linux-kernel - Re: [PATCH 2/4] i2c: nomadik: support Mobileye EyeQ6H I2C controller

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Message-ID: <oxcxs6n7y4bw33yfgaacd2cayf7otfochvlaofva2kabzjim6h@d6pam3gciepl>
Date: Tue, 8 Oct 2024 15:39:59 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Théo Lebrun <theo.lebrun@...tlin.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, 
	Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>, 
	Grégory Clement <gregory.clement@...tlin.com>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
	Tawfik Bayouk <tawfik.bayouk@...ileye.com>
Subject: Re: [PATCH 2/4] i2c: nomadik: support Mobileye EyeQ6H I2C controller

On Tue, Oct 08, 2024 at 12:29:41PM +0200, Théo Lebrun wrote:
> Add EyeQ6H support to the nmk-i2c AMBA driver. It shares the same quirk
> as EyeQ5: the memory bus only supports 32-bit accesses. Avoid writeb()
> and readb() by reusing the same `priv->has_32b_bus` flag.
> 
> It does NOT need to write speed-mode specific value into a register;
> therefore it does not depend on the mobileye,olb DT property.
> 
> Refactoring is done using is_eyeq5 and is_eyeq6h boolean local
> variables. Sort variables in reverse christmas tree to try and
> introduce some logic into the ordering.
> 
> Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
> ---
>  drivers/i2c/busses/i2c-nomadik.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
> index ad0f02acdb1215a1c04729f97bb14a4d93f88456..ea511d3a58073eaedb63850026e05b59427a69c6 100644
> --- a/drivers/i2c/busses/i2c-nomadik.c
> +++ b/drivers/i2c/busses/i2c-nomadik.c
> @@ -6,10 +6,10 @@
>   * I2C master mode controller driver, used in Nomadik 8815
>   * and Ux500 platforms.
>   *
> - * The Mobileye EyeQ5 platform is also supported; it uses
> + * The Mobileye EyeQ5 and EyeQ6H platforms are also supported; they use
>   * the same Ux500/DB8500 IP block with two quirks:
>   *  - The memory bus only supports 32-bit accesses.
> - *  - A register must be configured for the I2C speed mode;
> + *  - (only EyeQ5) A register must be configured for the I2C speed mode;
>   *    it is located in a shared register region called OLB.
>   *
>   * Author: Srinidhi Kasagar <srinidhi.kasagar@...ricsson.com>
> @@ -1046,8 +1046,6 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
>  	struct regmap *olb;
>  	unsigned int id;
>  
> -	priv->has_32b_bus = true;
> -
>  	olb = syscon_regmap_lookup_by_phandle_args(np, "mobileye,olb", 1, &id);
>  	if (IS_ERR(olb))
>  		return PTR_ERR(olb);
> @@ -1070,13 +1068,15 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
>  
>  static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>  {
> -	int ret = 0;
> -	struct nmk_i2c_dev *priv;
> -	struct device_node *np = adev->dev.of_node;
> -	struct device *dev = &adev->dev;
> -	struct i2c_adapter *adap;
>  	struct i2c_vendor_data *vendor = id->data;
> +	struct device_node *np = adev->dev.of_node;
> +	bool is_eyeq6h = of_device_is_compatible(np, "mobileye,eyeq6h-i2c");
> +	bool is_eyeq5 = of_device_is_compatible(np, "mobileye,eyeq5-i2c");

You should use match data, not add compatibles in the middle of code.
That's preferred, scallable pattern. What you added here last time does
not scale and above change is a proof for that.

Best regards,
Krzysztof