On Tue, Sep 2, 2014 at 4:31 PM, Stephen Warren <[email protected]> wrote:
> On 09/02/2014 11:18 AM, Sean Paul wrote:
>>
>> This patch adds MIPI CSI/DSIB pad control mux register
>> from the APB misc block to tegra pinctrl.
>>
>> Without writing to this register, the dsib pads are
>> muxed as csi, and cannot be used.
>>
>> The register is not yet documented in the TRM, here is
>> the description:
>>
>> 70000820: APB_MISC_GP_MIPI_PAD_CTRL_0
>> [31:02] RESERVED
>> [01:01] DSIB_MODE [CSI=0,DSIB=1]
>> [00:00] RESERVED
>
>
> That's a very unfortunate HW design, but oh well:-(
>
> I slightly wonder whether it's legitimate to even consider that register
> part of the pinmux controller; I certainly don't see any mention of it in
> the pinmux spreadsheets. It feels like some unrelated bolt-on feature.
> Still, I suppose requiring a separate driver for it just because the
> registers aren't all nicely grouped is a bit silly. At least a quick glance
> implies there aren't any other missing cases like this, so we shouldn't need
> to add any more later.
>
Yeah, the hw is unfortunate. It doesn't feel like this solution was Plan A :-)
> I don't suppose there's any chance you could update:
> git://github.com/NVIDIA/tegra-pinmux-scripts.git
> with an equivalent change?
>
Sure, I can do that.
>> diff --git a/drivers/pinctrl/pinctrl-tegra124.c
>> b/drivers/pinctrl/pinctrl-tegra124.c
>
>
>> +#define TEGRA_PIN_CSI_DSIB _PIN(8)
>
>
> Is that actually the name of the pin on the Tegra package? I don't see
> anything like that the board schematic I have.
>
Well, there's more than one pin affected by this register. They're named:
DSI_B_CLK_P
DSI_B_CLK_N
DSI_B_D0_P
DSI_B_D0_N
DSI_B_D1_P
DSI_B_D1_N
DSI_B_D2_P
DSI_B_D2_N
DSI_B_D3_P
DSI_B_D3_N
I'll change this to TEGRA_PIN_DSI_B, does that work for you?
>
>> #define DRV_PINGROUP_REG_A 0x868 /* bank 0 */
>> #define PINGROUP_REG_A 0x3000 /* bank 1 */
>> +#define APB_MISC_PINGROUP_REG_A 0x820 /* bank 2 */
>
>
> In order for that to work, an extra reg entry will be required in DT so that
> registers in bank 2 can be accessed. I would expect this patch (or series)
> to contain an addition to
> Documentation/devicetree/bindings/pinctrl/nvidia,tegra124-pinmux.txt to
> mention this. I assume you'll send a patch to
> arch/arm/boot/dts/tegra124.dtsi separately to add that entry.
>
Yep, sounds good.
>
>> +#define APB_MISC_PINGROUP(pg_name, r, b, f0, f1, f_safe) \
>
>
> f_safe isn't present in any of the upstream Tegra pinctrl drivers any more,
> so that parameter isn't needed any more...
>
>
>> + { \
>> + .name = #pg_name, \
>> + .pins = pg_name##_pins, \
>> + .npins = ARRAY_SIZE(pg_name##_pins), \
>> + .funcs = { \
>> + TEGRA_MUX_ ## f0, \
>> + TEGRA_MUX_ ## f1, \
>> + }, \
>> + .func_safe = TEGRA_MUX_ ## f_safe, \
>
>
> ... and I don't think that line will even compile, since that field doesn't
> exist?
>
Oh my, sorry about that. I mustn't have had my config set up correctly
when I built this.
> All 4 entries in .funcs[] should be initialized too. If two don't make
> sense, then they should at least be hard-coded to TEGRA_MUX_RSVD3/4. It
> would be nice if the driver knew that this pin only had two valid mux
> options, but I suppose updating the code to handle that special case isn't
> really worth it.
>
>
>> DRV_PINGROUP(ao4, 0x9c8, 2, 3, 4, 12, 7, 20, 7,
>> 28, 2, 30, 2, Y),
>> +
>> + /* pg_name, r b f0,
>> f1, f_safe */
>> + APB_MISC_PINGROUP( csi_dsib, 0x820, 1, CSI,
>> DSIB, DSIB)
>> };
>
>
> Can you make the indentation of the added lines consistent here. The
> existing code uses a TAB at the start of the line (but the patch uses
> spaces), and spaces internally (but the patch uses TABs) so columns don't
> have to waste space being TAB aligned. The pg_name column should be nestled
> right against the opening (, without any intervening space.
I'll upload a new version shortly.
Sean
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