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Subject[PATCH 4/4] iio: trigger: stm32-timer: add enable attribute
Date
In order to use encoder mode, timers needs to be enabled (e.g. CEN bit)
along with peripheral clock.
Add IIO_CHAN_INFO_ENABLE attribute to handle this.
Also, in triggered mode, CEN bit is set automatically in hardware.
Then clock must be enabled before starting triggered mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
drivers/iio/trigger/stm32-timer-trigger.c | 55 +++++++++++++++++++++++--------
1 file changed, 41 insertions(+), 14 deletions(-)

diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
index d28aa02..14e6eb0 100644
--- a/drivers/iio/trigger/stm32-timer-trigger.c
+++ b/drivers/iio/trigger/stm32-timer-trigger.c
@@ -366,34 +366,32 @@ static int stm32_counter_read_raw(struct iio_dev *indio_dev,
int *val, int *val2, long mask)
{
struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+ u32 dat;

switch (mask) {
case IIO_CHAN_INFO_RAW:
- {
- u32 cnt;
-
- regmap_read(priv->regmap, TIM_CNT, &cnt);
- *val = cnt;
+ regmap_read(priv->regmap, TIM_CNT, &dat);
+ *val = dat;
+ return IIO_VAL_INT;

+ case IIO_CHAN_INFO_ENABLE:
+ regmap_read(priv->regmap, TIM_CR1, &dat);
+ *val = (dat & TIM_CR1_CEN) ? 1 : 0;
return IIO_VAL_INT;
- }
- case IIO_CHAN_INFO_SCALE:
- {
- u32 smcr;

- regmap_read(priv->regmap, TIM_SMCR, &smcr);
- smcr &= TIM_SMCR_SMS;
+ case IIO_CHAN_INFO_SCALE:
+ regmap_read(priv->regmap, TIM_SMCR, &dat);
+ dat &= TIM_SMCR_SMS;

*val = 1;
*val2 = 0;

/* in quadrature case scale = 0.25 */
- if (smcr == 3)
+ if (dat == 3)
*val2 = 2;

return IIO_VAL_FRACTIONAL_LOG2;
}
- }

return -EINVAL;
}
@@ -403,6 +401,7 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
struct stm32_timer_trigger *priv = iio_priv(indio_dev);
+ u32 dat;

switch (mask) {
case IIO_CHAN_INFO_RAW:
@@ -411,6 +410,22 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
case IIO_CHAN_INFO_SCALE:
/* fixed scale */
return -EINVAL;
+
+ case IIO_CHAN_INFO_ENABLE:
+ if (val) {
+ regmap_read(priv->regmap, TIM_CR1, &dat);
+ if (!(dat & TIM_CR1_CEN))
+ clk_enable(priv->clk);
+ regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
+ TIM_CR1_CEN);
+ } else {
+ regmap_read(priv->regmap, TIM_CR1, &dat);
+ regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
+ 0);
+ if (dat & TIM_CR1_CEN)
+ clk_disable(priv->clk);
+ }
+ return 0;
}

return -EINVAL;
@@ -506,9 +521,19 @@ static int stm32_set_enable_mode(struct iio_dev *indio_dev,
{
struct stm32_timer_trigger *priv = iio_priv(indio_dev);
int sms = stm32_enable_mode2sms(mode);
+ u32 val;

if (sms < 0)
return sms;
+ /*
+ * Triggered mode sets CEN bit automatically by hardware. So, first
+ * enable counter clock, so it can use it. Keeps it in sync with CEN.
+ */
+ if (sms == 6) {
+ regmap_read(priv->regmap, TIM_CR1, &val);
+ if (!(val & TIM_CR1_CEN))
+ clk_enable(priv->clk);
+ }

regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);

@@ -681,7 +706,9 @@ static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
static const struct iio_chan_spec stm32_trigger_channel = {
.type = IIO_COUNT,
.channel = 0,
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_ENABLE) |
+ BIT(IIO_CHAN_INFO_SCALE),
.ext_info = stm32_trigger_count_info,
.indexed = 1
};
--
1.9.1
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