linux-kernel - Re: [PATCH 6/7] [RFC] ds2760 battery driver

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Message-ID: <20070415194001.GF10097@ucw.cz>
Date:	Sun, 15 Apr 2007 19:40:01 +0000
From:	Pavel Machek <pavel@....cz>
To:	Anton Vorontsov <cbou@...l.ru>
Cc:	linux-kernel@...r.kernel.org, kernel-discuss@...dhelds.org,
	dwmw2@...radead.org
Subject: Re: [PATCH 6/7] [RFC] ds2760 battery driver

Hi!

> This is driver for batteries with ds2760 chip inside. Such batteries
> used in almost every HP iPaq and HTC PDAs/phones.

Looks nice to me. It even knows about dependency between temperature
and remaining power :-).


> +	di->update_time = jiffies;
> +
> +	/* DS2760 reports voltage in units of 4.88mV, but the battery class
> +	 * reports in units of mV, so convert by multiplying by 4.875.
> +	 * We approximate because integer math is cheap, and close enough. */
> +	di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
> +	                  (di->raw[DS2760_VOLTAGE_LSB] >> 5);
> +	di->voltage_mV = (di->voltage_raw * 5) - (di->voltage_raw / 8);

Hmm, not sure if such tricks re really worth it... should not compiler
be doing this?


> +	/* Calculate the empty level at the present temperature. */
> +	scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
> +	for (i = 3; i >= 0; i--)
> +		scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
> +
> +	di->empty_mAh = battery_interpolate(scale, di->temp_C / 10);

Wow.

> +static struct platform_driver ds2760_battery_driver = {
> +	.driver = {
> +		.name = "ds2760-battery",
> +	},
> +	.probe	  = ds2760_battery_probe,
> +	.remove   = ds2760_battery_remove,
> +	#ifdef CONFIG_PM
> +	.suspend  = ds2760_battery_suspend,
> +	.resume	  = ds2760_battery_resume,
> +	#endif

I thought ifdefs need to be at column 0?

							Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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