diff options
| author | Vic Yang <victoryang@google.com> | 2015-02-20 11:24:52 -0800 |
|---|---|---|
| committer | ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> | 2015-02-21 09:19:57 +0000 |
| commit | 1ef0f27e65e20a6a25b40fe427ab6d538f4b25ee (patch) | |
| tree | 13a73dcc3da0e84fdb1d840408b1afab4f05022a | |
| parent | e9c6a03c8ae34dc6eb36b3d1e227521f99c256d3 (diff) | |
| download | chrome-ec-1ef0f27e65e20a6a25b40fe427ab6d538f4b25ee.tar.gz | |
stm32f3: Allow per-board ADC sampling time
Depending on the hardware, each ADC channel may need a different
sampling time. To keep things simple, let's allow per-board ADC sampling
time configuration instead of per-channel configuration.
BRANCH=Ryu
BUG=None
TEST=Configure sampling time to 3 and measure IADP on Ryu P4 and check
it's more accurate.
Change-Id: I3c1eeea22439c0340f84fdeb3624fc84450358ca
Signed-off-by: Vic Yang <victoryang@google.com>
Reviewed-on: https://chromium-review.googlesource.com/251701
Tested-by: Vic Yang <victoryang@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Vic Yang <victoryang@chromium.org>
| -rw-r--r-- | chip/stm32/adc-stm32f.c | 19 | ||||
| -rw-r--r-- | include/config.h | 3 |
2 files changed, 16 insertions, 6 deletions
diff --git a/chip/stm32/adc-stm32f.c b/chip/stm32/adc-stm32f.c index d6ff369ef9..072c71b9df 100644 --- a/chip/stm32/adc-stm32f.c +++ b/chip/stm32/adc-stm32f.c @@ -16,6 +16,16 @@ #define ADC_SINGLE_READ_TIMEOUT 3000 /* 3 ms */ +#define SMPR1_EXPAND(v) ((v) | ((v) << 3) | ((v) << 6) | ((v) << 9) | \ + ((v) << 12) | ((v) << 15) | ((v) << 18) | \ + ((v) << 21)) +#define SMPR2_EXPAND(v) (SMPR1_EXPAND(v) | ((v) << 24) | ((v) << 27)) + +/* Default ADC sample time = 13.5 cycles */ +#ifndef CONFIG_ADC_SAMPLE_TIME +#define CONFIG_ADC_SAMPLE_TIME 2 +#endif + struct mutex adc_lock; static int watchdog_ain_id; @@ -290,11 +300,8 @@ static void adc_init(void) /* Set right alignment */ STM32_ADC_CR2 &= ~(1 << 11); - /* - * Set sample time of all channels to 13.5 cycles. - * Conversion takes 15.75 us. - */ - STM32_ADC_SMPR1 = 0x00492492; - STM32_ADC_SMPR2 = 0x12492492; + /* Set sample time of all channels */ + STM32_ADC_SMPR1 = SMPR1_EXPAND(CONFIG_ADC_SAMPLE_TIME); + STM32_ADC_SMPR2 = SMPR2_EXPAND(CONFIG_ADC_SAMPLE_TIME); } DECLARE_HOOK(HOOK_INIT, adc_init, HOOK_PRIO_DEFAULT); diff --git a/include/config.h b/include/config.h index 5c6d17f99e..f458b670b9 100644 --- a/include/config.h +++ b/include/config.h @@ -51,6 +51,9 @@ */ #undef CONFIG_ADC_CLOCK +/* ADC sample time selection. The value is chip-dependent. */ +#undef CONFIG_ADC_SAMPLE_TIME + /* * Some ALS modules may be connected to the EC. We need the command, and * specific drivers for each module. |