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SubjectRe: [PATCH 3/3] ARM: imx6q: switch to use pinctrl driver
On 04/13/2012 10:18 AM, Dong Aisheng wrote:
> From: Dong Aisheng <dong.aisheng@linaro.org>
>
> ---
> This patch is used for test the new pinctrl driver.

> diff --git a/arch/arm/boot/dts/imx6q-arm2.dts b/arch/arm/boot/dts/imx6q-arm2.dts

> usdhc@0219c000 { /* uSDHC4 */
> fsl,card-wired;
> vmmc-supply = <&reg_3p3v>;
> status = "okay";
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_usdhc4_1>;
> };
>
> uart4: uart@021f0000 {
> status = "okay";
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_uart4_1>;
> };

That seems reasonable.

> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi

> + usdhc4 {
> + pinctrl_usdhc4_1: usdhc4grp-1 {

I'm slightly confused about how this part of the binding is structured.

I'd expect the label "pinctrl_usdhc4_1:" to point at the node "usdhc4"
here. As written, there's no possibility of using a different pin
configuration values such as pull/drive-strength/... for some of the
pins, which I'm pretty sure will be an issue.

For example, see tegra-cardhu.dts - it has a pull up on the SDMMC data
and clock lines, but no pull on the SDMMC command line. I assume it's
this way because of some aspect of the SDMMC specification, rather than
something odd about Tegra.

I guess you've allowed a list of mux functions in the fsl,mux property.
Perhaps you can also allow a list in the other properties.

In that case though, what is the top-level usdhc4 node for? Perhaps it
groups multiple different available pin configurations for the USDHC4
controller together just as documentation? I don't think it's that
useful to do that; it doesn't actually convey any extra information, and
the fact the node is a configuration for the USDHC4 controller is
readily apparent from the node's label and name.

> + fsl,pins = "MX6Q_PAD_SD4_CMD",
> + "MX6Q_PAD_SD4_CLK",
> + "MX6Q_PAD_SD4_DAT0",
> + "MX6Q_PAD_SD4_DAT1",
> + "MX6Q_PAD_SD4_DAT2",
> + "MX6Q_PAD_SD4_DAT3",
> + "MX6Q_PAD_SD4_DAT4",
> + "MX6Q_PAD_SD4_DAT5",
> + "MX6Q_PAD_SD4_DAT6",
> + "MX6Q_PAD_SD4_DAT7";
> + fsl,mux = <0 0 1 1 1 1 1 1 1 1>;
> + fsl,pull = <1>;
> + fsl,pue = <1>;
> + fsl,pke = <1>;
> + fsl,speed = <1>;
> + fsl,drive-strength = <3>;
> + fsl,slew-rate = <1>;
> + fsl,hysteresis = <1>;
> + };

> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c

> @@ -467,6 +469,12 @@ static int __devinit sdhci_esdhc_imx_probe(struct platform_device *pdev)
> clk_prepare_enable(clk);
> pltfm_host->clk = clk;
>
> + imx_data->p = pinctrl_get_select_default(&pdev->dev);

If you use devm_pinctrl_get_select_default() here (once it's checked in) ...

> no_card_detect_pin:
> no_board_data:
> + pinctrl_put(imx_data->p);

... you don't need that ...

> @@ -586,6 +596,8 @@ static int __devexit sdhci_esdhc_imx_remove(struct platform_device *pdev)
> gpio_free(boarddata->cd_gpio);
> }
>
> + pinctrl_put(imx_data->p);

... or that.


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