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Message-ID: <0c2841f5-5e70-402a-b299-2d9fb96d5372@ti.com>
Date: Thu, 28 Aug 2025 12:03:20 +0530
From: Gokul Praveen <g-praveen@...com>
To: <daniel.lezcano@...aro.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] clocksource: timer-ti-dm : Capture functionality for
OMAP DM timer
Hi Daniel,
Is this patch good to be merged?
Regards
Gokul
On 21/08/25 19:13, Neha Malcom Francis wrote:
> Hi Gokul
>
> On 12/08/25 16:23, Gokul Praveen wrote:
>> Add PWM capture function in DM timer driver.
>>
>> OMAP DM timer hardware supports capture feature.It can be used to
>> timestamp events (falling/rising edges) detected on input signal.
>>
>> Signed-off-by: Gokul Praveen <g-praveen@...com>
>> ---
>> v2<==> v1
>> ===========
>> * Optimized the code and fixed some comment spacing and newline issues
>>
>> Precondition : Before calling driver API,it is assumed that the
>> capture signal is active else both duty cycle
>> and period returned by driver will not be valid.
>> ---
>> drivers/clocksource/timer-ti-dm.c | 119 ++++++++++++++++++++-
>> include/linux/platform_data/dmtimer-omap.h | 4 +
>> 2 files changed, 121 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
>> index e9e32df6b566..793e7cdcb1b1 100644
>> --- a/drivers/clocksource/timer-ti-dm.c
>> +++ b/drivers/clocksource/timer-ti-dm.c
>> @@ -31,6 +31,7 @@
>> #include <linux/platform_data/dmtimer-omap.h>
>>
>> #include <clocksource/timer-ti-dm.h>
>> +#include <linux/delay.h>
>>
>> /*
>> * timer errata flags
>> @@ -836,6 +837,48 @@ static int omap_dm_timer_set_match(struct omap_dm_timer *cookie, int enable,
>> return 0;
>> }
>>
>> +static int omap_dm_timer_set_cap(struct omap_dm_timer *cookie,
>> + int autoreload, bool config_period)
>> +{
>> + struct dmtimer *timer;
>> + struct device *dev;
>> + int rc;
>> + u32 l;
>> +
>> + timer = to_dmtimer(cookie);
>> + if (unlikely(!timer))
>> + return -EINVAL;
>> +
>> + dev = &timer->pdev->dev;
>> + rc = pm_runtime_resume_and_get(dev);
>> + if (rc)
>> + return rc;
>> + /*
>> + * 1. Select autoreload mode. TIMER_TCLR[1] AR bit.
>> + * 2. TIMER_TCLR[14]: Sets the functionality of the TIMER IO pin.
>> + * 3. TIMER_TCLR[13] : Capture mode select bit.
>> + * 3. TIMER_TCLR[9-8] : Select transition capture mode.
>> + */
>> +
>> + l = dmtimer_read(timer, OMAP_TIMER_CTRL_REG);
>> +
>> + if (autoreload)
>> + l |= OMAP_TIMER_CTRL_AR;
>> +
>> + l |= OMAP_TIMER_CTRL_CAPTMODE | OMAP_TIMER_CTRL_GPOCFG;
>> +
>> + if (config_period == true)
>> + l |= OMAP_TIMER_CTRL_TCM_LOWTOHIGH; /* Time Period config */
>> + else
>> + l |= OMAP_TIMER_CTRL_TCM_BOTHEDGES; /* Duty Cycle config */
>> +
>> + dmtimer_write(timer, OMAP_TIMER_CTRL_REG, l);
>> +
>> + pm_runtime_put_sync(dev);
>> +
>> + return 0;
>> +}
>> +
>> static int omap_dm_timer_set_pwm(struct omap_dm_timer *cookie, int def_on,
>> int toggle, int trigger, int autoreload)
>> {
>> @@ -1023,23 +1066,92 @@ static unsigned int omap_dm_timer_read_counter(struct omap_dm_timer *cookie)
>> return __omap_dm_timer_read_counter(timer);
>> }
>>
>> +static inline unsigned int __omap_dm_timer_cap(struct dmtimer *timer, int idx)
>> +{
>> + return idx == 0 ? dmtimer_read(timer, OMAP_TIMER_CAPTURE_REG) :
>> + dmtimer_read(timer, OMAP_TIMER_CAPTURE2_REG);
>> +}
>> +
>> static int omap_dm_timer_write_counter(struct omap_dm_timer *cookie, unsigned int value)
>> {
>> struct dmtimer *timer;
>> + struct device *dev;
>>
>> timer = to_dmtimer(cookie);
>> - if (unlikely(!timer || !atomic_read(&timer->enabled))) {
>> - pr_err("%s: timer not available or enabled.\n", __func__);
>> + if (unlikely(!timer)) {
>> + pr_err("%s: timer not available.\n", __func__);
>> return -EINVAL;
>> }
>>
>> + dev = &timer->pdev->dev;
>> +
>> + pm_runtime_resume_and_get(dev);
>> dmtimer_write(timer, OMAP_TIMER_COUNTER_REG, value);
>> + pm_runtime_put_sync(dev);
>>
>> /* Save the context */
>> timer->context.tcrr = value;
>> return 0;
>> }
>>
>> +/**
>> + * omap_dm_timer_cap_counter() - Calculate the high count or period count depending on the
>> + * configuration.
>> + * @cookie:Pointer to OMAP DM timer
>> + * @is_period:Whether to configure timer in period or duty cycle mode
>> + *
>> + * Return high count or period count if timer is enabled else appropriate error.
>> + */
>> +static unsigned int omap_dm_timer_cap_counter(struct omap_dm_timer *cookie, bool is_period)
>> +{
>> + struct dmtimer *timer;
>> + unsigned int cap1 = 0;
>> + unsigned int cap2 = 0;
>> + u32 l, ret;
>> +
>> + timer = to_dmtimer(cookie);
>> + if (unlikely(!timer || !atomic_read(&timer->enabled))) {
>> + pr_err("%s:timer is not available or enabled.%p\n", __func__, (void *)timer);
>> + return -EINVAL;
>> + }
>> +
>> + /* Stop the timer */
>> + omap_dm_timer_stop(cookie);
>> +
>> + /* Clear the timer counter value to 0 */
>> + ret = omap_dm_timer_write_counter(cookie, 0);
>> + if (ret)
>> + return ret;
>> +
>> + /* Sets the timer capture configuration for period/duty cycle calculation */
>> + ret = omap_dm_timer_set_cap(cookie, true, is_period);
>> + if (ret) {
>> + pr_err("%s: Failed to set timer capture configuration.\n", __func__);
>> + return ret;
>> + }
>> + /* Start the timer */
>> + omap_dm_timer_start(cookie);
>> +
>> + /*
>> + * 1 sec delay is given so as to provide
>> + * enough time to capture low frequency signals.
>> + */
>> + msleep(1000);
>> +
>> + cap1 = __omap_dm_timer_cap(timer, 0);
>> + cap2 = __omap_dm_timer_cap(timer, 1);
>> +
>> + /*
>> + * Clears the TCLR configuration.
>> + * The start bit must be set to 1 as the timer is already in start mode.
>> + */
>> + l = dmtimer_read(timer, OMAP_TIMER_CTRL_REG);
>> + l &= ~(0xffff) | 0x1;
>> + dmtimer_write(timer, OMAP_TIMER_CTRL_REG, l);
>> +
>> + return (cap2-cap1);
>> +}
>> +
>> static int __maybe_unused omap_dm_timer_runtime_suspend(struct device *dev)
>> {
>> struct dmtimer *timer = dev_get_drvdata(dev);
>> @@ -1246,6 +1358,9 @@ static const struct omap_dm_timer_ops dmtimer_ops = {
>> .write_counter = omap_dm_timer_write_counter,
>> .read_status = omap_dm_timer_read_status,
>> .write_status = omap_dm_timer_write_status,
>> + .set_cap = omap_dm_timer_set_cap,
>> + .get_cap_status = omap_dm_timer_get_pwm_status,
>> + .read_cap = omap_dm_timer_cap_counter,
>> };
>>
>> static const struct dmtimer_platform_data omap3plus_pdata = {
>> diff --git a/include/linux/platform_data/dmtimer-omap.h b/include/linux/platform_data/dmtimer-omap.h
>> index 95d852aef130..726d89143842 100644
>> --- a/include/linux/platform_data/dmtimer-omap.h
>> +++ b/include/linux/platform_data/dmtimer-omap.h
>> @@ -36,9 +36,13 @@ struct omap_dm_timer_ops {
>> int (*set_pwm)(struct omap_dm_timer *timer, int def_on,
>> int toggle, int trigger, int autoreload);
>> int (*get_pwm_status)(struct omap_dm_timer *timer);
>> + int (*set_cap)(struct omap_dm_timer *timer,
>> + int autoreload, bool config_period);
>> + int (*get_cap_status)(struct omap_dm_timer *timer);
>> int (*set_prescaler)(struct omap_dm_timer *timer, int prescaler);
>>
>> unsigned int (*read_counter)(struct omap_dm_timer *timer);
>> + unsigned int (*read_cap)(struct omap_dm_timer *timer, bool is_period);
>> int (*write_counter)(struct omap_dm_timer *timer,
>> unsigned int value);
>> unsigned int (*read_status)(struct omap_dm_timer *timer);
>
> LGTM
>
> Reviewed-by: Neha Malcom Francis <n-francis@...com>
>
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