+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright 2022 TQ-Systems GmbH
- * Author: Alexander Stein <linux@ew.tq-group.com>
- */
-
-#include <linux/err.h>
-#include <linux/gpio/consumer.h>
-#include <linux/gpio/driver.h>
-#include <linux/module.h>
-#include <linux/mod_devicetable.h>
-#include <linux/platform_device.h>
-#include <linux/delay.h>
-
-#include "gpiolib.h"
-
-struct gpio_delay_timing {
- unsigned long ramp_up_delay_us;
- unsigned long ramp_down_delay_us;
-};
-
-struct gpio_delay_priv {
- struct gpio_chip gc;
- struct gpio_descs *input_gpio;
- struct gpio_delay_timing *delay_timings;
-};
-
-static int gpio_delay_get_direction(struct gpio_chip *gc, unsigned int offset)
-{
- return GPIO_LINE_DIRECTION_OUT;
-}
-
-static void gpio_delay_set(struct gpio_chip *gc, unsigned int offset, int val)
-{
- struct gpio_delay_priv *priv = gpiochip_get_data(gc);
- struct gpio_desc *gpio_desc = priv->input_gpio->desc[offset];
- const struct gpio_delay_timing *delay_timings;
- bool ramp_up;
-
- gpiod_set_value(gpio_desc, val);
-
- delay_timings = &priv->delay_timings[offset];
- ramp_up = (!gpiod_is_active_low(gpio_desc) && val) ||
- (gpiod_is_active_low(gpio_desc) && !val);
-
- if (ramp_up && delay_timings->ramp_up_delay_us)
- udelay(delay_timings->ramp_up_delay_us);
- if (!ramp_up && delay_timings->ramp_down_delay_us)
- udelay(delay_timings->ramp_down_delay_us);
-}
-
-static void gpio_delay_set_can_sleep(struct gpio_chip *gc, unsigned int offset, int val)
-{
- struct gpio_delay_priv *priv = gpiochip_get_data(gc);
- struct gpio_desc *gpio_desc = priv->input_gpio->desc[offset];
- const struct gpio_delay_timing *delay_timings;
- bool ramp_up;
-
- gpiod_set_value_cansleep(gpio_desc, val);
-
- delay_timings = &priv->delay_timings[offset];
- ramp_up = (!gpiod_is_active_low(gpio_desc) && val) ||
- (gpiod_is_active_low(gpio_desc) && !val);
-
- if (ramp_up && delay_timings->ramp_up_delay_us)
- fsleep(delay_timings->ramp_up_delay_us);
- if (!ramp_up && delay_timings->ramp_down_delay_us)
- fsleep(delay_timings->ramp_down_delay_us);
-}
-
-static int gpio_delay_of_xlate(struct gpio_chip *gc,
- const struct of_phandle_args *gpiospec,
- u32 *flags)
-{
- struct gpio_delay_priv *priv = gpiochip_get_data(gc);
- struct gpio_delay_timing *timings;
- u32 line;
-
- if (gpiospec->args_count != gc->of_gpio_n_cells)
- return -EINVAL;
-
- line = gpiospec->args[0];
- if (line >= gc->ngpio)
- return -EINVAL;
-
- timings = &priv->delay_timings[line];
- timings->ramp_up_delay_us = gpiospec->args[1];
- timings->ramp_down_delay_us = gpiospec->args[2];
-
- return line;
-}
-
-static bool gpio_delay_can_sleep(const struct gpio_delay_priv *priv)
-{
- int i;
-
- for (i = 0; i < priv->input_gpio->ndescs; i++)
- if (gpiod_cansleep(priv->input_gpio->desc[i]))
- return true;
-
- return false;
-}
-
-static int gpio_delay_probe(struct platform_device *pdev)
-{
- struct gpio_delay_priv *priv;
-
- priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
-
- priv->input_gpio = devm_gpiod_get_array(&pdev->dev, NULL, GPIOD_OUT_LOW);
- if (IS_ERR(priv->input_gpio))
- return dev_err_probe(&pdev->dev, PTR_ERR(priv->input_gpio),
- "Failed to get input-gpios");
-
- priv->delay_timings = devm_kcalloc(&pdev->dev,
- priv->input_gpio->ndescs,
- sizeof(*priv->delay_timings),
- GFP_KERNEL);
- if (!priv->delay_timings)
- return -ENOMEM;
-
- if (gpio_delay_can_sleep(priv)) {
- priv->gc.can_sleep = true;
- priv->gc.set = gpio_delay_set_can_sleep;
- } else {
- priv->gc.can_sleep = false;
- priv->gc.set = gpio_delay_set;
- }
-
- priv->gc.get_direction = gpio_delay_get_direction;
- priv->gc.of_xlate = gpio_delay_of_xlate;
- priv->gc.of_gpio_n_cells = 3;
- priv->gc.ngpio = priv->input_gpio->ndescs;
- priv->gc.owner = THIS_MODULE;
- priv->gc.base = -1;
- priv->gc.parent = &pdev->dev;
-
- platform_set_drvdata(pdev, priv);
-
- return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
-}
-
-static const struct of_device_id gpio_delay_ids[] = {
- {
- .compatible = "gpio-delay",
- },
- { /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, gpio_delay_ids);
-
-static struct platform_driver gpio_delay_driver = {
- .driver = {
- .name = "gpio-delay",
- .of_match_table = gpio_delay_ids,
- },
- .probe = gpio_delay_probe,
-};
-module_platform_driver(gpio_delay_driver);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Alexander Stein <alexander.stein@ew.tq-group.com>");
-MODULE_DESCRIPTION("GPIO delay driver");