linux-kernel - RE: [PATCH v3] mfd: ADP5520 Multifunction LCD Backlight and KeypadInput Device Driver

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Date:	Tue, 6 Oct 2009 13:23:52 +0100
From:	"Hennerich, Michael" <Michael.Hennerich@...log.com>
To:	"Mark Brown" <broonie@...nsource.wolfsonmicro.com>,
	"Mike Frysinger" <vapier@...too.org>
CC:	"Samuel Ortiz" <sameo@...ux.intel.com>,
	<uclinux-dist-devel@...ckfin.uclinux.org>,
	<linux-kernel@...r.kernel.org>, "Bryan Wu" <cooloney@...nel.org>
Subject: RE: [PATCH v3] mfd: ADP5520 Multifunction LCD Backlight and KeypadInput Device Driver

Hi Mark,

>From: Mark Brown [mailto:broonie@...nsource.wolfsonmicro.com]
>On Tue, Oct 06, 2009 at 03:44:31AM -0400, Mike Frysinger wrote:
>
>> +int adp5520_register_notifier(struct device *dev, struct
notifier_block *nb,
>> +				unsigned int events)
>> +{
>
>This notifier stuff looks an awful lot like an interrupt controller
>driver.  Now that it's possible to implement support for an I2C/SPI
>driven interrupt controller it'd be good to use that rather than having
>a custom API if that's possible.

Honestly this notifier chain is a clean approach and serves its purpose
here pretty well.
IMHO it's much more preferable than pretending there is a virtual GPIO
that doesn't exist and a MFD subdev could request.

>
>> +#define GPIO_R3		(1 << 3)	/* LED3 or GPIO3 aka R3
*/
>> +#define GPIO_R2		(1 << 2)
>> +#define GPIO_R1		(1 << 1)
>> +#define GPIO_R0		(1 << 0)
>
>> +struct adp5520_gpio_platfrom_data {
>> +	unsigned gpio_start;
>> +	u8 gpio_en_mask;
>> +	u8 gpio_pullup_mask;
>> +};
>
>Since there's platform data in here it'd probably be better to
namespace
>the #defines or put them in a separate header in case there are
>collisions with some other chip used on a board.

Will do.


>
>> +struct adp5520_leds_platfrom_data {
>
>There's some 'platfrom' rather than 'platform' typos.

Good catch - this happens to me all the time


>
>> +	int num_leds;
>> +	struct led_info	*leds;
>> +	u8 fade_in;		/* Backlight Fade-In Timer */
>> +	u8 fade_out;		/* Backlight Fade-Out Timer */
>> +	u8 led_on_time;
>
>I don't know exactly what the on_time option does but if it controls
>hardware-implemented blinking there's actually a callback function the
>LED driver can implement to allow triggers to use the hardware assisted
>blinking at runtime.  If it returns an error or isn't implemented
>there's a software fallback.

Yes its hardware controlled blinking. I noticed the leds timer trigger
driver.
People can still use it - the downside with the hardware assisted
blinking is that all LEDs share the same on_time. So I decided against
using the callback.

-Michael 
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