_set_drvdata(pdev, gpio);
|
|
|
|
chip = &gpio->chip;
|
|
chip->label = "gpio-kempld";
|
|
chip->owner = THIS_MODULE;
|
|
chip->parent = dev;
|
|
chip->can_sleep = true;
|
|
if (pdata && pdata->gpio_base)
|
|
chip->base = pdata->gpio_base;
|
|
else
|
|
chip->base = -1;
|
|
chip->direction_input = kempld_gpio_direction_input;
|
|
chip->direction_output = kempld_gpio_direction_output;
|
|
chip->get_direction = kempld_gpio_get_direction;
|
|
chip->get = kempld_gpio_get;
|
|
chip->set = kempld_gpio_set;
|
|
chip->ngpio = kempld_gpio_pincount(pld);
|
|
if (chip->ngpio == 0) {
|
|
dev_err(dev, "No GPIO pins detected\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
ret = devm_gpiochip_add_data(dev, chip, gpio);
|
|
if (ret) {
|
|
dev_err(dev, "Could not register GPIO chip\n");
|
|
return ret;
|
|
}
|
|
|
|
dev_info(dev, "GPIO functionality initialized with %d pins\n",
|
|
chip->ngpio);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver kempld_gpio_driver = {
|
|
.driver = {
|
|
.name = "kempld-gpio",
|
|
},
|
|
.probe = kempld_gpio_probe,
|
|
};
|
|
|
|
module_platform_driver(kempld_gpio_driver);
|
|
|
|
MODULE_DESCRIPTION("KEM PLD GPIO Driver");
|
|
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:kempld-gpio");
|