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regulator: rpi-panel: Add GPIO control for panel and touch resets 

We need independent control of the resets for the panel&bridge,
vs the touch controller.

Expose the reset lines that are on the Atmel's port C via the GPIO
API so that they can be controlled appropriately.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-7-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Dave Stevenson 2022-01-24 17:01:26 -05:00 committed by Mark Brown
parent 4866e35e48
commit 8c518eb403
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
2 changed files with 98 additions and 18 deletions
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1
drivers/regulator/Kconfig
View File

@ -984,6 +984,7 @@ config REGULATOR_RASPBERRYPI_TOUCHSCREEN_ATTINY
tristate "Raspberry Pi 7-inch touchscreen panel ATTINY regulator"
depends on BACKLIGHT_CLASS_DEVICE
depends on I2C
depends on OF_GPIO
select REGMAP_I2C
help
This driver supports ATTINY regulator on the Raspberry Pi 7-inch

115
drivers/regulator/rpi-panel-attiny-regulator.c
View File

@ -8,6 +8,7 @@
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
@ -44,10 +45,30 @@
#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 = {
@ -58,6 +79,17 @@ static const struct regmap_config attiny_regmap_config = {
.cache_type = REGCACHE_NONE,
};
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);
@ -65,7 +97,7 @@ static int attiny_lcd_power_enable(struct regulator_dev *rdev)
mutex_lock(&state->lock);
/* Ensure bridge, and tp stay in reset */
regmap_write(rdev->regmap, REG_PORTC, 0);
attiny_set_port_state(state, REG_PORTC, 0);
usleep_range(5000, 10000);
/* Default to the same orientation as the closed source
@ -73,26 +105,16 @@ static int attiny_lcd_power_enable(struct regulator_dev *rdev)
* configuration will be supported using VC4's plane
* orientation bits.
*/
regmap_write(rdev->regmap, REG_PORTA, PA_LCD_LR);
attiny_set_port_state(state, REG_PORTA, PA_LCD_LR);
usleep_range(5000, 10000);
regmap_write(rdev->regmap, REG_PORTB, PB_LCD_MAIN);
/* 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 */
regmap_write(rdev->regmap, REG_PORTC,
PC_LED_EN | PC_RST_BRIDGE_N | PC_RST_LCD_N | PC_RST_TP_N);
attiny_set_port_state(state, REG_PORTC, PC_LED_EN);
msleep(80);
regmap_write(rdev->regmap, REG_ADDR_H, 0x04);
usleep_range(5000, 8000);
regmap_write(rdev->regmap, REG_ADDR_L, 0x7c);
usleep_range(5000, 8000);
regmap_write(rdev->regmap, REG_WRITE_DATA_H, 0x00);
usleep_range(5000, 8000);
regmap_write(rdev->regmap, REG_WRITE_DATA_L, 0x00);
msleep(100);
mutex_unlock(&state->lock);
return 0;
@ -106,11 +128,12 @@ static int attiny_lcd_power_disable(struct regulator_dev *rdev)
regmap_write(rdev->regmap, REG_PWM, 0);
usleep_range(5000, 10000);
regmap_write(rdev->regmap, REG_PORTA, 0);
attiny_set_port_state(state, REG_PORTA, 0);
usleep_range(5000, 10000);
regmap_write(rdev->regmap, REG_PORTB, PB_LCD_VCC_N);
attiny_set_port_state(state, REG_PORTB, PB_LCD_VCC_N);
usleep_range(5000, 10000);
regmap_write(rdev->regmap, REG_PORTC, 0);
attiny_set_port_state(state, REG_PORTC, 0);
msleep(30);
mutex_unlock(&state->lock);
@ -211,6 +234,45 @@ static const struct backlight_ops attiny_bl = {
.get_brightness = attiny_get_brightness,
};
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);
}
/*
* I2C driver interface functions
*/
@ -289,6 +351,23 @@ static int attiny_i2c_probe(struct i2c_client *i2c,
bl->props.brightness = 0xff;
state->gc.parent = &i2c->dev;
state->gc.label = i2c->name;
state->gc.owner = THIS_MODULE;
state->gc.of_node = i2c->dev.of_node;
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: