alistair23-linux/drivers/gpio/gpio-madera.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * GPIO support for Cirrus Logic Madera codecs
 *
 * Copyright (C) 2015-2018 Cirrus Logic
 */

#include <linux/gpio/driver.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <linux/mfd/madera/core.h>
#include <linux/mfd/madera/pdata.h>
#include <linux/mfd/madera/registers.h>

struct madera_gpio {
	struct madera *madera;
	/* storage space for the gpio_chip we're using */
	struct gpio_chip gpio_chip;
};

static int madera_gpio_get_direction(struct gpio_chip *chip,
				     unsigned int offset)
{
	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
	struct madera *madera = madera_gpio->madera;
	unsigned int reg_offset = 2 * offset;
	unsigned int val;
	int ret;

	ret = regmap_read(madera->regmap, MADERA_GPIO1_CTRL_2 + reg_offset,
			  &val);
	if (ret < 0)
		return ret;

	return !!(val & MADERA_GP1_DIR_MASK);
}

static int madera_gpio_direction_in(struct gpio_chip *chip, unsigned int offset)
{
	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
	struct madera *madera = madera_gpio->madera;
	unsigned int reg_offset = 2 * offset;

	return regmap_update_bits(madera->regmap,
				  MADERA_GPIO1_CTRL_2 + reg_offset,
				  MADERA_GP1_DIR_MASK, MADERA_GP1_DIR);
}

static int madera_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
	struct madera *madera = madera_gpio->madera;
	unsigned int reg_offset = 2 * offset;
	unsigned int val;
	int ret;

	ret = regmap_read(madera->regmap, MADERA_GPIO1_CTRL_1 + reg_offset,
			  &val);
	if (ret < 0)
		return ret;

	return !!(val & MADERA_GP1_LVL_MASK);
}

static int madera_gpio_direction_out(struct gpio_chip *chip,
				     unsigned int offset, int value)
{
	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
	struct madera *madera = madera_gpio->madera;
	unsigned int reg_offset = 2 * offset;
	unsigned int reg_val = value ? MADERA_GP1_LVL : 0;
	int ret;

	ret = regmap_update_bits(madera->regmap,
				 MADERA_GPIO1_CTRL_2 + reg_offset,
				 MADERA_GP1_DIR_MASK, 0);
	if (ret < 0)
		return ret;

	return regmap_update_bits(madera->regmap,
				  MADERA_GPIO1_CTRL_1 + reg_offset,
				  MADERA_GP1_LVL_MASK, reg_val);
}

static void madera_gpio_set(struct gpio_chip *chip, unsigned int offset,
			    int value)
{
	struct madera_gpio *madera_gpio = gpiochip_get_data(chip);
	struct madera *madera = madera_gpio->madera;
	unsigned int reg_offset = 2 * offset;
	unsigned int reg_val = value ? MADERA_GP1_LVL : 0;
	int ret;

	ret = regmap_update_bits(madera->regmap,
				 MADERA_GPIO1_CTRL_1 + reg_offset,
				 MADERA_GP1_LVL_MASK, reg_val);

	/* set() doesn't return an error so log a warning */
	if (ret)
		dev_warn(madera->dev, "Failed to write to 0x%x (%d)\n",
			 MADERA_GPIO1_CTRL_1 + reg_offset, ret);
}

static const struct gpio_chip madera_gpio_chip = {
	.label			= "madera",
	.owner			= THIS_MODULE,
	.request		= gpiochip_generic_request,
	.free			= gpiochip_generic_free,
	.get_direction		= madera_gpio_get_direction,
	.direction_input	= madera_gpio_direction_in,
	.get			= madera_gpio_get,
	.direction_output	= madera_gpio_direction_out,
	.set			= madera_gpio_set,
	.set_config		= gpiochip_generic_config,
	.can_sleep		= true,
};

static int madera_gpio_probe(struct platform_device *pdev)
{
	struct madera *madera = dev_get_drvdata(pdev->dev.parent);
	struct madera_pdata *pdata = &madera->pdata;
	struct madera_gpio *madera_gpio;
	int ret;

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

	madera_gpio->madera = madera;

	/* Construct suitable gpio_chip from the template in madera_gpio_chip */
	madera_gpio->gpio_chip = madera_gpio_chip;
	madera_gpio->gpio_chip.parent = pdev->dev.parent;

	switch (madera->type) {
	case CS47L15:
		madera_gpio->gpio_chip.ngpio = CS47L15_NUM_GPIOS;
		break;
	case CS47L35:
		madera_gpio->gpio_chip.ngpio = CS47L35_NUM_GPIOS;
		break;
	case CS47L85:
	case WM1840:
		madera_gpio->gpio_chip.ngpio = CS47L85_NUM_GPIOS;
		break;
	case CS47L90:
	case CS47L91:
		madera_gpio->gpio_chip.ngpio = CS47L90_NUM_GPIOS;
		break;
	case CS42L92:
	case CS47L92:
	case CS47L93:
		madera_gpio->gpio_chip.ngpio = CS47L92_NUM_GPIOS;
		break;
	default:
		dev_err(&pdev->dev, "Unknown chip variant %d\n", madera->type);
		return -EINVAL;
	}

	/* We want to be usable on systems that don't use devicetree or acpi */
	if (pdata->gpio_base)
		madera_gpio->gpio_chip.base = pdata->gpio_base;
	else
		madera_gpio->gpio_chip.base = -1;

	ret = devm_gpiochip_add_data(&pdev->dev,
				     &madera_gpio->gpio_chip,
				     madera_gpio);
	if (ret < 0) {
		dev_dbg(&pdev->dev, "Could not register gpiochip, %d\n", ret);
		return ret;
	}

	/*
	 * This is part of a composite MFD device which can only be used with
	 * the corresponding pinctrl driver. On all supported silicon the GPIO
	 * to pinctrl mapping is fixed in the silicon, so we register it
	 * explicitly instead of requiring a redundant gpio-ranges in the
	 * devicetree.
	 * In any case we also want to work on systems that don't use devicetree
	 * or acpi.
	 */
	ret = gpiochip_add_pin_range(&madera_gpio->gpio_chip, "madera-pinctrl",
				     0, 0, madera_gpio->gpio_chip.ngpio);
	if (ret) {
		dev_dbg(&pdev->dev, "Failed to add pin range (%d)\n", ret);
		return ret;
	}

	return 0;
}

static struct platform_driver madera_gpio_driver = {
	.driver = {
		.name	= "madera-gpio",
	},
	.probe		= madera_gpio_probe,
};

module_platform_driver(madera_gpio_driver);

MODULE_SOFTDEP("pre: pinctrl-madera");
MODULE_DESCRIPTION("GPIO interface for Madera codecs");
MODULE_AUTHOR("Nariman Poushin <nariman@opensource.cirrus.com>");
MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:madera-gpio");