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Message-ID: <CA+M3ks51O6+5C4xYrRNOewSOq7NWB_ARiNuGkFQu3cOByKOXTA@mail.gmail.com>
Date: Sun, 26 Feb 2017 16:03:11 +0100
From: Benjamin Gaignard <benjamin.gaignard@...aro.org>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-iio@...r.kernel.org, Hartmut Knaack <knaack.h@....de>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Fabrice Gasnier <fabrice.gasnier@...com>,
Linaro Kernel Mailman List <linaro-kernel@...ts.linaro.org>,
Benjamin Gaignard <benjamin.gaignard@...com>
Subject: Re: [PATCH v3 2/2] iio: stm32 trigger: Implement parent trigger feature
2017-02-26 15:59 GMT+01:00 Benjamin Gaignard <benjamin.gaignard@...aro.org>:
> 2017-02-25 18:53 GMT+01:00 Jonathan Cameron <jic23@...nel.org>:
>> On 24/02/17 14:48, Benjamin Gaignard wrote:
>>> Add validate_trigger function in iio_trigger_ops and
>>> dev_attr_parent_trigger into trigger attribute group to be able
>>> to accept triggers as parents.
>>>
>>> Introduce an IIO device with one IIO_COUNT channel to get access
>>> to counter value. Counter directions can be set/get when writing/reading
>>> /sys/bus/iio/devices/iio:deviceX/in_count0_count_direction.
>>>
>>> The hardware have multiple way to use inputs edges and levels to
>>> performing counting, those different modes are exposed in:
>>> /sys/bus/iio/devices/iio:deviceX/in_count_count_mode_available.
>> Funny though it sounds, this is to general to generalize.
>> See below.
>>>
>>> "trigger_rising_edges" mode is automatically set when a valid
>>> parent trigger is set.
>> We still have an issue of two overlapping concepts here, that
>> of a clock and that of a parent trigger. Perhaps it's valid
>> to have a clock set to be the parent trigger, but that is
>> kind of the odd case rather than the normal use of
>> parent triggers (in my head at least :)
>>
>> So what we end up with here is something we have kind of messed
>> around with before...
>>
>> An event acting as a trigger.
>> Conceptually your 'preset' occurring is an event in IIO terms
>> (there is on going work to present exactly that event to userspace
>> for the other encoder driver we have).
>>
>> That event is then acting as a trigger, even if that trigger
>> is not 'visible' as such to userspace.
>>
>> This event as trigger is something we have messed around with
>> from the very start but never formalized. It is one of the things
>> that would make good use of an inkernel consumer interface
>> for events. If we had one of those, a tiny driver and a bit of
>> configfs magic interface and we'd be able to use any event as
>> a trigger.
>>
>> Hence I rather like this. You could say it fits with my
>> world view ;)
>>
>> Only remaining question to my mind is whether we need to make that
>> presence of an 'event' explicit? Doesn't necessarily have
>> to happen now, but if it existed in some sense it might make
>> it easier for generic userspace to interpret what is going on.
>>
>> Maybe something for the future.
>>
>> Anyhow, still some work to do here, but moving in a viable
>> direction (I think) so keep up the good work!
>
An other way is to get a device which is a trigger consumer without
having buffer or an event signaled in userland.
Maybe it doesn't fit with IIO concepts since it is only a way to drive
the device and not expose a real control in userland (no pull function
in this case).
>>
>> Jonathan
>>>
>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...com>
>>>
>>> version 2:
>>> - use dev_attr_parent_trigger
>>> - improve slave modes documentation
>>>
>>> version 3:
>>> - add one channel to get counter raw value
>>> ---
>>> .../ABI/testing/sysfs-bus-iio-timer-stm32 | 63 +++++
>>> drivers/iio/trigger/stm32-timer-trigger.c | 256 ++++++++++++++++++++-
>>> include/linux/mfd/stm32-timers.h | 2 +
>>> 3 files changed, 315 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> index 6534a60..63852a9 100644
>>> --- a/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32
>>> @@ -27,3 +27,66 @@ Description:
>>> Reading returns the current sampling frequency.
>>> Writing an value different of 0 set and start sampling.
>>> Writing 0 stop sampling.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_raw
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>>> + Reading returns counter current value.
>> Assuming it counts every one this can definitely be in_count0_input (so processed)
>> as it's in the 'base' units. Kind of hard not to be with a counter.
>>
>> Hohum. Just checked docs and this is documented as _raw.
>> Oh well no real harm in doing that I guess so perhaps we just stay with that even
>> if it's a little silly.
>>
>> Anyhow, no need to document stuff in here that is in the main docs
>> sysfs-bus-iio
>
> Ok I will remove it from stm32-timer documentation
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count_count_direction_available
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>>> + Reading returns the list of possible counting directions which
>>> + are:
>>> + - "up" : counter is increasing.
>>> + - "down": counter is decreasing.
>> This is now generic enough we should probably move it into the main docs rather than
>> repeating for each device.
>>
>> So cut this out of here and out of the 104_counter file and put it in
>> sysfs-bus-iio.
>>
>> Note that for some you'll have to drop the bits in the 104-counter-quad-8 file that say
>> if things are read only or not. The sysfs ABI docs don't need to say so that is fine.
>
> Okay
>
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_count_direction
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>>> + Reading returns the counting directions:
>>> + - "up" : counter is increasing.
>>> + - "down": counter is decreasing.
>>> + Writing set the counting direction.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count_count_mode_available
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>> I still think this needs breaking up if we are going to have any hope of a generic interface.
>>
>>> + Reading returns the list of possible counting modes which are:
>>> + - "internal_clock": Counter is clocked by the internal clock rising edges.
>> This is about the feed clock - not a mode as such.
>>
>>> + - "encoder_1" : Counter counts up/down on channel 2 edge depending on channel 1 level.
>>> + - "encoder_2" : Counter counts up/down on channel 1 edge depending on channel 2 level.
>>> + - "encoder_3" : Counter counts up/down on channels 1 & 2 edge depending on channel 1 & 2 level.
>> These combine the feed clock and the interpretation. To my mind, two different things.
>>
>> I kind of dislike the fact we can be either an internal clock or an encoder. seems that if you have an encoder
>> wired it would be nuts to use the internal clock, but given we do this on various rigs at work to fake
>> things when the encoder isn't moving I can't claim there is no use case ;)
>>
>>> + - "reset" : Rising edges on parent trigger reinitializes the counter value to preset value.
>>> + - "gated" : Counter counts when the parent trigger input is high.
>>> + Counter stops (but is not reset) as soon as the parent trigger becomes low.
>>> + - "trigger" : Counter starts at a rising edge of the parent trigger (but it is not reset).
>> These are gating of the feed clock
>>
>>> + - "trigger_rising_edges": Rising edges of the parent trigger are used as clock by the counter.
>> This one is about the feed clock again.
>>
>> So we need at least 3 different things.
>> 1. Feed clock selection.
>> 2. Encoder interpretation selection - arguably we should have an explicit description of the encoder
>> as a device in it's own right but I guess we can ignore that for now.
>> 3. The parent trigger 'use'.
>
> Here all is about how is clocked device counter, it could be by:
> - the internal SoC clock rising edges
> - the rising edges of some external pins (encoder, reset, gated, trigger)
> - the rising edges of an internal signal which is represented by a trigger.
>
> Without parent trigger I can already push the all except the last one.
> Maybe doing like this is a better solution ?
>
>>> +
>>> + Encoder modes are used to automatically handle the counting direction of the internal counter.
>>> + Those modes are typically used for high-accuracy rotor position sensing in electrical motors
>>> + or for digital potentiometers. From the two outputs of a quadrature encoder sensor the timer
>>> + extracts a clock on each and every active edge and adjusts the counting direction depending on
>>> + the relative phase-shift between the two incomings signals. The timer counter thus directly
>>> + holds the angular position of the motor.
>>> +
>>> + "trigger_rising_edges" mode is automatically set when a valid parent trigger is set.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_count_mode
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>>> + Reading returns the current counting mode.
>>> +
>>> +What: /sys/bus/iio/devices/iio:deviceX/in_count0_preset
>>> +KernelVersion: 4.12
>>> +Contact: benjamin.gaignard@...com
>>> +Description:
>>> + Reading returns the current preset value.
>>> + Writing set the preset value.
>>> + When counting up the counter start from 0 and fire an event when reach preset value.
>>> + When counting down the counter start from preset value and fire event when reach 0.
>> Fair enough, I hadn't thought if it like this, but makes sense.
>>
>>> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
>>> index 994b96d..04f5f05 100644
>>> --- a/drivers/iio/trigger/stm32-timer-trigger.c
>>> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
>>> @@ -15,6 +15,7 @@
>>> #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] = {
>>> @@ -32,12 +33,29 @@
>>> { TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
>>> };
>>>
>>> +/* List the triggers accepted by each timer */
>>> +static const void *valids_table[][MAX_VALIDS] = {
>>> + { TIM5_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
>>> + { TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
>>> + { TIM1_TRGO, TIM2_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,},
>>> + { }, /* timer 10 */
>>> + { }, /* timer 11 */
>>> + { 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,
>>> @@ -180,8 +198,7 @@ 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);
>>> + struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
>>> u32 cr2;
>>>
>>> regmap_read(priv->regmap, TIM_CR2, &cr2);
>>> @@ -194,10 +211,10 @@ 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);
>>> + struct stm32_timer_trigger *priv = dev_get_drvdata(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]))) {
>>> @@ -225,6 +242,7 @@ static IIO_DEVICE_ATTR(master_mode, 0660,
>>> &iio_dev_attr_sampling_frequency.dev_attr.attr,
>>> &iio_dev_attr_master_mode.dev_attr.attr,
>>> &iio_const_attr_master_mode_available.dev_attr.attr,
>>> + &dev_attr_parent_trigger.attr,
>>> NULL,
>>> };
>>>
>>> @@ -237,8 +255,49 @@ static IIO_DEVICE_ATTR(master_mode, 0660,
>>> NULL,
>>> };
>>>
>>> +static int stm32_validate_trigger(struct iio_trigger *trig,
>>> + struct iio_trigger *parent)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
>>> + const char * const *cur = priv->valids;
>>> + unsigned int i = 0;
>>> +
>>> + if (!parent) {
>>> + regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_TS, 0);
>>> + return 0;
>>> + }
>>> +
>>> + if (!is_stm32_timer_trigger(parent))
>>> + return -EINVAL;
>>> +
>>> + while (cur && *cur) {
>>> + if (!strncmp(parent->name, *cur, strlen(parent->name))) {
>>> + regmap_update_bits(priv->regmap,
>>> + TIM_SMCR, TIM_SMCR_TS,
>>> + i << TIM_SMCR_TS_SHIFT);
>>> +
>>> + /*
>>> + * By default make parent trigger rising edges
>>> + * use as clock for the counter
>>> + */
>>> + regmap_update_bits(priv->regmap, TIM_SMCR,
>>> + TIM_SMCR_SMS, TIM_SMCR_SMS);
>>> +
>>> + /* Enable controller */
>>> + regmap_update_bits(priv->regmap, TIM_CR1,
>>> + TIM_CR1_CEN, TIM_CR1_CEN);
>>> + return 0;
>>> + }
>>> + cur++;
>>> + i++;
>>> + }
>>> +
>>> + return -EINVAL;
>>> +}
>>> +
>>> static const struct iio_trigger_ops timer_trigger_ops = {
>>> .owner = THIS_MODULE,
>>> + .validate_trigger = stm32_validate_trigger,
>>> };
>>>
>>> static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>>> @@ -275,6 +334,185 @@ static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
>>> return 0;
>>> }
>>>
>>> +static int stm32_trigger_read_raw(struct iio_dev *indio_dev,
>>> + struct iio_chan_spec const *chan,
>>> + int *val, int *val2, long mask)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_RAW:
>>> + {
>>> + u32 cnt;
>>> +
>>> + regmap_read(priv->regmap, TIM_CNT, &cnt);
>>> + *val = cnt;
>>> +
>>> + return IIO_VAL_INT;
>>> + }
>>> + }
>>> +
>>> + return -EINVAL;
>>> +}
>>> +
>>> +static const struct iio_info stm32_trigger_info = {
>>> + .driver_module = THIS_MODULE,
>>> + .read_raw = stm32_trigger_read_raw,
>>> +};
>>> +
>>> +static const char *const stm32_count_modes[] = {
>>> + "internal_clock",
>>> + "encoder_1",
>>> + "encoder_2",
>>> + "encoder_3",
>>> + "reset",
>>> + "gated",
>>> + "trigger",
>>> + "trigger_rising_edges"
>>> +};
>>> +
>>> +static int stm32_set_count_mode(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan,
>>> + unsigned int mode)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, mode);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int stm32_get_count_mode(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + u32 smcr;
>>> +
>>> + regmap_read(priv->regmap, TIM_SMCR, &smcr);
>>> + smcr &= TIM_SMCR_SMS;
>>> +
>>> + return smcr;
>>> +}
>>> +
>>> +static const struct iio_enum stm32_count_mode_enum = {
>>> + .items = stm32_count_modes,
>>> + .num_items = ARRAY_SIZE(stm32_count_modes),
>>> + .set = stm32_set_count_mode,
>>> + .get = stm32_get_count_mode
>>> +};
>>> +
>>> +static const char *const stm32_count_direction_states[] = {
>>> + "up",
>>> + "down"
>>> +};
>>> +
>>> +static int stm32_set_count_direction(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan,
>>> + unsigned int mode)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> +
>>> + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_DIR, mode);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int stm32_get_count_direction(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + u32 cr1;
>>> +
>>> + regmap_read(priv->regmap, TIM_CR1, &cr1);
>>> +
>>> + return (cr1 & TIM_CR1_DIR);
>>> +}
>>> +
>>> +static const struct iio_enum stm32_count_direction_enum = {
>>> + .items = stm32_count_direction_states,
>>> + .num_items = ARRAY_SIZE(stm32_count_direction_states),
>>> + .set = stm32_set_count_direction,
>>> + .get = stm32_get_count_direction
>>> +};
>>> +
>>> +static ssize_t stm32_count_get_preset(struct iio_dev *indio_dev,
>>> + uintptr_t private,
>>> + const struct iio_chan_spec *chan,
>>> + char *buf)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + u32 arr;
>>> +
>>> + regmap_read(priv->regmap, TIM_ARR, &arr);
>>> +
>>> + return snprintf(buf, PAGE_SIZE, "%u\n", arr);
>>> +}
>>> +
>>> +static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
>>> + uintptr_t private,
>>> + const struct iio_chan_spec *chan,
>>> + const char *buf, size_t len)
>>> +{
>>> + struct stm32_timer_trigger *priv = iio_priv(indio_dev);
>>> + unsigned int preset;
>>> + int ret;
>>> +
>>> + ret = kstrtouint(buf, 0, &preset);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + regmap_write(priv->regmap, TIM_ARR, preset);
>>> + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
>>> +
>>> + return len;
>>> +}
>>> +
>>> +static const struct iio_chan_spec_ext_info stm32_trigger_count_info[] = {
>>> + {
>>> + .name = "preset",
>>> + .shared = IIO_SEPARATE,
>>> + .read = stm32_count_get_preset,
>>> + .write = stm32_count_set_preset
>>> + },
>>> + IIO_ENUM("count_direction", IIO_SEPARATE, &stm32_count_direction_enum),
>>> + IIO_ENUM_AVAILABLE("count_direction", &stm32_count_direction_enum),
>>> + IIO_ENUM("count_mode", IIO_SEPARATE, &stm32_count_mode_enum),
>>> + IIO_ENUM_AVAILABLE("count_mode", &stm32_count_mode_enum),
>>> + {}
>>> +};
>>> +
>>> +static const struct iio_chan_spec stm32_trigger_channel = {
>>> + .type = IIO_COUNT,
>>> + .channel = 0,
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>>> + .ext_info = stm32_trigger_count_info,
>>> + .indexed = 1
>>> +};
>>> +
>>> +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->num_channels = 1;
>>> + indio_dev->channels = &stm32_trigger_channel;
>>> + 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);
>>> +}
>>> +
>>> /**
>>> * is_stm32_timer_trigger
>>> * @trig: trigger to be checked
>>> @@ -299,10 +537,15 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>> if (of_property_read_u32(dev->of_node, "reg", &index))
>>> return -EINVAL;
>>>
>>> - if (index >= ARRAY_SIZE(triggers_table))
>>> + if (index >= ARRAY_SIZE(triggers_table)
>>> + || index >= ARRAY_SIZE(valids_table))
>>> return -EINVAL;
>>>
>>> - priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>>> + /* Create an IIO device only if we have triggers to be validated */
>>> + if (*valids_table[index])
>>> + priv = stm32_setup_iio_device(dev);
>>> + else
>>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>>>
>>> if (!priv)
>>> return -ENOMEM;
>>> @@ -312,6 +555,7 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
>>> 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)
>>> diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
>>> index d030004..4a0abbc 100644
>>> --- a/include/linux/mfd/stm32-timers.h
>>> +++ b/include/linux/mfd/stm32-timers.h
>>> @@ -21,6 +21,7 @@
>>> #define TIM_CCMR1 0x18 /* Capt/Comp 1 Mode Reg */
>>> #define TIM_CCMR2 0x1C /* Capt/Comp 2 Mode Reg */
>>> #define TIM_CCER 0x20 /* Capt/Comp Enable Reg */
>>> +#define TIM_CNT 0x24 /* Counter */
>>> #define TIM_PSC 0x28 /* Prescaler */
>>> #define TIM_ARR 0x2c /* Auto-Reload Register */
>>> #define TIM_CCR1 0x34 /* Capt/Comp Register 1 */
>>> @@ -30,6 +31,7 @@
>>> #define TIM_BDTR 0x44 /* Break and Dead-Time Reg */
>>>
>>> #define TIM_CR1_CEN BIT(0) /* Counter Enable */
>>> +#define TIM_CR1_DIR BIT(4) /* Counter Direction */
>>> #define TIM_CR1_ARPE BIT(7) /* Auto-reload Preload Ena */
>>> #define TIM_CR2_MMS (BIT(4) | BIT(5) | BIT(6)) /* Master mode selection */
>>> #define TIM_SMCR_SMS (BIT(0) | BIT(1) | BIT(2)) /* Slave mode selection */
>>>
>>
>
>
>
> --
> Benjamin Gaignard
>
> Graphic Study Group
>
> Linaro.org │ Open source software for ARM SoCs
>
> Follow Linaro: Facebook | Twitter | Blog
--
Benjamin Gaignard
Graphic Study Group
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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