Re: [PATCH] iio: stm32 trigger: Add support for TRGO2 triggers

From: Jonathan Cameron
Date: Sun Apr 30 2017 - 13:07:47 EST

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In reply to: Fabrice Gasnier: "Re: [PATCH] iio: stm32 trigger: Add support for TRGO2 triggers"
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On 28/04/17 15:52, Fabrice Gasnier wrote:
> On 04/27/2017 07:49 AM, Jonathan Cameron wrote:
>> On 26/04/17 09:55, Benjamin Gaignard wrote:
>>> 2017-04-26 10:17 GMT+02:00 Fabrice Gasnier <fabrice.gasnier@xxxxxx>:
>>>> Add support for TRGO2 trigger that can be found on STM32F7.
>>>> Add additional master modes supported by TRGO2.
>> These additional modes would benefit from more information in the
>> ABI docs. Otherwise patch seems fine, though this may win
>> the award for hardest hardware to come up with a generic
>> interface for...
>>>> Register additional "tim[1/8]_trgo2" triggers for timer1 & timer8.
>>>> Detect TRGO2 timer capability (master mode selection 2).
>>>>
>>>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
>>>> ---
>>>> .../ABI/testing/sysfs-bus-iio-timer-stm32 | 15 +++
>>>> drivers/iio/trigger/stm32-timer-trigger.c | 113 ++++++++++++++++++---
>>>> include/linux/iio/timer/stm32-timer-trigger.h | 2 +
>>>> include/linux/mfd/stm32-timers.h | 2 +
>>>> 4 files changed, 118 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>>> index 230020e..47647b4 100644
>>>> --- a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>>> @@ -16,6 +16,21 @@ Description:
>>>> - "OC2REF" : OC2REF signal is used as trigger output.
>>>> - "OC3REF" : OC3REF signal is used as trigger output.
>>>> - "OC4REF" : OC4REF signal is used as trigger output.
>>>> + Additional modes (on TRGO2 only):
>>>> + - "OC5REF" : OC5REF signal is used as trigger output.
>>>> + - "OC6REF" : OC6REF signal is used as trigger output.
>>>> + - "compare_pulse_OC4REF":
>>>> + OC4REF rising or falling edges generate pulses.
>> I'd like this to be fairly understandable without resorting to reading the
>> datasheet. As I understand it you get a fixed term pulse on both edges
>> of the waveform? Perhaps this calls for some ascii art :)
>
> Hi Jonathan,
>
> If you feel like it needs more documentation, I'd rather prefer to add
> reference or link to the datasheet... That will be more accurate,
> up-to-date (e.g. like RM0385 pdf). Does this sound ok ? Or...
Datasheet is good, but give it 10 years and chances are it will disappear
into a black hole, whereas the hardware might still be in use by someone.
Some of the hardware I use is at least that old. Frankly this laptop is
getting close ;)
>
> Just in case, I prepared some ascii art, hope it clarify things.
> I'm wondering if this is best place to put it ?
> Shouldn't this be added in source code, instead of ABI Doc ?
Could be either, but arguably the ABI docs should be all that a
userspace developer should need to see. This isn't an internal
detail afterall.
> Maybe I can skip 1st part of it, heading boxes? (only example is enough?
> or not...)
>
> +-----------+ +-------------+ +---------+
> | Prescaler +-> | Counter | +-> | Master | TRGO(2)
> +-----------+ +--+--------+-+ |-> | Control +-->
> | | || +---------+
> +--v--------+-+ OCxREF || +---------+
> | Chx compare +----------> | Output | ChX
> +-----------+-+ | | Control +-->
> . | | +---------+
> . | | .
> +-----------v-+ OC6REF | .
> | Ch6 compare +---------+>
> +-------------+
>
> Example with: "compare_pulse_OC4REF_r_or_OC6REF_r":
>
> X
> X X
> X . . X
> X . . X
> X . . X
> count X . . . . X
> . . . .
> . . . .
> +---------------+
> OC4REF | . . |
> +-+ . . +-+
> . +---+ .
> OC6REF . | | .
> +-------+ +-------+
> +-+ +-+
> TRGO2 | | | |
> +-+ +---+ +---------+
This is good stuff so I'd put it in the ABI docs.

Jonathan
>
>
> side note: this isn't my house ;-)
:)
>
> Please advise,
> Thanks,
> Fabrice
>
>
>>>> + - "compare_pulse_OC6REF":
>>>> + OC6REF rising or falling edges generate pulses.
>>>> + - "compare_pulse_OC4REF_r_or_OC6REF_r":
>>>> + OC4REF or OC6REF rising edges generate pulses.
>>>> + - "compare_pulse_OC4REF_r_or_OC6REF_f":
>>>> + OC4REF rising or OC6REF falling edges generate pulses.
>>>> + - "compare_pulse_OC5REF_r_or_OC6REF_r":
>>>> + OC5REF or OC6REF rising edges generate pulses.
>>>> + - "compare_pulse_OC5REF_r_or_OC6REF_f":
>>>> + OC5REF rising or OC6REF falling edges generate pulses.
>>>>
>>>> What: /sys/bus/iio/devices/triggerX/master_mode
>>>> KernelVersion: 4.11
>>>> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
>>>> index 0f1a2cf..a0031b7 100644
>>>> --- a/drivers/iio/trigger/stm32-timer-trigger.c
>>>> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
>>>> @@ -14,19 +14,19 @@
>>>> #include <linux/module.h>
>>>> #include <linux/platform_device.h>
>>>>
>>>> -#define MAX_TRIGGERS 6
>>>> +#define MAX_TRIGGERS 7
>>>> #define MAX_VALIDS 5
>>>>
>>>> /* List the triggers created by each timer */
>>>> static const void *triggers_table[][MAX_TRIGGERS] = {
>>>> - { TIM1_TRGO, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
>>>> + { TIM1_TRGO, TIM1_TRGO2, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
>>>> { TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
>>>> { TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
>>>> { TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
>>>> { TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
>>>> { TIM6_TRGO,},
>>>> { TIM7_TRGO,},
>>>> - { TIM8_TRGO, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
>>>> + { TIM8_TRGO, TIM8_TRGO2, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
>>>> { TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
>>>> { }, /* timer 10 */
>>>> { }, /* timer 11 */
>>>> @@ -56,9 +56,16 @@ struct stm32_timer_trigger {
>>>> u32 max_arr;
>>>> const void *triggers;
>>>> const void *valids;
>>>> + bool has_trgo2;
>>>> };
>>>>
>>>> +static bool stm32_timer_is_trgo2_name(const char *name)
>>>> +{
>>>> + return !!strstr(name, "trgo2");
>>>> +}
>>>> +
>>>> static int stm32_timer_start(struct stm32_timer_trigger *priv,
>>>> + struct iio_trigger *trig,
>>>> unsigned int frequency)
>>>> {
>>>> unsigned long long prd, div;
>>>> @@ -102,7 +109,12 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
>>>> regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
>>>>
>>>> /* Force master mode to update mode */
>>>> - regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS, 0x20);
>>>> + if (stm32_timer_is_trgo2_name(trig->name))
>>>> + regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2,
>>>> + 0x2 << TIM_CR2_MMS2_SHIFT);
>>>> + else
>>>> + regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS,
>>>> + 0x2 << TIM_CR2_MMS_SHIFT);
>>>>
>>>> /* Make sure that registers are updated */
>>>> regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
>>>> @@ -150,7 +162,7 @@ static ssize_t stm32_tt_store_frequency(struct device *dev,
>>>> if (freq == 0) {
>>>> stm32_timer_stop(priv);
>>>> } else {
>>>> - ret = stm32_timer_start(priv, freq);
>>>> + ret = stm32_timer_start(priv, trig, freq);
>>>> if (ret)
>>>> return ret;
>>>> }
>>>> @@ -183,6 +195,9 @@ static IIO_DEV_ATTR_SAMP_FREQ(0660,
>>>> stm32_tt_read_frequency,
>>>> stm32_tt_store_frequency);
>>>>
>>>> +#define MASTER_MODE_MAX 7
>>>> +#define MASTER_MODE2_MAX 15
>>>> +
>>>> static char *master_mode_table[] = {
>>>> "reset",
>>>> "enable",
>>>> @@ -191,7 +206,16 @@ static IIO_DEV_ATTR_SAMP_FREQ(0660,
>>>> "OC1REF",
>>>> "OC2REF",
>>>> "OC3REF",
>>>> - "OC4REF"
>>>> + "OC4REF",
>>>> + /* Master mode selection 2 only */
>>>> + "OC5REF",
>>>> + "OC6REF",
>>>> + "compare_pulse_OC4REF",
>>>> + "compare_pulse_OC6REF",
>>>> + "compare_pulse_OC4REF_r_or_OC6REF_r",
>>>> + "compare_pulse_OC4REF_r_or_OC6REF_f",
>>>> + "compare_pulse_OC5REF_r_or_OC6REF_r",
>>>> + "compare_pulse_OC5REF_r_or_OC6REF_f",
>>>> };
>>>>
>>>> static ssize_t stm32_tt_show_master_mode(struct device *dev,
>>>> @@ -199,10 +223,15 @@ static ssize_t stm32_tt_show_master_mode(struct device *dev,
>>>> char *buf)
>>>> {
>>>> struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
>>>> + struct iio_trigger *trig = to_iio_trigger(dev);
>>>> u32 cr2;
>>>>
>>>> regmap_read(priv->regmap, TIM_CR2, &cr2);
>>>> - cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
>>>> +
>>>> + if (stm32_timer_is_trgo2_name(trig->name))
>>>> + cr2 = (cr2 & TIM_CR2_MMS2) >> TIM_CR2_MMS2_SHIFT;
>>>> + else
>>>> + cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
>>>>
>>>> return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
>>>> }
>>>> @@ -212,13 +241,25 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
>>>> const char *buf, size_t len)
>>>> {
>>>> struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
>>>> + struct iio_trigger *trig = to_iio_trigger(dev);
>>>> + u32 mask, shift, master_mode_max;
>>>> int i;
>>>>
>>>> - for (i = 0; i < ARRAY_SIZE(master_mode_table); i++) {
>>>> + if (stm32_timer_is_trgo2_name(trig->name)) {
>>>> + mask = TIM_CR2_MMS2;
>>>> + shift = TIM_CR2_MMS2_SHIFT;
>>>> + master_mode_max = MASTER_MODE2_MAX;
>>>> + } else {
>>>> + mask = TIM_CR2_MMS;
>>>> + shift = TIM_CR2_MMS_SHIFT;
>>>> + master_mode_max = MASTER_MODE_MAX;
>>>> + }
>>>> +
>>>> + for (i = 0; i <= master_mode_max; i++) {
>>>> if (!strncmp(master_mode_table[i], buf,
>>>> strlen(master_mode_table[i]))) {
>>>> - regmap_update_bits(priv->regmap, TIM_CR2,
>>>> - TIM_CR2_MMS, i << TIM_CR2_MMS_SHIFT);
>>>> + regmap_update_bits(priv->regmap, TIM_CR2, mask,
>>>> + i << shift);
>>>> /* Make sure that registers are updated */
>>>> regmap_update_bits(priv->regmap, TIM_EGR,
>>>> TIM_EGR_UG, TIM_EGR_UG);
>>>> @@ -229,8 +270,31 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
>>>> return -EINVAL;
>>>> }
>>>>
>>>> -static IIO_CONST_ATTR(master_mode_available,
>>>> - "reset enable update compare_pulse OC1REF OC2REF OC3REF OC4REF");
>>>> +static ssize_t stm32_tt_show_master_mode_avail(struct device *dev,
>>>> + struct device_attribute *attr,
>>>> + char *buf)
>>>> +{
>>>> + struct iio_trigger *trig = to_iio_trigger(dev);
>>>> + unsigned int i, master_mode_max;
>>>> + size_t len = 0;
>>>> +
>>>> + if (stm32_timer_is_trgo2_name(trig->name))
>>>> + master_mode_max = MASTER_MODE2_MAX;
>>>> + else
>>>> + master_mode_max = MASTER_MODE_MAX;
>>>> +
>>>> + for (i = 0; i <= master_mode_max; i++)
>>>> + len += scnprintf(buf + len, PAGE_SIZE - len,
>>>> + "%s ", master_mode_table[i]);
>>>> +
>>>> + /* replace trailing space by newline */
>>>> + buf[len - 1] = '\n';
>>>> +
>>>> + return len;
>>>> +}
>>>> +
>>>> +static IIO_DEVICE_ATTR(master_mode_available, 0444,
>>>> + stm32_tt_show_master_mode_avail, NULL, 0);
>>>>
>>>> static IIO_DEVICE_ATTR(master_mode, 0660,
>>>> stm32_tt_show_master_mode,
>>>> @@ -240,7 +304,7 @@ static IIO_DEVICE_ATTR(master_mode, 0660,
>>>> static struct attribute *stm32_trigger_attrs[] = {
>>>> &iio_dev_attr_sampling_frequency.dev_attr.attr,
>>>> &iio_dev_attr_master_mode.dev_attr.attr,
>>>> - &iio_const_attr_master_mode_available.dev_attr.attr,
>>>> + &iio_dev_attr_master_mode_available.dev_attr.attr,
>>>> NULL,
>>>> };
>>>>
>>>> @@ -264,6 +328,12 @@ static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>>>>
>>>> while (cur && *cur) {
>>>> struct iio_trigger *trig;
>>>> + bool cur_is_trgo2 = stm32_timer_is_trgo2_name(*cur);
>>>> +
>>>> + if (cur_is_trgo2 && !priv->has_trgo2) {
>>>> + cur++;
>>>> + continue;
>>>> + }
>>>>
>>>> trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
>>>> if (!trig)
>>>> @@ -277,7 +347,7 @@ static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>>>> * should only be available on trgo trigger which
>>>> * is always the first in the list.
>>>> */
>>>> - if (cur == priv->triggers)
>>>> + if (cur == priv->triggers || cur_is_trgo2)
>>>> trig->dev.groups = stm32_trigger_attr_groups;
>>>>
>>>> iio_trigger_set_drvdata(trig, priv);
>>>> @@ -584,6 +654,20 @@ bool is_stm32_timer_trigger(struct iio_trigger *trig)
>>>> }
>>>> EXPORT_SYMBOL(is_stm32_timer_trigger);
>>>>
>>>> +static void stm32_timer_detect_trgo2(struct stm32_timer_trigger *priv)
>>>> +{
>>>> + u32 val;
>>>> +
>>>> + /*
>>>> + * Master mode selection 2 bits can only be written and read back when
>>>> + * timer supports it.
>>>> + */
>>>> + regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, TIM_CR2_MMS2);
>>>> + regmap_read(priv->regmap, TIM_CR2, &val);
>>>> + regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, 0);
>>>> + priv->has_trgo2 = !!val;
>>>> +}
>>>> +
>>>> static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>>> {
>>>> struct device *dev = &pdev->dev;
>>>> @@ -614,6 +698,7 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>>> priv->max_arr = ddata->max_arr;
>>>> priv->triggers = triggers_table[index];
>>>> priv->valids = valids_table[index];
>>>> + stm32_timer_detect_trgo2(priv);
>>>>
>>>> ret = stm32_setup_iio_triggers(priv);
>>>> if (ret)
>>>> diff --git a/include/linux/iio/timer/stm32-timer-trigger.h b/include/linux/iio/timer/stm32-timer-trigger.h
>>>> index 55535ae..fa7d786 100644
>>>> --- a/include/linux/iio/timer/stm32-timer-trigger.h
>>>> +++ b/include/linux/iio/timer/stm32-timer-trigger.h
>>>> @@ -10,6 +10,7 @@
>>>> #define _STM32_TIMER_TRIGGER_H_
>>>>
>>>> #define TIM1_TRGO "tim1_trgo"
>>>> +#define TIM1_TRGO2 "tim1_trgo2"
>>>> #define TIM1_CH1 "tim1_ch1"
>>>> #define TIM1_CH2 "tim1_ch2"
>>>> #define TIM1_CH3 "tim1_ch3"
>>>> @@ -44,6 +45,7 @@
>>>> #define TIM7_TRGO "tim7_trgo"
>>>>
>>>> #define TIM8_TRGO "tim8_trgo"
>>>> +#define TIM8_TRGO2 "tim8_trgo2"
>>>> #define TIM8_CH1 "tim8_ch1"
>>>> #define TIM8_CH2 "tim8_ch2"
>>>> #define TIM8_CH3 "tim8_ch3"
>>>> diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
>>>> index 4a0abbc..ce7346e 100644
>>>> --- a/include/linux/mfd/stm32-timers.h
>>>> +++ b/include/linux/mfd/stm32-timers.h
>>>> @@ -34,6 +34,7 @@
>>>> #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_CR2_MMS2 GENMASK(23, 20) /* Master mode selection 2 */
>>>> #define TIM_SMCR_SMS (BIT(0) | BIT(1) | BIT(2)) /* Slave mode selection */
>>>> #define TIM_SMCR_TS (BIT(4) | BIT(5) | BIT(6)) /* Trigger selection */
>>>> #define TIM_DIER_UIE BIT(0) /* Update interrupt */
>>>> @@ -60,6 +61,7 @@
>>>>
>>>> #define MAX_TIM_PSC 0xFFFF
>>>> #define TIM_CR2_MMS_SHIFT 4
>>>> +#define TIM_CR2_MMS2_SHIFT 20
>>>> #define TIM_SMCR_TS_SHIFT 4
>>>> #define TIM_BDTR_BKF_MASK 0xF
>>>> #define TIM_BDTR_BKF_SHIFT 16
>>>> --
>>>> 1.9.1
>>>>
>>>
>>> Acked-by: Benjamin Gaiganrd <benjamin.gaignard@xxxxxxxxxx>
>>> --
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>>
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>

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Previous message: Jonathan Cameron: "Re: [PATCH] iio: st_pressure: st_accel: Initialise sensor platform data properly"
In reply to: Fabrice Gasnier: "Re: [PATCH] iio: stm32 trigger: Add support for TRGO2 triggers"
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