linux-kernel - Re: [PATCH 1/2] phy: ti: j721e-wiz: Manage TypeC lane swap if typec-gpio-dir not specified

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Message-ID: <efb41211-e0aa-96f2-5099-677ca6b6d99b@kernel.org>
Date:   Wed, 14 Dec 2022 11:00:39 +0200
From:   Roger Quadros <rogerq@...nel.org>
To:     Sinthu Raja <sinthu.raja@...tralsolutions.com>,
        Vinod Koul <vkoul@...nel.org>,
        Ravi Gunasekaran <r-gunasekaran@...com>,
        Siddharth Vadapalli <s-vadapalli@...com>
Cc:     Vignesh Raghavendra <vigneshr@...com>,
        linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Sinthu Raja <sinthu.raja@...com>
Subject: Re: [PATCH 1/2] phy: ti: j721e-wiz: Manage TypeC lane swap if
 typec-gpio-dir not specified

Hi Sinthu,

On 13/12/2022 14:48, Sinthu Raja wrote:
> It's possible that the Type-C plug orientation on the DIR line will be
> implemented through hardware design. In that situation, there won't be
> an external GPIO line available, but the driver still needs to address
> this since the DT won't use the typec-gpio-dir property.

The property is actually "typec-dir-gpios"

> 
> Add code to handle LN10 Type-C swap if typec-gpio-dir property is not
> specified in DT.
> 
> Remove typec-gpio-dir check to use minimum debounce from Type-C spec if
> it is not provided in DT

Why?

> 
> Signed-off-by: Sinthu Raja <sinthu.raja@...com>
> ---
>  drivers/phy/ti/phy-j721e-wiz.c | 65 +++++++++++++++++++++-------------
>  1 file changed, 40 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/phy/ti/phy-j721e-wiz.c b/drivers/phy/ti/phy-j721e-wiz.c
> index 141b51af4427..b17eec632d49 100644
> --- a/drivers/phy/ti/phy-j721e-wiz.c
> +++ b/drivers/phy/ti/phy-j721e-wiz.c
> @@ -375,6 +375,7 @@ struct wiz {
>  	struct gpio_desc	*gpio_typec_dir;
>  	int			typec_dir_delay;
>  	u32 lane_phy_type[WIZ_MAX_LANES];
> +	u32 lane_phy_reg[WIZ_MAX_LANES];
>  	struct clk		*input_clks[WIZ_MAX_INPUT_CLOCKS];
>  	struct clk		*output_clks[WIZ_MAX_OUTPUT_CLOCKS];
>  	struct clk_onecell_data	clk_data;
> @@ -1231,14 +1232,28 @@ static int wiz_phy_reset_deassert(struct reset_controller_dev *rcdev,
>  	int ret;
>  
>  	/* if typec-dir gpio was specified, set LN10 SWAP bit based on that */
> -	if (id == 0 && wiz->gpio_typec_dir) {
> -		if (wiz->typec_dir_delay)
> -			msleep_interruptible(wiz->typec_dir_delay);
> -
> -		if (gpiod_get_value_cansleep(wiz->gpio_typec_dir))
> -			regmap_field_write(wiz->typec_ln10_swap, 1);
> -		else
> -			regmap_field_write(wiz->typec_ln10_swap, 0);
> +	if (id == 0 && wiz->typec_dir_delay) {
> +		msleep_interruptible(wiz->typec_dir_delay);

Why do you need to have this debounce delay if there was no GPIO to begin with.
You need to move the msleep call within the next if {} block.

> +
> +		if (wiz->gpio_typec_dir) {
> +			if (gpiod_get_value_cansleep(wiz->gpio_typec_dir))
> +				regmap_field_write(wiz->typec_ln10_swap, 1);
> +			else
> +				regmap_field_write(wiz->typec_ln10_swap, 0);
> +		} else {
> +			/* if no typec-dir gpio was specified, and USB lines
> +			 * are connected to Lane 0 then set LN10 SWAP bit to 1.
> +			 */
> +			u32 num_lanes = wiz->num_lanes;
> +			int i;
> +
> +			for (i = 0; i < num_lanes; i++) {typec-dir-gpios:
> +				if ((wiz->lane_phy_type[i] == PHY_TYPE_USB3) \
> +						&& wiz->lane_phy_reg[i] == 0) {
> +					regmap_field_write(wiz->typec_ln10_swap, 1);
> +				}
> +			}
> +		}
>  	}
>  
>  	if (id == 0) {
> @@ -1370,8 +1385,10 @@ static int wiz_get_lane_phy_types(struct device *dev, struct wiz *wiz)
>  		dev_dbg(dev, "%s: Lanes %u-%u have phy-type %u\n", __func__,
>  			reg, reg + num_lanes - 1, phy_type);
>  
> -		for (i = reg; i < reg + num_lanes; i++)
> +		for (i = reg; i < reg + num_lanes; i++) {
> +			wiz->lane_phy_reg[i] = reg;
>  			wiz->lane_phy_type[i] = phy_type;
> +		}
>  	}
>  
>  	return 0;
> @@ -1464,24 +1481,22 @@ static int wiz_probe(struct platform_device *pdev)
>  		goto err_addr_to_resource;
>  	}
>  
> -	if (wiz->gpio_typec_dir) {
> -		ret = of_property_read_u32(node, "typec-dir-debounce-ms",
> -					   &wiz->typec_dir_delay);
> -		if (ret && ret != -EINVAL) {
> -			dev_err(dev, "Invalid typec-dir-debounce property\n");
> -			goto err_addr_to_resource;
> -		}
> +	ret = of_property_read_u32(node, "typec-dir-debounce-ms",
> +				   &wiz->typec_dir_delay);
> +	if (ret && ret != -EINVAL) {
> +		dev_err(dev, "Invalid typec-dir-debounce property\n");
> +		goto err_addr_to_resource;
> +	}

Why do you need to know this debounce value if you don't have a valid GPIO line?

>  
> -		/* use min. debounce from Type-C spec if not provided in DT  */
> -		if (ret == -EINVAL)
> -			wiz->typec_dir_delay = WIZ_TYPEC_DIR_DEBOUNCE_MIN;
> +	/* use min. debounce from Type-C spec if not provided in DT  */
> +	if (ret == -EINVAL)
> +		wiz->typec_dir_delay = WIZ_TYPEC_DIR_DEBOUNCE_MIN;
>  
> -		if (wiz->typec_dir_delay < WIZ_TYPEC_DIR_DEBOUNCE_MIN ||
> -		    wiz->typec_dir_delay > WIZ_TYPEC_DIR_DEBOUNCE_MAX) {
> -			ret = -EINVAL;
> -			dev_err(dev, "Invalid typec-dir-debounce property\n");
> -			goto err_addr_to_resource;
> -		}
> +	if (wiz->typec_dir_delay < WIZ_TYPEC_DIR_DEBOUNCE_MIN ||
> +	    wiz->typec_dir_delay > WIZ_TYPEC_DIR_DEBOUNCE_MAX) {
> +		ret = -EINVAL;
> +		dev_err(dev, "Invalid typec-dir-debounce property\n");
> +		goto err_addr_to_resource;
>  	}

All these changes are unnecessary.

>  
>  	ret = wiz_get_lane_phy_types(dev, wiz);

cheers,
-roger