Re: [PATCH v6 6/8] IIO: add STM32 timer trigger driver

[Benjamin Gaignard]

2016-12-30 22:12 GMT+01:00 Jonathan Cameron <jic23@xxxxxxxxxx>:
> On 09/12/16 14:15, Benjamin Gaignard wrote:
>> Timers IPs can be used to generate triggers for other IPs like
>> DAC, ADC or other timers.
>> Each trigger may result of timer internals signals like counter enable,
>> reset or edge, this configuration could be done through "master_mode"
>> device attribute.
>>
>> A timer device could be triggered by other timers, we use the trigger
>> name and is_stm32_iio_timer_trigger() function to distinguish them
>> and configure IP input switch.
>>
>> Timer may also decide on which event (edge, level) they could
>> be activated by a trigger, this configuration is done by writing in
>> "slave_mode" device attribute.
>>
>> Since triggers could also be used by DAC or ADC their names are defined
>> in include/ nux/iio/timer/stm32-timer-trigger.h so those IPs will be able
>> to configure themselves in valid_trigger function
>>
>> Trigger have a "sampling_frequency" attribute which allow to configure
>> timer sampling frequency without using PWM interface
>>
>> version 5:
>> - simplify tables of triggers
>> - only create an IIO device when needed
>>
>> version 4:
>> - get triggers configuration from "reg" in DT
>> - add tables of triggers
>> - sampling frequency is enable/disable when writing in trigger
>>   sampling_frequency attribute
>> - no more use of interruptions
>>
>> version 3:
>> - change compatible to "st,stm32-timer-trigger"
>> - fix attributes access right
>> - use string instead of int for master_mode and slave_mode
>> - document device attributes in sysfs-bus-iio-timer-stm32
>>
>> version 2:
>> - keep only one compatible
>> - use st,input-triggers-names and st,output-triggers-names
>>   to know which triggers are accepted and/or create by the device
> Firstly, sorry it has taken me so long to get back to this.
>
> I'm still not keen on this use of iio_device elements just to act as
> glue between triggers.  I think we need to work out a more light weight
> way to do this.  As you are only using them for validation and to provide
> somewhere to hang the control attibutes off, there is nothing stopping us
> moving that over to the iio_trigger instead which would avoid the messy
> duality going on here.

I have add an iio_device because each hardware can generate multiple
triggers (up to 5: trgo, ch 1...4) and slave_mode attribute will impact all the
triggers of a device. For me it was making sense to centralize that in an
iio_device rather than having an attribute "shared" (from hardware
point of view)
on multiple triggers.
Since master_mode attribute is only used by trgo and not impact ch1...4
triggers I will move it to trigger instead of the iio_device.

I also wanted to be able to connect triggers on a iio_device as I
could do for an
ADC with a command like 'echo "tim1_trgo" > iio_deviceX/trigger/current_trigger'
If I change that to parent_trigger attribute it change this behavior
and I will have to
duplicated what is done in iio_trigger_write_current() to find and
validate triggers.

> I might still be missing something though!
>
> You would only I think need 3 attributes
>
> parrent_trigger
> and something like your master_mode and slave_mode attributes.
>
> The parrent_trigger would need some validation etc, but if we keep it
> within this driver initially that won't be hard to do. Checking the device
> parent matches will do most of it.
>
> Jonathan
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
>> ---
>>  .../ABI/testing/sysfs-bus-iio-timer-stm32          |  55 +++
>>  drivers/iio/Kconfig                                |   2 +-
>>  drivers/iio/Makefile                               |   1 +
>>  drivers/iio/timer/Kconfig                          |  13 +
>>  drivers/iio/timer/Makefile                         |   1 +
>>  drivers/iio/timer/stm32-timer-trigger.c            | 466 +++++++++++++++++++++
>>  drivers/iio/trigger/Kconfig                        |   1 -
>>  include/linux/iio/timer/stm32-timer-trigger.h      |  62 +++
>>  8 files changed, 599 insertions(+), 2 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>  create mode 100644 drivers/iio/timer/Kconfig
>>  create mode 100644 drivers/iio/timer/Makefile
>>  create mode 100644 drivers/iio/timer/stm32-timer-trigger.c
>>  create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>> new file mode 100644
>> index 0000000..26583dd
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>> @@ -0,0 +1,55 @@
>> +What:                /sys/bus/iio/devices/iio:deviceX/master_mode_available
>> +KernelVersion:       4.10
>> +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.
>> +             - "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.
>> +             - "OC1REF"    : OC1REF signal is used as trigger output.
>> +             - "OC2REF"    : OC2REF signal is used as trigger output.
>> +             - "OC3REF"    : OC3REF signal is used as trigger output.
>> +             - "OC4REF"    : OC4REF signal is used as trigger output.
>> +
>> +What:                /sys/bus/iio/devices/iio:deviceX/master_mode
>> +KernelVersion:       4.10
>> +Contact:     benjamin.gaignard@xxxxxx
>> +Description:
>> +             Reading returns the current master modes.
>> +             Writing set the master mode
>> +
>> +What:                /sys/bus/iio/devices/iio:deviceX/slave_mode_available
>> +KernelVersion:       4.10
>> +Contact:     benjamin.gaignard@xxxxxx
>> +Description:
>> +             Reading returns the list possible slave modes which are:
>> +             - "disabled"  : The prescaler is clocked directly by the internal clock.
>> +             - "encoder_1" : Counter counts up/down on TI2FP1 edge depending on TI1FP2 level.
>> +             - "encoder_2" : Counter counts up/down on TI1FP2 edge depending on TI2FP1 level.
>> +             - "encoder_3" : Counter counts up/down on both TI1FP1 and TI2FP2 edges depending
>> +                             on the level of the other input.
>> +             - "reset"     : Rising edge of the selected trigger input reinitializes the counter
>> +                             and generates an update of the registers.
>> +             - "gated"     : The counter clock is enabled when the trigger input is high.
>> +                             The counter stops (but is not reset) as soon as the trigger becomes low.
>> +                             Both start and stop of the counter are controlled.
>> +             - "trigger"   : The counter starts at a rising edge of the trigger TRGI (but it is not
>> +                             reset). Only the start of the counter is controlled.
>> +             - "external_clock": Rising edges of the selected trigger (TRGI) clock the counter.
>> +
>> +What:                /sys/bus/iio/devices/iio:deviceX/slave_mode
>> +KernelVersion:       4.10
>> +Contact:     benjamin.gaignard@xxxxxx
>> +Description:
>> +             Reading returns the current slave mode.
>> +             Writing set the slave mode
>> +
>> +What:                /sys/bus/iio/devices/triggerX/sampling_frequency
>> +KernelVersion:       4.10
>> +Contact:     benjamin.gaignard@xxxxxx
>> +Description:
>> +             Reading returns the current sampling frequency.
>> +             Writing an value different of 0 set and start sampling.
>> +             Writing 0 stop sampling.
>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
>> index 6743b18..2de2a80 100644
>> --- a/drivers/iio/Kconfig
>> +++ b/drivers/iio/Kconfig
>> @@ -90,5 +90,5 @@ source "drivers/iio/potentiometer/Kconfig"
>>  source "drivers/iio/pressure/Kconfig"
>>  source "drivers/iio/proximity/Kconfig"
>>  source "drivers/iio/temperature/Kconfig"
>> -
>> +source "drivers/iio/timer/Kconfig"
>>  endif # IIO
>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
>> index 87e4c43..b797c08 100644
>> --- a/drivers/iio/Makefile
>> +++ b/drivers/iio/Makefile
>> @@ -32,4 +32,5 @@ obj-y += potentiometer/
>>  obj-y += pressure/
>>  obj-y += proximity/
>>  obj-y += temperature/
>> +obj-y += timer/
>>  obj-y += trigger/
>> diff --git a/drivers/iio/timer/Kconfig b/drivers/iio/timer/Kconfig
>> new file mode 100644
>> index 0000000..e3c21f2
>> --- /dev/null
>> +++ b/drivers/iio/timer/Kconfig
>> @@ -0,0 +1,13 @@
>> +#
>> +# Timers drivers
>> +
>> +menu "Timers"
>> +
>> +config IIO_STM32_TIMER_TRIGGER
>> +     tristate "STM32 Timer Trigger"
>> +     depends on (ARCH_STM32 && OF && MFD_STM32_TIMERS) || COMPILE_TEST
>> +     select IIO_TRIGGERED_EVENT
>> +     help
>> +       Select this option to enable STM32 Timer Trigger
>> +
>> +endmenu
>> diff --git a/drivers/iio/timer/Makefile b/drivers/iio/timer/Makefile
>> new file mode 100644
>> index 0000000..4ad95ec9
>> --- /dev/null
>> +++ b/drivers/iio/timer/Makefile
>> @@ -0,0 +1 @@
>> +obj-$(CONFIG_IIO_STM32_TIMER_TRIGGER) += stm32-timer-trigger.o
>> diff --git a/drivers/iio/timer/stm32-timer-trigger.c b/drivers/iio/timer/stm32-timer-trigger.c
>> new file mode 100644
>> index 0000000..8d16e8f
>> --- /dev/null
>> +++ b/drivers/iio/timer/stm32-timer-trigger.c
>> @@ -0,0 +1,466 @@
>> +/*
>> + * Copyright (C) STMicroelectronics 2016
>> + *
>> + * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
>> + *
>> + * License terms:  GNU General Public License (GPL), version 2
>> + */
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +#include <linux/iio/timer/stm32-timer-trigger.h>
>> +#include <linux/iio/trigger.h>
>> +#include <linux/iio/triggered_event.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/mfd/stm32-timers.h>
>> +#include <linux/module.h>
>> +#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] = {
>> +     { TIM1_TRGO, 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,},
>> +     { TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
>> +     { TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
>> +};
>> +
>> +/* List the triggers accepted by each timer */
>> +static const void *valids_table[][MAX_VALIDS] = {
>> +     { TIM5_TRGO, TIM2_TRGO, TIM4_TRGO, TIM3_TRGO,},
>> +     { TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
>> +     { TIM1_TRGO, TIM8_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,},
>> +     { 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,
>> +                          unsigned int frequency)
>> +{
>> +     unsigned long long prd, div;
>> +     int prescaler = 0;
>> +     u32 ccer, cr1;
>> +
>> +     /* Period and prescaler values depends of clock rate */
>> +     div = (unsigned long long)clk_get_rate(priv->clk);
>> +
>> +     do_div(div, frequency);
>> +
>> +     prd = div;
>> +
>> +     /*
>> +      * Increase prescaler value until we get a result that fit
>> +      * with auto reload register maximum value.
>> +      */
>> +     while (div > priv->max_arr) {
>> +             prescaler++;
>> +             div = prd;
>> +             do_div(div, (prescaler + 1));
>> +     }
>> +     prd = div;
>> +
>> +     if (prescaler > MAX_TIM_PSC) {
>> +             dev_err(priv->dev, "prescaler exceeds the maximum value\n");
>> +             return -EINVAL;
>> +     }
>> +
>> +     /* Check if nobody else use the timer */
>> +     regmap_read(priv->regmap, TIM_CCER, &ccer);
>> +     if (ccer & TIM_CCER_CCXE)
>> +             return -EBUSY;
>> +
>> +     regmap_read(priv->regmap, TIM_CR1, &cr1);
>> +     if (!(cr1 & TIM_CR1_CEN))
>> +             clk_enable(priv->clk);
>> +
>> +     regmap_write(priv->regmap, TIM_PSC, prescaler);
>> +     regmap_write(priv->regmap, TIM_ARR, prd - 1);
>> +     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);
>> +
>> +     /* Make sure that registers are updated */
>> +     regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
>> +
>> +     /* Enable controller */
>> +     regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
>> +
>> +     return 0;
>> +}
>> +
>> +static void stm32_timer_stop(struct stm32_timer_trigger *priv)
>> +{
>> +     u32 ccer, cr1;
>> +
>> +     regmap_read(priv->regmap, TIM_CCER, &ccer);
>> +     if (ccer & TIM_CCER_CCXE)
>> +             return;
>> +
>> +     regmap_read(priv->regmap, TIM_CR1, &cr1);
>> +     if (cr1 & TIM_CR1_CEN)
>> +             clk_disable(priv->clk);
>> +
>> +     /* Stop timer */
>> +     regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
>> +     regmap_write(priv->regmap, TIM_PSC, 0);
>> +     regmap_write(priv->regmap, TIM_ARR, 0);
>> +}
>> +
>> +static ssize_t stm32_tt_store_frequency(struct device *dev,
>> +                                     struct device_attribute *attr,
>> +                                     const char *buf, size_t len)
>> +{
>> +     struct iio_trigger *trig = to_iio_trigger(dev);
>> +     struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
>> +     unsigned int freq;
>> +     int ret;
>> +
>> +     ret = kstrtouint(buf, 10, &freq);
>> +     if (ret)
>> +             return ret;
>> +
>> +     if (freq == 0) {
>> +             stm32_timer_stop(priv);
>> +     } else {
>> +             ret = stm32_timer_start(priv, freq);
>> +             if (ret)
>> +                     return ret;
>> +     }
>> +
>> +     return len;
>> +}
>> +
>> +static ssize_t stm32_tt_read_frequency(struct device *dev,
>> +                                    struct device_attribute *attr, char *buf)
>> +{
>> +     struct iio_trigger *trig = to_iio_trigger(dev);
>> +     struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
>> +     u32 psc, arr, cr1;
>> +     unsigned long long freq = 0;
>> +
>> +     regmap_read(priv->regmap, TIM_CR1, &cr1);
>> +     regmap_read(priv->regmap, TIM_PSC, &psc);
>> +     regmap_read(priv->regmap, TIM_ARR, &arr);
>> +
>> +     if (psc && arr && (cr1 & TIM_CR1_CEN)) {
>> +             freq = (unsigned long long)clk_get_rate(priv->clk);
>> +             do_div(freq, psc);
>> +             do_div(freq, arr);
>> +     }
>> +
>> +     return sprintf(buf, "%d\n", (unsigned int)freq);
>> +}
>> +
>> +static IIO_DEV_ATTR_SAMP_FREQ(0660,
>> +                           stm32_tt_read_frequency,
>> +                           stm32_tt_store_frequency);
>> +
>> +static struct attribute *stm32_trigger_attrs[] = {
>> +     &iio_dev_attr_sampling_frequency.dev_attr.attr,
>> +     NULL,
>> +};
>> +
>> +static const struct attribute_group stm32_trigger_attr_group = {
>> +     .attrs = stm32_trigger_attrs,
>> +};
>> +
>> +static const struct attribute_group *stm32_trigger_attr_groups[] = {
>> +     &stm32_trigger_attr_group,
>> +     NULL,
>> +};
>> +
>> +static char *master_mode_table[] = {
>> +     "reset",
>> +     "enable",
>> +     "update",
>> +     "compare_pulse",
>> +     "OC1REF",
>> +     "OC2REF",
>> +     "OC3REF",
>> +     "OC4REF"
>> +};
>> +
>> +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);
>> +     u32 cr2;
>> +
>> +     regmap_read(priv->regmap, TIM_CR2, &cr2);
>> +     cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
>> +
>> +     return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
>> +}
>> +
>> +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);
>> +     int i;
>> +
>> +     for (i = 0; i < ARRAY_SIZE(master_mode_table); 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);
>> +                     return len;
>> +             }
>> +     }
>> +
>> +     return -EINVAL;
>> +}
>> +
>> +static IIO_CONST_ATTR(master_mode_available,
>> +     "reset enable update compare_pulse OC1REF OC2REF OC3REF OC4REF");
>> +
>> +static IIO_DEVICE_ATTR(master_mode, 0660,
>> +                    stm32_tt_show_master_mode,
>> +                    stm32_tt_store_master_mode,
>> +                    0);
>> +
>> +static char *slave_mode_table[] = {
>> +     "disabled",
>> +     "encoder_1",
>> +     "encoder_2",
>> +     "encoder_3",
>> +     "reset",
>> +     "gated",
>> +     "trigger",
>> +     "external_clock",
>> +};
>> +
>> +static ssize_t stm32_tt_show_slave_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);
>> +     u32 smcr;
>> +
>> +     regmap_read(priv->regmap, TIM_SMCR, &smcr);
>> +     smcr &= TIM_SMCR_SMS;
>> +
>> +     return snprintf(buf, PAGE_SIZE, "%s\n", slave_mode_table[smcr]);
>> +}
>> +
>> +static ssize_t stm32_tt_store_slave_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);
>> +     int i;
>> +
>> +     for (i = 0; i < ARRAY_SIZE(slave_mode_table); i++) {
>> +             if (!strncmp(slave_mode_table[i], buf,
>> +                          strlen(slave_mode_table[i]))) {
>> +                     regmap_update_bits(priv->regmap,
>> +                                        TIM_SMCR, TIM_SMCR_SMS, i);
>> +                     return len;
>> +             }
>> +     }
>> +
>> +     return -EINVAL;
>> +}
>> +
>> +static IIO_CONST_ATTR(slave_mode_available,
>> +"disabled encoder_1 encoder_2 encoder_3 reset gated trigger external_clock");
>> +
>> +static IIO_DEVICE_ATTR(slave_mode, 0660,
>> +                    stm32_tt_show_slave_mode,
>> +                    stm32_tt_store_slave_mode,
>> +                    0);
>> +
>> +static struct attribute *stm32_timer_attrs[] = {
>> +     &iio_dev_attr_master_mode.dev_attr.attr,
>> +     &iio_const_attr_master_mode_available.dev_attr.attr,
>> +     &iio_dev_attr_slave_mode.dev_attr.attr,
>> +     &iio_const_attr_slave_mode_available.dev_attr.attr,
>> +     NULL,
>> +};
>> +
>> +static const struct attribute_group stm32_timer_attr_group = {
>> +     .attrs = stm32_timer_attrs,
>> +};
>> +
>> +static const struct iio_trigger_ops timer_trigger_ops = {
>> +     .owner = THIS_MODULE,
>> +};
>> +
>> +static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>> +{
>> +     int ret;
>> +     const char * const *cur = priv->triggers;
>> +
>> +     while (cur && *cur) {
>> +             struct iio_trigger *trig;
>> +
>> +             trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
>> +             if  (!trig)
>> +                     return -ENOMEM;
>> +
>> +             trig->dev.parent = priv->dev->parent;
>> +             trig->ops = &timer_trigger_ops;
>> +             trig->dev.groups = stm32_trigger_attr_groups;
>> +             iio_trigger_set_drvdata(trig, priv);
>> +
>> +             ret = devm_iio_trigger_register(priv->dev, trig);
>> +             if (ret)
>> +                     return ret;
>> +             cur++;
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +/**
>> + * is_stm32_timer_trigger
>> + * @trig: trigger to be checked
>> + *
>> + * return true if the trigger is a valid stm32 iio timer trigger
>> + * either return false
>> + */
>> +bool is_stm32_timer_trigger(struct iio_trigger *trig)
>> +{
>> +     return (trig->ops == &timer_trigger_ops);
>> +}
>> +EXPORT_SYMBOL(is_stm32_timer_trigger);
>> +
>> +static int stm32_validate_trigger(struct iio_dev *indio_dev,
>> +                               struct iio_trigger *trig)
>> +{
>> +     struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>> +     const char * const *cur = priv->valids;
>> +     unsigned int i = 0;
>> +
>> +     if (!is_stm32_timer_trigger(trig))
>> +             return -EINVAL;
>> +
>> +     while (cur && *cur) {
>> +             if (!strncmp(trig->name, *cur, strlen(trig->name))) {
>> +                     regmap_update_bits(priv->regmap,
>> +                                        TIM_SMCR, TIM_SMCR_TS,
>> +                                        i << TIM_SMCR_TS_SHIFT);
>> +                     return 0;
>> +             }
>> +             cur++;
>> +             i++;
>> +     }
>> +
>> +     return -EINVAL;
>> +}
>> +
>> +static const struct iio_info stm32_trigger_info = {
>> +     .driver_module = THIS_MODULE,
>> +     .validate_trigger = stm32_validate_trigger,
>> +     .attrs = &stm32_timer_attr_group,
>> +};
>> +
>> +static struct stm32_timer_trigger *stm32_setup_iio_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->modes = INDIO_EVENT_TRIGGERED;
>> +     indio_dev->num_channels = 0;
>> +     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);
>> +}
>> +
>> +static int stm32_timer_trigger_probe(struct platform_device *pdev)
>> +{
>> +     struct device *dev = &pdev->dev;
>> +     struct stm32_timer_trigger *priv;
>> +     struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
>> +     unsigned int index;
>> +     int ret;
>> +
>> +     if (of_property_read_u32(dev->of_node, "reg", &index))
>> +             return -EINVAL;
>> +
>> +     if (index >= ARRAY_SIZE(triggers_table))
>> +             return -EINVAL;
>> +
>> +     /* Create an IIO device only if we have triggers to be validated */
>> +     if (*valids_table[index])
>> +             priv = stm32_setup_iio_device(dev);
>
> I still don't like this. Really feels like we shouldn't be creating an
> iio device with all the bagage that carries just to allow us to do the
> trigger trees.  We ought to have a much more light weight solution for this
> functionality - we aren't typically even using the interrupt tree stuff
> that the triggers for devices are all really about.
>
> A simpler approach of allowing each trigger the option of a parent seems like
> it would be cleaner.  Could be done entirely within this driver in the first
> instance.  Basically it would just look like your master and slave attributes
> but have those under triggerX not iio:deviceX.
>
> We can work out how to make it more generic later - including perhaps the
> option to trigger from triggers outside this driver, using some parallel
> infrastructure to the device triggering.
>
>
>> +     else
>> +             priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +
>> +     if (!priv)
>> +             return -ENOMEM;
>> +
>> +     priv->dev = dev;
>> +     priv->regmap = ddata->regmap;
>> +     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)
>> +             return ret;
>> +
>> +     platform_set_drvdata(pdev, priv);
>> +
>> +     return 0;
>> +}
>> +
>> +static const struct of_device_id stm32_trig_of_match[] = {
>> +     { .compatible = "st,stm32-timer-trigger", },
>> +     { /* end node */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
>> +
>> +static struct platform_driver stm32_timer_trigger_driver = {
>> +     .probe = stm32_timer_trigger_probe,
>> +     .driver = {
>> +             .name = "stm32-timer-trigger",
>> +             .of_match_table = stm32_trig_of_match,
>> +     },
>> +};
>> +module_platform_driver(stm32_timer_trigger_driver);
>> +
>> +MODULE_ALIAS("platform: stm32-timer-trigger");
>> +MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
>> index 809b2e7..f2af4fe 100644
>> --- a/drivers/iio/trigger/Kconfig
>> +++ b/drivers/iio/trigger/Kconfig
>> @@ -46,5 +46,4 @@ config IIO_SYSFS_TRIGGER
>>
>>         To compile this driver as a module, choose M here: the
>>         module will be called iio-trig-sysfs.
>> -
> Clean this up.

ok

>>  endmenu
>> diff --git a/include/linux/iio/timer/stm32-timer-trigger.h b/include/linux/iio/timer/stm32-timer-trigger.h
>> new file mode 100644
>> index 0000000..55535ae
>> --- /dev/null
>> +++ b/include/linux/iio/timer/stm32-timer-trigger.h
>> @@ -0,0 +1,62 @@
>> +/*
>> + * Copyright (C) STMicroelectronics 2016
>> + *
>> + * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
>> + *
>> + * License terms:  GNU General Public License (GPL), version 2
>> + */
>> +
>> +#ifndef _STM32_TIMER_TRIGGER_H_
>> +#define _STM32_TIMER_TRIGGER_H_
>> +
>> +#define TIM1_TRGO    "tim1_trgo"
>> +#define TIM1_CH1     "tim1_ch1"
>> +#define TIM1_CH2     "tim1_ch2"
>> +#define TIM1_CH3     "tim1_ch3"
>> +#define TIM1_CH4     "tim1_ch4"
>> +
>> +#define TIM2_TRGO    "tim2_trgo"
>> +#define TIM2_CH1     "tim2_ch1"
>> +#define TIM2_CH2     "tim2_ch2"
>> +#define TIM2_CH3     "tim2_ch3"
>> +#define TIM2_CH4     "tim2_ch4"
>> +
>> +#define TIM3_TRGO    "tim3_trgo"
>> +#define TIM3_CH1     "tim3_ch1"
>> +#define TIM3_CH2     "tim3_ch2"
>> +#define TIM3_CH3     "tim3_ch3"
>> +#define TIM3_CH4     "tim3_ch4"
>> +
>> +#define TIM4_TRGO    "tim4_trgo"
>> +#define TIM4_CH1     "tim4_ch1"
>> +#define TIM4_CH2     "tim4_ch2"
>> +#define TIM4_CH3     "tim4_ch3"
>> +#define TIM4_CH4     "tim4_ch4"
>> +
>> +#define TIM5_TRGO    "tim5_trgo"
>> +#define TIM5_CH1     "tim5_ch1"
>> +#define TIM5_CH2     "tim5_ch2"
>> +#define TIM5_CH3     "tim5_ch3"
>> +#define TIM5_CH4     "tim5_ch4"
>> +
>> +#define TIM6_TRGO    "tim6_trgo"
>> +
>> +#define TIM7_TRGO    "tim7_trgo"
>> +
>> +#define TIM8_TRGO    "tim8_trgo"
>> +#define TIM8_CH1     "tim8_ch1"
>> +#define TIM8_CH2     "tim8_ch2"
>> +#define TIM8_CH3     "tim8_ch3"
>> +#define TIM8_CH4     "tim8_ch4"
>> +
>> +#define TIM9_TRGO    "tim9_trgo"
>> +#define TIM9_CH1     "tim9_ch1"
>> +#define TIM9_CH2     "tim9_ch2"
>> +
>> +#define TIM12_TRGO   "tim12_trgo"
>> +#define TIM12_CH1    "tim12_ch1"
>> +#define TIM12_CH2    "tim12_ch2"
>> +
>> +bool is_stm32_timer_trigger(struct iio_trigger *trig);
>> +
>> +#endif
>>
>



-- 
Benjamin Gaignard

Graphic Study Group

Linaro.org â Open source software for ARM SoCs

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