The patch titled
Subject: drivers/leds/leds-lp5521.c: check if reset is successful
has been added to the -mm tree. Its filename is
drivers-leds-leds-lp5521c-check-if-reset-is-successful.patch
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------------------------------------------------------
From: Srinidhi KASAGAR <srinidhi.kasagar@xxxxxxxxxxxxxx>
Subject: drivers/leds/leds-lp5521.c: check if reset is successful
Make sure that the reset is successful by issuing a dummy read to R
channel current register and check its default value. On some platforms,
without this dummy read, any further access to {R/G/B}_EXEC will not have
any impact.
Signed-off-by: srinidhi kasagar <srinidhi.kasagar@xxxxxxxxxxxxxx>
Tested-by: Naga Radhesh <naga.radheshy@xxxxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Richard Purdie <richard.purdie@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/leds/leds-lp5521.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff -puN drivers/leds/leds-lp5521.c~drivers-leds-leds-lp5521c-check-if-reset-is-successful drivers/leds/leds-lp5521.c
--- a/drivers/leds/leds-lp5521.c~drivers-leds-leds-lp5521c-check-if-reset-is-successful
+++ a/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;
@@ -643,6 +646,7 @@ static int __devinit lp5521_probe(struct
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 +685,21 @@ static int __devinit lp5521_probe(struct
* Exact value is not available. 10 - 20ms
* appears to be enough for reset.
*/
+
+ /*
+ * Make sure that the chip is reset by reading back
+ * r channel current reg. This is a dummy read, otherwise
+ * in some platforms, access to R G B channel program
+ * execution mode to 'Run' in LP5521_REG_ENABLE register
+ * will not have any affect - 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) {
_
Subject: Subject: drivers/leds/leds-lp5521.c: check if reset is successful
Patches currently in -mm which might be from srinidhi.kasagar@xxxxxxxxxxxxxx are
origin.patch
linux-next.patch
arch-arm-mach-ux500-mbox-db5500c-world-writable-sysfs-fifo-file.patch
drivers-leds-leds-lp5521c-check-if-reset-is-successful.patch
drivers-leds-leds-lp5521c-check-if-reset-is-successful-fix.patch
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