linux-kernel - Re: [PATCH] i2c: ocores: generate stop condition after timeout in polling mode

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Message-ID: <a1e701cc-aa4f-4098-95c9-0cb7aaf5b281@lunn.ch>
Date:   Wed, 12 Apr 2023 14:43:51 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Matthias Schiffer <matthias.schiffer@...tq-group.com>
Cc:     Peter Korsgaard <peter@...sgaard.com>,
        Federico Vaga <federico.vaga@...n.ch>,
        Wolfram Sang <wsa@...nel.org>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux@...tq-group.com
Subject: Re: [PATCH] i2c: ocores: generate stop condition after timeout in
 polling mode

Hi Matthias

I also don't have access to the hardware, but the change looks O.K.

>  static int ocores_xfer_core(struct ocores_i2c *i2c,
> @@ -387,16 +389,16 @@ static int ocores_xfer_core(struct ocores_i2c *i2c,
>  	oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));
>  	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
>  
> -	if (polling) {
> -		ocores_process_polling(i2c);
> -	} else {
> +	if (polling)
> +		ret = ocores_process_polling(i2c);
> +	else
>  		ret = wait_event_timeout(i2c->wait,
>  					 (i2c->state == STATE_ERROR) ||
> -					 (i2c->state == STATE_DONE), HZ);
> -		if (ret == 0) {
> -			ocores_process_timeout(i2c);
> -			return -ETIMEDOUT;
> -		}
> +					 (i2c->state == STATE_DONE), HZ) ?
> +						0 : -ETIMEDOUT;
> +	if (ret) {
> +		ocores_process_timeout(i2c);
> +		return ret;
>  	}

The ret == 0 becoming ret is not so obvious. Rather than having the
trinary, do

		if (ret == 0)
		   ret = -ETIMEDOUT;

and then fall into your new if clause. I think that makes it more
obvious that wait_event_timeout() returns 0 on timeout.

	Andrew