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@xxxxxxx>
> Cc: Detlev Zundel <dzu@xxxxxxx>
> CC: Dong Aisheng <b29396@xxxxxxxxxxxxx>
> CC: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx>
> Cc: Linux ARM kernel <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>
> Cc: linux-i2c@xxxxxxxxxxxxxxx
> CC: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> CC: Shawn Guo <shawn.guo@xxxxxxxxxx>
> Cc: Stefano Babic <sbabic@xxxxxxx>
> CC: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> Cc: Wolfgang Denk <wd@xxxxxxx>
> Cc: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
> ---
> 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
>
--
Regards,
Shawn
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