Patchwork [1/2] MXS: Set I2C timing registers for mxs-i2c

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Submitter Marek Vasut
Date May 27, 2012, 2:10 a.m.
Message ID <1338084656-11961-1-git-send-email-marex@denx.de>
Download mbox | patch
Permalink /patch/161519/
State New
Headers show

Comments

Marek Vasut - May 27, 2012, 2:10 a.m.
This patch configures the I2C bus timing registers according
to information passed via DT. Currently, 100kHz and 400kHz
modes are supported.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c@vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>
---
 Documentation/devicetree/bindings/i2c/i2c-mxs.txt |    1 +
 arch/arm/boot/dts/imx28.dtsi                      |    2 +
 drivers/i2c/busses/i2c-mxs.c                      |   64 +++++++++++++++++++++
 3 files changed, 67 insertions(+)
Ben Dooks - May 28, 2012, 10:55 a.m.
On 27/05/12 03:10, Marek Vasut wrote:
> This patch configures the I2C bus timing registers according
> to information passed via DT. Currently, 100kHz and 400kHz
> modes are supported.
>
> Signed-off-by: Marek Vasut<marex@denx.de>
> Cc: Detlev Zundel<dzu@denx.de>
> CC: Dong Aisheng<b29396@freescale.com>
> CC: Fabio Estevam<fabio.estevam@freescale.com>
> Cc: Linux ARM kernel<linux-arm-kernel@lists.infradead.org>
> Cc: linux-i2c@vger.kernel.org
> CC: Sascha Hauer<s.hauer@pengutronix.de>
> CC: Shawn Guo<shawn.guo@linaro.org>
> Cc: Stefano Babic<sbabic@denx.de>
> CC: Uwe Kleine-König<u.kleine-koenig@pengutronix.de>
> Cc: Wolfgang Denk<wd@denx.de>
> Cc: Wolfram Sang<w.sang@pengutronix.de>
> ---
>   Documentation/devicetree/bindings/i2c/i2c-mxs.txt |    1 +
>   arch/arm/boot/dts/imx28.dtsi                      |    2 +
>   drivers/i2c/busses/i2c-mxs.c                      |   64 +++++++++++++++++++++
>   3 files changed, 67 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> index 1bfc02d..790b5c6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> @@ -4,6 +4,7 @@ Required properties:
>   - compatible: Should be "fsl,<chip>-i2c"
>   - reg: Should contain registers location and length
>   - interrupts: Should contain ERROR and DMA interrupts
> +- speed: Speed of the bus in kHz (400 or 100 are supported)
>
>   Examples:
>
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index 4634cb8..d927155 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -381,6 +381,7 @@
>   				compatible = "fsl,imx28-i2c";
>   				reg =<0x80058000 2000>;
>   				interrupts =<111 68>;
> +				fsl,speed =<400>;
>   				status = "disabled";
>   			};
>
> @@ -390,6 +391,7 @@
>   				compatible = "fsl,imx28-i2c";
>   				reg =<0x8005a000 2000>;
>   				interrupts =<110 69>;
> +				fsl,speed =<400>;
>   				status = "disabled";
>   			};

Is there not a standard speed setting in the i2c binding?
Marek Vasut - May 29, 2012, 6:46 a.m.
Dear Ben Dooks,

> On 27/05/12 03:10, Marek Vasut wrote:
> > This patch configures the I2C bus timing registers according
> > to information passed via DT. Currently, 100kHz and 400kHz
> > modes are supported.
> > 
> > Signed-off-by: Marek Vasut<marex@denx.de>
> > Cc: Detlev Zundel<dzu@denx.de>
> > CC: Dong Aisheng<b29396@freescale.com>
> > CC: Fabio Estevam<fabio.estevam@freescale.com>
> > Cc: Linux ARM kernel<linux-arm-kernel@lists.infradead.org>
> > Cc: linux-i2c@vger.kernel.org
> > CC: Sascha Hauer<s.hauer@pengutronix.de>
> > CC: Shawn Guo<shawn.guo@linaro.org>
> > Cc: Stefano Babic<sbabic@denx.de>
> > CC: Uwe Kleine-König<u.kleine-koenig@pengutronix.de>
> > Cc: Wolfgang Denk<wd@denx.de>
> > Cc: Wolfram Sang<w.sang@pengutronix.de>
> > ---
> > 
> >   Documentation/devicetree/bindings/i2c/i2c-mxs.txt |    1 +
> >   arch/arm/boot/dts/imx28.dtsi                      |    2 +
> >   drivers/i2c/busses/i2c-mxs.c                      |   64
> >   +++++++++++++++++++++ 3 files changed, 67 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> > b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt index
> > 1bfc02d..790b5c6 100644
> > --- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> > +++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> > 
> > @@ -4,6 +4,7 @@ Required properties:
> >   - compatible: Should be "fsl,<chip>-i2c"
> >   - reg: Should contain registers location and length
> >   - interrupts: Should contain ERROR and DMA interrupts
> > 
> > +- speed: Speed of the bus in kHz (400 or 100 are supported)
> > 
> >   Examples:
> > diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> > index 4634cb8..d927155 100644
> > --- a/arch/arm/boot/dts/imx28.dtsi
> > +++ b/arch/arm/boot/dts/imx28.dtsi
> > @@ -381,6 +381,7 @@
> > 
> >   				compatible = "fsl,imx28-i2c";
> >   				reg =<0x80058000 2000>;
> >   				interrupts =<111 68>;
> > 
> > +				fsl,speed =<400>;
> > 
> >   				status = "disabled";
> >   			
> >   			};
> > 
> > @@ -390,6 +391,7 @@
> > 
> >   				compatible = "fsl,imx28-i2c";
> >   				reg =<0x8005a000 2000>;
> >   				interrupts =<110 69>;
> > 
> > +				fsl,speed =<400>;
> > 
> >   				status = "disabled";
> >   			
> >   			};
> 
> Is there not a standard speed setting in the i2c binding?

Not that I know of, but if someone hinted one to me, I'd gladly rework the 
patches :)

Best regards,
Marek Vasut
Wolfram Sang - June 2, 2012, 6:48 a.m.
> > Is there not a standard speed setting in the i2c binding?
> 
> Not that I know of, but if someone hinted one to me, I'd gladly rework the 
> patches :)

It is "clock-frequency". Check 'Documentation/devicetree/bindings/i2c'.
Shawn Guo - June 6, 2012, 2:53 a.m.
Welcome to mxs device tree, Marek :)

On Sun, May 27, 2012 at 04:10:55AM +0200, Marek Vasut wrote:
> This patch configures the I2C bus timing registers according
> to information passed via DT. Currently, 100kHz and 400kHz
> modes are supported.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Detlev Zundel <dzu@denx.de>
> CC: Dong Aisheng <b29396@freescale.com>
> CC: Fabio Estevam <fabio.estevam@freescale.com>
> Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
> Cc: linux-i2c@vger.kernel.org
> CC: Sascha Hauer <s.hauer@pengutronix.de>
> CC: Shawn Guo <shawn.guo@linaro.org>
> Cc: Stefano Babic <sbabic@denx.de>
> CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Cc: Wolfgang Denk <wd@denx.de>
> Cc: Wolfram Sang <w.sang@pengutronix.de>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-mxs.txt |    1 +
>  arch/arm/boot/dts/imx28.dtsi                      |    2 +
>  drivers/i2c/busses/i2c-mxs.c                      |   64 +++++++++++++++++++++
>  3 files changed, 67 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> index 1bfc02d..790b5c6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> @@ -4,6 +4,7 @@ Required properties:
>  - compatible: Should be "fsl,<chip>-i2c"
>  - reg: Should contain registers location and length
>  - interrupts: Should contain ERROR and DMA interrupts
> +- speed: Speed of the bus in kHz (400 or 100 are supported)
>  
>  Examples:
>  
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index 4634cb8..d927155 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -381,6 +381,7 @@
>  				compatible = "fsl,imx28-i2c";
>  				reg = <0x80058000 2000>;
>  				interrupts = <111 68>;
> +				fsl,speed = <400>;
>  				status = "disabled";
>  			};
>  
> @@ -390,6 +391,7 @@
>  				compatible = "fsl,imx28-i2c";
>  				reg = <0x8005a000 2000>;
>  				interrupts = <110 69>;
> +				fsl,speed = <400>;
>  				status = "disabled";
>  			};
>  
> diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
> index 04eb441..fff0a09 100644
> --- a/drivers/i2c/busses/i2c-mxs.c
> +++ b/drivers/i2c/busses/i2c-mxs.c
> @@ -46,6 +46,10 @@
>  #define MXS_I2C_CTRL0_DIRECTION			0x00010000
>  #define MXS_I2C_CTRL0_XFER_COUNT(v)		((v) & 0x0000FFFF)
>  
> +#define MXS_I2C_TIMING0		(0x10)
> +#define MXS_I2C_TIMING1		(0x20)
> +#define MXS_I2C_TIMING2		(0x30)
> +
>  #define MXS_I2C_CTRL1		(0x40)
>  #define MXS_I2C_CTRL1_SET	(0x44)
>  #define MXS_I2C_CTRL1_CLR	(0x48)
> @@ -97,6 +101,24 @@
>  #define MXS_CMD_I2C_READ	(MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
>  				 MXS_I2C_CTRL0_MASTER_MODE)
>  
> +struct mxs_i2c_speed_config {
> +	uint32_t	timing0;
> +	uint32_t	timing1;
> +	uint32_t	timing2;
> +};
> +
> +const struct mxs_i2c_speed_config mxs_i2c_95kHz_config = {
> +	.timing0	= 0x00780030,
> +	.timing1	= 0x00800030,
> +	.timing2	= 0x0015000d,
> +};
> +
> +const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
> +	.timing0	= 0x000f0007,
> +	.timing1	= 0x001f000f,
> +	.timing2	= 0x0015000d,
> +};
> +
>  /**
>   * struct mxs_i2c_dev - per device, private MXS-I2C data
>   *
> @@ -112,11 +134,17 @@ struct mxs_i2c_dev {
>  	struct completion cmd_complete;
>  	u32 cmd_err;
>  	struct i2c_adapter adapter;
> +	const struct mxs_i2c_speed_config *speed;
>  };
>  
>  static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
>  {
>  	stmp_reset_block(i2c->regs);
> +
> +	writel(i2c->speed->timing0, i2c->regs + MXS_I2C_TIMING0);
> +	writel(i2c->speed->timing1, i2c->regs + MXS_I2C_TIMING1);
> +	writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
> +
>  	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
>  	writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
>  			i2c->regs + MXS_I2C_QUEUECTRL_SET);
> @@ -319,6 +347,38 @@ static const struct i2c_algorithm mxs_i2c_algo = {
>  	.functionality = mxs_i2c_func,
>  };
>  
> +#ifdef CONFIG_OF

We already force ARCH_MXS to select USE_OF while I2C_MXS only depends
on SOC_IMX28, so this #ifdef is not really needed?

> +static int mxs_i2c_get_ofdata(struct platform_device *pdev,
> +				struct mxs_i2c_dev *i2c)
> +{
> +	const __be32 *speed;
> +	uint32_t speed_khz;
> +	struct device_node *node = pdev->dev.of_node;
> +
> +	if (!node)
> +		return -EINVAL;
> +
> +	i2c->speed = &mxs_i2c_95kHz_config;
> +	speed = of_get_property(node, "fsl,speed", NULL);
> +	if (!speed)
> +		dev_warn(&pdev->dev,
> +			"No I2C speed selected, using 100kHz\n");
> +
> +	speed_khz = be32_to_cpup(speed);

You may want to try of_property_read_u32().

> +	if (speed_khz == 400)
> +		i2c->speed = &mxs_i2c_400kHz_config;
> +	else if (speed_khz != 100)
> +		dev_warn(&pdev->dev,
> +			"Invalid I2C speed selected, using 100kHz\n");
> +
> +	return 0;
> +}
> +#else
> +static int mxs_i2c_get_ofdata(struct platform_device *pdev,
> +				struct mxs_i2c_dev *i2c)
> +{ }
> +#endif /* CONFIG_OF */
> +
>  static int __devinit mxs_i2c_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -357,6 +417,10 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
>  	if (err)
>  		return err;
>  
> +	err = mxs_i2c_get_ofdata(pdev, i2c);
> +	if (err)
> +		return err;
> +

If we have this block put after the following line, we can save pdev
parameter of mxs_i2c_get_ofdata()?

>  	i2c->dev = dev;
>  	platform_set_drvdata(pdev, i2c);
>  
> -- 
> 1.7.10
>

Patch

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
index 1bfc02d..790b5c6 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
@@ -4,6 +4,7 @@  Required properties:
 - compatible: Should be "fsl,<chip>-i2c"
 - reg: Should contain registers location and length
 - interrupts: Should contain ERROR and DMA interrupts
+- speed: Speed of the bus in kHz (400 or 100 are supported)
 
 Examples:
 
diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
index 4634cb8..d927155 100644
--- a/arch/arm/boot/dts/imx28.dtsi
+++ b/arch/arm/boot/dts/imx28.dtsi
@@ -381,6 +381,7 @@ 
 				compatible = "fsl,imx28-i2c";
 				reg = <0x80058000 2000>;
 				interrupts = <111 68>;
+				fsl,speed = <400>;
 				status = "disabled";
 			};
 
@@ -390,6 +391,7 @@ 
 				compatible = "fsl,imx28-i2c";
 				reg = <0x8005a000 2000>;
 				interrupts = <110 69>;
+				fsl,speed = <400>;
 				status = "disabled";
 			};
 
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 04eb441..fff0a09 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -46,6 +46,10 @@ 
 #define MXS_I2C_CTRL0_DIRECTION			0x00010000
 #define MXS_I2C_CTRL0_XFER_COUNT(v)		((v) & 0x0000FFFF)
 
+#define MXS_I2C_TIMING0		(0x10)
+#define MXS_I2C_TIMING1		(0x20)
+#define MXS_I2C_TIMING2		(0x30)
+
 #define MXS_I2C_CTRL1		(0x40)
 #define MXS_I2C_CTRL1_SET	(0x44)
 #define MXS_I2C_CTRL1_CLR	(0x48)
@@ -97,6 +101,24 @@ 
 #define MXS_CMD_I2C_READ	(MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
 				 MXS_I2C_CTRL0_MASTER_MODE)
 
+struct mxs_i2c_speed_config {
+	uint32_t	timing0;
+	uint32_t	timing1;
+	uint32_t	timing2;
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_95kHz_config = {
+	.timing0	= 0x00780030,
+	.timing1	= 0x00800030,
+	.timing2	= 0x0015000d,
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
+	.timing0	= 0x000f0007,
+	.timing1	= 0x001f000f,
+	.timing2	= 0x0015000d,
+};
+
 /**
  * struct mxs_i2c_dev - per device, private MXS-I2C data
  *
@@ -112,11 +134,17 @@  struct mxs_i2c_dev {
 	struct completion cmd_complete;
 	u32 cmd_err;
 	struct i2c_adapter adapter;
+	const struct mxs_i2c_speed_config *speed;
 };
 
 static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
 {
 	stmp_reset_block(i2c->regs);
+
+	writel(i2c->speed->timing0, i2c->regs + MXS_I2C_TIMING0);
+	writel(i2c->speed->timing1, i2c->regs + MXS_I2C_TIMING1);
+	writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
+
 	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
 	writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
 			i2c->regs + MXS_I2C_QUEUECTRL_SET);
@@ -319,6 +347,38 @@  static const struct i2c_algorithm mxs_i2c_algo = {
 	.functionality = mxs_i2c_func,
 };
 
+#ifdef CONFIG_OF
+static int mxs_i2c_get_ofdata(struct platform_device *pdev,
+				struct mxs_i2c_dev *i2c)
+{
+	const __be32 *speed;
+	uint32_t speed_khz;
+	struct device_node *node = pdev->dev.of_node;
+
+	if (!node)
+		return -EINVAL;
+
+	i2c->speed = &mxs_i2c_95kHz_config;
+	speed = of_get_property(node, "fsl,speed", NULL);
+	if (!speed)
+		dev_warn(&pdev->dev,
+			"No I2C speed selected, using 100kHz\n");
+
+	speed_khz = be32_to_cpup(speed);
+	if (speed_khz == 400)
+		i2c->speed = &mxs_i2c_400kHz_config;
+	else if (speed_khz != 100)
+		dev_warn(&pdev->dev,
+			"Invalid I2C speed selected, using 100kHz\n");
+
+	return 0;
+}
+#else
+static int mxs_i2c_get_ofdata(struct platform_device *pdev,
+				struct mxs_i2c_dev *i2c)
+{ }
+#endif /* CONFIG_OF */
+
 static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -357,6 +417,10 @@  static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
+	err = mxs_i2c_get_ofdata(pdev, i2c);
+	if (err)
+		return err;
+
 	i2c->dev = dev;
 	platform_set_drvdata(pdev, i2c);