// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Marek Vasut <[email protected]>
*
* Based on rpi_touchscreen.c by Eric Anholt <[email protected]>
*/
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/gpio/driver.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_PORTB 0x82
#define REG_PORTC 0x83
#define REG_POWERON 0x85
#define REG_PWM 0x86
#define REG_ADDR_L 0x8c
#define REG_ADDR_H 0x8d
#define REG_WRITE_DATA_H 0x90
#define REG_WRITE_DATA_L 0x91
#define PA_LCD_DITHB BIT(0)
#define PA_LCD_MODE BIT(1)
#define PA_LCD_LR BIT(2)
#define PA_LCD_UD BIT(3)
#define PB_BRIDGE_PWRDNX_N BIT(0)
#define PB_LCD_VCC_N BIT(1)
#define PB_LCD_MAIN BIT(7)
#define PC_LED_EN BIT(0)
#define PC_RST_TP_N BIT(1)
#define PC_RST_LCD_N BIT(2)
#define PC_RST_BRIDGE_N BIT(3)
enum gpio_signals {
RST_BRIDGE_N, /* TC358762 bridge reset */
RST_TP_N, /* Touch controller reset */
NUM_GPIO
};
struct gpio_signal_mappings {
unsigned int reg;
unsigned int mask;
};
static const struct gpio_signal_mappings mappings[NUM_GPIO] = {
[RST_BRIDGE_N] = { REG_PORTC, PC_RST_BRIDGE_N | PC_RST_LCD_N },
[RST_TP_N] = { REG_PORTC, PC_RST_TP_N },
};
struct attiny_lcd {
/* lock to serialise overall accesses to the Atmel */
struct mutex lock;
struct regmap *regmap;
bool gpio_states[NUM_GPIO];
u8 port_states[3];
struct gpio_chip gc;
};
static const struct regmap_config attiny_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.disable_locking = 1,
.max_register = REG_WRITE_DATA_L,
.cache_type = REGCACHE_MAPLE,
};
static int attiny_set_port_state(struct attiny_lcd *state, int reg, u8 val)
{
state->port_states[reg - REG_PORTA] = val;
return regmap_write(state->regmap, reg, val);
};
static u8 attiny_get_port_state(struct attiny_lcd *state, int reg)
{
return state->port_states[reg - REG_PORTA];
};
static int attiny_lcd_power_enable(struct regulator_dev *rdev)
{
struct attiny_lcd *state = rdev_get_drvdata(rdev);
mutex_lock(&state->lock);
/* Ensure bridge, and tp stay in reset */
attiny_set_port_state(state, REG_PORTC, 0);
usleep_range(5000, 10000);
/* 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.
*/
attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);
usleep_range(5000, 10000);
/* Main regulator on, and power to the panel (LCD_VCC_N) */
attiny_set_port_state(state, REG_PORTB, PB_LCD_MAIN);
usleep_range(5000, 10000);
/* Bring controllers out of reset */
attiny_set_port_state(state, REG_PORTC, PC_LED_EN);
msleep(80);
mutex_unlock(&state->lock);
return 0;
}
static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
struct attiny_lcd *state = rdev_get_drvdata(rdev);
mutex_lock(&state->lock);
regmap_write(rdev->regmap, REG_PWM, 0);
usleep_range(5000, 10000);
attiny_set_port_state(state, REG_PORTA, 0);
usleep_range(5000, 10000);
attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);
usleep_range(5000, 10000);
attiny_set_port_state(state, REG_PORTC, 0);
msleep(30);
mutex_unlock(&state->lock);
return 0;
}
static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
struct attiny_lcd *state = rdev_get_drvdata(rdev);
unsigned int data;
int ret, i;
mutex_lock(&state->lock);
for (i = 0; i < 10; i++) {
ret = regmap_read(rdev->regmap, REG_PORTC, &data);
if (!ret)
break;
usleep_range(10000, 12000);
}
mutex_unlock(&state->lock);
if (ret < 0)
return ret;
return data & PC_RST_BRIDGE_N;
}
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 = backlight_get_brightness(bl);
int ret, i;
mutex_lock(&state->lock);
for (i = 0; i < 10; i++) {
ret = regmap_write(regmap, REG_PWM, brightness);
if (!ret)
break;
}
mutex_unlock(&state->lock);
return ret;
}
static const struct backlight_ops attiny_bl = {
.update_status = attiny_update_status,
};
static int attiny_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
{
return GPIO_LINE_DIRECTION_OUT;
}
static void attiny_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
{
struct attiny_lcd *state = gpiochip_get_data(gc);
u8 last_val;
if (off >= NUM_GPIO)
return;
mutex_lock(&state->lock);
last_val = attiny_get_port_state(state, mappings[off].reg);
if (val)
last_val |= mappings[off].mask;
else
last_val &= ~mappings[off].mask;
attiny_set_port_state(state, mappings[off].reg, last_val);
if (off == RST_BRIDGE_N && val) {
usleep_range(5000, 8000);
regmap_write(state->regmap, REG_ADDR_H, 0x04);
usleep_range(5000, 8000);
regmap_write(state->regmap, REG_ADDR_L, 0x7c);
usleep_range(5000, 8000);
regmap_write(state->regmap, REG_WRITE_DATA_H, 0x00);
usleep_range(5000, 8000);
regmap_write(state->regmap, REG_WRITE_DATA_L, 0x00);
msleep(100);
}
mutex_unlock(&state->lock);
}
static int attiny_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)
{
struct i2c_msg msgs[1];
u8 addr_buf[1] = { reg };
u8 data_buf[1] = { 0, };
int ret;
/* Write register address */
msgs[0].addr = client->addr;
msgs[0].flags = 0;
msgs[0].len = ARRAY_SIZE(addr_buf);
msgs[0].buf = addr_buf;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs))
return -EIO;
usleep_range(5000, 10000);
/* Read data from register */
msgs[0].addr = client->addr;
msgs[0].flags = I2C_M_RD;
msgs[0].len = 1;
msgs[0].buf = data_buf;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs))
return -EIO;
*buf = data_buf[0];
return 0;
}
/*
* I2C driver interface functions
*/
static int attiny_i2c_probe(struct i2c_client *i2c)
{
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 = attiny_i2c_read(i2c, 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;
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;
state->gc.parent = &i2c->dev;
state->gc.label = i2c->name;
state->gc.owner = THIS_MODULE;
state->gc.base = -1;
state->gc.ngpio = NUM_GPIO;
state->gc.set = attiny_gpio_set;
state->gc.get_direction = attiny_gpio_get_direction;
state->gc.can_sleep = true;
ret = devm_gpiochip_add_data(&i2c->dev, &state->gc, state);
if (ret) {
dev_err(&i2c->dev, "Failed to create gpiochip: %d\n", ret);
goto error;
}
return 0;
error:
mutex_destroy(&state->lock);
return ret;
}
static void attiny_i2c_remove(struct i2c_client *client)
{
struct attiny_lcd *state = i2c_get_clientdata(client);
mutex_destroy(&state->lock);
}
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",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = attiny_dt_ids,
},
.probe = attiny_i2c_probe,
.remove = attiny_i2c_remove,
};
module_i2c_driver(attiny_regulator_driver);
MODULE_AUTHOR("Marek Vasut <[email protected]>");
MODULE_DESCRIPTION("Regulator device driver for Raspberry Pi 7-inch touchscreen");
MODULE_LICENSE("GPL v2");
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