pwm: Some fixes preparing chardev support

[PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks

Posted by Uwe Kleine-König 10 months, 1 week ago

When you're interested in the actual register settings the driver
chooses or interprets you want to see them also for calls that hit
corner cases.

Make sure that all calls to stm32_pwm_round_waveform_tohw() and
stm32_pwm_round_waveform_fromhw() emit the debug message about the
register settings.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
---
 drivers/pwm/pwm-stm32.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index c6625f51a199..dca5d09d80b9 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -180,11 +180,11 @@ static int stm32_pwm_round_waveform_tohw(struct pwm_chip *chip,
 
 	wfhw->ccr = min_t(u64, ccr, wfhw->arr + 1);
 
+out:
 	dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] @%lu -> CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x\n",
 		pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
 		rate, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr);
 
-out:
 	clk_disable(priv->clk);
 
 	return ret;
@@ -236,17 +236,16 @@ static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
 			wf->duty_length_ns = ccr_ns;
 			wf->duty_offset_ns = 0;
 		}
-
-		dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
-			pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
-			wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
-
 	} else {
 		*wf = (struct pwm_waveform){
 			.period_length_ns = 0,
 		};
 	}
 
+	dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
+		pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
+		wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
+
 	return 0;
 }
 
-- 
2.47.2

Re: [PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks

Posted by kernel test robot 10 months, 1 week ago

Hi Uwe,

kernel test robot noticed the following build errors:

[auto build test ERROR on e48e99b6edf41c69c5528aa7ffb2daf3c59ee105]

url:    https://github.com/intel-lab-lkp/linux/commits/Uwe-Kleine-K-nig/pwm-Let-pwm_set_waveform-succeed-even-if-lowlevel-driver-rounded-up/20250405-173024
base:   e48e99b6edf41c69c5528aa7ffb2daf3c59ee105
patch link:    https://lore.kernel.org/r/fe154e79319da5ff4159cdc71201a9d3b395e491.1743844730.git.u.kleine-koenig%40baylibre.com
patch subject: [PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks
config: x86_64-buildonly-randconfig-001-20250406 (https://download.01.org/0day-ci/archive/20250406/202504061207.97zbNPvV-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250406/202504061207.97zbNPvV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504061207.97zbNPvV-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/pwm/pwm-stm32.c:246:60: error: use of undeclared identifier 'rate'
     246 |                 pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
         |                                                                          ^
   1 error generated.


vim +/rate +246 drivers/pwm/pwm-stm32.c

   208	
   209	static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
   210						   struct pwm_device *pwm,
   211						   const void *_wfhw,
   212						   struct pwm_waveform *wf)
   213	{
   214		const struct stm32_pwm_waveform *wfhw = _wfhw;
   215		struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
   216		unsigned int ch = pwm->hwpwm;
   217	
   218		if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
   219			unsigned long rate = clk_get_rate(priv->clk);
   220			u64 ccr_ns;
   221	
   222			/* The result doesn't overflow for rate >= 15259 */
   223			wf->period_length_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1),
   224										     NSEC_PER_SEC, rate);
   225	
   226			ccr_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * wfhw->ccr,
   227								       NSEC_PER_SEC, rate);
   228	
   229			if (wfhw->ccer & TIM_CCER_CCxP(ch + 1)) {
   230				wf->duty_length_ns =
   231					stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1 - wfhw->ccr),
   232									      NSEC_PER_SEC, rate);
   233	
   234				wf->duty_offset_ns = ccr_ns;
   235			} else {
   236				wf->duty_length_ns = ccr_ns;
   237				wf->duty_offset_ns = 0;
   238			}
   239		} else {
   240			*wf = (struct pwm_waveform){
   241				.period_length_ns = 0,
   242			};
   243		}
   244	
   245		dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
 > 246			pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
   247			wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
   248	
   249		return 0;
   250	}
   251	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks

Posted by kernel test robot 10 months, 1 week ago

Hi Uwe,

kernel test robot noticed the following build errors:

[auto build test ERROR on e48e99b6edf41c69c5528aa7ffb2daf3c59ee105]

url:    https://github.com/intel-lab-lkp/linux/commits/Uwe-Kleine-K-nig/pwm-Let-pwm_set_waveform-succeed-even-if-lowlevel-driver-rounded-up/20250405-173024
base:   e48e99b6edf41c69c5528aa7ffb2daf3c59ee105
patch link:    https://lore.kernel.org/r/fe154e79319da5ff4159cdc71201a9d3b395e491.1743844730.git.u.kleine-koenig%40baylibre.com
patch subject: [PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks
config: arm-randconfig-004-20250406 (https://download.01.org/0day-ci/archive/20250406/202504060517.dHXuUANs-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250406/202504060517.dHXuUANs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504060517.dHXuUANs-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/device.h:15,
                    from include/linux/dmaengine.h:8,
                    from include/linux/mfd/stm32-timers.h:11,
                    from drivers/pwm/pwm-stm32.c:12:
   drivers/pwm/pwm-stm32.c: In function 'stm32_pwm_round_waveform_fromhw':
>> drivers/pwm/pwm-stm32.c:246:60: error: 'rate' undeclared (first use in this function)
     246 |   pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
         |                                                            ^~~~
   include/linux/dev_printk.h:139:35: note: in definition of macro 'dev_no_printk'
     139 |    _dev_printk(level, dev, fmt, ##__VA_ARGS__); \
         |                                   ^~~~~~~~~~~
   drivers/pwm/pwm-stm32.c:245:2: note: in expansion of macro 'dev_dbg'
     245 |  dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
         |  ^~~~~~~
   drivers/pwm/pwm-stm32.c:246:60: note: each undeclared identifier is reported only once for each function it appears in
     246 |   pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
         |                                                            ^~~~
   include/linux/dev_printk.h:139:35: note: in definition of macro 'dev_no_printk'
     139 |    _dev_printk(level, dev, fmt, ##__VA_ARGS__); \
         |                                   ^~~~~~~~~~~
   drivers/pwm/pwm-stm32.c:245:2: note: in expansion of macro 'dev_dbg'
     245 |  dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
         |  ^~~~~~~


vim +/rate +246 drivers/pwm/pwm-stm32.c

   208	
   209	static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
   210						   struct pwm_device *pwm,
   211						   const void *_wfhw,
   212						   struct pwm_waveform *wf)
   213	{
   214		const struct stm32_pwm_waveform *wfhw = _wfhw;
   215		struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
   216		unsigned int ch = pwm->hwpwm;
   217	
   218		if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
   219			unsigned long rate = clk_get_rate(priv->clk);
   220			u64 ccr_ns;
   221	
   222			/* The result doesn't overflow for rate >= 15259 */
   223			wf->period_length_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1),
   224										     NSEC_PER_SEC, rate);
   225	
   226			ccr_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * wfhw->ccr,
   227								       NSEC_PER_SEC, rate);
   228	
   229			if (wfhw->ccer & TIM_CCER_CCxP(ch + 1)) {
   230				wf->duty_length_ns =
   231					stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1 - wfhw->ccr),
   232									      NSEC_PER_SEC, rate);
   233	
   234				wf->duty_offset_ns = ccr_ns;
   235			} else {
   236				wf->duty_length_ns = ccr_ns;
   237				wf->duty_offset_ns = 0;
   238			}
   239		} else {
   240			*wf = (struct pwm_waveform){
   241				.period_length_ns = 0,
   242			};
   243		}
   244	
   245		dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
 > 246			pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
   247			wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
   248	
   249		return 0;
   250	}
   251	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 1/6] pwm: Let pwm_set_waveform() succeed even if lowlevel driver rounded up
[PATCH 2/6] pwm: stm32: Search an appropriate duty_cycle if period cannot be modified
[PATCH 3/6] pwm: stm32: Don't open-code TIM_CCER_CCxE()
[PATCH 4/6] pwm: stm32: Emit debug output also for corner cases of the rounding callbacks
[PATCH 5/6] pwm: axi-pwmgen: Let .round_waveform_tohw() signal when request was rounded up
[PATCH 6/6] pwm: Do stricter return value checking for .round_waveform_tohw()