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SubjectRe: [PATCH v2 03/13] drm/sun4i: tcon: Add support for demuxing TCON output on A31
On Tue, Sep 26, 2017 at 5:56 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Hi,
>
> On Tue, Sep 26, 2017 at 06:59:09AM +0000, Chen-Yu Tsai wrote:
>> On systems with 2 TCONs such as the A31, it is possible to demux the
>> output of the TCONs to one encoder.
>>
>> Add support for this for the A31.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>> drivers/gpu/drm/sun4i/sun4i_tcon.c | 61 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 61 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
>> index e853dfe51389..770b843a6fa9 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
>> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
>> @@ -14,9 +14,12 @@
>> #include <drm/drm_atomic_helper.h>
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_crtc_helper.h>
>> +#include <drm/drm_encoder.h>
>> #include <drm/drm_modes.h>
>> #include <drm/drm_of.h>
>>
>> +#include <uapi/drm/drm_mode.h>
>> +
>> #include <linux/component.h>
>> #include <linux/ioport.h>
>> #include <linux/of_address.h>
>> @@ -109,11 +112,69 @@ void sun4i_tcon_enable_vblank(struct sun4i_tcon *tcon, bool enable)
>> }
>> EXPORT_SYMBOL(sun4i_tcon_enable_vblank);
>>
>> +static struct sun4i_tcon *sun4i_get_first_tcon(struct drm_device *drm)
>> +{
>> + struct sun4i_drv *drv = drm->dev_private;
>> + struct sun4i_tcon *tcon;
>> +
>> + list_for_each_entry(tcon, &drv->tcon_list, list)
>> + if (tcon->id == 0)
>> + return tcon;
>> +
>> + dev_warn(drm->dev,
>> + "TCON0 not found, display output muxing may not work\n");
>> +
>> + return tcon;
>> +}
>> +
>> +static int _sun6i_tcon_set_mux(struct drm_encoder *encoder)
>> +{
>> + struct sun4i_tcon *tcon = sun4i_get_first_tcon(encoder->dev);
>> + int tcon_id = drm_crtc_to_sun4i_crtc(encoder->crtc)->tcon->id;
>> + u32 shift;
>> +
>> + DRM_DEBUG_DRIVER("Muxing encoder %s to CRTC %s (TCON %d)\n",
>> + encoder->name, encoder->crtc->name, tcon_id);
>> +
>> + /* Only 2 TCONs */
>> + if (tcon_id >= 2)
>> + return -EINVAL;
>> +
>> + switch (encoder->encoder_type) {
>> + case DRM_MODE_ENCODER_TMDS:
>> + /* HDMI */
>> + shift = 8;
>> + break;
>> + case DRM_MODE_ENCODER_DSI:
>> + /* No MIPI DSI on A31s */
>> + if (of_device_is_compatible(tcon->dev->of_node,
>> + "allwinner,sun6i-a31s-tcon"))
>
> I'm not sure that test is needed.
>
> We won't end up in that case if we don't have a connected DSI block,
> which isn't going to be the case on the A31. And I guess we can tackle
> DSI later (when I'll send my patches...).

OK. I'll leave a comment instead.

>
>> + return -EINVAL;
>> + shift = 0;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + regmap_update_bits(tcon->regs, SUN4I_TCON_MUX_CTRL_REG,
>> + 0x3 << shift, tcon_id << shift);
>> +
>> + return 0;
>> +}
>> +
>> void sun4i_tcon_set_mux(struct sun4i_tcon *tcon, int channel,
>> struct drm_encoder *encoder)
>> {
>> + /* Get the device node of the display engine */
>> + struct device_node *node = encoder->dev->dev->of_node;
>> u32 val;
>>
>> + if (of_device_is_compatible(node, "allwinner,sun6i-a31-display-engine") ||
>> + of_device_is_compatible(node, "allwinner,sun6i-a31s-display-engine")) {
>> + _sun6i_tcon_set_mux(encoder);
>> + return;
>> + }
>> +
>
> I'd really like to avoid mix and matching the structure defined
> behaviour and those of_device_is_compatible calls spread out
> everywhere.
>
> You can either add a flag or a function pointer.

Function pointer it is!

ChenYu

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