backlight: lm3630a: Bump REG_MAX value to 0x50 instead of 0x1F

In the lm3630a_chip_init we try to write to 0x50 register, which is
higher value then the max_register value, this resulted in regmap_write
return -EIO.

Fix this by bumping REG_MAX value to 0x50.

This code was introduced with the chip revision in commit 28e64a68a2ef,
however setting filter strength was failing silently because it used
unsigned int for storing and comparing the return values. Bug related to
signedness was fixed in 2a0c316bf3cc, which made it error out correctly
instead of failing silently.

I found this issue by using this driver on LGE Nexus 5 (hammerhead).
After this commit lm3630a_chip_init succeeds instead of failing with
-EIO.

Fixes: 28e64a68a2ef ("backlight: lm3630: apply chip revision")
Fixes: 2a0c316bf3cc ("drivers/video/backlight/lm3630a_bl.c: fix
signedness bug in lm3630a_chip_init()")

Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bhushan Shah <bshah@kde.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index 60d6c2ac87aa526b77d308532dc7289ddef85ab5..2030a6b77a09725e97bb1618b2695aea5c55f2a0 100644 (file)
--- a/drivers/video/backlight/lm3630a_bl.c
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -31,7 +31,8 @@
 #define REG_FAULT      0x0B
 #define REG_PWM_OUTLOW 0x12
 #define REG_PWM_OUTHIGH        0x13
-#define REG_MAX                0x1F
+#define REG_FILTER_STRENGTH    0x50
+#define REG_MAX                0x50
 
 #define INT_DEBOUNCE_MSEC      10
 struct lm3630a_chip {
@@ -80,7 +81,7 @@ static int lm3630a_chip_init(struct lm3630a_chip *pchip)
 
        usleep_range(1000, 2000);
        /* set Filter Strength Register */
-       rval = lm3630a_write(pchip, 0x50, 0x03);
+       rval = lm3630a_write(pchip, REG_FILTER_STRENGTH, 0x03);
        /* set Cofig. register */
        rval |= lm3630a_update(pchip, REG_CONFIG, 0x07, pdata->pwm_ctrl);
        /* set boost control */