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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>
This commit is contained in:
Samu Onkalo 2010-11-24 12:57:03 -08:00 committed by Linus Torvalds
parent 87dbf6234d
commit 09c76b0f6e
1 changed files with 16 additions and 9 deletions
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25
drivers/leds/leds-lp5521.c
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@ -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);