On Sat, Jun 9, 2012 at 12:24 AM, Marek Vasut <marex@xxxxxxx> 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 | 54 +++++++++++++++++++++
> 3 files changed, 57 insertions(+)
>
> V2: Use clock-frequency instead
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt
> index 1bfc02d..d2bf750 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
> +- clock-frequency: desired I2C bus clock frequency in Hz.
>
> Examples:
>
> diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi
> index a89da5a..714e63c 100644
> --- a/arch/arm/boot/dts/imx28.dtsi
> +++ b/arch/arm/boot/dts/imx28.dtsi
> @@ -398,6 +398,7 @@
> compatible = "fsl,imx28-i2c";
> reg = <0x80058000 2000>;
> interrupts = <111 68>;
> + clock-frequency = <400000>;
> status = "disabled";
> };
>
> @@ -407,6 +408,7 @@
> compatible = "fsl,imx28-i2c";
> reg = <0x8005a000 2000>;
> interrupts = <110 69>;
> + clock-frequency = <400000>;
> status = "disabled";
> };
>
> diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
> index 04eb441..b4d083f 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 = {
You are using 95k?
Didnt understand this.
> + .timing0 = 0x00780030,
> + .timing1 = 0x00800030,
> + .timing2 = 0x0015000d,
> +};
> +
> +const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
> + .timing0 = 0x000f0007,
> + .timing1 = 0x001f000f,
> + .timing2 = 0x0015000d,
> +};
> +
How are these values calculated?
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
