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| author | Samu Onkalo <samu.p.onkalo@nokia.com> | 2010-11-24 12:57:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-25 06:50:42 +0900 |
| commit | 09c76b0f6e8fcd78f2d194acb1f07e41789cc29b (patch) | |
| tree | bd6ab243f68b1cbda8e0d460dcb77ece72044a55 /drivers/leds | |
| parent | 87dbf6234d965851e7e13cbe80ad439f5fcb99c8 (diff) | |
| download | kernel_samsung_smdk4412-09c76b0f6e8fcd78f2d194acb1f07e41789cc29b.tar.gz kernel_samsung_smdk4412-09c76b0f6e8fcd78f2d194acb1f07e41789cc29b.tar.bz2 kernel_samsung_smdk4412-09c76b0f6e8fcd78f2d194acb1f07e41789cc29b.zip | |
drivers/leds/leds-lp5521.c: adjust delays and add comments to them
Delays were little bit too long. Adjust delay times and add some comments
to them.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/leds')
| -rw-r--r-- | drivers/leds/leds-lp5521.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c index fe69e5229a5..963c014be0b 100644 --- a/drivers/leds/leds-lp5521.c +++ b/drivers/leds/leds-lp5521.c @@ -196,14 +196,17 @@ static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern) /* move current engine to direct mode and remember the state */ ret = lp5521_set_engine_mode(eng, LP5521_CMD_DIRECT); - usleep_range(1000, 10000); + /* Mode change requires min 500 us delay. 1 - 2 ms with margin */ + usleep_range(1000, 2000); ret |= lp5521_read(client, LP5521_REG_OP_MODE, &mode); /* For loading, all the engines to load mode */ lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT); - usleep_range(1000, 10000); + /* Mode change requires min 500 us delay. 1 - 2 ms with margin */ + usleep_range(1000, 2000); lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_LOAD); - usleep_range(1000, 10000); + /* Mode change requires min 500 us delay. 1 - 2 ms with margin */ + usleep_range(1000, 2000); addr = LP5521_PROG_MEM_BASE + eng->prog_page * LP5521_PROG_MEM_SIZE; i2c_smbus_write_i2c_block_data(client, @@ -244,7 +247,10 @@ static int lp5521_configure(struct i2c_client *client, lp5521_write(client, LP5521_REG_RESET, 0xff); - usleep_range(10000, 20000); + usleep_range(10000, 20000); /* + * Exact value is not available. 10 - 20ms + * appears to be enough for reset. + */ /* Set all PWMs to direct control mode */ ret = lp5521_write(client, LP5521_REG_OP_MODE, 0x3F); @@ -262,8 +268,8 @@ static int lp5521_configure(struct i2c_client *client, ret |= lp5521_write(client, LP5521_REG_ENABLE, LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM | LP5521_EXEC_RUN); - /* enable takes 500us */ - usleep_range(500, 20000); + /* enable takes 500us. 1 - 2 ms leaves some margin */ + usleep_range(1000, 2000); return ret; } @@ -316,7 +322,8 @@ static int lp5521_detect(struct i2c_client *client) LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM); if (ret) return ret; - usleep_range(1000, 10000); + /* enable takes 500us. 1 - 2 ms leaves some margin */ + usleep_range(1000, 2000); ret = lp5521_read(client, LP5521_REG_ENABLE, &buf); if (ret) return ret; @@ -704,9 +711,9 @@ static int lp5521_probe(struct i2c_client *client, if (pdata->enable) { pdata->enable(0); - usleep_range(1000, 10000); + usleep_range(1000, 2000); /* Keep enable down at least 1ms */ pdata->enable(1); - usleep_range(1000, 10000); /* Spec says min 500us */ + usleep_range(1000, 2000); /* 500us abs min. */ } ret = lp5521_detect(client); |