linux-kernel - Re: [PATCH 2/2] spi: add SPI controller driver for UniPhier SoC

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Message-ID: <20180719165150.GI27938@sirena.org.uk>
Date:   Thu, 19 Jul 2018 17:51:50 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Keiji Hayashibara <hayashibara.keiji@...ionext.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        yamada.masahiro@...ionext.com, linux-spi@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        masami.hiramatsu@...aro.org, jaswinder.singh@...aro.org,
        linux-kernel@...r.kernel.org,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Subject: Re: [PATCH 2/2] spi: add SPI controller driver for UniPhier SoC

On Thu, Jul 19, 2018 at 03:51:57PM +0900, Keiji Hayashibara wrote:

This all looks good, just a small number of fairly minor things - mostly
style points.

> @@ -0,0 +1,532 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * spi-uniphier.c - Socionext UniPhier SPI controller driver
> + *
> + * Copyright 2012      Panasonic Corporation
> + * Copyright 2016-2018 Socionext Inc.
> + */

Please make the entire comment a C++ one, it makes things look a bit
more joined up/intentional.

> +#define BYTES_PER_WORD(x)			\
> +({						\
> +	int __x;				\
> +	__x = (x <= 8)  ? 1 :			\
> +	      (x <= 16) ? 2 : 4;		\
> +	__x;					\
> +})

Could this be replaced with an inline function?  The usage seems fine
but it's a bit big for a macro.  The end result should be similar.

> +static irqreturn_t uniphier_spi_handler(int irq, void *dev_id)
> +{
> +	struct uniphier_spi_priv *priv = dev_id;
> +	u32 val, stat;
> +
> +	stat = readl(priv->base + SSI_IS);
> +	val = SSI_IC_TCIC | SSI_IC_RCIC | SSI_IC_RORIC;
> +	writel(val, priv->base + SSI_IC);
> +
> +	/* rx fifo overrun */
> +	if (stat & SSI_IS_RORID) {
> +		priv->error = -EIO;
> +		goto done;
> +	}
> +
> +	/* rx complete */
> +	if ((stat & SSI_IS_RCID) && (stat & SSI_IS_RXRS)) {

> +	}
> +
> +	return IRQ_HANDLED;
> +
> +done:
> +	complete(&priv->xfer_done);
> +	return IRQ_HANDLED;

This will unconditionally report IRQ_HANDLED even if none of the flags
were set by the hardware which will cause problems if something goes
wrong - the interrupt will continually be serviced and the interrupt
framework won't be able to mitigate or provide diagnostics.  It's better
to return IRQ_NONE if nothing is detected from the hardware.

> +static const struct of_device_id uniphier_spi_match[] = {
> +	{ .compatible = "socionext,uniphier-scssi", },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, uniphier_spi_match);

The binding document also listed socionext,uniphier-mcssi as a
compatible but this driver doesn't match that.

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