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Subject: Re: [PATCH 1/7] iio: ep93xx: Prepare clock before using it
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Nikita Shubin <nikita.shubin@maquefel.me>,
        linux-iio@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
        linux-kernel@vger.kernel.org
References: <20210613233041.128961-1-alexander.sverdlin@gmail.com>
 <20210613233041.128961-2-alexander.sverdlin@gmail.com>
 <20210614115043.07ea0ae1@jic23-huawei>
From:   Alexander Sverdlin <alexander.sverdlin@gmail.com>
Message-ID: <24f29bc6-311c-4f96-2e1b-1a5df936bb3a@gmail.com>
Date:   Mon, 2 Aug 2021 09:30:23 +0200
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Hello Jonathan!

On 14/06/2021 12:50, Jonathan Cameron wrote:
> On Mon, 14 Jun 2021 01:30:35 +0200
> Alexander Sverdlin <alexander.sverdlin@gmail.com> wrote:
> 
>> Use clk_prepare_enable()/clk_disable_unprepare() in preparation for switch
>> to Common Clock Framework, otherwise the following is visible:
>>
>> WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:1011 clk_core_enable+0x9c/0xbc
>> Enabling unprepared ep93xx-adc
>> CPU: 0 PID: 1 Comm: swapper Not tainted 5.13.0-rc5-... #1
>> Hardware name: Cirrus Logic EDB9302 Evaluation Board
>> [<c000d5b0>] (unwind_backtrace) from [<c000c590>] (show_stack+0x10/0x18)
>> [<c000c590>] (show_stack) from [<c03a5f38>] (dump_stack+0x20/0x2c)
>> [<c03a5f38>] (dump_stack) from [<c03a2098>] (__warn+0x98/0xc0)
>> [<c03a2098>] (__warn) from [<c03a2150>] (warn_slowpath_fmt+0x90/0xc0)
>> [<c03a2150>] (warn_slowpath_fmt) from [<c01d8358>] (clk_core_enable+0x9c/0xbc)
>> [<c01d8358>] (clk_core_enable) from [<c01d8698>] (clk_core_enable_lock+0x18/0x30)
>> [<c01d8698>] (clk_core_enable_lock) from [<c0266560>] (ep93xx_adc_probe+0xe4/0x1a0)
>> [<c0266560>] (ep93xx_adc_probe) from [<c02126e0>] (platform_probe+0x34/0x80)
>> [<c02126e0>] (platform_probe) from [<c0210bf8>] (really_probe+0xe8/0x394)
>> [<c0210bf8>] (really_probe) from [<c0211464>] (device_driver_attach+0x5c/0x64)
>> [<c0211464>] (device_driver_attach) from [<c02114e8>] (__driver_attach+0x7c/0xec)
>> [<c02114e8>] (__driver_attach) from [<c020f1b4>] (bus_for_each_dev+0x78/0xc4)
>> [<c020f1b4>] (bus_for_each_dev) from [<c0211570>] (driver_attach+0x18/0x24)
>> [<c0211570>] (driver_attach) from [<c020fab4>] (bus_add_driver+0x140/0x1cc)
>> [<c020fab4>] (bus_add_driver) from [<c0211c44>] (driver_register+0x74/0x114)
>> [<c0211c44>] (driver_register) from [<c02134f8>] (__platform_driver_register+0x18/0x24)
>> [<c02134f8>] (__platform_driver_register) from [<c0470148>] (ep93xx_adc_driver_init+0x10/0x1c)
>> [<c0470148>] (ep93xx_adc_driver_init) from [<c045ce88>] (do_one_initcall+0x7c/0x1a4)
>> [<c045ce88>] (do_one_initcall) from [<c045d184>] (kernel_init_freeable+0x17c/0x1fc)
>> [<c045d184>] (kernel_init_freeable) from [<c03a64d0>] (kernel_init+0x8/0xf8)
>> [<c03a64d0>] (kernel_init) from [<c00082d8>] (ret_from_fork+0x14/0x3c)
>> ...
>> ep93xx-adc ep93xx-adc: Cannot enable clock
>> ep93xx-adc: probe of ep93xx-adc failed with error -108
>>
>> Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> From cover letter I'm assuming you want these to go through same route as
> the common clock conversion?  If not shout and I can pick this one up.

We didn't manage to consolidate the delivery path for this series, could
you please take this patch alone, as you proposed initially?

>> ---
>>  drivers/iio/adc/ep93xx_adc.c | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ep93xx_adc.c b/drivers/iio/adc/ep93xx_adc.c
>> index c08ab3c6dfaf..5c85257b814c 100644
>> --- a/drivers/iio/adc/ep93xx_adc.c
>> +++ b/drivers/iio/adc/ep93xx_adc.c
>> @@ -207,7 +207,7 @@ static int ep93xx_adc_probe(struct platform_device *pdev)
>>  		 */
>>  	}
>>  
>> -	ret = clk_enable(priv->clk);
>> +	ret = clk_prepare_enable(priv->clk);
>>  	if (ret) {
>>  		dev_err(&pdev->dev, "Cannot enable clock\n");
>>  		return ret;
>> @@ -215,7 +215,7 @@ static int ep93xx_adc_probe(struct platform_device *pdev)
>>  
>>  	ret = iio_device_register(iiodev);
>>  	if (ret)
>> -		clk_disable(priv->clk);
>> +		clk_disable_unprepare(priv->clk);
>>  
>>  	return ret;
>>  }
>> @@ -226,7 +226,7 @@ static int ep93xx_adc_remove(struct platform_device *pdev)
>>  	struct ep93xx_adc_priv *priv = iio_priv(iiodev);
>>  
>>  	iio_device_unregister(iiodev);
>> -	clk_disable(priv->clk);
>> +	clk_disable_unprepare(priv->clk);
>>  
>>  	return 0;
>>  }
>