linux-kernel - Re: [PATCH v6 1/4] iio: pressure: bmp280: Use sleep and forced mode for oneshot captures

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZuQLOwjQUTjo1nPg@smile.fi.intel.com>
Date: Fri, 13 Sep 2024 12:51:55 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Vasileios Amoiridis <vassilisamir@...il.com>
Cc: jic23@...nel.org, lars@...afoo.de, robh@...nel.org, krzk+dt@...nel.org,
	conor+dt@...nel.org, ang.iglesiasg@...il.com,
	linus.walleij@...aro.org, biju.das.jz@...renesas.com,
	javier.carrasco.cruz@...il.com, semen.protsenko@...aro.org,
	579lpy@...il.com, ak@...klinger.de, linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	christophe.jaillet@...adoo.fr
Subject: Re: [PATCH v6 1/4] iio: pressure: bmp280: Use sleep and forced mode
 for oneshot captures

On Fri, Sep 13, 2024 at 01:32:31AM +0200, Vasileios Amoiridis wrote:
> Add forced mode support in sensors BMP28x, BME28x, BMP3xx and BMP58x.
> Sensors BMP18x and BMP085 are old and do not support this feature so
> their operation is not affected at all.
> 
> Essentially, up to now, the rest of the sensors were used in normal mode
> all the time. This means that they are continuously doing measurements
> even though these measurements are not used. Even though the sensor does
> provide PM support, to cover all the possible use cases, the sensor needs
> to go into sleep mode and wake up whenever necessary.
> 
> The idea is that the sensor is by default in sleep mode, wakes up in
> forced mode when a oneshot capture is requested, or in normal mode
> when the buffer is enabled. The difference lays in the fact that in
> forced mode, the sensor does only one conversion and goes back to sleep
> while in normal mode, the sensor does continuous measurements with the
> frequency that was set in the ODR registers.
> 
> The bmpX_chip_config() functions which are responsible for applying
> the requested configuration to the sensor, are modified accordingly
> in order to set the sensor by default in sleep mode.
> 
> DEEP STANDBY, Low Power NORMAL and CONTINUOUS modes, supported only by
> the BMP58x version, are not added.

...

> +	if (!((reg & BMP380_STATUS_DRDY_PRESS_MASK) &&
> +	    (reg & BMP380_STATUS_DRDY_TEMP_MASK))) {

I would add one more space to make the indentation follow the logic.

(no need to resend until Jonathan asks for it, otherwise I believe
 he can amend this whilst applying)

> +		dev_err(data->dev, "Measurement cycle didn't complete.\n");
> +		return -EBUSY;
> +	}

...

> +		/*
> +		 * According to the BMP3 Sensor API, the sensor needs 5000us

Can we use 5ms...

> +		 * in order to go to the sleep mode.
> +		 */
> +		fsleep(5000);

...and 5 * USEC_PER_MSEC here respectively?

-- 
With Best Regards,
Andy Shevchenko