linux-kernel - Re: [PATCH v4 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC

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Message-ID: <20190520124107.GA25785@lunn.ch>
Date:   Mon, 20 May 2019 14:41:07 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Sagar Shrikant Kadam <sagar.kadam@...ive.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com, peter@...sgaard.com,
        palmer@...ive.com, paul.walmsley@...ive.com,
        linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/3] i2c-ocores: sifive: add polling mode workaround
 for FU540-C000 SoC

> @@ -406,7 +416,7 @@ static int ocores_xfer(struct i2c_adapter *adap,
>  {
>  	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
>  
> -	if (i2c->flags & OCORES_FLAG_POLL)
> +	if ((i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ)))
>  		return ocores_xfer_polling(adap, msgs, num);
>  	return ocores_xfer_core(i2c, msgs, num, false);
>  }

You are not listening to what i said. All you need to know here is
that you must poll. It does not matter if the IRQ is broken or not.

>  	irq = platform_get_irq(pdev, 0);
>  	if (irq == -ENXIO) {
> -		i2c->flags |= OCORES_FLAG_POLL;

If there is no interrupt, you need to poll. So keep this line.

> +		/*
> +		 * Set a OCORES_FLAG_BROKEN_IRQ to enable workaround for
> +		 * FU540-C000 SoC in polling mode interface of i2c-ocore driver.
> +		 * Else enable default polling mode interface for SIFIVE/OCORE
> +		 * device types.
> +		 */
> +		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
> +		if (match && (long)match->data == TYPE_SIFIVE_REV0)
> +			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;

If it is a OCORE, IRQ is broken, so OR in OCORES_FLAG_BROKEN_IRQ.

>  
> -	if (!(i2c->flags & OCORES_FLAG_POLL)) {
> +	if (!(i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ))) {
>  		ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
>  				       pdev->name, i2c);

Here you just need to know if you are polling. Broken IRQ does not
matter.

	Andrew