[PATCH 1/3] pwm: jz4740: Drop dependency on MACH_INGENIC

[PATCH 1/3] pwm: jz4740: Drop dependency on MACH_INGENIC

[Paul Cercueil]

Depending on MACH_INGENIC prevent us from creating a generic kernel that
works on more than one MIPS board. Instead, we just depend on MIPS being
set.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/pwm/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index eebbc917ac97..7814e5b2cad7 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -234,7 +234,7 @@ config PWM_IMX_TPM
 
 config PWM_JZ4740
 	tristate "Ingenic JZ47xx PWM support"
-	depends on MACH_INGENIC
+	depends on MIPS
 	depends on COMMON_CLK
 	select MFD_SYSCON
 	help
-- 
2.25.1

[PATCH 2/3] pwm: jz4740: Make PWM start with the active part

[Paul Cercueil]

The PWM would previously always start with the inactive part.
To counter that, the common trick is to use an inverted duty as the
real duty (as in, 'period - duty'), and invert the polarity when the
PWM is enabled.

However, for some reason the driver was already configuring the hardware
for an inverted duty, so inverting it again means we do configure the
hardware with the actual duty value.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/pwm/pwm-jz4740.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index 3cd5c054ad9a..f566f9d248d6 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -6,7 +6,6 @@
  * Limitations:
  * - The .apply callback doesn't complete the currently running period before
  *   reconfiguring the hardware.
- * - Each period starts with the inactive part.
  */
 
 #include <linux/clk.h>
@@ -163,7 +162,7 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	/* Calculate duty value */
 	tmp = (unsigned long long)period * state->duty_cycle;
 	do_div(tmp, state->period);
-	duty = period - tmp;
+	duty = (unsigned long)tmp;
 
 	if (duty >= period)
 		duty = period - 1;
@@ -190,17 +189,13 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			   TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
 
 	/* Set polarity */
-	switch (state->polarity) {
-	case PWM_POLARITY_NORMAL:
+	if ((state->polarity != PWM_POLARITY_INVERSED) ^ state->enabled)
 		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
 				   TCU_TCSR_PWM_INITL_HIGH, 0);
-		break;
-	case PWM_POLARITY_INVERSED:
+	else
 		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
 				   TCU_TCSR_PWM_INITL_HIGH,
 				   TCU_TCSR_PWM_INITL_HIGH);
-		break;
-	}
 
 	if (state->enabled)
 		jz4740_pwm_enable(chip, pwm);
-- 
2.25.1

Re: [PATCH 2/3] pwm: jz4740: Make PWM start with the active part

[Uwe Kleine-König]

On Mon, Apr 13, 2020 at 02:14:44PM +0200, Paul Cercueil wrote:
> The PWM would previously always start with the inactive part.
> To counter that, the common trick is to use an inverted duty as the
> real duty (as in, 'period - duty'), and invert the polarity when the
> PWM is enabled.
> 
> However, for some reason the driver was already configuring the hardware
> for an inverted duty, so inverting it again means we do configure the
> hardware with the actual duty value.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/pwm/pwm-jz4740.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
> index 3cd5c054ad9a..f566f9d248d6 100644
> --- a/drivers/pwm/pwm-jz4740.c
> +++ b/drivers/pwm/pwm-jz4740.c
> @@ -6,7 +6,6 @@
>   * Limitations:
>   * - The .apply callback doesn't complete the currently running period before
>   *   reconfiguring the hardware.
> - * - Each period starts with the inactive part.
>   */
>  
>  #include <linux/clk.h>
> @@ -163,7 +162,7 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,

Side note: in the calculation above the driver is loosing precision as
the calculation for the duty counter uses the (already rounded) stuff
for the period counter.

The currently used calculation is (somewhat simplified syntax):

	period = (rate * requested_period) // NSEC_PER_SEC;
	duty = (period * requested_duty) // requested_period

The output then is an actual period of

	period * NSEC_PER_SEC / rate

and the duty cycle is

	duty * NSEC_PER_SEC / rate

.

Consider the following:

	rate = 23856100
	requested_period = 20959
	requested_duty = 16000

With the currently implemented algorithm we get:

	period = 499
	duty = 380

yielding a real period of 20917.08 ns (ok) and a duty cycle of 15928.84
ns. With duty = 381 we'd get 15970.758 ns which is better.

To reach that we'd need:

	/* Calculate duty value */
	tmp = (unsigned long long)rate * state->duty_cycle;
	do_div(tmp, NSEC_PER_SEC);
	duty = tmp

>  	/* Calculate duty value */
>  	tmp = (unsigned long long)period * state->duty_cycle;
>  	do_div(tmp, state->period);
> -	duty = period - tmp;
> +	duty = (unsigned long)tmp;

That cast is unnecessary.

>  
>  	if (duty >= period)
>  		duty = period - 1;
> @@ -190,17 +189,13 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  			   TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
>  
>  	/* Set polarity */
> -	switch (state->polarity) {
> -	case PWM_POLARITY_NORMAL:
> +	if ((state->polarity != PWM_POLARITY_INVERSED) ^ state->enabled)

This needs to be more complicated than before as a disabled PWM needs
the other setting to yield its inactive level?

Maybe worth a comment?

>  		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
>  				   TCU_TCSR_PWM_INITL_HIGH, 0);
> -		break;
> -	case PWM_POLARITY_INVERSED:
> +	else
>  		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
>  				   TCU_TCSR_PWM_INITL_HIGH,
>  				   TCU_TCSR_PWM_INITL_HIGH);
> -		break;
> -	}

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

[PATCH 3/3] pwm: jz4740: Add support for the JZ4725B

[Paul Cercueil]

The PWM hardware in the JZ4725B works the same as in the JZ4740, but has
only six channels available.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---

Notes:
    I did not add documentation for the new jz4725b-pwm compatible
    string on purpose. The reason is that the documentation file
    for the Timer/Counter Unit (TCU) of Ingenic SoCs will be
    completely rewritten from .txt to YAML in a separate patchset.

 drivers/pwm/pwm-jz4740.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index f566f9d248d6..bb27934fb6c2 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -22,6 +22,10 @@
 
 #define NUM_PWM 8
 
+struct soc_info {
+	unsigned int num_pwms;
+};
+
 struct jz4740_pwm_chip {
 	struct pwm_chip chip;
 	struct regmap *map;
@@ -36,7 +40,7 @@ static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
 				   unsigned int channel)
 {
 	/* Enable all TCU channels for PWM use by default except channels 0/1 */
-	u32 pwm_channels_mask = GENMASK(NUM_PWM - 1, 2);
+	u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
 
 	device_property_read_u32(jz->chip.dev->parent,
 				 "ingenic,pwm-channels-mask",
@@ -214,6 +218,7 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct jz4740_pwm_chip *jz4740;
+	const struct soc_info *info = device_get_match_data(dev);
 
 	jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
 	if (!jz4740)
@@ -227,8 +232,8 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
 
 	jz4740->chip.dev = dev;
 	jz4740->chip.ops = &jz4740_pwm_ops;
-	jz4740->chip.npwm = NUM_PWM;
 	jz4740->chip.base = -1;
+	jz4740->chip.npwm = info ? info->num_pwms : NUM_PWM;
 	jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
 	jz4740->chip.of_pwm_n_cells = 3;
 
@@ -244,9 +249,18 @@ static int jz4740_pwm_remove(struct platform_device *pdev)
 	return pwmchip_remove(&jz4740->chip);
 }
 
+static const struct soc_info __maybe_unused jz4740_soc_info = {
+	.num_pwms = 8,
+};
+
+static const struct soc_info __maybe_unused jz4725b_soc_info = {
+	.num_pwms = 6,
+};
+
 #ifdef CONFIG_OF
 static const struct of_device_id jz4740_pwm_dt_ids[] = {
-	{ .compatible = "ingenic,jz4740-pwm", },
+	{ .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
+	{ .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
 	{},
 };
 MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
-- 
2.25.1

Re: [PATCH 3/3] pwm: jz4740: Add support for the JZ4725B

[Uwe Kleine-König]

On Mon, Apr 13, 2020 at 02:14:45PM +0200, Paul Cercueil wrote:
> The PWM hardware in the JZ4725B works the same as in the JZ4740, but has
> only six channels available.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
> 
> Notes:
>     I did not add documentation for the new jz4725b-pwm compatible
>     string on purpose. The reason is that the documentation file
>     for the Timer/Counter Unit (TCU) of Ingenic SoCs will be
>     completely rewritten from .txt to YAML in a separate patchset.
> 
>  drivers/pwm/pwm-jz4740.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
> index f566f9d248d6..bb27934fb6c2 100644
> --- a/drivers/pwm/pwm-jz4740.c
> +++ b/drivers/pwm/pwm-jz4740.c
> @@ -22,6 +22,10 @@
>  
>  #define NUM_PWM 8
>  
> +struct soc_info {
> +	unsigned int num_pwms;
> +};
> +
>  struct jz4740_pwm_chip {
>  	struct pwm_chip chip;
>  	struct regmap *map;
> @@ -36,7 +40,7 @@ static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
>  				   unsigned int channel)
>  {
>  	/* Enable all TCU channels for PWM use by default except channels 0/1 */
> -	u32 pwm_channels_mask = GENMASK(NUM_PWM - 1, 2);
> +	u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
>  
>  	device_property_read_u32(jz->chip.dev->parent,
>  				 "ingenic,pwm-channels-mask",
> @@ -214,6 +218,7 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct jz4740_pwm_chip *jz4740;
> +	const struct soc_info *info = device_get_match_data(dev);
>  
>  	jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
>  	if (!jz4740)
> @@ -227,8 +232,8 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
>  
>  	jz4740->chip.dev = dev;
>  	jz4740->chip.ops = &jz4740_pwm_ops;
> -	jz4740->chip.npwm = NUM_PWM;
>  	jz4740->chip.base = -1;
> +	jz4740->chip.npwm = info ? info->num_pwms : NUM_PWM;

Can info be actually NULL? I don't think so, so you can just use
info->num_pwms here and drop the definition of NUM_PWM.

>  	jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
>  	jz4740->chip.of_pwm_n_cells = 3;
>  

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Re: [PATCH 3/3] pwm: jz4740: Add support for the JZ4725B

[Paul Cercueil]

Hi Uwe,

Le dim. 24 mai 2020 à 19:37, Uwe Kleine-König 
<u.kleine-koenig@pengutronix.de> a écrit :
> On Mon, Apr 13, 2020 at 02:14:45PM +0200, Paul Cercueil wrote:
>>  The PWM hardware in the JZ4725B works the same as in the JZ4740, 
>> but has
>>  only six channels available.
>> 
>>  Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>  ---
>> 
>>  Notes:
>>      I did not add documentation for the new jz4725b-pwm compatible
>>      string on purpose. The reason is that the documentation file
>>      for the Timer/Counter Unit (TCU) of Ingenic SoCs will be
>>      completely rewritten from .txt to YAML in a separate patchset.
>> 
>>   drivers/pwm/pwm-jz4740.c | 20 +++++++++++++++++---
>>   1 file changed, 17 insertions(+), 3 deletions(-)
>> 
>>  diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
>>  index f566f9d248d6..bb27934fb6c2 100644
>>  --- a/drivers/pwm/pwm-jz4740.c
>>  +++ b/drivers/pwm/pwm-jz4740.c
>>  @@ -22,6 +22,10 @@
>> 
>>   #define NUM_PWM 8
>> 
>>  +struct soc_info {
>>  +	unsigned int num_pwms;
>>  +};
>>  +
>>   struct jz4740_pwm_chip {
>>   	struct pwm_chip chip;
>>   	struct regmap *map;
>>  @@ -36,7 +40,7 @@ static bool jz4740_pwm_can_use_chn(struct 
>> jz4740_pwm_chip *jz,
>>   				   unsigned int channel)
>>   {
>>   	/* Enable all TCU channels for PWM use by default except channels 
>> 0/1 */
>>  -	u32 pwm_channels_mask = GENMASK(NUM_PWM - 1, 2);
>>  +	u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
>> 
>>   	device_property_read_u32(jz->chip.dev->parent,
>>   				 "ingenic,pwm-channels-mask",
>>  @@ -214,6 +218,7 @@ static int jz4740_pwm_probe(struct 
>> platform_device *pdev)
>>   {
>>   	struct device *dev = &pdev->dev;
>>   	struct jz4740_pwm_chip *jz4740;
>>  +	const struct soc_info *info = device_get_match_data(dev);
>> 
>>   	jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
>>   	if (!jz4740)
>>  @@ -227,8 +232,8 @@ static int jz4740_pwm_probe(struct 
>> platform_device *pdev)
>> 
>>   	jz4740->chip.dev = dev;
>>   	jz4740->chip.ops = &jz4740_pwm_ops;
>>  -	jz4740->chip.npwm = NUM_PWM;
>>   	jz4740->chip.base = -1;
>>  +	jz4740->chip.npwm = info ? info->num_pwms : NUM_PWM;
> 
> Can info be actually NULL? I don't think so, so you can just use
> info->num_pwms here and drop the definition of NUM_PWM.

In *theory* it can be NULL if the kernel is configured without 
CONFIG_OF, which will never happen on any board supported by this 
driver. I can add a dependency on CONFIG_OF in V2, then use 
info->num_pwms there.

cheers,
-Paul

>>   	jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
>>   	jz4740->chip.of_pwm_n_cells = 3;
>> 
> 
> Best regards
> Uwe
> 
> --
> Pengutronix e.K.                           | Uwe Kleine-König        
>     |
> Industrial Linux Solutions                 | 
> https://www.pengutronix.de/ |

Re: [PATCH 3/3] pwm: jz4740: Add support for the JZ4725B

[Uwe Kleine-König]

Hello Paul,

On Sun, May 24, 2020 at 07:51:23PM +0200, Paul Cercueil wrote:
> Le dim. 24 mai 2020 à 19:37, Uwe Kleine-König
> <u.kleine-koenig@pengutronix.de> a écrit :
> > On Mon, Apr 13, 2020 at 02:14:45PM +0200, Paul Cercueil wrote:
> > >  @@ -214,6 +218,7 @@ static int jz4740_pwm_probe(struct
> > > platform_device *pdev)
> > >   {
> > >   	struct device *dev = &pdev->dev;
> > >   	struct jz4740_pwm_chip *jz4740;
> > >  +	const struct soc_info *info = device_get_match_data(dev);
> > > 
> > >   	jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
> > >   	if (!jz4740)
> > >  @@ -227,8 +232,8 @@ static int jz4740_pwm_probe(struct
> > > platform_device *pdev)
> > > 
> > >   	jz4740->chip.dev = dev;
> > >   	jz4740->chip.ops = &jz4740_pwm_ops;
> > >  -	jz4740->chip.npwm = NUM_PWM;
> > >   	jz4740->chip.base = -1;
> > >  +	jz4740->chip.npwm = info ? info->num_pwms : NUM_PWM;
> > 
> > Can info be actually NULL? I don't think so, so you can just use
> > info->num_pwms here and drop the definition of NUM_PWM.
> 
> In *theory* it can be NULL if the kernel is configured without CONFIG_OF,
> which will never happen on any board supported by this driver. I can add a
> dependency on CONFIG_OF in V2, then use info->num_pwms there.

I'd prefer just something like:

	if (!info)
		return -EINVAL;

instead of a dependency on CONFIG_OF.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Re: [PATCH 1/3] pwm: jz4740: Drop dependency on MACH_INGENIC

[Paul Cercueil]

Hi,

Any feedback on this patchset?

Cheers,
-Paul


Le lun. 13 avril 2020 à 14:14, Paul Cercueil <paul@crapouillou.net> a 
écrit :
> Depending on MACH_INGENIC prevent us from creating a generic kernel 
> that
> works on more than one MIPS board. Instead, we just depend on MIPS 
> being
> set.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/pwm/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index eebbc917ac97..7814e5b2cad7 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -234,7 +234,7 @@ config PWM_IMX_TPM
> 
>  config PWM_JZ4740
>  	tristate "Ingenic JZ47xx PWM support"
> -	depends on MACH_INGENIC
> +	depends on MIPS
>  	depends on COMMON_CLK
>  	select MFD_SYSCON
>  	help
> --
> 2.25.1
> 

Re: [PATCH 1/3] pwm: jz4740: Drop dependency on MACH_INGENIC

[Uwe Kleine-König]

On Mon, Apr 13, 2020 at 02:14:43PM +0200, Paul Cercueil wrote:
> Depending on MACH_INGENIC prevent us from creating a generic kernel that
> works on more than one MIPS board. Instead, we just depend on MIPS being
> set.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/pwm/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index eebbc917ac97..7814e5b2cad7 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -234,7 +234,7 @@ config PWM_IMX_TPM
>  
>  config PWM_JZ4740
>  	tristate "Ingenic JZ47xx PWM support"
> -	depends on MACH_INGENIC
> +	depends on MIPS

Looks good to me.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |