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

From: Benjamin Gaignard
Date: Tue Jan 03 2017 - 04:23:49 EST

2017-01-02 19:22 GMT+01:00 Jonathan Cameron <jic23@xxxxxxxxxx>:
> On 02/01/17 08:46, Benjamin Gaignard wrote:
>> 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'
> This is interesting, but with a bit of refactoring I would think it would
> be possible to share some of that code thus allowing non IIO devices to
> bind to triggers. Ultimately I want to be able to bind a trigger to
> a trigger - I appreciate here the topology is more limited than that
> so some complexity comes in.
>
> My gut feeling is that representing that topology explicitly is hard
> to do in a remotely general way, but lets try it and see.
> We run into this sort of interdependency issue between different bits of
> the hardware all the time. Setting a value somewhere effects the configuration
> elsewhere - often the best plan is to just let that happen and leave it up to
> userspace to check for changes if it cares.

okay

>> 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 get the reasoning, but we still end up with something represented
> by an IIO device that isn't providing any channels at all. It's simply
> using some of the infrastructure. To my mind it is 'something else'
> and should be represented as such. I have no problem at all with
> you registering additional elements in /sysfs/bus/iio/ to represent
> these shared elements - we already have drivers that do that to
> provide some centralized infrastructure (e.g. the sysfs-trigger)

My hardware block are timers maybe I can add a channel type "IIO_TIMER"
and declare a channel with info_mask_separate = BIT(IIO_CHAN_INFO_SAMP_FREQ)
so I will be able to write/read sampling frequency on IIO device.

> I'm worried about the scope spread we get for an IIO device otherwise.
> They serve a well defined purpose at the moment, and that isn't what
> is happening here.
>
> So my gut feeling is we are better deliberately not representing the
> inter dependence and claiming all triggers we are creating are
> independent. That way we can have a nice generic infrastructure
> that will work in all cases (be it pushing the sanity checking to
> userspace).
>
> So each trigger has direct access to what controls it. Changing anything
> can effect other triggers in weird ways.
>
> I'm finding it hard to see anything else generalizing sufficiently
> as we'll always get cases where we can't represent the topology without
> diving into the complexity of something like the media controller
> framework.
>
> Jonathan
>>
>>> 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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