bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 255 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0482-regulator-rpi-panel-Serialise-operations.patch b/target/linux/bcm27xx/patches-5.15/950-0482-regulator-rpi-panel-Serialise-operations.patch
new file mode 100644
index 0000000000..67543ea197
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0482-regulator-rpi-panel-Serialise-operations.patch
@@ -0,0 +1,255 @@
+From 354dfe9793ff5f814830c6841ca07ef04bfd66e9 Mon Sep 17 00:00:00 2001
+From: Dave Stevenson <dave.stevenson@raspberrypi.com>
+Date: Wed, 8 Sep 2021 15:02:05 +0100
+Subject: [PATCH] regulator: rpi-panel: Serialise operations.
+
+The driver was using the regmap lock to serialise the
+individual accesses, but we really need to protect the
+timings of enabling the regulators, including any communication
+with the Atmel.
+
+Use a mutex within the driver to control overall accesses to
+the Atmel, instead of the regmap lock.
+
+Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
+---
+ .../regulator/rpi-panel-attiny-regulator.c    | 91 ++++++++++++++++---
+ 1 file changed, 80 insertions(+), 11 deletions(-)
+
+--- a/drivers/regulator/rpi-panel-attiny-regulator.c
++++ b/drivers/regulator/rpi-panel-attiny-regulator.c
+@@ -27,18 +27,28 @@
+ #define REG_POWERON	0x85
+ #define REG_PWM		0x86
+ 
++struct attiny_lcd {
++	/* lock to serialise overall accesses to the Atmel */
++	struct mutex	lock;
++	struct regmap	*regmap;
++};
++
+ static const struct regmap_config attiny_regmap_config = {
+ 	.reg_bits = 8,
+ 	.val_bits = 8,
++	.disable_locking = 1,
+ 	.max_register = REG_PWM,
+ 	.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);
+ 
+@@ -63,33 +73,49 @@ static int attiny_lcd_power_enable(struc
+ 	 */
+ 	regmap_write(rdev->regmap, REG_PORTA, BIT(2));
+ 
++	mutex_unlock(lock);
++
+ 	return 0;
+ }
+ 
+ static int attiny_lcd_power_disable(struct regulator_dev *rdev)
+ {
++	struct mutex *lock = rdev_get_drvdata(rdev);
++
++	mutex_lock(lock);
++
+ 	regmap_write(rdev->regmap, REG_PWM, 0);
+ 	regmap_write(rdev->regmap, REG_POWERON, 0);
+ 	msleep(30);
++
++	mutex_unlock(lock);
++
+ 	return 0;
+ }
+ 
+ static int attiny_lcd_power_is_enabled(struct regulator_dev *rdev)
+ {
++	struct mutex *lock = 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)
++	if (ret < 0) {
++		mutex_unlock(lock);
+ 		return ret;
++	}
+ 
+-	if (!(data & BIT(0)))
++	if (!(data & BIT(0))) {
++		mutex_unlock(lock);
+ 		return 0;
++	}
+ 
+ 	for (i = 0; i < 10; i++) {
+ 		ret = regmap_read(rdev->regmap, REG_PORTB, &data);
+@@ -98,6 +124,8 @@ static int attiny_lcd_power_is_enabled(s
+ 		usleep_range(10000, 12000);
+ 	}
+ 
++	mutex_unlock(lock);
++
+ 	if (ret < 0)
+ 		return ret;
+ 
+@@ -125,10 +153,13 @@ static const struct regulator_desc attin
+ 
+ static int attiny_update_status(struct backlight_device *bl)
+ {
+-	struct regmap *regmap = bl_get_data(bl);
++	struct attiny_lcd *state = bl_get_data(bl);
++	struct regmap *regmap = state->regmap;
+ 	int brightness = bl->props.brightness;
+ 	int ret, i;
+ 
++	mutex_lock(&state->lock);
++
+ 	if (bl->props.power != FB_BLANK_UNBLANK ||
+ 	    bl->props.fb_blank != FB_BLANK_UNBLANK)
+ 		brightness = 0;
+@@ -139,20 +170,27 @@ static int attiny_update_status(struct b
+ 			break;
+ 	}
+ 
++	mutex_unlock(&state->lock);
++
+ 	return ret;
+ }
+ 
+ static int attiny_get_brightness(struct backlight_device *bl)
+ {
+-	struct regmap *regmap = bl_get_data(bl);
++	struct attiny_lcd *state = bl_get_data(bl);
++	struct regmap *regmap = state->regmap;
+ 	int ret, brightness, i;
+ 
++	mutex_lock(&state->lock);
++
+ 	for (i = 0; i < 10; i++) {
+ 		ret = regmap_read(regmap, REG_PWM, &brightness);
+ 		if (!ret)
+ 			break;
+ 	}
+ 
++	mutex_unlock(&state->lock);
++
+ 	if (ret)
+ 		return ret;
+ 
+@@ -174,22 +212,30 @@ static int attiny_i2c_probe(struct i2c_c
+ 	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);
+-		return ret;
++		goto error;
+ 	}
+ 
+ 	ret = regmap_read(regmap, REG_ID, &data);
+ 	if (ret < 0) {
+ 		dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
+-		return ret;
++		goto error;
+ 	}
+ 
+ 	switch (data) {
+@@ -198,7 +244,8 @@ static int attiny_i2c_probe(struct i2c_c
+ 		break;
+ 	default:
+ 		dev_err(&i2c->dev, "Unknown Atmel firmware revision: 0x%02x\n", data);
+-		return -ENODEV;
++		ret = -ENODEV;
++		goto error;
+ 	}
+ 
+ 	regmap_write(regmap, REG_POWERON, 0);
+@@ -208,24 +255,45 @@ static int attiny_i2c_probe(struct i2c_c
+ 	config.regmap = regmap;
+ 	config.of_node = i2c->dev.of_node;
+ 	config.init_data = &attiny_regulator_default;
++	config.driver_data = &state->lock;
+ 
+ 	rdev = devm_regulator_register(&i2c->dev, &attiny_regulator, &config);
+ 	if (IS_ERR(rdev)) {
+ 		dev_err(&i2c->dev, "Failed to register ATTINY regulator\n");
+-		return PTR_ERR(rdev);
++		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, regmap, &attiny_bl,
++					    &i2c->dev, state, &attiny_bl,
+ 					    &props);
+-	if (IS_ERR(bl))
+-		return PTR_ERR(bl);
++	if (IS_ERR(bl)) {
++		ret = PTR_ERR(bl);
++		goto error;
++	}
+ 
+ 	bl->props.brightness = 0xff;
+ 
+ 	return 0;
++
++error:
++	mutex_destroy(&state->lock);
++
++	return ret;
++}
++
++static int attiny_i2c_remove(struct i2c_client *client)
++{
++	struct attiny_lcd *state = i2c_get_clientdata(client);
++
++	mutex_destroy(&state->lock);
++
++	return 0;
+ }
+ 
+ static const struct of_device_id attiny_dt_ids[] = {
+@@ -240,6 +308,7 @@ static struct i2c_driver attiny_regulato
+ 		.of_match_table = of_match_ptr(attiny_dt_ids),
+ 	},
+ 	.probe = attiny_i2c_probe,
++	.remove	= attiny_i2c_remove,
+ };
+ 
+ module_i2c_driver(attiny_regulator_driver);