linux-kernel - Re: [PATCH v3 2/2] drm/panel: Add driver for Novatek NT36523

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Message-ID: <ZAh3MSpQ30YyPAVe@Gentoo>
Date:   Wed, 8 Mar 2023 19:53:21 +0800
From:   Jianhua Lu <lujianhua000@...il.com>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] drm/panel: Add driver for Novatek NT36523

On Wed, Mar 08, 2023 at 12:13:53PM +0100, Konrad Dybcio wrote:
> 
> 
> On 8.03.2023 05:37, Jianhua Lu wrote:
> > Add a driver for panels using the Novatek NT36523 display driver IC.
> > 
> > Signed-off-by: Jianhua Lu <lujianhua000@...il.com>
> > ---
> > Changes in v3:
> >   - Refactor source code
> > 
> > Changes in v2:
> >   - Refactor and clean up source code
> This is a veeery vague changelog, akin to "change patch", please
> be more specific the next time around.
> 
Acked, thanks
> 
> [...]
> 
> > +#define DSI_NUM_MIN 1
> > +
> > +/* Macro modified from mipi_dual_dsi_dcs_write_seq */
> > +#define mipi_dual_dsi_dcs_write_seq(dsi, cmd, seq...)           	   \
> > +	do {                                                               \
> > +		static const u8 d[] = { cmd, seq };                        \
> > +		int i, ret;                                                \
> > +		for (i = 0; i < ARRAY_SIZE(dsi); i++) {                    \
> > +			ret = mipi_dsi_dcs_write_buffer(dsi[i], d, ARRAY_SIZE(d));    \
> > +			if (ret < 0) {                                             \
> > +				dev_err_ratelimited(                               \
> > +					&dsi[i]->dev, "sending command %#02x failed: %d\n", \
> > +					cmd, ret);                                 \
> > +				return ret;                                        \
> > +			}                                                          \
> > +		}                                                                  \
> > +	} while (0)
> > +
> This should definitely be put in a common file..
Acked.
> 
> 
> > +static const struct drm_display_mode elish_boe_mode = {
> > +	/* Current max freqency is 104HZ, TODO 120HZ */
> Is it a DPU issue, or does the panel not work correctly when you
> jack up the clocks? Did you use the correct init sequence and porches
> for the 120Hz mode, including the mode switch command set?
> 
panel will turn into bluescreen when freqency overs 104HZ, downstream
seems use a dsi-cphy enhance feature to make it working. Init sequence
and porches are right

> Could you also implement a 60 (or whatever other value is also
> implemented downstream) Hz mode?
I will try to implement it.
> 
> > +	.clock = (1600 + 60 + 8 + 60) * (2560 + 26 + 4 + 168) * 104 / 1000,
> > +	.hdisplay = 1600,
> > +	.hsync_start = 1600 + 60,
> > +	.hsync_end = 1600 + 60 + 8,
> > +	.htotal = 1600 + 60 + 8 + 60,
> > +	.vdisplay = 2560,
> > +	.vsync_start = 2560 + 26,
> > +	.vsync_end = 2560 + 26 + 4,
> > +	.vtotal = 2560 + 26 + 4 + 168,
> > +};
> > +
> > +static const struct drm_display_mode elish_csot_mode = {
> > +	/* Current max freqency is 104HZ, TODO 120HZ */
> > +	.clock = (1600 + 200 + 40 + 52) * (2560 + 26 + 4 + 168) * 104 / 1000,
> > +	.hdisplay = 1600,
> > +	.hsync_start = 1600 + 200,
> > +	.hsync_end = 1600 + 200 + 40,
> > +	.htotal = 1600 + 200 + 40 + 52,
> > +	.vdisplay = 2560,
> > +	.vsync_start = 2560 + 26,
> > +	.vsync_end = 2560 + 26 + 4,
> > +	.vtotal = 2560 + 26 + 4 + 168,
> > +};
> > +
> > +static const struct panel_desc elish_boe_desc = {
> > +	.modes = &elish_boe_mode,
> > +	.dsi_info = {
> > +		.type = "NT36523",
> That's a bit vague, the driver IC is not very telling about the
> panel itself. Since we're not able to determine much more information,
> this could contain the panel manufacturer and the device name.
Acked.
> 
> > +		.channel = 0,
> > +		.node = NULL,
> > +	},
> > +	.width_mm = 127,
> > +	.height_mm = 203,
> > +	.bpc = 8,
> > +	.lanes = 3,
> > +	.format = MIPI_DSI_FMT_RGB888,
> > +	.mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_CLOCK_NON_CONTINUOUS | MIPI_DSI_MODE_LPM,
> > +	.init_sequence = elish_boe_init_sequence,
> > +	.is_dual_dsi = true,
> > +};
> > +
> [...]
> 
> > +static int nt36523_probe(struct mipi_dsi_device *dsi)
> > +{
> [...]
> 
> > +	/* If the panel is dual dsi, register DSI1 */
> > +	if (pinfo->desc->is_dual_dsi) {
> > +		info = &pinfo->desc->dsi_info;
> > +
> > +		dsi1 = of_graph_get_remote_node(dsi->dev.of_node, 1, -1);
> > +		if (!dsi1) {
> > +			dev_err(dev, "cannot get secondary DSI node.\n");
> > +			return -ENODEV;
> > +		}
> > +
> > +		dsi1_host = of_find_mipi_dsi_host_by_node(dsi1);
> > +		of_node_put(dsi1);
> Shouldn't you put the reference only if it's found?
thanks for spot it.
> 
> > +		if (!dsi1_host) {
> > +			dev_err(dev, "cannot get secondary DSI host\n");
> > +			return -EPROBE_DEFER;
> dev_err_probe, here and in neighbouring exit return paths?
Acked.
> 
> 
> Konrad