[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <c386a274-fae3-42ea-a2ab-a1c194ca2449@topic.nl>
Date: Mon, 19 Feb 2024 07:56:49 +0100
From: Mike Looijmans <mike.looijmans@...ic.nl>
To: Jonathan Cameron <jic23@...nel.org>
CC: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
devicetree@...r.kernel.org, linux-iio@...r.kernel.org,
Arnd Bergmann <arnd@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>,
Liam Beguin <liambeguin@...il.com>, Liam Girdwood <lgirdwood@...il.com>,
Maksim Kiselev <bigunclemax@...il.com>,
Marcus Folkesson <marcus.folkesson@...il.com>,
Marius Cristea <marius.cristea@...rochip.com>,
Mark Brown <broonie@...nel.org>, Niklas Schnelle <schnelle@...ux.ibm.com>,
Okan Sahin <okan.sahin@...log.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/2] iio: adc: ti-ads1298: Add driver
On 16-02-2024 18:19, Jonathan Cameron wrote:
> On Fri, 16 Feb 2024 17:07:49 +0100
> Mike Looijmans <mike.looijmans@...ic.nl> wrote:
>
>> On 16-02-2024 16:53, Andy Shevchenko wrote:
>>
>> ...
>>
>> + if (reset_gpio) {
>> + /*
>> + * Deassert reset now that clock and power are active.
>> + * Minimum reset pulsewidth is 2 clock cycles.
>> + */
>> + udelay(ADS1298_CLOCKS_TO_USECS(2));
>>
>> This is sleeping context and you are calling unsleeping function. I haven't
>> checked the macro implementation and I have no idea what is the maximum it may
>> give, but making code robust just use fsleep() call.
>>
>> It'll actually delay for 1 us (the "clock" is ~2MHz). So fsleep will compile to udelay anyway, which is fine, fsleep might get smarter in future and this would then profit.
>>
>>
>>
>> + gpiod_set_value_cansleep(reset_gpio, 0);
>> + } else {
>> + ret = ads1298_write_cmd(priv, ADS1298_CMD_RESET);
>> + if (ret)
>> + return dev_err_probe(dev, ret, "RESET failed\n");
>> + }
>> + /* Wait 18 clock cycles for reset command to complete */
>> + udelay(ADS1298_CLOCKS_TO_USECS(18));
>>
>> Ditto.
>>
>> ...
>>
>>
>> If it's the only issue I think Jonathan can modify when applying
>> (no new patch version would be needed).
>>
>> That'd be nice.
> ok. As this is still the top of my tree I'll just tweak it.
>
> Does anyone else read fsleep as femtosecond sleep every time? :)
> Maybe computers will go that fast one day.
>
> Jonathan
Noticed this triggered a kernel test robot report. Sent a v6 that fixes
the bug.
Can also make it a separate patch if you prefer, in that case ignore v6.
--
Mike Looijmans
System Expert
TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands
T: +31 (0) 499 33 69 69
E: mike.looijmans@...ic.nl
W: www.topic.nl
Powered by blists - more mailing lists