path: root/drivers/staging/greybus/gpio.c

// SPDX-License-Identifier: GPL-2.0
/*
 * GPIO Greybus driver.
 *
 * Copyright 2014 Google Inc.
 * Copyright 2014 Linaro Ltd.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/gpio/driver.h>
#include <linux/mutex.h>
#include <linux/greybus.h>

#include "gbphy.h"

struct gb_gpio_line {
	/* The following has to be an array of line_max entries */
	/* --> make them just a flags field */
	u8			active:    1,
				direction: 1,	/* 0 = output, 1 = input */
				value:     1;	/* 0 = low, 1 = high */
	u16			debounce_usec;

	u8			irq_type;
	bool			irq_type_pending;
	bool			masked;
	bool			masked_pending;
};

struct gb_gpio_controller {
	struct gbphy_device	*gbphy_dev;
	struct gb_connection	*connection;
	u8			line_max;	/* max line number */
	struct gb_gpio_line	*lines;

	struct gpio_chip	chip;
	struct irq_chip		irqc;
	struct mutex		irq_lock;
};
#define gpio_chip_to_gb_gpio_controller(chip) \
	container_of(chip, struct gb_gpio_controller, chip)
#define irq_data_to_gpio_chip(d) (d->domain->host_data)

static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
{
	struct gb_gpio_line_count_response response;
	int ret;

	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
				NULL, 0, &response, sizeof(response));
	if (!ret)
		ggc->line_max = response.count;
	return ret;
}

static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
{
	struct gb_gpio_activate_request request;
	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
	int ret;

	ret = gbphy_runtime_get_sync(gbphy_dev);
	if (ret)
		return ret;

	request.which = which;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
				&request, sizeof(request), NULL, 0);
	if (ret) {
		gbphy_runtime_put_autosuspend(gbphy_dev);
		return ret;
	}

	ggc->lines[which].active = true;

	return 0;
}

static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
					 u8 which)
{
	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
	struct device *dev = &gbphy_dev->dev;
	struct gb_gpio_deactivate_request request;
	int ret;

	request.which = which;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
				&request, sizeof(request), NULL, 0);
	if (ret) {
		dev_err(dev, "failed to deactivate gpio %u\n", which);
		goto out_pm_put;
	}

	ggc->lines[which].active = false;

out_pm_put:
	gbphy_runtime_put_autosuspend(gbphy_dev);
}

static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
					   u8 which)
{
	struct device *dev = &ggc->gbphy_dev->dev;
	struct gb_gpio_get_direction_request request;
	struct gb_gpio_get_direction_response response;
	int ret;
	u8 direction;

	request.which = which;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
				&request, sizeof(request),
				&response, sizeof(response));
	if (ret)
		return ret;

	direction = response.direction;
	if (direction && direction != 1) {
		dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
			 which, direction);
	}
	ggc->lines[which].direction = direction ? 1 : 0;
	return 0;
}

static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
					  u8 which)
{
	struct gb_gpio_direction_in_request request;
	int ret;

	request.which = which;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
				&request, sizeof(request), NULL, 0);
	if (!ret)
		ggc->lines[which].direction = 1;
	return ret;
}

static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
					   u8 which, bool value_high)
{
	struct gb_gpio_direction_out_request request;
	int ret;

	request.which = which;
	request.value = value_high ? 1 : 0;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
				&request, sizeof(request), NULL, 0);
	if (!ret)
		ggc->lines[which].direction = 0;
	return ret;
}

static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
				       u8 which)
{
	struct device *dev = &ggc->gbphy_dev->dev;
	struct gb_gpio_get_value_request request;
	struct gb_gpio_get_value_response response;
	int ret;
	u8 value;

	request.which = which;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
				&request, sizeof(request),
				&response, sizeof(response));
	if (ret) {
		dev_err(dev, "failed to get value of gpio %u\n", which);
		return ret;
	}

	value = response.value;
	if (value && value != 1) {
		dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
			 which, value);
	}
	ggc->lines[which].value = value ? 1 : 0;
	return 0;
}

static void gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
					u8 which, bool value_high)
{
	struct device *dev = &ggc->gbphy_dev->dev;
	struct gb_gpio_set_value_request request;
	int ret;

	if (ggc->lines[which].direction == 1) {
		dev_warn(dev, "refusing to set value of input gpio %u\n",
			 which);
		return;
	}

	request.which = which;
	request.value = value_high ? 1 : 0;
	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
				&request, sizeof(request), NULL, 0);
	if (ret) {
		dev_err(dev, "failed to set value of gpio %u\n", which);
		return;
	}

	ggc->lines[which].value = request.