Re: [PATCH 09/12] drm/rockchip: lvds: Add PX30 support

["sandy.huang" <hjc@rock-chips.com>]

Hi

     some mistakes with last mail, so resend this mail.

在 2019/12/18 上午11:17, sandy.huang 写道:
> Hi Maxime & Miquel,
>
> 在 2019/12/16 下午7:14, Maxime Ripard 写道:
>> On Mon, Dec 16, 2019 at 12:03:12PM +0100, Miquel Raynal wrote:
>>> Maxime Ripard <maxime@cerno.tech> wrote on Mon, 16 Dec 2019 11:58:27 
>>> +0100:
>>>> Hi,
>>>>
>>>> On Fri, Dec 13, 2019 at 07:10:48PM +0100, Miquel Raynal wrote:
>>>>> +static int px30_lvds_grf_config(struct drm_encoder *encoder,
>>>>> +                struct drm_display_mode *mode)
>>>>> +{
>>>>> +    struct rockchip_lvds *lvds = encoder_to_lvds(encoder);
>>>>> +    u8 nhsync = !(mode->flags & DRM_MODE_FLAG_PHSYNC);
>>>>> +    u8 nvsync = !(mode->flags & DRM_MODE_FLAG_PVSYNC);
>>>>> +    u8 ndclk = !(mode->flags & DRM_MODE_FLAG_PCSYNC);
>>>>> +    int ret;
>>>>> +
>>>>> +    if (lvds->output != DISPLAY_OUTPUT_LVDS) {
>>>>> +        DRM_DEV_ERROR(lvds->dev, "Unsupported display output %d\n",
>>>>> +                  lvds->output);
>>>>> +        return -EINVAL;
>>>>> +    }
>>>>> +
>>>>> +    if (nhsync ^ nvsync) {
>>>>> +        DRM_DEV_ERROR(lvds->dev, "Unsupported Hsync/Vsync 
>>>>> polarity\n");
>>>>> +        return -EINVAL;
>>>>> +    }
>>>>> +
>>>>> +    /* Set format */
>>>>> +    ret = regmap_update_bits(lvds->grf, PX30_LVDS_GRF_PD_VO_CON1,
>>>>> +                 PX30_LVDS_FORMAT(lvds->format),
>>>>> +                 PX30_LVDS_FORMAT(lvds->format));
>>>>> +    if (ret)
>>>>> +        return ret;
>>>>> +
>>>>> +    /* Control Hsync/Vsync polarity */
>>>>> +    ret = regmap_update_bits(lvds->grf, PX30_LVDS_GRF_PD_VO_CON0,
>>>>> +                 PX30_LVDS_TIE_CLKS(1),
>>>>> +                 PX30_LVDS_TIE_CLKS(1));
>>>>> +    if (ret)
>>>>> +        return ret;
>>>>> +
>>>>> +    /* Set Hsync/Vsync polarity */
>>>>> +    ret = regmap_update_bits(lvds->grf, PX30_LVDS_GRF_PD_VO_CON0,
>>>>> +                 PX30_LVDS_INVERT_CLKS(1),
>>>>> +                 PX30_LVDS_INVERT_CLKS(nhsync));
>>>>> +    if (ret)
>>>>> +        return ret;
>>>> I don't know the hardware but it seems pretty weird to me. hsync and
>>>> vsync in LVDS are not clocks (or even signals), they're a bit in the
>>>> payload. Is there any explanation in the datasheet (or even a
>>>> datasheet in the first place)?
>>> There is no explanation about this in the PX30 TRM part 1 (public). But
>>> you are right the naming is weird. Could the "tie clocks" thing above
>>> mean something to you/people knowing the LVDS world?
>> I have no idea what that could mean :)
>
> This two bit(GRF_CON0[9,8]) is not for hsync/vsync polarity config, 
> the polarity is done at vop_crtc_atomic_enable@rockchip_drm_vop.c.
>
> Before px30, all rockchip platform lvds output payload is include 
> hsync,vsync and den clock signal. About years ago, we meet a lvds 
> panel can't work normally at rk3288,  from the panel spec we know the 
> panel need lvds work den mode only, the hsync/vsync need to set 0 at 
> blank time, so we add this two bit(GRF_CON0[9,8]) for this mode.
>
> but now we can't get in touch with the customer and get the panel to 
> test this function, so we can't verify the panel work unnormally is 
> because of  the den mode only and the hsync vsync signal level at 
> blank time.
>
> I recommend not including this part of configuration before we test 
> this funcion at den mode only lvds panel,thanks.
>
>>
>> Maxime
>>
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>