Re: [PATCH 2/7] iio: adc: stm32: Enable use of stm32 timer triggers

Fabrice Gasnier
2017-01-24T14:37:52Z

On 01/22/2017 01:55 PM, Jonathan Cameron wrote:
> On 19/01/17 13:34, Fabrice Gasnier wrote:
>> STM32 ADC has external timer trigger sources. Use stm32 timer triggers
>> API (e.g. is_stm32_timer_trigger()) with local ADC lookup table to
>> validate a trigger can be used.
>> This also provides correct trigger selection value (e.g. extsel).
>>
>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> Looks good. Observations inline.
>> ---
>> drivers/iio/adc/Kconfig | 2 ++
>> drivers/iio/adc/stm32-adc.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 62 insertions(+)
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index 33341f4..9a7b090 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -447,6 +447,8 @@ config STM32_ADC_CORE
>> depends on OF
>> depends on REGULATOR
>> select IIO_BUFFER
>> + select MFD_STM32_TIMERS
>> + select IIO_STM32_TIMER_TRIGGER
>> select IIO_TRIGGERED_BUFFER
>> help
>> Select this option to enable the core driver for STMicroelectronics
>> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
>> index 8d0b74b..30708bc 100644
>> --- a/drivers/iio/adc/stm32-adc.c
>> +++ b/drivers/iio/adc/stm32-adc.c
>> @@ -23,6 +23,7 @@
>> #include <linux/delay.h>
>> #include <linux/iio/iio.h>
>> #include <linux/iio/buffer.h>
>> +#include <linux/iio/timer/stm32-timer-trigger.h>
>> #include <linux/iio/trigger.h>
>> #include <linux/iio/trigger_consumer.h>
>> #include <linux/iio/triggered_buffer.h>
>> @@ -122,6 +123,35 @@ enum stm32_adc_exten {
>> STM32_EXTEN_HWTRIG_BOTH_EDGES,
>> };
>>
>> +/* extsel - trigger mux selection value */
>> +enum stm32_adc_extsel {
>> + STM32_EXT0,
>> + STM32_EXT1,
>> + STM32_EXT2,
>> + STM32_EXT3,
>> + STM32_EXT4,
>> + STM32_EXT5,
>> + STM32_EXT6,
>> + STM32_EXT7,
>> + STM32_EXT8,
>> + STM32_EXT9,
>> + STM32_EXT10,
>> + STM32_EXT11,
>> + STM32_EXT12,
>> + STM32_EXT13,
>> + STM32_EXT14,
>> + STM32_EXT15,
>> +};
>> +
>> +/**
>> + * struct stm32_adc_trig_info - ADC trigger info
>> + * @name: name of the trigger, corresponding to its source
>> + * @extsel: trigger selection
>> + */
>> +struct stm32_adc_trig_info {
>> + const char *name;
>> + enum stm32_adc_extsel extsel;
>> +};
>>
>> /**
>> * struct stm32_adc - private data of each ADC IIO instance
>> @@ -218,6 +248,26 @@ struct stm32_adc_regs {
>> { STM32F4_ADC_SQR1, STM32F4_SQ16_MASK, STM32F4_SQ16_SHIFT },
>> };
>>
>> +/* STM32F4 external trigger sources for all instances */
>> +static struct stm32_adc_trig_info stm32f4_adc_timer_trigs[] = {
>> + { TIM1_CH1, STM32_EXT0 },
>> + { TIM1_CH2, STM32_EXT1 },
>> + { TIM1_CH3, STM32_EXT2 },
>> + { TIM2_CH2, STM32_EXT3 },
>> + { TIM2_CH3, STM32_EXT4 },
>> + { TIM2_CH4, STM32_EXT5 },
>> + { TIM2_TRGO, STM32_EXT6 },
>> + { TIM3_CH1, STM32_EXT7 },
>> + { TIM3_TRGO, STM32_EXT8 },
>> + { TIM4_CH4, STM32_EXT9 },
>> + { TIM5_CH1, STM32_EXT10 },
>> + { TIM5_CH2, STM32_EXT11 },
>> + { TIM5_CH3, STM32_EXT12 },
>> + { TIM8_CH1, STM32_EXT13 },
>> + { TIM8_TRGO, STM32_EXT14 },
>> + {}, /* sentinel */
>> +};
>> +
>> /**
>> * STM32 ADC registers access routines
>> * @adc: stm32 adc instance
>> @@ -362,6 +412,16 @@ static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
>> static int stm32_adc_get_trig_extsel(struct iio_dev *indio_dev,
>> struct iio_trigger *trig)
>> {
>> + int i;
> Ah. This makes more sense than patch 1 on it's own did.
>> +
>> + /* lookup triggers registered by stm32 timer trigger driver */
>> + for (i = 0; stm32f4_adc_timer_trigs[i].name; i++) {
>> + if (is_stm32_timer_trigger(trig) &&
>> + !strcmp(stm32f4_adc_timer_trigs[i].name, trig->name)) {
>> + return stm32f4_adc_timer_trigs[i].extsel;
> Good. The combination of the first check and the name match should make this safe
> against those triggers that can be assigned arbitrary names.

Do you wish I add a comment about it ?

Best Regards,
Fabrice

>> + }
>> + }
>> +
>> return -EINVAL;
>> }
>>
>>
>