linux-kernel - Re: [resend rfc v4]pwm: add BCM2835 PWM driver

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Date:	Mon, 29 Sep 2014 17:21:27 +0200
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Bart Tanghe <bart.tanghe@...masmore.be>, thierry.reding@...il.com
CC:	matt.porter@...aro.org, linux-rpi-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org
Subject: Re: [resend rfc v4]pwm: add BCM2835 PWM driver

On 09/29/2014 04:40 PM, Bart Tanghe wrote:
> +static int bcm2835_pwm_probe(struct platform_device *pdev)
> +{
> +	struct bcm2835_pwm *pwm;
> +	int ret;
> +	struct resource *r;
> +	struct clk *clk;
> +
> +	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
> +	if (!pwm)
> +		return -ENOMEM;
> +
> +	pwm->dev = &pdev->dev;
> +
> +	clk = clk_get(&pdev->dev, NULL);

Better use devm_, as you don't free the clock in case of an error and
during remove()

> +	if (IS_ERR(clk)) {
> +		dev_err(&pdev->dev, "no clock found: %ld\n", PTR_ERR(clk));
> +		return PTR_ERR(clk);
> +	}
> +
> +	pwm->clk = clk;
> +	clk_prepare_enable(pwm->clk);

Please check the return value of clk_prepare_enable()

> +	pwm->scaler = NSEC_PER_SEC / clk_get_rate(clk);
> +
> +	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	pwm->base = devm_ioremap_resource(&pdev->dev, r);
> +	if (IS_ERR(pwm->base))
> +		return PTR_ERR(pwm->base);
> +
> +	pwm->chip.dev = &pdev->dev;
> +	pwm->chip.ops = &bcm2835_pwm_ops;
> +	pwm->chip.npwm = 2;
> +
> +	ret = pwmchip_add(&pwm->chip);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
> +		return -1;

Please propagate the error vlaue:

    return ret;

> +	}
> +	platform_set_drvdata(pdev, pwm);

Better do this before pwmchip_add()

> +	return 0;
> +}
> +
> +static int bcm2835_pwm_remove(struct platform_device *pdev)
> +{
> +	struct bcm2835_pwm *pc = platform_get_drvdata(pdev);
> +	clk_disable_unprepare(pc->clk);
> +	return pwmchip_remove(&pc->chip);
> +}
> +
> +static const struct of_device_id bcm2835_pwm_of_match[] = {
> +	{ .compatible = "brcm,bcm2835-pwm", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, bcm2835_pwm_of_match);
> +
> +static struct platform_driver bcm2835_pwm_driver = {
> +	.driver = {
> +		.name = "bcm2835-pwm",
> +		.of_match_table = bcm2835_pwm_of_match,
> +	},
> +	.probe = bcm2835_pwm_probe,
> +	.remove = bcm2835_pwm_remove,
> +};
> +module_platform_driver(bcm2835_pwm_driver);
> +
> +MODULE_AUTHOR("Bart Tanghe <bart.tanghe@...masmore.be");
> +MODULE_DESCRIPTION("Broadcom BCM2835 PWM driver");
> +MODULE_LICENSE("GPL v2");

regards,
Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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