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    SubjectRe: [PATCH 2/2] pinctrl: Add simple pinmux driver using device tree data
    On Mon, Feb 13, 2012 at 11:11:13AM -0800, Tony Lindgren wrote:
    ...
    > > Put it in pinctrl device node?
    > > Then how do we name each pin?
    > > And for IMX, currently we name all pins in driver.
    > > I still can not find a good reason that i should name all pins in dt file.
    >
    > But do you actually need the pin names in kernel? :)
    >
    Yes, i meant name pins in driver.

    > > Yes, we indeed have such a case.
    > > For IMX, some special pins mux still need a setting called 'select input' which
    > > is controlled in other registers.
    > > But a rough idea in my mind that may choose different way to fix this issue.
    > > It's a little like:
    > > pinctrl_usdhc4: pinconfig-usdhc4 {
    > > mux =
    > > <MX6Q_SD4_CMD 0 SELECT_INPUT>
    > > <MX6Q_SD4_CLK 0 0>
    > > <MX6Q_SD4_DAT0 1 0>
    > > <MX6Q_SD4_DAT1 1 0>
    > > <MX6Q_SD4_DAT2 1 SELECT_INPUT>
    > > <MX6Q_SD4_DAT3 1 0>
    > > <MX6Q_SD4_DAT4 1 0>
    > > <MX6Q_SD4_DAT5 1 0>
    > > <MX6Q_SD4_DAT6 1 0>
    > > <MX6Q_SD4_DAT7 1 0>;
    > > }
    > > This format would not make the dts writer to take too much care of
    > > register address
    > > and value. For this case, the #pinmux-cells would be <3>;
    > > It is a little different from OMAP.
    >
    > If you don't want to keep the extra register entry around, then you
    > could have a custom .data entry in the pinctrl driver that contains
    > the mapping of these special registers.
    >
    Yes, that's what i think.
    But we still need pass the value for thoes sepcial registers from dt.

    > > For your proposal, I'm afraid it is a little too much depend on the SoC register
    > > layout. We need to find a flexible enough way to cover all possible
    > > register layout
    > > difference for all SoCs.
    > > (Considering one register controls multi muxs?)
    >
    > Most likely those special cases are best handled in hardware specific
    > drivers.
    >
    Yes, common driver needs provide a way to cover that.

    > > Did i misunderstand?
    > > I still can not understand why need this.
    > > The pinctrl properly in device node can support multi pinmuxs .
    > > serial@48020000 {
    > > pinctrl = <&pmx_uart3_x &pmx_uart3_y>;
    > > It's good to me that the consensus we reached at Linaro Connect is much like
    > > my proposal in above URL. :)
    >
    > I meant like what you have in the second option here, the count is
    > used to parse each entry.
    You're right, i misunderstood before.
    Sorry for the noise.

    Regards
    Dong Aisheng


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