Subject: [PATCH] pwm: pxa: add device tree support to pwm driver

From: [email-masked] (Marek Vasut)
Date: Wed, 4 Sep 2013 16:35:26 +0200

Dear Mike Dunn,

> On 09/03/2013 03:20 PM, Marek Vasut wrote:
> 
> [...]
> 
> >> +#ifdef CONFIG_OF
> >> +/* use the platform_device id table for OF match table data */
> >> +static struct of_device_id pwm_of_match[] = {
> >> +	{ .compatible = "marvell,pxa25x-pwm", .data = &pwm_id_table[0] },
> >> +	{ .compatible = "marvell,pxa27x-pwm", .data = &pwm_id_table[1] },
> >> +	{ .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[2] },
> >> +	{ .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[3] },
> >> +	{ }
> >> +};
> >> +MODULE_DEVICE_TABLE(of, pwm_of_match);
> > 
> > Are PXA2xx and PXA3xx PWM impleemntations not all the same ? If so, why
> > not just stick with pxa25x-pwm only for all of the CPUs (aka. the lowest
> > CPU model). Then the table would have but a single entry.
> 
> I'm just echoing the existing platform_device_id table...
> 
> static const struct platform_device_id pwm_id_table[] = {
> 	/*   PWM    has_secondary_pwm? */
> 	{ "pxa25x-pwm", 0 },
> 	{ "pxa27x-pwm", HAS_SECONDARY_PWM },
> 	{ "pxa168-pwm", 0 },
> 	{ "pxa910-pwm", 0 },
> 	{ },
> };
> MODULE_DEVICE_TABLE(platform, pwm_id_table);
> 
> ... so that my changes to the driver are minimal.  Yes, apparently the only
> difference is the existance of a "secondary" pwm for pxa27x.
> 
> BTW, the pxa27x actually has four pwms, which is why the addition I made to
> pxa27x.dtsi has two nodes (the driver handles two pwms for each device
> instance in the pxa27x case).
> 

What's that "secondary PWM" there? I no longer remember, sorry. The question 
remains still, we can have two entries there (pxa25x and pxa27x) ORR have one 
entry (pxa25x) + mrvl,has-secondary-pwm entry.

Best regards,
Marek Vasut