linux-kernel - Re: [PATCH 3/3] phy: rockchip: Add Samsung HDMI/DP Combo PHY driver

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Date: Fri, 19 Jan 2024 23:47:18 +0100
From: Sebastian Reichel <sebastian.reichel@...labora.com>
To: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
Cc: Vinod Koul <vkoul@...nel.org>, 
	Kishon Vijay Abraham I <kishon@...nel.org>, Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Heiko Stuebner <heiko@...ech.de>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Johan Jonker <jbx6244@...il.com>, Sascha Hauer <s.hauer@...gutronix.de>, 
	Andy Yan <andy.yan@...k-chips.com>, Algea Cao <algea.cao@...k-chips.com>, 
	linux-phy@...ts.infradead.org, devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, kernel@...labora.com
Subject: Re: [PATCH 3/3] phy: rockchip: Add Samsung HDMI/DP Combo PHY driver

Hi Cristian,

On Fri, Jan 19, 2024 at 09:38:03PM +0200, Cristian Ciocaltea wrote:
> Add driver for the Rockchip HDMI/eDP TX Combo PHY found on RK3588 SoC.
> 
> The PHY is based on a Samsung IP block and supports HDMI 2.1 TMDS, FRL
> and eDP links.  The maximum data rate is 12Gbps (HDMI 2.1 FRL), while
> the minimum is 250Mbps (HDMI 2.1 TMDS).
> 
> Co-developed-by: Algea Cao <algea.cao@...k-chips.com>
> Signed-off-by: Algea Cao <algea.cao@...k-chips.com>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
> ---

The driver has multiple sequences looking like this (this is just one
example of many):

> +	hdptx_write(hdptx, CMN_REG0087, 0x04);
> +	hdptx_write(hdptx, CMN_REG0089, 0x00);
> +	hdptx_write(hdptx, CMN_REG008A, 0x55);
> +	hdptx_write(hdptx, CMN_REG008B, 0x25);
> +	hdptx_write(hdptx, CMN_REG008C, 0x2c);
> +	hdptx_write(hdptx, CMN_REG008D, 0x22);
> +	hdptx_write(hdptx, CMN_REG008E, 0x14);
> +	hdptx_write(hdptx, CMN_REG008F, 0x20);
> +	hdptx_write(hdptx, CMN_REG0090, 0x00);
> +	hdptx_write(hdptx, CMN_REG0091, 0x00);
> +	hdptx_write(hdptx, CMN_REG0092, 0x00);
> +	hdptx_write(hdptx, CMN_REG0093, 0x00);
> +	hdptx_write(hdptx, CMN_REG0095, 0x00);
> +	hdptx_write(hdptx, CMN_REG0097, 0x02);
> +	hdptx_write(hdptx, CMN_REG0099, 0x04);
> +	hdptx_write(hdptx, CMN_REG009A, 0x11);
> +	hdptx_write(hdptx, CMN_REG009B, 0x00);

Instead of the repetitive calls to regmap_write, it's better to do
it like this:

static const struct reg_sequence some_init_seq[] = {
	REG_SEQ0(CMN_REG0087, 0x04),
	REG_SEQ0(CMN_REG0089, 0x00),
	REG_SEQ0(CMN_REG008A, 0x55),
	REG_SEQ0(CMN_REG008B, 0x25),
	REG_SEQ0(CMN_REG008C, 0x2c),
	REG_SEQ0(CMN_REG008D, 0x22),
	REG_SEQ0(CMN_REG008E, 0x14),
	REG_SEQ0(CMN_REG008F, 0x20),
	REG_SEQ0(CMN_REG0090, 0x00),
	REG_SEQ0(CMN_REG0091, 0x00),
	REG_SEQ0(CMN_REG0092, 0x00),
	REG_SEQ0(CMN_REG0093, 0x00),
	REG_SEQ0(CMN_REG0095, 0x00),
	REG_SEQ0(CMN_REG0097, 0x02),
	REG_SEQ0(CMN_REG0099, 0x04),
	REG_SEQ0(CMN_REG009A, 0x11),
	REG_SEQ0(CMN_REG009B, 0x00),
};

regmap_multi_reg_write(hdptx->regmap, some_init_seq, ARRAY_SIZE(some_init_seq));

> +static const struct of_device_id rockchip_hdptx_phy_of_match[] = {
> +	{ .compatible = "rockchip,rk3588-hdptx-phy", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, rockchip_hdptx_phy_of_match);
> +
> +static struct platform_driver rockchip_hdptx_phy_driver = {
> +	.probe  = rockchip_hdptx_phy_probe,
> +	.driver = {
> +		.name = "rockchip-hdptx-phy",
> +		.pm = &rockchip_hdptx_phy_pm_ops,
> +		.of_match_table = of_match_ptr(rockchip_hdptx_phy_of_match),

Remove of_match_ptr(). It's a nop, since the driver depends on OF.

Greetings,

-- Sebastian

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