linux-kernel - Re: [PATCH v5 03/15] USB: typec: Add patch mode to tps6598x

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Message-ID: <ZQgvgJRLK+ysS30D@kuha.fi.intel.com>
Date:   Mon, 18 Sep 2023 14:07:44 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Abdel Alkuor <alkuor@...il.com>
Cc:     krzysztof.kozlowski+dt@...aro.org, bryan.odonoghue@...aro.org,
        gregkh@...uxfoundation.org, robh+dt@...nel.org,
        linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        conor+dt@...nel.org, linux-kernel@...r.kernel.org,
        abdelalkuor@...tab.com
Subject: Re: [PATCH v5 03/15] USB: typec: Add patch mode to tps6598x

On Sun, Sep 17, 2023 at 11:26:27AM -0400, Abdel Alkuor wrote:
> TPS25750 has a patch mode indicating the device requires
> a configuration to get the device into operational mode
> 
> Signed-off-by: Abdel Alkuor <alkuor@...il.com>
> ---
>  drivers/usb/typec/tipd/core.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> index a8aee4e1aeba..6d2151325fbb 100644
> --- a/drivers/usb/typec/tipd/core.c
> +++ b/drivers/usb/typec/tipd/core.c
> @@ -68,6 +68,7 @@ enum {
>  	TPS_MODE_BOOT,
>  	TPS_MODE_BIST,
>  	TPS_MODE_DISC,
> +	TPS_MODE_PTCH,
>  };
>  
>  static const char *const modes[] = {
> @@ -75,6 +76,7 @@ static const char *const modes[] = {
>  	[TPS_MODE_BOOT]	= "BOOT",
>  	[TPS_MODE_BIST]	= "BIST",
>  	[TPS_MODE_DISC]	= "DISC",
> +	[TPS_MODE_PTCH] = "PTCH",
>  };
>  
>  /* Unrecognized commands will be replaced with "!CMD" */
> @@ -576,7 +578,7 @@ static void tps6598x_poll_work(struct work_struct *work)
>  			   &tps->wq_poll, msecs_to_jiffies(POLL_INTERVAL));
>  }
>  
> -static int tps6598x_check_mode(struct tps6598x *tps)
> +static int tps6598x_check_mode(struct tps6598x *tps, u8 *curr_mode)
>  {
>  	char mode[5] = { };
>  	int ret;
> @@ -585,8 +587,11 @@ static int tps6598x_check_mode(struct tps6598x *tps)
>  	if (ret)
>  		return ret;
>  
> -	switch (match_string(modes, ARRAY_SIZE(modes), mode)) {
> +	*curr_mode = match_string(modes, ARRAY_SIZE(modes), mode);
> +
> +	switch (*curr_mode) {
>  	case TPS_MODE_APP:
> +	case TPS_MODE_PTCH:

This check is OK, but it seems that you are not using that curr_mode
for anything yet, so don't change the paramaters of this function in
this patch.

I would also just return the mode. Then this function would be used
like this:

        ret = tps6598x_check_mode(...)
        if (ret < 0)
                return ret;

Now mode = ret.

>  		return 0;
>  	case TPS_MODE_BOOT:
>  		dev_warn(tps->dev, "dead-battery condition\n");
> @@ -715,6 +720,7 @@ static int tps6598x_probe(struct i2c_client *client)
>  	u32 vid;
>  	int ret;
>  	u64 mask1;
> +	u8 mode;
>  
>  	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
>  	if (!tps)
> @@ -759,7 +765,7 @@ static int tps6598x_probe(struct i2c_client *client)
>  
>  	tps->irq_handler = irq_handler;
>  	/* Make sure the controller has application firmware running */
> -	ret = tps6598x_check_mode(tps);
> +	ret = tps6598x_check_mode(tps, &mode);

Actually, if you need to know the mode in here later, then I'm not
sure tps6592x_check_mode() is useful after that. This is the only
place it's called. Just read and check the mode in here directly at
that point.

thanks,

-- 
heikki