Re: [PATCH v4 1/2] iio: stm32 trigger: Add quadrature encoder device

From: Jonathan Cameron
Date: Fri Apr 14 2017 - 10:10:28 EST

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In reply to: William Breathitt Gray: "Re: [PATCH v4 1/2] iio: stm32 trigger: Add quadrature encoder device"
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On 10/04/17 13:55, William Breathitt Gray wrote:
> On Sat, Apr 08, 2017 at 06:27:02PM +0100, Jonathan Cameron wrote:
>> On 04/04/17 08:47, Benjamin Gaignard wrote:
>>> One of the features of STM32 trigger hardware block is a quadrature
>>> encoder that can counts up/down depending of the levels and edges
>>> of the selected external pins.
>>>
>>> This patch allow to read/write the counter, get it direction,
>>> set/get quadrature modes and get scale factor.
>>>
>>> When counting up preset value is the limit of the counter.
>>> When counting down the counter start from preset value down to 0.
>>> This preset value could be set/get by using
>>> /sys/bus/iio/devices/iio:deviceX/in_count0_preset attribute.
>>>
>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
>>>
>>> ---
>>> version 4:
>>> - fix indentation in documentation
>> Would have preferred that initial fixes as a separate patch, but
>> doesn't matter that much.
>>
>> Applied to the togreg branch of iio.git. If William for example
>> wants to give a reviewed-by or similar then there is time whilst
>> this is still in testing going through the autobuilders.
>>
>> Jonathan
>
> Hi Jonathan,
>
> It looks like this version 4 is the same code as the version 3, but with
> some minor formatting adjustments for the documentation. The code itself
> looks all right by me, so feel free to tack on a reviewed-by line for me
> if there's still time.
>
> Reviewed-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
Added.
>
> Just as we saw with the 104-QUAD-8 driver, I'm certain we will come back
> to this eventually with another pass when we introduce the next counter
> driver or device support, but for now the ABI looks like it's evolving
> nicely.
True enough though we'll hopefully not go through too many more as we need
to keep supporting the old ABI as we go.

Jonathan
>
> William Breathitt Gray
>
>>>
>>> version 3:
>>> - fix typo in documentation
>>> - change some functions names
>>>
>>> .../ABI/testing/sysfs-bus-iio-timer-stm32 | 46 +++-
>>> drivers/iio/trigger/stm32-timer-trigger.c | 244 ++++++++++++++++++++-
>>> include/linux/mfd/stm32-timers.h | 2 +
>>> 3 files changed, 282 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> index 6534a60..a55ad44 100644
>>> --- a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> @@ -3,11 +3,15 @@ KernelVersion: 4.11
>>> Contact: benjamin.gaignard@xxxxxx
>>> Description:
>>> Reading returns the list possible master modes which are:
>>> - - "reset" : The UG bit from the TIMx_EGR register is used as trigger output (TRGO).
>>> - - "enable" : The Counter Enable signal CNT_EN is used as trigger output.
>>> + - "reset" : The UG bit from the TIMx_EGR register is
>>> + used as trigger output (TRGO).
>>> + - "enable" : The Counter Enable signal CNT_EN is used
>>> + as trigger output.
>>> - "update" : The update event is selected as trigger output.
>>> - For instance a master timer can then be used as a prescaler for a slave timer.
>>> - - "compare_pulse" : The trigger output send a positive pulse when the CC1IF flag is to be set.
>>> + For instance a master timer can then be used
>>> + as a prescaler for a slave timer.
>>> + - "compare_pulse" : The trigger output send a positive pulse
>>> + when the CC1IF flag is to be set.
>>> - "OC1REF" : OC1REF signal is used as trigger output.
>>> - "OC2REF" : OC2REF signal is used as trigger output.
>>> - "OC3REF" : OC3REF signal is used as trigger output.
>>> @@ -27,3 +31,37 @@ Description:
>>> Reading returns the current sampling frequency.
>>> Writing an value different of 0 set and start sampling.
>>> Writing 0 stop sampling.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_preset
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@xxxxxx
>>> +Description:
>>> + Reading returns the current preset value.
>>> + Writing sets the preset value.
>>> + When counting up the counter starts from 0 and fires an
>>> + event when reach preset value.
>>> + When counting down the counter start from preset value
>>> + and fire event when reach 0.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count_quadrature_mode_available
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@xxxxxx
>>> +Description:
>>> + Reading returns the list possible quadrature modes.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_quadrature_mode
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@xxxxxx
>>> +Description:
>>> + Configure the device counter quadrature modes:
>>> + channel_A:
>>> + Encoder A input servers as the count input and B as
>>> + the UP/DOWN direction control input.
>>> +
>>> + channel_B:
>>> + Encoder B input serves as the count input and A as
>>> + the UP/DOWN direction control input.
>>> +
>>> + quadrature:
>>> + Encoder A and B inputs are mixed to get direction
>>> + and count with a scale of 0.25.
>>> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
>>> index 994b96d..7db904c 100644
>>> --- a/drivers/iio/trigger/stm32-timer-trigger.c
>>> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
>>> @@ -15,6 +15,7 @@
>>> #include <linux/platform_device.h>
>>>
>>> #define MAX_TRIGGERS 6
>>> +#define MAX_VALIDS 5
>>>
>>> /* List the triggers created by each timer */
>>> static const void *triggers_table[][MAX_TRIGGERS] = {
>>> @@ -32,12 +33,29 @@
>>> { TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
>>> };
>>>
>>> +/* List the triggers accepted by each timer */
>>> +static const void *valids_table[][MAX_VALIDS] = {
>>> + { TIM5_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
>>> + { TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
>>> + { TIM1_TRGO, TIM2_TRGO, TIM5_TRGO, TIM4_TRGO,},
>>> + { TIM1_TRGO, TIM2_TRGO, TIM3_TRGO, TIM8_TRGO,},
>>> + { TIM2_TRGO, TIM3_TRGO, TIM4_TRGO, TIM8_TRGO,},
>>> + { }, /* timer 6 */
>>> + { }, /* timer 7 */
>>> + { TIM1_TRGO, TIM2_TRGO, TIM4_TRGO, TIM5_TRGO,},
>>> + { TIM2_TRGO, TIM3_TRGO,},
>>> + { }, /* timer 10 */
>>> + { }, /* timer 11 */
>>> + { TIM4_TRGO, TIM5_TRGO,},
>>> +};
>>> +
>>> struct stm32_timer_trigger {
>>> struct device *dev;
>>> struct regmap *regmap;
>>> struct clk *clk;
>>> u32 max_arr;
>>> const void *triggers;
>>> + const void *valids;
>>> };
>>>
>>> static int stm32_timer_start(struct stm32_timer_trigger *priv,
>>> @@ -180,8 +198,7 @@ static ssize_t stm32_tt_show_master_mode(struct device *dev,
>>> struct device_attribute *attr,
>>> char *buf)
>>> {
>>> - struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> - struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
>>> u32 cr2;
>>>
>>> regmap_read(priv->regmap, TIM_CR2, &cr2);
>>> @@ -194,8 +211,7 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
>>> struct device_attribute *attr,
>>> const char *buf, size_t len)
>>> {
>>> - struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>>> - struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
>>> int i;
>>>
>>> for (i = 0; i < ARRAY_SIZE(master_mode_table); i++) {
>>> @@ -275,6 +291,216 @@ static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>>> return 0;
>>> }
>>>
>>> +static int stm32_counter_read_raw(struct iio_dev *indio_dev,
>>> + struct iio_chan_spec const *chan,
>>> + int *val, int *val2, long mask)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_RAW:
>>> + {
>>> + u32 cnt;
>>> +
>>> + regmap_read(priv->regmap, TIM_CNT, &cnt);
>>> + *val = cnt;
>>> +
>>> + return IIO_VAL_INT;
>>> + }
>>> + case IIO_CHAN_INFO_SCALE:
>>> + {
>>> + u32 smcr;
>>> +
>>> + regmap_read(priv->regmap, TIM_SMCR, &smcr);
>>> + smcr &= TIM_SMCR_SMS;
>>> +
>>> + *val = 1;
>>> + *val2 = 0;
>>> +
>>> + /* in quadrature case scale = 0.25 */
>>> + if (smcr == 3)
>>> + *val2 = 2;
>>> +
>>> + return IIO_VAL_FRACTIONAL_LOG2;
>>> + }
>>> + }
>>> +
>>> + return -EINVAL;
>>> +}
>>> +
>>> +static int stm32_counter_write_raw(struct iio_dev *indio_dev,
>>> + struct iio_chan_spec const *chan,
>>> + int val, int val2, long mask)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_RAW:
>>> + regmap_write(priv->regmap, TIM_CNT, val);
>>> +
>>> + return IIO_VAL_INT;
>>> + case IIO_CHAN_INFO_SCALE:
>>> + /* fixed scale */
>>> + return -EINVAL;
>>> + }
>>> +
>>> + return -EINVAL;
>>> +}
>>> +
>>> +static const struct iio_info stm32_trigger_info = {
>>> + .driver_module = THIS_MODULE,
>>> + .read_raw = stm32_counter_read_raw,
>>> + .write_raw = stm32_counter_write_raw
>>> +};
>>> +
>>> +static const char *const stm32_quadrature_modes[] = {
>>> + "channel_A",
>>> + "channel_B",
>>> + "quadrature",
>>> +};
>>> +
>>> +static int stm32_set_quadrature_mode(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan,
>>> + unsigned int mode)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, mode + 1);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int stm32_get_quadrature_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 smcr - 1;
>>> +}
>>> +
>>> +static const struct iio_enum stm32_quadrature_mode_enum = {
>>> + .items = stm32_quadrature_modes,
>>> + .num_items = ARRAY_SIZE(stm32_quadrature_modes),
>>> + .set = stm32_set_quadrature_mode,
>>> + .get = stm32_get_quadrature_mode
>>> +};
>>> +
>>> +static const char *const stm32_count_direction_states[] = {
>>> + "up",
>>> + "down"
>>> +};
>>> +
>>> +static int stm32_set_count_direction(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan,
>>> + unsigned int mode)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_DIR, mode);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int stm32_get_count_direction(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + u32 cr1;
>>> +
>>> + regmap_read(priv->regmap, TIM_CR1, &cr1);
>>> +
>>> + return (cr1 & TIM_CR1_DIR);
>>> +}
>>> +
>>> +static const struct iio_enum stm32_count_direction_enum = {
>>> + .items = stm32_count_direction_states,
>>> + .num_items = ARRAY_SIZE(stm32_count_direction_states),
>>> + .set = stm32_set_count_direction,
>>> + .get = stm32_get_count_direction
>>> +};
>>> +
>>> +static ssize_t stm32_count_get_preset(struct iio_dev *indio_dev,
>>> + uintptr_t private,
>>> + const struct iio_chan_spec *chan,
>>> + char *buf)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + u32 arr;
>>> +
>>> + regmap_read(priv->regmap, TIM_ARR, &arr);
>>> +
>>> + return snprintf(buf, PAGE_SIZE, "%u\n", arr);
>>> +}
>>> +
>>> +static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
>>> + uintptr_t private,
>>> + const struct iio_chan_spec *chan,
>>> + const char *buf, size_t len)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + unsigned int preset;
>>> + int ret;
>>> +
>>> + ret = kstrtouint(buf, 0, &preset);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + regmap_write(priv->regmap, TIM_ARR, preset);
>>> + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
>>> +
>>> + return len;
>>> +}
>>> +
>>> +static const struct iio_chan_spec_ext_info stm32_trigger_count_info[] = {
>>> + {
>>> + .name = "preset",
>>> + .shared = IIO_SEPARATE,
>>> + .read = stm32_count_get_preset,
>>> + .write = stm32_count_set_preset
>>> + },
>>> + IIO_ENUM("count_direction", IIO_SEPARATE, &stm32_count_direction_enum),
>>> + 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),
>>> + {}
>>> +};
>>> +
>>> +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),
>>> + .ext_info = stm32_trigger_count_info,
>>> + .indexed = 1
>>> +};
>>> +
>>> +static struct stm32_timer_trigger *stm32_setup_counter_device(struct device *dev)
>>> +{
>>> + struct iio_dev *indio_dev;
>>> + int ret;
>>> +
>>> + indio_dev = devm_iio_device_alloc(dev,
>>> + sizeof(struct stm32_timer_trigger));
>>> + if (!indio_dev)
>>> + return NULL;
>>> +
>>> + indio_dev->name = dev_name(dev);
>>> + indio_dev->dev.parent = dev;
>>> + indio_dev->info = &stm32_trigger_info;
>>> + indio_dev->num_channels = 1;
>>> + indio_dev->channels = &stm32_trigger_channel;
>>> + indio_dev->dev.of_node = dev->of_node;
>>> +
>>> + ret = devm_iio_device_register(dev, indio_dev);
>>> + if (ret)
>>> + return NULL;
>>> +
>>> + return iio_priv(indio_dev);
>>> +}
>>> +
>>> /**
>>> * is_stm32_timer_trigger
>>> * @trig: trigger to be checked
>>> @@ -299,10 +525,15 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>> if (of_property_read_u32(dev->of_node, "reg", &index))
>>> return -EINVAL;
>>>
>>> - if (index >= ARRAY_SIZE(triggers_table))
>>> + if (index >= ARRAY_SIZE(triggers_table) ||
>>> + index >= ARRAY_SIZE(valids_table))
>>> return -EINVAL;
>>>
>>> - priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>>> + /* Create an IIO device only if we have triggers to be validated */
>>> + if (*valids_table[index])
>>> + priv = stm32_setup_counter_device(dev);
>>> + else
>>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>>>
>>> if (!priv)
>>> return -ENOMEM;
>>> @@ -312,6 +543,7 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>> priv->clk = ddata->clk;
>>> priv->max_arr = ddata->max_arr;
>>> priv->triggers = triggers_table[index];
>>> + priv->valids = valids_table[index];
>>>
>>> ret = stm32_setup_iio_triggers(priv);
>>> if (ret)
>>> diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
>>> index d030004..4a0abbc 100644
>>> --- a/include/linux/mfd/stm32-timers.h
>>> +++ b/include/linux/mfd/stm32-timers.h
>>> @@ -21,6 +21,7 @@
>>> #define TIM_CCMR1 0x18 /* Capt/Comp 1 Mode Reg */
>>> #define TIM_CCMR2 0x1C /* Capt/Comp 2 Mode Reg */
>>> #define TIM_CCER 0x20 /* Capt/Comp Enable Reg */
>>> +#define TIM_CNT 0x24 /* Counter */
>>> #define TIM_PSC 0x28 /* Prescaler */
>>> #define TIM_ARR 0x2c /* Auto-Reload Register */
>>> #define TIM_CCR1 0x34 /* Capt/Comp Register 1 */
>>> @@ -30,6 +31,7 @@
>>> #define TIM_BDTR 0x44 /* Break and Dead-Time Reg */
>>>
>>> #define TIM_CR1_CEN BIT(0) /* Counter Enable */
>>> +#define TIM_CR1_DIR BIT(4) /* Counter Direction */
>>> #define TIM_CR1_ARPE BIT(7) /* Auto-reload Preload Ena */
>>> #define TIM_CR2_MMS (BIT(4) | BIT(5) | BIT(6)) /* Master mode selection */
>>> #define TIM_SMCR_SMS (BIT(0) | BIT(1) | BIT(2)) /* Slave mode selection */
>>>
>>

Next message: Jonathan Cameron: "Re: [PATCH v2] IIO: bmp280-core.c: fix error in humidity calculation"
Previous message: Andrey Ryabinin: "[PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO"
In reply to: William Breathitt Gray: "Re: [PATCH v4 1/2] iio: stm32 trigger: Add quadrature encoder device"
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