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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2022 Raspberry Pi Ltd.
* Copyright (C) 2025 Marek Vasut
*/
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/regmap.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
/* I2C registers of the microcontroller. */
#define REG_ID 0x01
#define REG_POWERON 0x02
#define REG_PWM 0x03
/* Bits for poweron register */
#define LCD_RESET_BIT BIT(0)
#define CTP_RESET_BIT BIT(1)
/* Bits for the PWM register */
#define PWM_BL_ENABLE BIT(7)
#define PWM_BL_MASK GENMASK(4, 0)
/* Treat LCD_RESET and CTP_RESET as GPIOs */
#define NUM_GPIO 2
static const struct regmap_config rpi_panel_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = REG_PWM,
.can_sleep = true,
};
static int rpi_panel_v2_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct regmap *regmap = pwmchip_get_drvdata(chip);
unsigned int duty;
if (state->polarity != PWM_POLARITY_NORMAL)
return -EINVAL;
if (!state->enabled)
return regmap_write(regmap, REG_PWM, 0);
duty = pwm_get_relative_duty_cycle(state, PWM_BL_MASK);
return regmap_write(regmap, REG_PWM, duty | PWM_BL_ENABLE);
}
static const struct pwm_ops rpi_panel_v2_pwm_ops = {
.apply = rpi_panel_v2_pwm_apply,
};
/*
* I2C driver interface functions
*/
static int rpi_panel_v2_i2c_probe(struct i2c_client *i2c)
{
struct gpio_regmap_config gconfig = {
.ngpio = NUM_GPIO,
.ngpio_per_reg = NUM_GPIO,
.parent = &i2c->dev,
.reg_set_base = REG_POWERON,
};
struct regmap *regmap;
struct pwm_chip *pc;
int ret;
pc = devm_pwmchip_alloc(&i2c->dev, 1, 0);
if (IS_ERR(pc))
return PTR_ERR(pc);
pc->ops = &rpi_panel_v2_pwm_ops;
regmap = devm_regmap_init_i2c(i2c, &rpi_panel_regmap_config);
if (IS_ERR(regmap))
return dev_err_probe(&i2c->dev, PTR_ERR(regmap), "Failed to allocate regmap\n");
pwmchip_set_drvdata(pc, regmap);
regmap_write(regmap, REG_POWERON, 0);
gconfig.regmap = regmap;
ret = PTR_ERR_OR_ZERO(devm_gpio_regmap_register(&i2c->dev, &gconfig));
if (ret)
return dev_err_probe(&i2c->dev, ret, "Failed to create gpiochip\n");
i2c_set_clientdata(i2c, regmap);
return devm_pwmchip_add(&i2c->dev, pc);
}
static void rpi_panel_v2_i2c_shutdown(struct i2c_client *client)
{
struct regmap *regmap = i2c_get_clientdata(client);
regmap_write(regmap, REG_PWM, 0);
regmap_write(regmap, REG_POWERON, 0);
}
static const struct of_device_id rpi_panel_v2_dt_ids[] = {
{ .compatible = "raspberrypi,touchscreen-panel-regulator-v2" },
{ },
};
MODULE_DEVICE_TABLE(of, rpi_panel_v2_dt_ids);
static struct i2c_driver rpi_panel_v2_regulator_driver = {
.driver = {
.name = "rpi_touchscreen_v2",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = rpi_panel_v2_dt_ids,
},
.probe = rpi_panel_v2_i2c_probe,
.shutdown = rpi_panel_v2_i2c_shutdown,
};
module_i2c_driver(rpi_panel_v2_regulator_driver);
MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.com>");
MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch V2 touchscreen");
MODULE_LICENSE("GPL");
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