Patchwork [2/2] imx6q: Set pwm control register during enable and config call

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Submitter hachimi.samir@gmail.com
Date Aug. 23, 2012, 3:32 p.m.
Message ID <1345735959-12964-3-git-send-email-hachimi.samir@gmail.com>
Download mbox | patch
Permalink /patch/179672/
State New
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Comments

hachimi.samir@gmail.com - Aug. 23, 2012, 3:32 p.m.
From: Samir Hachimi <hachimi.samir@gmail.com>

Bind pwm node with driver.
Activate stop_enable mode when imx_pwm_config and set enable bit in pwm
CR register during imx_pwm_enable.

Signed-off-by: Samir Hachimi <shachimi@adeneo-embedded.com>
---
 arch/arm/boot/dts/imx6q.dtsi  |    8 ++++++++
 arch/arm/mach-imx/clk-imx6q.c |    4 ++++
 drivers/pwm/pwm-imx.c         |   34 +++++++++++++++++++++++-----------
 3 files changed, 35 insertions(+), 11 deletions(-)
Shawn Guo - Aug. 24, 2012, 7:30 a.m.
On Thu, Aug 23, 2012 at 05:32:39PM +0200, hachimi.samir@gmail.com wrote:
> From: Samir Hachimi <hachimi.samir@gmail.com>
> 
> Bind pwm node with driver.
> Activate stop_enable mode when imx_pwm_config and set enable bit in pwm
> CR register during imx_pwm_enable.
> 
> Signed-off-by: Samir Hachimi <shachimi@adeneo-embedded.com>

You should use same one email address for author/From: and
Signed-off-by.

> ---
>  arch/arm/boot/dts/imx6q.dtsi  |    8 ++++++++
>  arch/arm/mach-imx/clk-imx6q.c |    4 ++++
>  drivers/pwm/pwm-imx.c         |   34 +++++++++++++++++++++++-----------
>  3 files changed, 35 insertions(+), 11 deletions(-)

The patch should be split into two, one for arch/arm/ part, and the
other for drivers/pwm part.  The arch/arm/ part will go via arm-soc
tree, while drivers/pwm part should go via pwm tree.

See following info from MAINTAINERS file for drivers/pwm part.

PWM SUBSYSTEM
M:      Thierry Reding <thierry.reding@avionic-design.de>
L:      linux-kernel@vger.kernel.org
S:      Maintained
W:      http://gitorious.org/linux-pwm
T:      git git://gitorious.org/linux-pwm/linux-pwm.git
F:      Documentation/pwm.txt
F:      Documentation/devicetree/bindings/pwm/
F:      include/linux/pwm.h
F:      include/linux/of_pwm.h
F:      drivers/pwm/


> 
> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
> index c913b99..7ce9dc1 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -248,6 +248,8 @@
>  			};
>  
>  			pwm@02080000 { /* PWM1 */
> +				compatible = "fsl,imx6q-pwm";
> +				#pwm-cells = <2>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&pinctrl_pwm1_1>;
>  				reg = <0x02080000 0x4000>;
> @@ -256,6 +258,8 @@
>  			};
>  
>  			pwm@02084000 { /* PWM2 */
> +				compatible = "fsl,imx6q-pwm";
> +				#pwm-cells = <2>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&pinctrl_pwm2_1>;
>  				reg = <0x02084000 0x4000>;
> @@ -264,6 +268,8 @@
>  			};
>  
>  			pwm@02088000 { /* PWM3 */
> +				compatible = "fsl,imx6q-pwm";
> +				#pwm-cells = <2>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&pinctrl_pwm3_1>;
>  				reg = <0x02088000 0x4000>;
> @@ -272,6 +278,8 @@
>  			};
>  
>  			pwm@0208c000 { /* PWM4 */
> +				compatible = "fsl,imx6q-pwm";
> +				#pwm-cells = <2>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&pinctrl_pwm4_1>;
>  				reg = <0x0208c000 0x4000>;
> diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
> index ea89520..057740b 100644
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -430,6 +430,10 @@ int __init mx6q_clocks_init(void)
>  	clk_register_clkdev(clk[ecspi3], NULL, "2010000.ecspi");
>  	clk_register_clkdev(clk[ecspi4], NULL, "2014000.ecspi");
>  	clk_register_clkdev(clk[ecspi5], NULL, "2018000.ecspi");
> +	clk_register_clkdev(clk[pwm1], "pwm", "2080000.pwm");
> +	clk_register_clkdev(clk[pwm2], "pwm", "2084000.pwm");
> +	clk_register_clkdev(clk[pwm3], "pwm", "2088000.pwm");
> +	clk_register_clkdev(clk[pwm4], "pwm", "208c000.pwm");

We are moving clock lookup into device tree, so these changes are not
welcomed at this point.

>  	clk_register_clkdev(clk[sdma], NULL, "20ec000.sdma");
>  	clk_register_clkdev(clk[dummy], NULL, "20bc000.wdog");
>  	clk_register_clkdev(clk[dummy], NULL, "20c0000.wdog");
> diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
> index 2a0b353..0b13f34 100644
> --- a/drivers/pwm/pwm-imx.c
> +++ b/drivers/pwm/pwm-imx.c
> @@ -32,6 +33,7 @@
>  #define MX3_PWMSAR                0x0C    /* PWM Sample Register */
>  #define MX3_PWMPR                 0x10    /* PWM Period Register */
>  #define MX3_PWMCR_PRESCALER(x)    (((x - 1) & 0xFFF) << 4)
> +#define MX3_PWMCR_STOPEN		(1 << 25)
>  #define MX3_PWMCR_DOZEEN                (1 << 24)
>  #define MX3_PWMCR_WAITEN                (1 << 23)
>  #define MX3_PWMCR_DBGEN			(1 << 22)
> @@ -68,25 +70,21 @@ static int imx_pwm_config(struct pwm_chip *chip,
>  		prescale = period_cycles / 0x10000 + 1;
>  
>  		period_cycles /= prescale;
> -		c = (unsigned long long)period_cycles * duty_ns;
> -		do_div(c, period_ns);
> -		duty_cycles = c;
>  
> -		/*
> -		 * according to imx pwm RM, the real period value should be
> -		 * PERIOD value in PWMPR plus 2.
> +		/* the chip documentation says the counter counts up to
> +		 * period_cycles + 1 and then is reset to 0, so the
> +		 *  actual period of the PWM wave is period_cycles + 2
>  		 */
> -		if (period_cycles > 2)
> -			period_cycles -= 2;
> -		else
> -			period_cycles = 0;
> +		c = (unsigned long long)(period_cycles + 2) * duty_ns;
> +		do_div(c, period_ns);
> +		duty_cycles = c;
>  
>  		writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
>  		writel(period_cycles, imx->mmio_base + MX3_PWMPR);
>  
>  		cr = MX3_PWMCR_PRESCALER(prescale) |
>  			MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
> -			MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
> +			MX3_PWMCR_DBGEN | MX3_PWMCR_STOPEN;
>  
>  		if (cpu_is_mx25())
>  			cr |= MX3_PWMCR_CLKSRC_IPG;
> @@ -124,6 +122,7 @@ static int imx_pwm_config(struct pwm_chip *chip,
>  static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>  {
>  	struct imx_chip *imx = to_imx_chip(chip);
> +	unsigned long reg;
>  	int rc = 0;
>  
>  	if (!imx->clk_enabled) {
> @@ -131,6 +130,11 @@ static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>  		if (!rc)
>  			imx->clk_enabled = 1;
>  	}
> +
> +	reg = readl(imx->mmio_base + MX3_PWMCR);
> +	reg |= MX3_PWMCR_EN;
> +	writel(reg, imx->mmio_base + MX3_PWMCR);
> +
>  	return rc;
>  }
>  
> @@ -206,9 +212,15 @@ static int __devexit imx_pwm_remove(struct platform_device *pdev)
>  	return pwmchip_remove(&imx->chip);
>  }
>  
> +static const struct of_device_id mxc_pwm_dt_ids[] = {
> +	{ .compatible = "fsl,imx6q-pwm", },

The driver really needs a cleanup before we add device tree support for
it.  For example, all these cpu_is_xxx stuff need to go and use
device_id instead.

Regards,
Shawn

> +	{ /* sentinel */ }
> +};
> +
>  static struct platform_driver imx_pwm_driver = {
>  	.driver		= {
>  		.name	= "mxc_pwm",
> +		.of_match_table = of_match_ptr(mxc_pwm_dt_ids),
>  	},
>  	.probe		= imx_pwm_probe,
>  	.remove		= __devexit_p(imx_pwm_remove),
> -- 
> 1.7.1
>

Patch

diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
index c913b99..7ce9dc1 100644
--- a/arch/arm/boot/dts/imx6q.dtsi
+++ b/arch/arm/boot/dts/imx6q.dtsi
@@ -248,6 +248,8 @@ 
 			};
 
 			pwm@02080000 { /* PWM1 */
+				compatible = "fsl,imx6q-pwm";
+				#pwm-cells = <2>;
 				pinctrl-names = "default";
 				pinctrl-0 = <&pinctrl_pwm1_1>;
 				reg = <0x02080000 0x4000>;
@@ -256,6 +258,8 @@ 
 			};
 
 			pwm@02084000 { /* PWM2 */
+				compatible = "fsl,imx6q-pwm";
+				#pwm-cells = <2>;
 				pinctrl-names = "default";
 				pinctrl-0 = <&pinctrl_pwm2_1>;
 				reg = <0x02084000 0x4000>;
@@ -264,6 +268,8 @@ 
 			};
 
 			pwm@02088000 { /* PWM3 */
+				compatible = "fsl,imx6q-pwm";
+				#pwm-cells = <2>;
 				pinctrl-names = "default";
 				pinctrl-0 = <&pinctrl_pwm3_1>;
 				reg = <0x02088000 0x4000>;
@@ -272,6 +278,8 @@ 
 			};
 
 			pwm@0208c000 { /* PWM4 */
+				compatible = "fsl,imx6q-pwm";
+				#pwm-cells = <2>;
 				pinctrl-names = "default";
 				pinctrl-0 = <&pinctrl_pwm4_1>;
 				reg = <0x0208c000 0x4000>;
diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
index ea89520..057740b 100644
--- a/arch/arm/mach-imx/clk-imx6q.c
+++ b/arch/arm/mach-imx/clk-imx6q.c
@@ -430,6 +430,10 @@  int __init mx6q_clocks_init(void)
 	clk_register_clkdev(clk[ecspi3], NULL, "2010000.ecspi");
 	clk_register_clkdev(clk[ecspi4], NULL, "2014000.ecspi");
 	clk_register_clkdev(clk[ecspi5], NULL, "2018000.ecspi");
+	clk_register_clkdev(clk[pwm1], "pwm", "2080000.pwm");
+	clk_register_clkdev(clk[pwm2], "pwm", "2084000.pwm");
+	clk_register_clkdev(clk[pwm3], "pwm", "2088000.pwm");
+	clk_register_clkdev(clk[pwm4], "pwm", "208c000.pwm");
 	clk_register_clkdev(clk[sdma], NULL, "20ec000.sdma");
 	clk_register_clkdev(clk[dummy], NULL, "20bc000.wdog");
 	clk_register_clkdev(clk[dummy], NULL, "20c0000.wdog");
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 2a0b353..0b13f34 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -32,6 +33,7 @@ 
 #define MX3_PWMSAR                0x0C    /* PWM Sample Register */
 #define MX3_PWMPR                 0x10    /* PWM Period Register */
 #define MX3_PWMCR_PRESCALER(x)    (((x - 1) & 0xFFF) << 4)
+#define MX3_PWMCR_STOPEN		(1 << 25)
 #define MX3_PWMCR_DOZEEN                (1 << 24)
 #define MX3_PWMCR_WAITEN                (1 << 23)
 #define MX3_PWMCR_DBGEN			(1 << 22)
@@ -68,25 +70,21 @@  static int imx_pwm_config(struct pwm_chip *chip,
 		prescale = period_cycles / 0x10000 + 1;
 
 		period_cycles /= prescale;
-		c = (unsigned long long)period_cycles * duty_ns;
-		do_div(c, period_ns);
-		duty_cycles = c;
 
-		/*
-		 * according to imx pwm RM, the real period value should be
-		 * PERIOD value in PWMPR plus 2.
+		/* the chip documentation says the counter counts up to
+		 * period_cycles + 1 and then is reset to 0, so the
+		 *  actual period of the PWM wave is period_cycles + 2
 		 */
-		if (period_cycles > 2)
-			period_cycles -= 2;
-		else
-			period_cycles = 0;
+		c = (unsigned long long)(period_cycles + 2) * duty_ns;
+		do_div(c, period_ns);
+		duty_cycles = c;
 
 		writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
 		writel(period_cycles, imx->mmio_base + MX3_PWMPR);
 
 		cr = MX3_PWMCR_PRESCALER(prescale) |
 			MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
-			MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
+			MX3_PWMCR_DBGEN | MX3_PWMCR_STOPEN;
 
 		if (cpu_is_mx25())
 			cr |= MX3_PWMCR_CLKSRC_IPG;
@@ -124,6 +122,7 @@  static int imx_pwm_config(struct pwm_chip *chip,
 static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct imx_chip *imx = to_imx_chip(chip);
+	unsigned long reg;
 	int rc = 0;
 
 	if (!imx->clk_enabled) {
@@ -131,6 +130,11 @@  static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 		if (!rc)
 			imx->clk_enabled = 1;
 	}
+
+	reg = readl(imx->mmio_base + MX3_PWMCR);
+	reg |= MX3_PWMCR_EN;
+	writel(reg, imx->mmio_base + MX3_PWMCR);
+
 	return rc;
 }
 
@@ -206,9 +212,15 @@  static int __devexit imx_pwm_remove(struct platform_device *pdev)
 	return pwmchip_remove(&imx->chip);
 }
 
+static const struct of_device_id mxc_pwm_dt_ids[] = {
+	{ .compatible = "fsl,imx6q-pwm", },
+	{ /* sentinel */ }
+};
+
 static struct platform_driver imx_pwm_driver = {
 	.driver		= {
 		.name	= "mxc_pwm",
+		.of_match_table = of_match_ptr(mxc_pwm_dt_ids),
 	},
 	.probe		= imx_pwm_probe,
 	.remove		= __devexit_p(imx_pwm_remove),