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Subject: Re: [PATCH v3 1/4] drm: rockchip: introduce rk3066 hdmi
To:     Sam Ravnborg <sam@ravnborg.org>
Cc:     heiko@sntech.de, mark.rutland@arm.com, devicetree@vger.kernel.org,
        airlied@linux.ie, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
        robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org
References: <20190302104116.1535-1-jbx6244@gmail.com>
 <20190302104116.1535-2-jbx6244@gmail.com>
 <20190303202308.GD13157@ravnborg.org>
From:   Johan Jonker <jbx6244@gmail.com>
Message-ID: <b6b818d5-8c24-e01a-572e-97c1754c80e8@gmail.com>
Date:   Mon, 4 Mar 2019 23:48:30 +0100
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Thanks for the useful review comments.

With regard to the bugs something between rc1 and rc8 results
in a freeze on poweroff. Power domain doesn't seem to turn off
the vop and hdmi in rc8.
For testing only.

Forgot to ask rob+dt the prefered document name for "rockchip,rk3066-hdmi"
Please advise if this is OK? "rockchip_rk3066-hdmi.txt"

On 3/3/19 9:23 PM, Sam Ravnborg wrote:> Hi Johan.
>
> Thanks for this nive driver.
> A few review comments follows.
>
> 	Sam
>
> On Sat, Mar 02, 2019 at 11:41:13AM +0100, Johan Jonker wrote:
>> From: Zheng Yang <zhengyang@rock-chips.com>
>>
>> Introduce rk3066 hdmi.
> A little more info would be good here.
> Do not assume all reader knows as much as you do.

Will add more text in V4.

>> +#include <linux/clk.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/regmap.h>
>> +
>> +#include <drm/drm_of.h>
>> +#include <drm/drmP.h>
>> +#include <drm/drm_probe_helper.h>
> Please do not use drmP.h in new files. The usage of drmP.h is deprecated.
> Also please sort the include files, but keep the nice grouping.

You try to get rid of it and now I add one more to it ...
Thank you for letting me know.
The file drmP.h is used for:
to_platform_device, platform_get_resource, platform_get_irq
Replaced <drm/drmP.h> by <linux/platform_device.h>

>> +	int vic;
> vic is used so much. It deserves an explanation.

Is this OK?
	int vic; // pointer to the current cea mode in the edid_cea_modes array

hdmi->hdmi_data.vic = drm_match_cea_mode(mode);

>> +	unsigned int enc_in_format;
>
> enc_in_format is in this patch only assinged.
> aybe drop it (if not used in later patches)

Will drop it. Possible leftover when they reused
the inno-hdmi driver as template?

>> +	u8 ddc_addr;
>> +	u8 segment_addr;
> The two members above are only used in rk3066_hdmi_i2c_write()
> Maybe they can be made local variables?

ddc_addr and segment_addr only get a value in the condition below and
are reused.
Should remain global.

	if (msgs->addr == DDC_SEGMENT_ADDR)
		hdmi->i2c->segment_addr = msgs->buf[0];
	if (msgs->addr == DDC_ADDR)
		hdmi->i2c->ddc_addr = msgs->buf[0];

>> +	struct mutex lock; /*for i2c operation*/
> Name the lock after what is protects, to avoid mis-use.

Will change the name to i2c_lock.

>> +	struct completion cmp;
>
> cmp is shorthand for "compare" - as we have a command named so.
> Find a better name.

Agree.

>> +	struct drm_device *drm_dev;
> The new way to do this is to embed the device.
> See latest patches by Noralf in drm-misc-next, which include a nice
example.

That sounds more like a job for the Rockchip maintainers and
not for a individual. With this driver they have 8 more to go ...

	ADD_ROCKCHIP_SUB_DRIVER(vop_platform_driver, CONFIG_DRM_ROCKCHIP);
	ADD_ROCKCHIP_SUB_DRIVER(rockchip_lvds_driver,
				CONFIG_ROCKCHIP_LVDS);
	ADD_ROCKCHIP_SUB_DRIVER(rockchip_dp_driver,
				CONFIG_ROCKCHIP_ANALOGIX_DP);
	ADD_ROCKCHIP_SUB_DRIVER(cdn_dp_driver, CONFIG_ROCKCHIP_CDN_DP);
	ADD_ROCKCHIP_SUB_DRIVER(dw_hdmi_rockchip_pltfm_driver,
				CONFIG_ROCKCHIP_DW_HDMI);
	ADD_ROCKCHIP_SUB_DRIVER(dw_mipi_dsi_rockchip_driver,
				CONFIG_ROCKCHIP_DW_MIPI_DSI);
	ADD_ROCKCHIP_SUB_DRIVER(inno_hdmi_driver, CONFIG_ROCKCHIP_INNO_HDMI);
	ADD_ROCKCHIP_SUB_DRIVER(rk3066_hdmi_driver,
				CONFIG_ROCKCHIP_RK3066_HDMI);

>> +	struct regmap *regmap;
> +1 for using regmap.
> But then there is still several readl_relaxed() writel_relaxed() calls?
> They are in hdmi_readb() and hdmi_writeb(). Should a regmap had been
used here too?

Will rename hdmi->regmap to hdmi->grf_regmap to make it look more different
between hdmi devm_ioremap and grf syscon_regmap.

>> +	value |= vsync_offset << 4;
> Replace 4 with HDMI_VIDEO_VSYNC_OFFSET_SHIFT??

Looks like it. That's something only the author can tell.

>> +	hdmi->regmap =
>> +		syscon_regmap_lookup_by_phandle(hdmi->dev->of_node,
>> +						"rockchip,grf");
>
> dev->of_node would be fine here. No reason to go via hdmi->

Will replace the other hdmi->dev in this function by dev as well.

>> +	hdmi->connector.funcs->destroy(&hdmi->connector);
>> +	hdmi->encoder.funcs->destroy(&hdmi->encoder);
> I think the destroy() function should not be called directly.

Don't know what should be used instead. Please advise.

>> +static const struct of_device_id rk3066_hdmi_dt_ids[] = {
>> +	{ .compatible = "rockchip,rk3066-hdmi",
>> +	},
> MAke this a one-liner.
>
>> +	{},
> Us { /* sentinal */ }, like most other drivers.

Agree. But I prefere sentinel ...

{ .compatible = "rockchip,rk3066-hdmi"},
{ /* sentinel */ },

>> +	.driver = {
>> +		.name = "rockchip-rk3066hdmi",
> Different naming are used for the driver in this file.
> Coniser using a macro to align the naming.

"rockchip,rk3066-hdmi" is related to "rockchip,rk3066-vop"

"rockchip-rk3066hdmi" should remain in line with the other debug messages,
else it gets a mess if you do a dmesg | grep ...

[    0.576237] rockchip-pm-domain 20004000.pmu:power-controller:
rockchip_pm_domain_probe
[    1.198354] rockchip-vop 1010c000.vop: attaching to power domain 'pd_vio'
[    1.437444] rockchip-drm display-subsystem: bound 10116000.hdmi (ops
0xc0842d38)
[    0.397567] rockchip-rk3066hdmi 10116000.hdmi: registered RK3066 HDMI
I2C bus driver

Not so good example.
[   12.726332] dwmmc_rockchip 10214000.dwmmc: Using external DMA controller.