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![Matti Vaittinen](/assets/img/avatar_default.png)
It's hard for occasional GPIO code reader/writer to know if values 0/1 equal to IN or OUT. Use defined GPIO_LINE_DIRECTION_IN and GPIO_LINE_DIRECTION_OUT to help them out. NOTE - for gpio-amd-fch and gpio-bd9571mwv: This commit also changes the return value for direction get to equal 1 for direction INPUT. Prior this commit these drivers might have returned some other positive value but 1 for INPUT. Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> Acked-by: Scott Branden <scott.branden@broadcom.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Reviewed-by: Michal Simek <michal.simek@xilinx.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Acked-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
200 lines
5.1 KiB
C
200 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Kontron PLD GPIO driver
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*
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* Copyright (c) 2010-2013 Kontron Europe GmbH
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* Author: Michael Brunner <michael.brunner@kontron.com>
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/platform_device.h>
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#include <linux/gpio/driver.h>
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#include <linux/mfd/kempld.h>
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#define KEMPLD_GPIO_MAX_NUM 16
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#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8))
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#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
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#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
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#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
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#define KEMPLD_GPIO_IEN 0x4A
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struct kempld_gpio_data {
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struct gpio_chip chip;
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struct kempld_device_data *pld;
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};
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/*
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* Set or clear GPIO bit
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* kempld_get_mutex must be called prior to calling this function.
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*/
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static void kempld_gpio_bitop(struct kempld_device_data *pld,
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u8 reg, u8 bit, u8 val)
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{
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u8 status;
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status = kempld_read8(pld, reg);
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if (val)
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status |= KEMPLD_GPIO_MASK(bit);
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else
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status &= ~KEMPLD_GPIO_MASK(bit);
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kempld_write8(pld, reg, status);
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}
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static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
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{
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u8 status;
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kempld_get_mutex(pld);
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status = kempld_read8(pld, reg);
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kempld_release_mutex(pld);
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return !!(status & KEMPLD_GPIO_MASK(bit));
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}
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static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
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{
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
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struct kempld_device_data *pld = gpio->pld;
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return !!kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);
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}
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static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
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{
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
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struct kempld_device_data *pld = gpio->pld;
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kempld_get_mutex(pld);
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kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
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kempld_release_mutex(pld);
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}
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static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
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{
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
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struct kempld_device_data *pld = gpio->pld;
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kempld_get_mutex(pld);
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kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);
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kempld_release_mutex(pld);
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return 0;
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}
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static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
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int value)
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{
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
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struct kempld_device_data *pld = gpio->pld;
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kempld_get_mutex(pld);
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kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
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kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);
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kempld_release_mutex(pld);
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return 0;
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}
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static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
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{
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
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struct kempld_device_data *pld = gpio->pld;
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if (kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset))
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return GPIO_LINE_DIRECTION_OUT;
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return GPIO_LINE_DIRECTION_IN;
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}
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static int kempld_gpio_pincount(struct kempld_device_data *pld)
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{
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u16 evt, evt_back;
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kempld_get_mutex(pld);
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/* Backup event register as it might be already initialized */
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evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
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/* Clear event register */
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kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
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/* Read back event register */
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evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
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/* Restore event register */
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kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
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kempld_release_mutex(pld);
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return evt ? __ffs(evt) : 16;
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}
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static int kempld_gpio_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
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struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
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struct kempld_gpio_data *gpio;
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struct gpio_chip *chip;
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int ret;
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if (pld->info.spec_major < 2) {
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dev_err(dev,
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"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
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return -ENODEV;
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}
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gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
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if (!gpio)
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return -ENOMEM;
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gpio->pld = pld;
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platform_set_drvdata(pdev, gpio);
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chip = &gpio->chip;
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chip->label = "gpio-kempld";
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chip->owner = THIS_MODULE;
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chip->parent = dev;
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chip->can_sleep = true;
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if (pdata && pdata->gpio_base)
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chip->base = pdata->gpio_base;
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else
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chip->base = -1;
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chip->direction_input = kempld_gpio_direction_input;
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chip->direction_output = kempld_gpio_direction_output;
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chip->get_direction = kempld_gpio_get_direction;
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chip->get = kempld_gpio_get;
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chip->set = kempld_gpio_set;
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chip->ngpio = kempld_gpio_pincount(pld);
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if (chip->ngpio == 0) {
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dev_err(dev, "No GPIO pins detected\n");
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return -ENODEV;
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}
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ret = devm_gpiochip_add_data(dev, chip, gpio);
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if (ret) {
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dev_err(dev, "Could not register GPIO chip\n");
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return ret;
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}
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dev_info(dev, "GPIO functionality initialized with %d pins\n",
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chip->ngpio);
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return 0;
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}
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static struct platform_driver kempld_gpio_driver = {
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.driver = {
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.name = "kempld-gpio",
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},
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.probe = kempld_gpio_probe,
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};
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module_platform_driver(kempld_gpio_driver);
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MODULE_DESCRIPTION("KEM PLD GPIO Driver");
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MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:kempld-gpio");
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