Thu, 14 Aug 2014 15:13:39 +0300 от Grygorii Strashko <grygorii.strashko@xxxxxx>:
> Hi Alexander,
>
> On 08/13/2014 07:06 PM, Alexander Shiyan wrote:
> > Wed, 13 Aug 2014 19:16:22 +0300 от Grygorii Strashko <grygorii.strashko@xxxxxx>:
> >> Add Keystone 2 DSP GPIO nodes.
> >> DSP GPIO banks 0-7 correspond to DSP0-DSP7
> >>
> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> >> ---
> >> arch/arm/boot/dts/k2hk.dtsi | 56 +++++++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 56 insertions(+)
> >>
> >> diff --git a/arch/arm/boot/dts/k2hk.dtsi b/arch/arm/boot/dts/k2hk.dtsi
> >> index 321ba2f..009e180 100644
> >> --- a/arch/arm/boot/dts/k2hk.dtsi
> >> +++ b/arch/arm/boot/dts/k2hk.dtsi
> >> @@ -50,5 +50,61 @@
> >> #interrupt-cells = <1>;
> >> ti,syscon-dev = <&devctrl 0x2a0>;
> >> };
> >> +
> >> + dspgpio0: keystone_dsp_gpio@02620240 {
> >> + compatible = "ti,keystone-mctrl-gpio";
> >> + gpio-controller;
> >> + #gpio-cells = <2>;
> >> + gpio,syscon-dev = <&devctrl 0x240>;
> >> + };
> >> +
> >> + dspgpio1: keystone_dsp_gpio@2620244 {
> >> + compatible = "ti,keystone-mctrl-gpio";
> >> + gpio-controller;
> >> + #gpio-cells = <2>;
> >> + gpio,syscon-dev = <&devctrl 0x244>;
> >> + };
> > ...
> >> + dspgpio7: keystone_dsp_gpio@262025C {
> >> + compatible = "ti,keystone-mctrl-gpio";
> >> + gpio-controller;
> >> + #gpio-cells = <2>;
> >> + gpio,syscon-dev = <&devctrl 0x25c>;
> >> + };
> >
> > So, devctrl is a syscon device and this DTS introduce several
> > identical GPIO descriptions?
> >
> > On my opinion this should be placed in the gpio-syscon.c,
> > where you can add support for ti,keystone-dsp0{..7}-gpio.
> > Such change will avoid parts 2 and 3 of this patch.
> >
> > static const struct syscon_gpio_data ti_keystone_dsp0_gpio = {
> > .compatible = "ti,keystone-syscon",
> > .dat_bit_offset = 0x240 * 8,
> > ...
> > .set = etc...
> > };
>
> So, if I understand you right, you propose to add 8 additional compatible
> strings just to encode different register offsets. Is it?
> 1) add "ti,keystone-mctrl-gpio0"..."ti,keystone-mctrl-gpio7"
Yes, but replace "mctrl" with "dsp" since mctrl is not applicable here.
> 2) add 8 structures keystone_mctrl_gpio0..keystone_mctrl_gpio7 in gpio-syscon.c
> (which will have only different values of field - .dat_bit_offset = 0x2yy * 8,)
>
> 3) add 8 additional items in array syscon_gpio_ids
> {
> .compatible = "ti,keystone-mctrl-gpio0",
> .data = &keystone_mctrl_gpio0,
> }, ...
>
> I can do it if you strictly insist, BUT I don't like it :(
> - just imagine how your driver will look look like if 5 or 6 SoCs will re-use it ;)
> - as I mentioned in cover letter and commit messages even each SoC revision can have
> different Syscon implementation with different registers offsets and with different
> number of Syscon register ranges (for example for Keystone 2 we already have two
> Syscon devices defined in DT).
The initial version of this driver contains addresses and offsets in, but this approach has
been criticized by DT maintainers.
"different Syscon with different registers" - is OK, since we use compatible string in definition.
If you have two identical syscon, just append an unique additional string and use it in this driver.
> Now we already have 3 Keystone 2 SoC revisions (K2HK, K2L, K2E) and there are no guarantee
> that the next revision k2X will have the same register offset for GPIO0.
Then use more exact string for syscon-gpio, like ti,keystone-k2hk-dsp-gpio0.
---
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