From: Christian Hitz christian.hitz@bbv.ch
If a GPIO is used to control the chip's enable pin, it needs to be pulled high before any SPI communication is attempted. Split lp50xx_enable_disable() into two distinct functions to enforce correct ordering. Observe correct timing after manipulating the enable GPIO and SPI communication.
Fixes: 242b81170fb8 ("leds: lp50xx: Add the LP50XX family of the RGB LED driver")
Signed-off-by: Christian Hitz christian.hitz@bbv.ch Cc: stable@vger.kernel.org --- drivers/leds/leds-lp50xx.c | 51 +++++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 15 deletions(-)
diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c index d19b6a459151..f23e9ae434e4 100644 --- a/drivers/leds/leds-lp50xx.c +++ b/drivers/leds/leds-lp50xx.c @@ -52,6 +52,8 @@
#define LP50XX_SW_RESET 0xff #define LP50XX_CHIP_EN BIT(6) +#define LP50XX_START_TIME_US 500 +#define LP50XX_RESET_TIME_US 3
/* There are 3 LED outputs per bank */ #define LP50XX_LEDS_PER_MODULE 3 @@ -374,19 +376,42 @@ static int lp50xx_reset(struct lp50xx *priv) return regmap_write(priv->regmap, priv->chip_info->reset_reg, LP50XX_SW_RESET); }
-static int lp50xx_enable_disable(struct lp50xx *priv, int enable_disable) +static int lp50xx_enable(struct lp50xx *priv) { int ret;
- ret = gpiod_direction_output(priv->enable_gpio, enable_disable); + if (priv->enable_gpio) { + ret = gpiod_direction_output(priv->enable_gpio, 1); + if (ret) + return ret; + + udelay(LP50XX_START_TIME_US); + } else { + ret = lp50xx_reset(priv); + if (ret) + return ret; + } + + return regmap_write(priv->regmap, LP50XX_DEV_CFG0, LP50XX_CHIP_EN); +} + +static int lp50xx_disable(struct lp50xx *priv) +{ + int ret; + + ret = regmap_write(priv->regmap, LP50XX_DEV_CFG0, 0); if (ret) return ret;
- if (enable_disable) - return regmap_write(priv->regmap, LP50XX_DEV_CFG0, LP50XX_CHIP_EN); - else - return regmap_write(priv->regmap, LP50XX_DEV_CFG0, 0); + if (priv->enable_gpio) { + ret = gpiod_direction_output(priv->enable_gpio, 0); + if (ret) + return ret; + + udelay(LP50XX_RESET_TIME_US); + }
+ return 0; }
static int lp50xx_probe_leds(struct fwnode_handle *child, struct lp50xx *priv, @@ -453,6 +478,10 @@ static int lp50xx_probe_dt(struct lp50xx *priv) return dev_err_probe(priv->dev, PTR_ERR(priv->enable_gpio), "Failed to get enable GPIO\n");
+ ret = lp50xx_enable(priv); + if (ret) + return ret; + priv->regulator = devm_regulator_get(priv->dev, "vled"); if (IS_ERR(priv->regulator)) priv->regulator = NULL; @@ -550,14 +579,6 @@ static int lp50xx_probe(struct i2c_client *client) return ret; }
- ret = lp50xx_reset(led); - if (ret) - return ret; - - ret = lp50xx_enable_disable(led, 1); - if (ret) - return ret; - return lp50xx_probe_dt(led); }
@@ -566,7 +587,7 @@ static void lp50xx_remove(struct i2c_client *client) struct lp50xx *led = i2c_get_clientdata(client); int ret;
- ret = lp50xx_enable_disable(led, 0); + ret = lp50xx_disable(led); if (ret) dev_err(led->dev, "Failed to disable chip\n");