Date:   Mon, 3 Apr 2017 12:17:08 +0200
From:   Benjamin Gaignard <benjamin.gaignard@...aro.org>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-iio@...r.kernel.org, Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        William Breathitt Gray <vilhelm.gray@...il.com>,
        mwelling@...e.org, Fabrice Gasnier <fabrice.gasnier@...com>,
        Linaro Kernel Mailman List <linaro-kernel@...ts.linaro.org>,
        Benjamin Gaignard <benjamin.gaignard@...com>
Subject: Re: [PATCH v3 2/2] iio: stm32 trigger: Add counter enable modes

2017-04-02 13:12 GMT+02:00 Jonathan Cameron <jic23@...nel.org>:
> On 27/03/17 10:43, Benjamin Gaignard wrote:
>> Device counting could be controlled by the level or the edges of
>> a trigger.
>> in_count0_enable_mode attibute allow to set the control mode.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...com>
>> ---
>>  .../ABI/testing/sysfs-bus-iio-timer-stm32          | 23 +++++++
>>  drivers/iio/trigger/stm32-timer-trigger.c          | 70 ++++++++++++++++++++++
>>  2 files changed, 93 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>> index bf795ad..c0a1edc 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>> @@ -59,3 +59,26 @@ Description:
>>               quadrature:
>>                       Encoder A and B inputs are mixed to get direction
>>                       and count with a scale of 0.25.
>> +
>> +What:                /sys/bus/iio/devices/iio:deviceX/in_count_enable_mode_available
>> +KernelVersion:       4.12
>> +Contact:     benjamin.gaignard@...com
>> +Description:
>> +             Reading returns the list possible enable modes.
>> +
>> +What:                /sys/bus/iio/devices/iio:deviceX/in_count0_enable_mode
>> +KernelVersion:       4.12
>> +Contact:     benjamin.gaignard@...com
>> +Description:
>> +             Configure the device counter enable modes, in all case
>> +             counting direction is set by in_count0_count_direction
>> +             attribute and the counter is clocked by the internal clock.
> Silly question, how does one use the encoder modes then?

When setting an encoder mode internal counter is enabled no need to touch to
in_count0_enable_mode in those cases

>
>> +             always:
>> +                     Counter is always ON.
>> +
>> +             gated:
>> +                     Counting is enabled when connected trigger signal
>> +                     level is high else counting is disabled.
>> +
>> +             triggered:
>> +                     Counting start on rising edge of the connected trigger.
>
>
>> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
>> index 7db904c..0f1a2cf 100644
>> --- a/drivers/iio/trigger/stm32-timer-trigger.c
>> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
>> @@ -353,6 +353,74 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
>>       .write_raw = stm32_counter_write_raw
>>  };
>>
>> +static const char *const stm32_enable_modes[] = {
>> +     "always",
>> +     "gated",
>> +     "triggered",
>> +};
>> +
>> +static int stm32_enable_mode2sms(int mode)
>> +{
>> +     switch (mode) {
>> +     case 0:
>> +             return 0;
>> +     case 1:
>> +             return 5;
>> +     case 2:
>> +             return 6;
>> +     }
>> +
>> +     return -EINVAL;
>> +}
>> +
>> +static int stm32_set_enable_mode(struct iio_dev *indio_dev,
>> +                              const struct iio_chan_spec *chan,
>> +                              unsigned int mode)
>> +{
>> +     struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>> +     int sms = stm32_enable_mode2sms(mode);
>> +
>> +     if (sms < 0)
>> +             return sms;
>> +
>> +     regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
>> +
>> +     return 0;
>> +}
>> +
>> +static int stm32_sms2enable_mode(int mode)
>> +{
>> +     switch (mode) {
>> +     case 0:
>> +             return 0;
>> +     case 5:
>> +             return 1;
>> +     case 6:
>> +             return 2;
>> +     }
>> +
>> +     return -EINVAL;
>> +}
>> +
>> +static int stm32_get_enable_mode(struct iio_dev *indio_dev,
>> +                              const struct iio_chan_spec *chan)
>> +{
>> +     struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>> +     u32 smcr;
>> +
>> +     regmap_read(priv->regmap, TIM_SMCR, &smcr);
>> +     smcr &= TIM_SMCR_SMS;
>> +
>> +     return stm32_sms2enable_mode(smcr);
>> +}
>> +
>> +static const struct iio_enum stm32_enable_mode_enum = {
>> +     .items = stm32_enable_modes,
>> +     .num_items = ARRAY_SIZE(stm32_enable_modes),
>> +     .set = stm32_set_enable_mode,
>> +     .get = stm32_get_enable_mode
>> +};
>> +
>>  static const char *const stm32_quadrature_modes[] = {
>>       "channel_A",
>>       "channel_B",
>> @@ -466,6 +534,8 @@ static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
>>       IIO_ENUM_AVAILABLE("count_direction", &stm32_count_direction_enum),
>>       IIO_ENUM("quadrature_mode", IIO_SEPARATE, &stm32_quadrature_mode_enum),
>>       IIO_ENUM_AVAILABLE("quadrature_mode", &stm32_quadrature_mode_enum),
>> +     IIO_ENUM("enable_mode", IIO_SEPARATE, &stm32_enable_mode_enum),
>> +     IIO_ENUM_AVAILABLE("enable_mode", &stm32_enable_mode_enum),
>>       {}
>>  };
>>
>>
>



-- 
Benjamin Gaignard

Graphic Study Group

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