From 4d91d1df2f16b511ab80dec50c80e050ba0d841e Mon Sep 17 00:00:00 2001 From: Stefan Roese Date: Fri, 16 May 2008 11:06:06 +0200 Subject: [PATCH] DTT: Issue one-shot command on AD7414 (LM75 code) to read temp On AD7414 the first value upon bootup is not read correctly. This is most likely because of the 800ms update time of the temp register in normal update mode. To get current values each time we issue the "dtt" command including upon powerup we switch into one-short mode. This patch fixes the problem on AD7414 equipped boards (Sequoia, Canyonlands etc), that temp value printed in the bootup log was incorrect. Signed-off-by: Stefan Roese --- drivers/hwmon/lm75.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c index e29b29440f..c34851725e 100644 --- a/drivers/hwmon/lm75.c +++ b/drivers/hwmon/lm75.c @@ -47,6 +47,19 @@ int dtt_read(int sensor, int reg) int dlen; uchar data[2]; +#ifdef CONFIG_DTT_AD7414 + /* + * On AD7414 the first value upon bootup is not read correctly. + * This is most likely because of the 800ms update time of the + * temp register in normal update mode. To get current values + * each time we issue the "dtt" command including upon powerup + * we switch into one-short mode. + * + * Issue one-shot mode command + */ + dtt_write(sensor, DTT_CONFIG, 0x64); +#endif + /* * Validate 'reg' param */ -- 2.30.2