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authorDave Stevenson <dave.stevenson@raspberrypi.com>2022-01-25 01:01:23 +0300
committerMark Brown <broonie@kernel.org>2022-01-28 23:55:47 +0300
commit00440bcd211a3cac686b730447c4efa3d4c84c2a (patch)
treed557ecccb9bf3e83ba0686f5bac56048e707ab1f /drivers/regulator
parent5665eee7a3800430e7dc3ef6f25722476b603186 (diff)
downloadlinux-00440bcd211a3cac686b730447c4efa3d4c84c2a.tar.xz
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> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com> Link: https://lore.kernel.org/r/20220124220129.158891-4-detlev.casanova@collabora.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/regulator')
-rw-r--r--drivers/regulator/rpi-panel-attiny-regulator.c91
1 files changed, 80 insertions, 11 deletions
diff --git a/drivers/regulator/rpi-panel-attiny-regulator.c b/drivers/regulator/rpi-panel-attiny-regulator.c
index 00fb69efcfa2..a4af7adad2b5 100644
--- 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(struct regulator_dev *rdev)
*/
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(struct regulator_dev *rdev)
usleep_range(10000, 12000);
}
+ mutex_unlock(lock);
+
if (ret < 0)
return ret;
@@ -125,10 +153,13 @@ static const struct regulator_desc attiny_regulator = {
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 backlight_device *bl)
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_client *i2c,
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_client *i2c,
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_client *i2c,
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_regulator_driver = {
.of_match_table = of_match_ptr(attiny_dt_ids),
},
.probe = attiny_i2c_probe,
+ .remove = attiny_i2c_remove,
};
module_i2c_driver(attiny_regulator_driver);