Unverified Commit 8c518eb4 authored by Dave Stevenson's avatar Dave Stevenson Committed by Mark Brown
Browse files

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: default avatarDave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: default avatarDetlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-7-detlev.casanova@collabora.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 4866e35e

drivers/regulator/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/regulator/rpi-panel-attiny-regulator.c

+97 −18
Original line number Diff line number Diff line
@@ -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: