root/drivers/gpio/gpio-wm831x.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * gpiolib support for Wolfson WM831x PMICs
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 */

#include <linux/cleanup.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/mfd/core.h>
#include <linux/platform_device.h>
#include <linux/seq_file.h>
#include <linux/string_choices.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/gpio.h>
#include <linux/mfd/wm831x/irq.h>

struct wm831x_gpio {
        struct wm831x *wm831x;
        struct gpio_chip gpio_chip;
};

static int wm831x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;
        int val = WM831X_GPN_DIR;

        if (wm831x->has_gpio_ena)
                val |= WM831X_GPN_TRI;

        return wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
                               WM831X_GPN_DIR | WM831X_GPN_TRI |
                               WM831X_GPN_FN_MASK, val);
}

static int wm831x_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;
        int ret;

        ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
        if (ret < 0)
                return ret;

        if (ret & 1 << offset)
                return 1;
        else
                return 0;
}

static int wm831x_gpio_set(struct gpio_chip *chip, unsigned int offset,
                           int value)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;

        return wm831x_set_bits(wm831x, WM831X_GPIO_LEVEL, 1 << offset,
                               value << offset);
}

static int wm831x_gpio_direction_out(struct gpio_chip *chip,
                                     unsigned offset, int value)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;
        int val = 0;
        int ret;

        if (wm831x->has_gpio_ena)
                val |= WM831X_GPN_TRI;

        ret = wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + offset,
                              WM831X_GPN_DIR | WM831X_GPN_TRI |
                              WM831X_GPN_FN_MASK, val);
        if (ret < 0)
                return ret;

        /* Can only set GPIO state once it's in output mode */
        return wm831x_gpio_set(chip, offset, value);
}

static int wm831x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;

        return irq_create_mapping(wm831x->irq_domain,
                                  WM831X_IRQ_GPIO_1 + offset);
}

static int wm831x_gpio_set_debounce(struct wm831x *wm831x, unsigned offset,
                                    unsigned debounce)
{
        int reg = WM831X_GPIO1_CONTROL + offset;
        int ret, fn;

        ret = wm831x_reg_read(wm831x, reg);
        if (ret < 0)
                return ret;

        switch (ret & WM831X_GPN_FN_MASK) {
        case 0:
        case 1:
                break;
        default:
                /* Not in GPIO mode */
                return -EBUSY;
        }

        if (debounce >= 32 && debounce <= 64)
                fn = 0;
        else if (debounce >= 4000 && debounce <= 8000)
                fn = 1;
        else
                return -EINVAL;

        return wm831x_set_bits(wm831x, reg, WM831X_GPN_FN_MASK, fn);
}

static int wm831x_set_config(struct gpio_chip *chip, unsigned int offset,
                             unsigned long config)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;
        int reg = WM831X_GPIO1_CONTROL + offset;

        switch (pinconf_to_config_param(config)) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                return wm831x_set_bits(wm831x, reg,
                                       WM831X_GPN_OD_MASK, WM831X_GPN_OD);
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                return wm831x_set_bits(wm831x, reg,
                                       WM831X_GPN_OD_MASK, 0);
        case PIN_CONFIG_INPUT_DEBOUNCE:
                return wm831x_gpio_set_debounce(wm831x, offset,
                        pinconf_to_config_argument(config));
        default:
                break;
        }

        return -ENOTSUPP;
}

#ifdef CONFIG_DEBUG_FS
static void wm831x_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
        struct wm831x_gpio *wm831x_gpio = gpiochip_get_data(chip);
        struct wm831x *wm831x = wm831x_gpio->wm831x;
        int i, tristated;

        for (i = 0; i < chip->ngpio; i++) {
                int reg;
                const char *pull, *powerdomain;

                /* We report the GPIO even if it's not requested since
                 * we're also reporting things like alternate
                 * functions which apply even when the GPIO is not in
                 * use as a GPIO.
                 */
                char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
                if (IS_ERR(label)) {
                        dev_err(wm831x->dev, "Failed to duplicate label\n");
                        continue;
                }

                seq_printf(s, " gpio-%-3d (%-20.20s) ",
                           i, label ?: "Unrequested");

                reg = wm831x_reg_read(wm831x, WM831X_GPIO1_CONTROL + i);
                if (reg < 0) {
                        dev_err(wm831x->dev,
                                "GPIO control %d read failed: %d\n",
                                i, reg);
                        seq_putc(s, '\n');
                        continue;
                }

                switch (reg & WM831X_GPN_PULL_MASK) {
                case WM831X_GPIO_PULL_NONE:
                        pull = "nopull";
                        break;
                case WM831X_GPIO_PULL_DOWN:
                        pull = "pulldown";
                        break;
                case WM831X_GPIO_PULL_UP:
                        pull = "pullup";
                        break;
                default:
                        pull = "INVALID PULL";
                        break;
                }

                switch (i + 1) {
                case 1 ... 3:
                case 7 ... 9:
                        if (reg & WM831X_GPN_PWR_DOM)
                                powerdomain = "VPMIC";
                        else
                                powerdomain = "DBVDD";
                        break;

                case 4 ... 6:
                case 10 ... 12:
                        if (reg & WM831X_GPN_PWR_DOM)
                                powerdomain = "SYSVDD";
                        else
                                powerdomain = "DBVDD";
                        break;

                case 13 ... 16:
                        powerdomain = "TPVDD";
                        break;

                default:
                        BUG();
                        break;
                }

                tristated = reg & WM831X_GPN_TRI;
                if (wm831x->has_gpio_ena)
                        tristated = !tristated;

                seq_printf(s, " %s %s %s %s%s\n"
                           "                                  %s%s (0x%4x)\n",
                           reg & WM831X_GPN_DIR ? "in" : "out",
                           str_high_low(wm831x_gpio_get(chip, i)),
                           pull,
                           powerdomain,
                           reg & WM831X_GPN_POL ? "" : " inverted",
                           reg & WM831X_GPN_OD ? "open-drain" : "push-pull",
                           tristated ? " tristated" : "",
                           reg);
        }
}
#else
#define wm831x_gpio_dbg_show NULL
#endif

static const struct gpio_chip template_chip = {
        .label                  = "wm831x",
        .owner                  = THIS_MODULE,
        .direction_input        = wm831x_gpio_direction_in,
        .get                    = wm831x_gpio_get,
        .direction_output       = wm831x_gpio_direction_out,
        .set                    = wm831x_gpio_set,
        .to_irq                 = wm831x_gpio_to_irq,
        .set_config             = wm831x_set_config,
        .dbg_show               = wm831x_gpio_dbg_show,
        .can_sleep              = true,
};

static int wm831x_gpio_probe(struct platform_device *pdev)
{
        struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
        struct wm831x_pdata *pdata = &wm831x->pdata;
        struct wm831x_gpio *wm831x_gpio;

        device_set_node(&pdev->dev, dev_fwnode(pdev->dev.parent));

        wm831x_gpio = devm_kzalloc(&pdev->dev, sizeof(*wm831x_gpio),
                                   GFP_KERNEL);
        if (wm831x_gpio == NULL)
                return -ENOMEM;

        wm831x_gpio->wm831x = wm831x;
        wm831x_gpio->gpio_chip = template_chip;
        wm831x_gpio->gpio_chip.ngpio = wm831x->num_gpio;
        wm831x_gpio->gpio_chip.parent = &pdev->dev;
        if (pdata && pdata->gpio_base)
                wm831x_gpio->gpio_chip.base = pdata->gpio_base;
        else
                wm831x_gpio->gpio_chip.base = -1;

        return devm_gpiochip_add_data(&pdev->dev, &wm831x_gpio->gpio_chip, wm831x_gpio);
}

static struct platform_driver wm831x_gpio_driver = {
        .driver.name    = "wm831x-gpio",
        .probe          = wm831x_gpio_probe,
};

static int __init wm831x_gpio_init(void)
{
        return platform_driver_register(&wm831x_gpio_driver);
}
subsys_initcall(wm831x_gpio_init);

static void __exit wm831x_gpio_exit(void)
{
        platform_driver_unregister(&wm831x_gpio_driver);
}
module_exit(wm831x_gpio_exit);

MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("GPIO interface for WM831x PMICs");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-gpio");