[PATCH] ARM: dts: lpc32xx: add pwm-cells to base dts file

[PATCH] ARM: dts: lpc32xx: add pwm-cells to base dts file

[Sylvain Lemieux]

From: Sylvain Lemieux <slemieux@tycoint.com>

There is no need to define the "pwm-cells" in the board
specific dts file; move the entry to the base dts file.

Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
---
Note:
* This patch should be apply after
  "ARM: dts: lpc32xx: set default parent clock for pwm1 & pwm2"
  http://www.spinics.net/lists/arm-kernel/msg530277.html
  - There is no dependency between the patches.

 arch/arm/boot/dts/lpc32xx.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/lpc32xx.dtsi b/arch/arm/boot/dts/lpc32xx.dtsi
index 218d9fa..c031c94 100644
--- a/arch/arm/boot/dts/lpc32xx.dtsi
+++ b/arch/arm/boot/dts/lpc32xx.dtsi
@@ -472,6 +472,7 @@
 				assigned-clocks = <&clk LPC32XX_CLK_PWM1>;
 				assigned-clock-parents = <&clk LPC32XX_CLK_PERIPH>;
 				status = "disabled";
+				#pwm-cells = <2>;
 			};
 
 			pwm2: pwm at 4005C004 {
@@ -481,6 +482,7 @@
 				assigned-clocks = <&clk LPC32XX_CLK_PWM2>;
 				assigned-clock-parents = <&clk LPC32XX_CLK_PERIPH>;
 				status = "disabled";
+				#pwm-cells = <2>;
 			};
 
 			timer3: timer at 40060000 {
-- 
1.8.3.1

[PATCH] ARM: dts: lpc32xx: add pwm-cells to base dts file

[Vladimir Zapolskiy]

Hi Sylvain,

On 26.09.2016 21:47, Sylvain Lemieux wrote:
> From: Sylvain Lemieux <slemieux@tycoint.com>
> 
> There is no need to define the "pwm-cells" in the board
> specific dts file; move the entry to the base dts file.
> 
> Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
> ---
> Note:
> * This patch should be apply after
>   "ARM: dts: lpc32xx: set default parent clock for pwm1 & pwm2"
>   http://www.spinics.net/lists/arm-kernel/msg530277.html
>   - There is no dependency between the patches.
> 
>  arch/arm/boot/dts/lpc32xx.dtsi | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/lpc32xx.dtsi b/arch/arm/boot/dts/lpc32xx.dtsi
> index 218d9fa..c031c94 100644
> --- a/arch/arm/boot/dts/lpc32xx.dtsi
> +++ b/arch/arm/boot/dts/lpc32xx.dtsi
> @@ -472,6 +472,7 @@
>  				assigned-clocks = <&clk LPC32XX_CLK_PWM1>;
>  				assigned-clock-parents = <&clk LPC32XX_CLK_PERIPH>;
>  				status = "disabled";
> +				#pwm-cells = <2>;
>  			};
>  
>  			pwm2: pwm at 4005C004 {
> @@ -481,6 +482,7 @@
>  				assigned-clocks = <&clk LPC32XX_CLK_PWM2>;
>  				assigned-clock-parents = <&clk LPC32XX_CLK_PERIPH>;
>  				status = "disabled";
> +				#pwm-cells = <2>;
>  			};
>  
>  			timer3: timer at 40060000 {
> 

that's something I have done locally and in a different manner, but I haven't
published it yet, please find below a draft.

First of all from multiple places in the User's Manual you can find that there
are "two single output PWM blocks" or "the LPC32x0 provides two 8-bit PWMs" etc.

In this case it does not make sense to set PWM cells to 2 (there is only one
channel), and 1 cell for frequency is good enough, and that's the proposed
change to support it:

diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
index a9b3cff..447ae44 100644
--- a/drivers/pwm/pwm-lpc32xx.c
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -99,6 +99,22 @@ static const struct pwm_ops lpc32xx_pwm_ops = {
 	.owner = THIS_MODULE,
 };
 
+static struct pwm_device *lpc32xx_pwm_of_xlate(struct pwm_chip *pc,
+				       const struct of_phandle_args *args)
+{
+	struct pwm_device *pwm;
+
+	pwm = pwm_request_from_chip(pc, 0, NULL);
+	if (IS_ERR(pwm))
+		return pwm;
+
+	pwm->args.period = args->args[0];
+
+	return pwm;
+}
+
 static int lpc32xx_pwm_probe(struct platform_device *pdev)
 {
 	struct lpc32xx_pwm_chip *lpc32xx;
@@ -123,6 +139,8 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
 	lpc32xx->chip.ops = &lpc32xx_pwm_ops;
 	lpc32xx->chip.npwm = 1;
 	lpc32xx->chip.base = -1;
+	lpc32xx->chip.of_xlate = lpc32xx_pwm_of_xlate;
+	lpc32xx->chip.of_pwm_n_cells = 1;
 
 	ret = pwmchip_add(&lpc32xx->chip);
 	if (ret < 0) {


What is your opinion about this proposal?

If this change is applied, then lpc32xx.dtsi should contain #pwm-cells = <1>.

--
With best wishes,
Vladimir

[PATCH] ARM: dts: lpc32xx: add pwm-cells to base dts file

[Sylvain Lemieux (gmail)]

Hi Vladimir,

On Tue, 2016-09-27 at 01:07 +0300, Vladimir Zapolskiy wrote:
> Hi Sylvain,
> 
> On 26.09.2016 21:47, Sylvain Lemieux wrote:
> > From: Sylvain Lemieux <slemieux@tycoint.com>
> > 
> > There is no need to define the "pwm-cells" in the board
> > specific dts file; move the entry to the base dts file.
> > 
> > Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
> > ---
> > Note:
> > * This patch should be apply after
> >   "ARM: dts: lpc32xx: set default parent clock for pwm1 & pwm2"
> >   http://www.spinics.net/lists/arm-kernel/msg530277.html
> >   - There is no dependency between the patches.
> > 
> >  arch/arm/boot/dts/lpc32xx.dtsi | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
[...] 
> 
> that's something I have done locally and in a different manner, but I haven't
> published it yet, please find below a draft.
> 
> First of all from multiple places in the User's Manual you can find that there
> are "two single output PWM blocks" or "the LPC32x0 provides two 8-bit PWMs" etc.
> 
> In this case it does not make sense to set PWM cells to 2 (there is only one
> channel), and 1 cell for frequency is good enough, and that's the proposed
> change to support it:
> 
> diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
> index a9b3cff..447ae44 100644
> --- a/drivers/pwm/pwm-lpc32xx.c
> +++ b/drivers/pwm/pwm-lpc32xx.c
> @@ -99,6 +99,22 @@ static const struct pwm_ops lpc32xx_pwm_ops = {
>  	.owner = THIS_MODULE,
>  };
>  
> +static struct pwm_device *lpc32xx_pwm_of_xlate(struct pwm_chip *pc,
> +				       const struct of_phandle_args *args)
> +{
> +	struct pwm_device *pwm;
> +
> +	pwm = pwm_request_from_chip(pc, 0, NULL);
> +	if (IS_ERR(pwm))
> +		return pwm;
> +
> +	pwm->args.period = args->args[0];
> +
> +	return pwm;
> +}
> +
>  static int lpc32xx_pwm_probe(struct platform_device *pdev)
>  {
>  	struct lpc32xx_pwm_chip *lpc32xx;
> @@ -123,6 +139,8 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
>  	lpc32xx->chip.ops = &lpc32xx_pwm_ops;
>  	lpc32xx->chip.npwm = 1;
>  	lpc32xx->chip.base = -1;
> +	lpc32xx->chip.of_xlate = lpc32xx_pwm_of_xlate;
> +	lpc32xx->chip.of_pwm_n_cells = 1;
>  
>  	ret = pwmchip_add(&lpc32xx->chip);
>  	if (ret < 0) {
> 
> 
> What is your opinion about this proposal?
> 
I agree with you, this clean-up make sense; the PWM cell should be 1.

> If this change is applied, then lpc32xx.dtsi should contain #pwm-cells = <1>.
> 
Can you submit your change on the mailing list?
I will send a version 2 of this patch after.

If it is helping, I can take care of submitting a patch
to update the documentation (lpc32xx-pwm.txt).

Did you have a change to look at the 2 others PWM related change:
* clk: lpc32xx: fix pwm clock divider computation
  http://www.spinics.net/lists/arm-kernel/msg534048.html
* ARM: dts: lpc32xx: set pwm1 & pwm2 default clock rate
  http://www.spinics.net/lists/arm-kernel/msg534051.html
 
> --
> With best wishes,
> Vladimir

Sylvain

[PATCH] ARM: dts: lpc32xx: add pwm-cells to base dts file

[Sylvain Lemieux]

Hi Vladimir,

On Tue, 2016-09-27 at 08:34 -0400, Sylvain Lemieux (gmail) wrote:
> Hi Vladimir,
> 
> On Tue, 2016-09-27 at 01:07 +0300, Vladimir Zapolskiy wrote:
> > Hi Sylvain,
> > 
> > On 26.09.2016 21:47, Sylvain Lemieux wrote:
> > > From: Sylvain Lemieux <slemieux@tycoint.com>
> > > 
> > > There is no need to define the "pwm-cells" in the board
> > > specific dts file; move the entry to the base dts file.
> > > 
> > > Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
> > > ---
> > > Note:
> > > * This patch should be apply after
> > >   "ARM: dts: lpc32xx: set default parent clock for pwm1 & pwm2"
> > >   http://www.spinics.net/lists/arm-kernel/msg530277.html
> > >   - There is no dependency between the patches.
> > > 
> > >  arch/arm/boot/dts/lpc32xx.dtsi | 2 ++
> > >  1 file changed, 2 insertions(+)
> > > 
> [...] 
> > 
> > that's something I have done locally and in a different manner, but I haven't
> > published it yet, please find below a draft.
> > 
> > First of all from multiple places in the User's Manual you can find that there
> > are "two single output PWM blocks" or "the LPC32x0 provides two 8-bit PWMs" etc.
> > 
> > In this case it does not make sense to set PWM cells to 2 (there is only one
> > channel), and 1 cell for frequency is good enough, and that's the proposed
> > change to support it:
> > 
[..]
> > 
> > What is your opinion about this proposal?
> > 
> I agree with you, this clean-up make sense; the PWM cell should be 1.
> 
> > If this change is applied, then lpc32xx.dtsi should contain #pwm-cells = <1>.
> > 
> Can you submit your change on the mailing list?
> I will send a version 2 of this patch after.
> 
> If it is helping, I can take care of submitting a patch
> to update the documentation (lpc32xx-pwm.txt).
> 
Just doing a quick follow-up; 
when do you think you can submit your change to the mailling list?

> > --
> > With best wishes,
> > Vladimir
> 
> Sylvain
> 
Regards,
Sylvain