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    SubjectRe: [PATCH 1/2] pinmux: Add TB10x pinmux driver
    On Thu, Jun 06, 2013 at 10:32:21PM +0800, Haojian Zhuang wrote:
    > On 6 June 2013 22:11, Christian Ruppert <christian.ruppert@abilis.com> wrote:
    > > On Wed, Jun 05, 2013 at 09:44:27AM +0800, Haojian Zhuang wrote:
    > >> On 3 June 2013 20:30, Christian Ruppert <christian.ruppert@abilis.com> wrote:
    > >> > OK, here's a simplified example of what we would like to do (this seems
    > >> > pretty common so I suppose there is a way I haven't understood). Our
    > >> > situation is slightly more complex but for the purpose of discussion
    > >> > let's assume a chip with 8 pins which can be configured for the
    > >> > following functions:
    > >> >
    > >> > Pin GPIO-A I2C SPI0 SPI1
    > >> > ------------------------------------
    > >> > 1 GPIOA0 SDA MISO1
    > >> > 2 GPIOA1 SCL MOSI1
    > >> > 3 GPIOA2 SS1_B
    > >> > 4 GPIOA3 SCLK1
    > >> > 5 GPIOA4 MISO0
    > >> > 6 GPIOA5 MOSI0
    > >> > 7 GPIOA6 SS0_B
    > >> > 8 GPIOA7 SCLK0
    > >> >
    > >> > We can now define the following pinctrl-single:
    > >> >
    > >> > pinmux: pinmux@0xFFEE0000 {
    > >> > compatible = "pinctrl-single";
    > >> > reg = <0xFFEE0000 0x8>;
    > >> > #address-cells = <1>;
    > >> > #size-cells = <0>;
    > >> > #gpio-range-cells = <3>;
    > >> > pinctrl-single,register-width = <32>;
    > >> > pinctrl-single,function-mask = <0xffffffff>;
    > >> > pinctrl-single,gpio-range = <&range 1 8 0>;
    > >> > gpioa_pins: pinmux_gpioa_pins {
    > >> > pinctrl-single,pins = <0x0 0 0x4 0>
    > >> > };
    > >> > i2c_pins: pinmux_i2c_pins {
    > >> > pinctrl-single,pins = <0x0 1>
    > >> > };
    > >> > spi0_pins: pinmux_spi0_pins {
    > >> > pinctrl-single,pins = <0x1 1>
    > >> <0x1 1>?
    > >>
    > >> If each pinmux register is only for one pin in your SoC.
    > >> I think that your definitions are wrong above. We use
    > >> register offset as the first argument, not pin number.
    > >> And the second argument should be pin function number.
    > >
    > > In our case each pinmux register (bit field) actually controls an entire
    > > group of pins.
    > >
    > >> If multiple pins are sharing one register with different bits,
    > >> you need to enable "pinctrl-single,bit-per-mux".
    > >
    > > Multiple pins are sharing the same bits in the same register. Do you
    > > think this prevents us from using pinctrl-single?
    > >
    > Could you give me your register definition? Then I can understand you
    > better.

    In our example, the register map would look a bit like the following.
    Note that every register configures four pins at a time.

    Register 0x0:
    Mode GPIO-A I2C SPI1
    Value 0x0 0x1 0x2
    ---------------------------
    Pin1 GPIOA0 SDA MISO1
    Pin2 GPIOA1 SCL MOSI1
    Pin3 GPIOA2 SS1_B
    Pin4 GPIOA3 SCLK1

    Register 0x4:
    Mode GPIO-A SPI0
    Value 0x0 0x1
    ---------------------
    Pin5 GPIOA4 MISO0
    Pin6 GPIOA5 MOSI0
    Pin7 GPIOA6 SS0_B
    Pin8 GPIOA7 SCLK0

    Greetings,
    Christian

    --
    Christian Ruppert , <christian.ruppert@abilis.com>
    /|
    Tel: +41/(0)22 816 19-42 //| 3, Chemin du Pré-Fleuri
    _// | bilis Systems CH-1228 Plan-les-Ouates
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