[PATCH 5/7] fix-backlight-disable-on-zero-intensity.patch

[Andy Green]

It's never right to put 0 intensity into LEDOUT according to datasheet
But having a floor at intensity 2 means backlight isn't properly off
when "dimmed".  So change to intensity 0 --> disable backlight.

Signed-off-by: Andy Green <[EMAIL PROTECTED]>
---

 drivers/i2c/chips/pcf50633.c |   34 +++++++++++++++++++++-------------
 1 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/i2c/chips/pcf50633.c b/drivers/i2c/chips/pcf50633.c
index dc4ea0a..205f4e3 100644
--- a/drivers/i2c/chips/pcf50633.c
+++ b/drivers/i2c/chips/pcf50633.c
@@ -1458,6 +1458,9 @@ static int pcf50633bl_get_intensity(struct 
backlight_device *bd)
        struct pcf50633_data *pcf = bl_get_data(bd);
        int intensity = reg_read(pcf, PCF50633_REG_LEDOUT);
 
+       if (!(reg_read(pcf, PCF50633_REG_LEDOUT) & 1))
+               intensity = 0;
+
        return intensity & 0x3f;
 }
 
@@ -1466,31 +1469,36 @@ static int pcf50633bl_set_intensity(struct 
backlight_device *bd)
        struct pcf50633_data *pcf = bl_get_data(bd);
        int intensity = bd->props.brightness;
        int old_intensity = reg_read(pcf, PCF50633_REG_LEDOUT);
-       u_int8_t ledena = 2;
        int ret;
 
-       if (bd->props.power != FB_BLANK_UNBLANK)
-               intensity = 0;
-       if (bd->props.fb_blank != FB_BLANK_UNBLANK)
+       if (!(reg_read(pcf, PCF50633_REG_LEDOUT) & 1))
+               old_intensity = 0;
+
+       if ((bd->props.power != FB_BLANK_UNBLANK) ||
+           (bd->props.fb_blank != FB_BLANK_UNBLANK))
                intensity = 0;
 
-       /* The PCF50633 cannot handle LEDOUT = 0 (datasheet p60)
+       /*
+        * The PCF50633 cannot handle LEDOUT = 0 (datasheet p60)
         * if seen, you have to re-enable the LED unit
+        * we treat intensity 0 as disable
         */
 
-       if (intensity != 0 && old_intensity == 0) {
-               ledena = reg_read(pcf, PCF50633_REG_LEDENA);
-               reg_write(pcf, PCF50633_REG_LEDENA, 0x00);
+       if (intensity && !old_intensity) {
+               ret = reg_set_bit_mask(pcf, PCF50633_REG_LEDENA, 0x01, 0x00);
+               if (ret)
+                       return ret;
        }
 
        if (!intensity) /* illegal to set LEDOUT to 0 */
-               ret = reg_set_bit_mask(pcf, PCF50633_REG_LEDOUT, 0x3f, 2);
-       else
+               ret = reg_set_bit_mask(pcf, PCF50633_REG_LEDENA, 0x01, 0x00);
+       else {
                ret = reg_set_bit_mask(pcf, PCF50633_REG_LEDOUT, 0x3f,
                               intensity);
-
-       if (intensity != 0 && old_intensity == 0)
-               reg_write(pcf, PCF50633_REG_LEDENA, ledena);
+               if (ret)
+                       return ret;
+               ret = reg_set_bit_mask(pcf, PCF50633_REG_LEDENA, 0x01, 0x01);
+       }
 
        return ret;
 }