[PATCH v2 5/9] regulator: rpi-panel: Convert to drive lines directly

Detlev Casanova
2022-01-21T15:21:50Z

The Atmel was doing a load of automatic sequencing of
control lines, however it was combining the touch controller's
reset with the bridge/panel control.

Change to control the control signals directly rather than
through the automatic POWERON control.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
.../regulator/rpi-panel-attiny-regulator.c | 111 ++++++++++--------
1 file changed, 60 insertions(+), 51 deletions(-)

diff --git a/drivers/regulator/rpi-panel-attiny-regulator.c b/drivers/regulator/rpi-panel-attiny-regulator.c
index b3629a1e0e50..995915ca4a9b 100644
--- a/drivers/regulator/rpi-panel-attiny-regulator.c
+++ b/drivers/regulator/rpi-panel-attiny-regulator.c
@@ -21,11 +21,28 @@
/* 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_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)

struct attiny_lcd {
/* lock to serialise overall accesses to the Atmel */
@@ -37,99 +54,91 @@ static const struct regmap_config attiny_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.disable_locking = 1,
- .max_register = REG_PWM,
+ .max_register = REG_WRITE_DATA_L,
.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);
+ struct attiny_lcd *state = rdev_get_drvdata(rdev);

- /* 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);
+ mutex_lock(&state->lock);

- if (ret)
- pr_err("%s: regmap_read_poll_timeout failed %d\n", __func__, ret);
+ /* Ensure bridge, and tp stay in reset */
+ regmap_write(rdev->regmap, 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.
*/
- regmap_write(rdev->regmap, REG_PORTA, BIT(2));
+ regmap_write(rdev->regmap, REG_PORTA, PA_LCD_LR);
+ usleep_range(5000, 10000);
+ regmap_write(rdev->regmap, 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);
+
+ 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(lock);
+ mutex_unlock(&state->lock);

return 0;
}

static int attiny_lcd_power_disable(struct regulator_dev *rdev)
{
- struct mutex *lock = rdev_get_drvdata(rdev);
+ struct attiny_lcd *state = rdev_get_drvdata(rdev);

- mutex_lock(lock);
+ mutex_lock(&state->lock);

regmap_write(rdev->regmap, REG_PWM, 0);
- regmap_write(rdev->regmap, REG_POWERON, 0);
+ usleep_range(5000, 10000);
+ regmap_write(rdev->regmap, REG_PORTA, 0);
+ usleep_range(5000, 10000);
+ regmap_write(rdev->regmap, REG_PORTB, PB_LCD_VCC_N);
+ usleep_range(5000, 10000);
+ regmap_write(rdev->regmap, REG_PORTC, 0);
msleep(30);

- mutex_unlock(lock);
+ mutex_unlock(&state->lock);

return 0;
}

static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
{
- struct mutex *lock = rdev_get_drvdata(rdev);
+ struct attiny_lcd *state = 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;
- }
+ mutex_lock(&state->lock);

for (i = 0; i < 10; i++) {
- ret = regmap_read(rdev->regmap, REG_PORTB, &data);
+ ret = regmap_read(rdev->regmap, REG_PORTC, &data);
if (!ret)
break;
usleep_range(10000, 12000);
}

- mutex_unlock(lock);
+ mutex_unlock(&state->lock);

if (ret < 0)
return ret;

- return data & BIT(0);
+ return data & PC_RST_BRIDGE_N;
}

static const struct regulator_init_data attiny_regulator_default = {
@@ -256,7 +265,7 @@ static int attiny_i2c_probe(struct i2c_client *i2c,
config.regmap = regmap;
config.of_node = i2c->dev.of_node;
config.init_data = &attiny_regulator_default;
- config.driver_data = &state->lock;
+ config.driver_data = state;

rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
if (IS_ERR(rdev)) {
--
2.34.1