regulator: rpi-panel: Convert to drive lines directly

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>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Link: https://lore.kernel.org/r/20220124220129.158891-6-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/rpi-panel-attiny-regulator.c b/drivers/regulator/rpi-panel-attiny-regulator.c
index b3629a1..995915c 100644 (file)
--- 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)) {