drivers/leds/leds-lp5521.c: check if reset is successful

[pandora-kernel.git] / drivers / leds / leds-lp5521.c

diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c
index 9fc122c..cb641f1 100644 (file)
--- a/drivers/leds/leds-lp5521.c
+++ b/drivers/leds/leds-lp5521.c
@@ -97,6 +97,9 @@
 /* Status */
 #define LP5521_EXT_CLK_USED            0x08
 
+/* default R channel current register value */
+#define LP5521_REG_R_CURR_DEFAULT      0xAF
+
 struct lp5521_engine {
        int             id;
        u8              mode;
@@ -175,14 +178,14 @@ static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode)
                mode = LP5521_CMD_DIRECT;
 
        ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state);
+       if (ret < 0)
+               return ret;
 
        /* set mode only for this engine */
        engine_state &= ~(engine->engine_mask);
        mode &= engine->engine_mask;
        engine_state |= mode;
-       ret |= lp5521_write(client, LP5521_REG_OP_MODE, engine_state);
-
-       return ret;
+       return lp5521_write(client, LP5521_REG_OP_MODE, engine_state);
 }
 
 static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
@@ -643,6 +646,7 @@ static int __devinit lp5521_probe(struct i2c_client *client,
        struct lp5521_chip              *chip;
        struct lp5521_platform_data     *pdata;
        int ret, i, led;
+       u8 buf;
 
        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (!chip)
@@ -681,6 +685,20 @@ static int __devinit lp5521_probe(struct i2c_client *client,
                                     * Exact value is not available. 10 - 20ms
                                     * appears to be enough for reset.
                                     */
+
+       /*
+        * Make sure that the chip is reset by reading back the r channel
+        * current reg. This is dummy read is required on some platforms -
+        * otherwise further access to the R G B channels in the
+        * LP5521_REG_ENABLE register will not have any effect - strange!
+        */
+       lp5521_read(client, LP5521_REG_R_CURRENT, &buf);
+       if (buf != LP5521_REG_R_CURR_DEFAULT) {
+               dev_err(&client->dev, "error in reseting chip\n");
+               goto fail2;
+       }
+       usleep_range(10000, 20000);
+
        ret = lp5521_detect(client);
 
        if (ret) {