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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Marek Vasut <marex@denx.de>
*
* Based on rpi_touchscreen.c by Eric Anholt <eric@anholt.net>
*/
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/slab.h>
/* I2C registers of the Atmel microcontroller. */
#define REG_ID 0x80
#define REG_PORTA 0x81
#define REG_PORTA_HF BIT(2)
#define REG_PORTA_VF BIT(3)
#define REG_PORTB 0x82
#define REG_POWERON 0x85
#define REG_PWM 0x86
static const struct regmap_config attiny_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = REG_PWM,
.cache_type = REGCACHE_NONE,
};
static int attiny_lcd_power_enable(struct regulator_dev *rdev)
{
unsigned int data;
regmap_write(rdev->regmap, REG_POWERON, 1);
/* Wait for nPWRDWN to go low to indicate poweron is done. */
regmap_read_poll_timeout(rdev->regmap, REG_PORTB, data,
data & BIT(0), 10, 1000000);
/* Default to the same orientation as the closed source
* firmware used for the panel. Runtime rotation
* configuration will be supported using VC4's plane
* orientation bits.
*/
regmap_write(rdev->regmap, REG_PORTA, BIT(2));
return 0;
}
static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
regmap_write(rdev->regmap, REG_PWM, 0);
regmap_write(rdev->regmap, REG_POWERON, 0);
udelay(1);
return 0;
}
static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
unsigned int data;
int ret;
ret = regmap_read(rdev->regmap, REG_POWERON, &data);
if (ret < 0)
return ret;
if (!(data & BIT(0)))
return 0;
ret = regmap_read(rdev->regmap, REG_PORTB, &data);
if (ret < 0)
return ret;
return data & BIT(0);
}
static const struct regulator_init_data attiny_regulator_default = {
.constraints = {
.valid_ops_mask = REGULATOR_CHANGE_STATUS,
},
};
static const struct regulator_ops attiny_regulator_ops = {
.enable = attiny_lcd_power_enable,
.disable = attiny_lcd_power_disable,
.is_enabled = attiny_lcd_power_is_enabled,
};
static const struct regulator_desc attiny_regulator = {
.name = "tc358762-power",
.ops = &attiny_regulator_ops,
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
};
static int attiny_update_status(struct backlight_device *bl)
{
struct regmap *regmap = bl_get_data(bl);
int brightness = bl->props.brightness;
if (bl->props.power != FB_BLANK_UNBLANK ||
bl->props.fb_blank != FB_BLANK_UNBLANK)
brightness = 0;
return regmap_write(regmap, REG_PWM, brightness);
}
static int attiny_get_brightness(struct backlight_device *bl)
{
struct regmap *regmap = bl_get_data(bl);
int ret, brightness;
ret = regmap_read(regmap, REG_PWM, &brightness);
if (ret)
return ret;
return brightness;
}
static const struct backlight_ops attiny_bl = {
.update_status = attiny_update_status,
.get_brightness = attiny_get_brightness,
};
/*
* I2C driver interface functions
*/
static int attiny_i2c_probe(struct i2c_client *i2c,
const struct i2c_device_id *id)
{
struct backlight_properties props = { };
struct regulator_config config = { };
struct backlight_device *bl;
struct regulator_dev *rdev;
struct regmap *regmap;
unsigned int data;
int ret;
regmap = devm_regmap_init_i2c(i2c, &attiny_regmap_config);
if (IS_ERR(regmap)) {
ret = PTR_ERR(regmap);
dev_err(&i2c->dev, "Failed to allocate register map: %d\n",
ret);
return ret;
}
ret = regmap_read(regmap, REG_ID, &data);
if (ret < 0) {
dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
return ret;
}
switch (data) {
case 0xde: /* ver 1 */
case 0xc3: /* ver 2 */
break;
default:
dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
return -ENODEV;
}
regmap_write(regmap, REG_POWERON, 0);
mdelay(1);
config.dev = &i2c->dev;
config.regmap = regmap;
config.of_node = i2c->dev.of_node;
config.init_data = &attiny_regulator_default;
rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
if (IS_ERR(rdev)) {
dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
return PTR_ERR(rdev);
}
props.type = BACKLIGHT_RAW;
props.max_brightness = 0xff;
bl = devm_backlight_device_register(&i2c->dev,
"7inch-touchscreen-panel-bl",
&i2c->dev, regmap, &attiny_bl,
&props);
if (IS_ERR(bl))
return PTR_ERR(bl);
bl->props.brightness = 0xff;
return 0;
}
static const struct of_device_id attiny_dt_ids[] = {
{ .compatible = "raspberrypi,7inch-touchscreen-panel-regulator" },
{},
};
MODULE_DEVICE_TABLE(of, attiny_dt_ids);
static struct i2c_driver attiny_regulator_driver = {
.driver = {
.name = "rpi_touchscreen_attiny",
.of_match_table = of_match_ptr(attiny_dt_ids),
},
.probe = attiny_i2c_probe,
};
module_i2c_driver(attiny_regulator_driver);
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");
MODULE_LICENSE("GPL v2");
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