linux-kernel - Re: [PATCH 9/9] spi: atmel-quadspi: add support for sam9x60 qspi controller

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Date:   Wed, 30 Jan 2019 18:43:13 +0100
From:   Boris Brezillon <bbrezillon@...nel.org>
To:     <Tudor.Ambarus@...rochip.com>
Cc:     <broonie@...nel.org>, <Nicolas.Ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>, <Ludovic.Desroches@...rochip.com>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-spi@...r.kernel.org
Subject: Re: [PATCH 9/9] spi: atmel-quadspi: add support for sam9x60 qspi
 controller

On Wed, 30 Jan 2019 15:08:47 +0000
<Tudor.Ambarus@...rochip.com> wrote:

> +static int atmel_sam9x60_qspi_clk_prepare_enable(struct atmel_qspi *aq)
> +{
> +	struct device *dev = &aq->pdev->dev;
> +	int ret;
> +
> +	if (!aq->clk) {
> +		/* Get the peripheral clock */
> +		aq->clk = devm_clk_get(dev, "pclk");
> +		if (IS_ERR(aq->clk)) {
> +			dev_err(dev, "missing peripheral clock\n");
> +			return PTR_ERR(aq->clk);
> +		}
> +	}
> +
> +	if (!aq->qspick) {
> +		/* Get the QSPI system clock */
> +		aq->qspick = devm_clk_get(dev, "qspick");
> +		if (IS_ERR(aq->qspick)) {
> +			dev_err(dev, "missing system clock\n");
> +			return PTR_ERR(aq->qspick);
> +		}
> +	}

Move the devm_clk_get() calls to the probe path instead of doing it at
prepare time, and you can make it generic for both compats with
something like:

	aq->clk = devm_clk_get(dev, "pclk");
	if (IS_ERR(aq->clk))
		aq->clk = devm_clk_get(dev, NULL);

	if (IS_ERR(aq->clk))
		return PTR_ERR(aq->clk);

	if (aq->caps->qspick_required) {
		aq->qspick = devm_clk_get(dev, "qspick");
		if (IS_ERR(aq->qspick)) {
			return PTR_ERR(aq->qspick);
	}

> +
> +	/* Enable the peripheral clock */
> +	ret = clk_prepare_enable(aq->clk);
> +	if (ret) {
> +		dev_err(dev, "failed to enable the peripheral clock\n");
> +		return ret;
> +	}
> +
> +	/* Enable the QSPI system clock */
> +	ret = clk_prepare_enable(aq->qspick);
> +	if (ret) {
> +		dev_err(dev, "failed to enable the QSPI system clock\n");
> +		clk_disable_unprepare(aq->clk);
> +	}

Again, you can make the enable function generic since
clk_prepare_enable(NULL) is a NO-OP that returns 0 and aq->qspick will
be NULL when it's not required.

> +
> +	return ret;
> +}
> +
> +static void atmel_sam9x60_qspi_clk_disable_unprepare(struct atmel_qspi *aq)
> +{
> +	clk_disable_unprepare(aq->qspick);
> +	clk_disable_unprepare(aq->clk);

Ditto.

> +}