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

From: Jonathan Cameron <hidden>
Date: 2017-01-03 17:17:35
Also in: linux-devicetree, linux-iio, linux-pwm, lkml


On 3 January 2017 09:23:34 GMT+00:00, Benjamin Gaignard [off-list ref] wrote:

2017-01-02 19:22 GMT+01:00 Jonathan Cameron [off-list ref]:

quoted

On 02/01/17 08:46, Benjamin Gaignard wrote:

quoted

2016-12-30 22:12 GMT+01:00 Jonathan Cameron [off-list ref]:

quoted

On 09/12/16 14:15, Benjamin Gaignard wrote:

quoted

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,

quoted

reset or edge, this configuration could be done through

"master_mode"

quoted

device attribute.

A timer device could be triggered by other timers, we use the

trigger

quoted

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

quoted

"slave_mode" device attribute.

Since triggers could also be used by DAC or ADC their names are

defined

quoted

in include/ nux/iio/timer/stm32-timer-trigger.h so those IPs will

be able

quoted

to configure themselves in valid_trigger function

Trigger have a "sampling_frequency" attribute which allow to

configure

quoted

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

quoted

glue between triggers.  I think we need to work out a more light

weight

quoted

way to do this.  As you are only using them for validation and to

provide

quoted

somewhere to hang the control attibutes off, there is nothing

stopping us

quoted

moving that over to the iio_trigger instead which would avoid the

messy

quoted

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

quoted

triggers of a device. For me it was making sense to centralize that

in an

quoted

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

quoted

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'

quoted

This is interesting, but with a bit of refactoring I would think it

would

quoted

be possible to share some of that code thus allowing non IIO devices

to

quoted

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

quoted

the hardware all the time.  Setting a value somewhere effects the

configuration

quoted

elsewhere - often the best plan is to just let that happen and leave

it up to

quoted

userspace to check for changes if it cares.

okay

quoted

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

quoted

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.

Hmm stretching a point. There aren't really input or output channels. 

Still not convinced there should be any IIO devices near this at all.

quoted

I'm worried about the scope spread we get for an IIO device

otherwise.

quoted

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

quoted

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

quoted

diving into the complexity of something like the media controller
framework.

Jonathan

quoted

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

quoted

within this driver initially that won't be hard to do. Checking the

device

quoted

parent matches will do most of it.

Jonathan

quoted

Signed-off-by: Benjamin Gaignard <redacted>
---
 .../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

+++++++++++++++++++++

quoted

 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

quoted

 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

quoted

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

quoted

+KernelVersion:       4.10
+Contact:     benjamin.gaignard at st.com
+Description:
+             Reading returns the list possible master modes which

are:

quoted

+             - "reset"     : The UG bit from the TIMx_EGR

register is used as trigger output (TRGO).

quoted

+             - "enable"    : The Counter Enable signal CNT_EN is

used as trigger output.

quoted

+             - "update"    : The update event is selected as

trigger output.

quoted

+                             For instance a master timer can then

be used as a prescaler for a slave timer.

quoted

+             - "compare_pulse" : The trigger output send a

positive pulse when the CC1IF flag is to be set.

quoted

+             - "OC1REF"    : OC1REF signal is used as trigger

output.

quoted

+             - "OC2REF"    : OC2REF signal is used as trigger

output.

quoted

+             - "OC3REF"    : OC3REF signal is used as trigger

output.

quoted

+             - "OC4REF"    : OC4REF signal is used as trigger

output.

quoted

+
+What:                /sys/bus/iio/devices/iio:deviceX/master_mode
+KernelVersion:       4.10
+Contact:     benjamin.gaignard at st.com
+Description:
+             Reading returns the current master modes.
+             Writing set the master mode
+
+What:

/sys/bus/iio/devices/iio:deviceX/slave_mode_available

quoted

+KernelVersion:       4.10
+Contact:     benjamin.gaignard at st.com
+Description:
+             Reading returns the list possible slave modes which

are:

quoted

+             - "disabled"  : The prescaler is clocked directly by

the internal clock.

quoted

+             - "encoder_1" : Counter counts up/down on TI2FP1

edge depending on TI1FP2 level.

quoted

+             - "encoder_2" : Counter counts up/down on TI1FP2

edge depending on TI2FP1 level.

quoted

+             - "encoder_3" : Counter counts up/down on both

TI1FP1 and TI2FP2 edges depending

quoted

+                             on the level of the other input.
+             - "reset"     : Rising edge of the selected trigger

input reinitializes the counter

quoted

+                             and generates an update of the

registers.

quoted

+             - "gated"     : The counter clock is enabled when

the trigger input is high.

quoted

+                             The counter stops (but is not reset)

as soon as the trigger becomes low.

quoted

+                             Both start and stop of the counter

are controlled.

quoted

+             - "trigger"   : The counter starts at a rising edge

of the trigger TRGI (but it is not

quoted

+                             reset). Only the start of the

counter is controlled.

quoted

+             - "external_clock": Rising edges of the selected

trigger (TRGI) clock the counter.

quoted

+
+What:                /sys/bus/iio/devices/iio:deviceX/slave_mode
+KernelVersion:       4.10
+Contact:     benjamin.gaignard at st.com
+Description:
+             Reading returns the current slave mode.
+             Writing set the slave mode
+
+What:

/sys/bus/iio/devices/triggerX/sampling_frequency

quoted

+KernelVersion:       4.10
+Contact:     benjamin.gaignard at st.com
+Description:
+             Reading returns the current sampling frequency.
+             Writing an value different of 0 set and start

sampling.

quoted

+             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

quoted

+     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

quoted

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

quoted

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@st.com>
+ *
+ * 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");

quoted

+             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);

quoted

+
+     /* Force master mode to update mode */
+     regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS,

0x20);

quoted

+
+     /* Make sure that registers are updated */
+     regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG,

TIM_EGR_UG);

quoted

+
+     /* Enable controller */
+     regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,

TIM_CR1_CEN);

quoted

+
+     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,

quoted

+                                     const char *buf, size_t len)
+{
+     struct iio_trigger *trig = to_iio_trigger(dev);
+     struct stm32_timer_trigger *priv =

iio_trigger_get_drvdata(trig);

quoted

+     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)

quoted

+{
+     struct iio_trigger *trig = to_iio_trigger(dev);
+     struct stm32_timer_trigger *priv =

iio_trigger_get_drvdata(trig);

quoted

+     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[]

= {

quoted

+     &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,

quoted

+                                      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]);

quoted

+}
+
+static ssize_t stm32_tt_store_master_mode(struct device *dev,
+                                       struct device_attribute

*attr,

quoted

+                                       const char *buf, size_t

len)

quoted

+{
+     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);

quoted

+                     return len;
+             }
+     }
+
+     return -EINVAL;
+}
+
+static IIO_CONST_ATTR(master_mode_available,
+     "reset enable update compare_pulse OC1REF OC2REF OC3REF

OC4REF");

quoted

+
+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,

quoted

+                                     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]);

quoted

+}
+
+static ssize_t stm32_tt_store_slave_mode(struct device *dev,
+                                      struct device_attribute

*attr,

quoted

+                                      const char *buf, size_t

len)

quoted

+{
+     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);

quoted

+                     return len;
+             }
+     }
+
+     return -EINVAL;
+}
+
+static IIO_CONST_ATTR(slave_mode_available,
+"disabled encoder_1 encoder_2 encoder_3 reset gated trigger

external_clock");

quoted

+
+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)

quoted

+{
+     int ret;
+     const char * const *cur = priv->triggers;
+
+     while (cur && *cur) {
+             struct iio_trigger *trig;
+
+             trig = devm_iio_trigger_alloc(priv->dev, "%s",

*cur);

quoted

+             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)))

quoted

+                     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)

quoted

+{
+     struct iio_dev *indio_dev;
+     int ret;
+
+     indio_dev = devm_iio_device_alloc(dev,
+                                       sizeof(struct

stm32_timer_trigger));

quoted

+     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)

quoted

+{
+     struct device *dev = &pdev->dev;
+     struct stm32_timer_trigger *priv;
+     struct stm32_timers *ddata =

dev_get_drvdata(pdev->dev.parent);

quoted

+     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 */

quoted

+     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

quoted

iio device with all the bagage that carries just to allow us to do

the

quoted

trigger trees.  We ought to have a much more light weight solution

for this

quoted

functionality - we aren't typically even using the interrupt tree

stuff

quoted

that the triggers for devices are all really about.

A simpler approach of allowing each trigger the option of a parent

seems like

quoted

it would be cleaner.  Could be done entirely within this driver in

the first

quoted

instance.  Basically it would just look like your master and slave

attributes

quoted

but have those under triggerX not iio:deviceX.

We can work out how to make it more generic later - including

perhaps the

quoted

option to trigger from triggers outside this driver, using some

parallel

quoted

infrastructure to the device triggering.

quoted

+     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");

quoted

+MODULE_LICENSE("GPL v2");

diff --git a/drivers/iio/trigger/Kconfig

b/drivers/iio/trigger/Kconfig

quoted

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

quoted

 endmenu

diff --git a/include/linux/iio/timer/stm32-timer-trigger.h

b/include/linux/iio/timer/stm32-timer-trigger.h

quoted

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@st.com>
+ *
+ * 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

-- 
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