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Date:   Tue, 1 Nov 2022 11:16:45 +0100
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Subject: Re: [v2 3/3] hwmon: Add Aspeed ast2600 TACH support
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To:     Billy Tsai <billy_tsai@aspeedtech.com>
References: <20221101095156.30591-1-billy_tsai@aspeedtech.com>
 <20221101095156.30591-4-billy_tsai@aspeedtech.com>
From:   Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc:     jdelvare@suse.com, linux@roeck-us.net, robh+dt@kernel.org,
        joel@jms.id.au, andrew@aj.id.au, lee.jones@linaro.org,
        thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de,
        p.zabel@pengutronix.de, linux-hwmon@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        linux-pwm@vger.kernel.org, BMC-SW@aspeedtech.com,
        garnermic@meta.com
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Le 01/11/2022 à 10:51, Billy Tsai a écrit :
> This patch add the support of Tachometer which can use to monitor the
> frequency of the input. The tach supports up to 16 channels and it's part
> function of multi-function device "pwm-tach controller".
> 
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>

Hi,
a few nits below,

[...]

> +
> +	if (ret) {
> +		/* return 0 if we didn't get an answer because of timeout*/

Missing space at the end of the comment

> +		if (ret == -ETIMEDOUT)
> +			return 0;
> +		else
> +			return ret;

[...]

> +static int aspeed_tach_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np, *child;
> +	struct aspeed_tach_data *priv;
> +	struct device *hwmon;
> +	struct platform_device *parent_dev;
> +	int ret;
> +
> +	np = dev->parent->of_node;
> +	if (!of_device_is_compatible(np, "aspeed,ast2600-pwm-tach"))
> +		return dev_err_probe(dev, -ENODEV,
> +				     "Unsupported tach device binding\n");
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +	priv->dev = &pdev->dev;
> +	priv->tach_channel =
> +		devm_kzalloc(dev,
> +			     TACH_ASPEED_NR_TACHS * sizeof(*priv->tach_channel),
> +			     GFP_KERNEL);

use devm_kcalloc() instead of devm_kzalloc()?
Error handling?

> +
> +	priv->regmap = syscon_node_to_regmap(np);
> +	if (IS_ERR(priv->regmap)) {
> +		dev_err(priv->dev, "Couldn't get regmap\n");

In order to be conistent with the other error handling paths:
return dev_err_probe()?

> +		return -ENODEV;
> +	}

[...]