linux/drivers/regulator/rpi-panel-attiny-regulator.c
Dave Stevenson 89339a2ae7
regulator: rpi-panel: Ensure the backlight is off during probe.
The initial state of the Atmel is not defined, so ensure the
backlight PWM is set to 0 by default.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-5-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-01-28 20:55:48 +00:00

320 lines
6.7 KiB
C

// 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
struct attiny_lcd {
/* lock to serialise overall accesses to the Atmel */
struct mutex lock;
struct regmap *regmap;
};
static const struct regmap_config attiny_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.disable_locking = 1,
.max_register = REG_PWM,
.cache_type = REGCACHE_NONE,
};
static int attiny_lcd_power_enable(struct regulator_dev *rdev)
{
struct mutex *lock = rdev_get_drvdata(rdev);
unsigned int data;
int ret, i;
mutex_lock(lock);
regmap_write(rdev->regmap, REG_POWERON, 1);
msleep(80);
/* Wait for nPWRDWN to go low to indicate poweron is done. */
for (i = 0; i < 20; i++) {
ret = regmap_read(rdev->regmap, REG_PORTB, &data);
if (!ret) {
if (data & BIT(0))
break;
}
usleep_range(10000, 12000);
}
usleep_range(10000, 12000);
if (ret)
pr_err("%s: regmap_read_poll_timeout failed %d\n", __func__, ret);
/* 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));
mutex_unlock(lock);
return 0;
}
static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
struct mutex *lock = rdev_get_drvdata(rdev);
mutex_lock(lock);
regmap_write(rdev->regmap, REG_PWM, 0);
regmap_write(rdev->regmap, REG_POWERON, 0);
msleep(30);
mutex_unlock(lock);
return 0;
}
static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
struct mutex *lock = rdev_get_drvdata(rdev);
unsigned int data;
int ret, i;
mutex_lock(lock);
for (i = 0; i < 10; i++) {
ret = regmap_read(rdev->regmap, REG_POWERON, &data);
if (!ret)
break;
usleep_range(10000, 12000);
}
if (ret < 0) {
mutex_unlock(lock);
return ret;
}
if (!(data & BIT(0))) {
mutex_unlock(lock);
return 0;
}
for (i = 0; i < 10; i++) {
ret = regmap_read(rdev->regmap, REG_PORTB, &data);
if (!ret)
break;
usleep_range(10000, 12000);
}
mutex_unlock(lock);
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 attiny_lcd *state = bl_get_data(bl);
struct regmap *regmap = state->regmap;
int brightness = bl->props.brightness;
int ret, i;
mutex_lock(&state->lock);
if (bl->props.power != FB_BLANK_UNBLANK ||
bl->props.fb_blank != FB_BLANK_UNBLANK)
brightness = 0;
for (i = 0; i < 10; i++) {
ret = regmap_write(regmap, REG_PWM, brightness);
if (!ret)
break;
}
mutex_unlock(&state->lock);
return ret;
}
static int attiny_get_brightness(struct backlight_device *bl)
{
struct attiny_lcd *state = bl_get_data(bl);
struct regmap *regmap = state->regmap;
int ret, brightness, i;
mutex_lock(&state->lock);
for (i = 0; i < 10; i++) {
ret = regmap_read(regmap, REG_PWM, &brightness);
if (!ret)
break;
}
mutex_unlock(&state->lock);
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 attiny_lcd *state;
struct regmap *regmap;
unsigned int data;
int ret;
state = devm_kzalloc(&i2c->dev, sizeof(*state), GFP_KERNEL);
if (!state)
return -ENOMEM;
mutex_init(&state->lock);
i2c_set_clientdata(i2c, state);
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);
goto error;
}
ret = regmap_read(regmap, REG_ID, &data);
if (ret < 0) {
dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
goto error;
}
switch (data) {
case 0xde: /* ver 1 */
case 0xc3: /* ver 2 */
break;
default:
dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
ret = -ENODEV;
goto error;
}
regmap_write(regmap, REG_POWERON, 0);
msleep(30);
regmap_write(regmap, REG_PWM, 0);
config.dev = &i2c->dev;
config.regmap = regmap;
config.of_node = i2c->dev.of_node;
config.init_data = &attiny_regulator_default;
config.driver_data = &state->lock;
rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
if (IS_ERR(rdev)) {
dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
ret = PTR_ERR(rdev);
goto error;
}
props.type = BACKLIGHT_RAW;
props.max_brightness = 0xff;
state->regmap = regmap;
bl = devm_backlight_device_register(&i2c->dev, dev_name(&i2c->dev),
&i2c->dev, state, &attiny_bl,
&props);
if (IS_ERR(bl)) {
ret = PTR_ERR(bl);
goto error;
}
bl->props.brightness = 0xff;
return 0;
error:
mutex_destroy(&state->lock);
return ret;
}
static int attiny_i2c_remove(struct i2c_client *client)
{
struct attiny_lcd *state = i2c_get_clientdata(client);
mutex_destroy(&state->lock);
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,
.remove = attiny_i2c_remove,
};
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");