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

[Jonathan Cameron]

On 3 January 2017 12:59:20 GMT+00:00, Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx> wrote:
>2017-01-03 10:23 GMT+01:00 Benjamin Gaignard
><benjamin.gaignard@xxxxxxxxxx>:
>> 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.
>>
>
>If it isn't possible to implement IIO_TIMER I will simply drop device
>part of
>my driver until we find a solution because I would like to upstream at
>least what is
>need to ADC/DAC.

Agreed. Let's move forward with the easy stuff.
I might get a chance to look at trigger trees later
this week depending on how some tedious time in a pharma clean room and on planes goes.

I think we can mock most of this up with software triggers and the dummy driver.

Perhaps a sysfs trigger driving a timer trigger will get us moving in the right direction API wise.
Might let us figure out something generic without needing hardware.

A few other bits of hardware can do similar to yours but I don't think I have any in my pile of boards.

J
>
>>> 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
>>
>> Follow Linaro: Facebook | Twitter | Blog

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