linux-kernel - Re: [PATCH] counter: ti-eqep: enable clock at probe

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Date: Mon, 10 Jun 2024 08:44:08 -0500
From: Judith Mendez <jm@...com>
To: David Lechner <dlechner@...libre.com>,
        William Breathitt Gray
	<wbg@...nel.org>
CC: <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] counter: ti-eqep: enable clock at probe

Hi David,

On 6/9/24 3:27 PM, David Lechner wrote:
> The TI eQEP clock is both a functional and interface clock. Since it is
> required for the device to function, we should be enabling it at probe.
> 
> Up to now, we've just been lucky that the clock was enabled by something
> else on the system already.
> 
> Signed-off-by: David Lechner <dlechner@...libre.com>
> ---
>   drivers/counter/ti-eqep.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
> index 072b11fd6b32..825ae22c3ebc 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -6,6 +6,7 @@
>    */
>   
>   #include <linux/bitops.h>
> +#include <linux/clk.h>
>   #include <linux/counter.h>
>   #include <linux/kernel.h>
>   #include <linux/mod_devicetable.h>
> @@ -376,6 +377,7 @@ static int ti_eqep_probe(struct platform_device *pdev)
>   	struct counter_device *counter;
>   	struct ti_eqep_cnt *priv;
>   	void __iomem *base;
> +	struct clk *clk;
>   	int err;
>   
>   	counter = devm_counter_alloc(dev, sizeof(*priv));
> @@ -415,6 +417,10 @@ static int ti_eqep_probe(struct platform_device *pdev)
>   	pm_runtime_enable(dev);
>   	pm_runtime_get_sync(dev);
>   
> +	clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(clk))

I think it would be nice to have print here in case the we fail to get
the clock.

~ Judith

> +		return dev_err_probe(dev, PTR_ERR(clk), "failed to enable clock\n");
> +
>   	err = counter_add(counter);
>   	if (err < 0) {
>   		pm_runtime_put_sync(dev);
> 
> ---
> base-commit: bb3f1c5fc434b0b177449f7f73ea9b112b397dd1
> change-id: 20240609-ti-eqep-enable-clock-91697095ca81