linux-kernel - Re: [PATCH v6 2/3] clocksource: Add JH7110 timer driver

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Message-ID: <338544e7-0be8-47c1-a7d7-89990da305d3@wanadoo.fr>
Date:   Thu, 12 Oct 2023 19:53:21 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     xingyu.wu@...rfivetech.com
Cc:     aou@...s.berkeley.edu, conor@...nel.org, daniel.lezcano@...aro.org,
        devicetree@...r.kernel.org, emil.renner.berthing@...onical.com,
        krzysztof.kozlowski+dt@...aro.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org, p.zabel@...gutronix.de,
        palmer@...belt.com, paul.walmsley@...ive.com, robh+dt@...nel.org,
        samin.guo@...rfivetech.com, tglx@...utronix.de,
        walker.chen@...rfivetech.com
Subject: Re: [PATCH v6 2/3] clocksource: Add JH7110 timer driver

Le 12/10/2023 à 10:10, Xingyu Wu a écrit :
> Add timer driver for the StarFive JH7110 SoC.
> 
> Signed-off-by: Xingyu Wu <xingyu.wu-bONrM45KWFOXmMXjJBpWqg@...lic.gmane.org>

...

> +static int jh7110_timer_probe(struct platform_device *pdev)
> +{
> +	struct jh7110_clkevt *clkevt[JH7110_TIMER_CH_MAX];
> +	char name[4];
> +	struct clk *pclk;
> +	struct reset_control *rst;
> +	int ch;
> +	int ret;
> +	void __iomem *base;
> +
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(base),
> +				     "failed to map registers\n");
> +
> +	rst = devm_reset_control_get_exclusive(&pdev->dev, "apb");
> +	if (IS_ERR(rst))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(rst), "failed to get apb reset\n");
> +
> +	pclk = devm_clk_get_enabled(&pdev->dev, "apb");
> +	if (IS_ERR(pclk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
> +				     "failed to get & enable apb clock\n");
> +
> +	ret = reset_control_deassert(rst);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to deassert apb reset\n");

Hi,

I'm not very familiar with the reset_control_[de]assert() functions, but 
shouldn't this be undone by a reset_control_assert() call if an error 
occurs later?

> +
> +	for (ch = 0; ch < JH7110_TIMER_CH_MAX; ch++) {
> +		clkevt[ch] = devm_kzalloc(&pdev->dev, sizeof(*clkevt[ch]), GFP_KERNEL);
> +		if (!clkevt[ch])
> +			return -ENOMEM;
> +
> +		snprintf(name, sizeof(name), "ch%d", ch);
> +
> +		clkevt[ch]->base = base + JH7110_TIMER_CH_BASE(ch);
> +		/* Ensure timer is disabled */
> +		jh7110_timer_disable(clkevt[ch]);
> +
> +		rst = devm_reset_control_get_exclusive(&pdev->dev, name);
> +		if (IS_ERR(rst))
> +			return PTR_ERR(rst);
> +
> +		clkevt[ch]->clk = devm_clk_get_enabled(&pdev->dev, name);
> +		if (IS_ERR(clkevt[ch]->clk))
> +			return PTR_ERR(clkevt[ch]->clk);
> +
> +		ret = reset_control_deassert(rst);
> +		if (ret)
> +			return ret;

Same here.

> +
> +		clkevt[ch]->evt.irq = platform_get_irq(pdev, ch);
> +		if (clkevt[ch]->evt.irq < 0)
> +			return clkevt[ch]->evt.irq;
> +
> +		snprintf(clkevt[ch]->name, sizeof(clkevt[ch]->name), "%s.ch%d", pdev->name, ch);
> +		jh7110_clockevents_register(clkevt[ch]);
> +
> +		ret = devm_request_irq(&pdev->dev, clkevt[ch]->evt.irq, jh7110_timer_interrupt,
> +				       IRQF_TIMER | IRQF_IRQPOLL,
> +				       clkevt[ch]->name, &clkevt[ch]->evt);
> +		if (ret)
> +			return ret;
> +
> +		ret = jh7110_clocksource_init(clkevt[ch]);

Does something should be done if this fails?

CJ

> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id jh7110_timer_match[] = {
> +	{ .compatible = "starfive,jh7110-timer", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, jh7110_timer_match);
> +
> +static struct platform_driver jh7110_timer_driver = {
> +	.probe = jh7110_timer_probe,
> +	.driver = {
> +		.name = "jh7110-timer",
> +		.of_match_table = jh7110_timer_match,
> +	},
> +};
> +module_platform_driver(jh7110_timer_driver);
> +
> +MODULE_AUTHOR("Xingyu Wu <xingyu.wu-bONrM45KWFOXmMXjJBpWqg@...lic.gmane.org>");
> +MODULE_DESCRIPTION("StarFive JH7110 timer driver");
> +MODULE_LICENSE("GPL");