linux-kernel - Re: [PATCH v2 2/2] pwm: add this patch to support the new pwm of Rockchip SoCs

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Date:	Fri, 25 Jul 2014 18:29:38 +0800
From:	caesar <caesar.wang@...k-chips.com>
To:	Thierry Reding <thierry.reding@...il.com>
CC:	linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] pwm: add this patch to support the new pwm of
 Rockchip SoCs

Hi Thierry,



在 2014年07月21日 21:27, Thierry Reding 写道:
> On Mon, Jul 21, 2014 at 08:58:42PM +0800, caesar wrote:
>> 于 2014年07月21日 16:50, Thierry Reding 写道:
>>> On Sat, Jul 19, 2014 at 08:55:29PM +0800, Caesar Wang wrote:
> [...]
>>>>   	struct rockchip_pwm_chip *pc;
>>>>   	struct resource *r;
>>>>   	int ret;
>>>> @@ -119,7 +182,10 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
>>>>   		return -ENOMEM;
>>>>   	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> -	pc->base = devm_ioremap_resource(&pdev->dev, r);
>>>> +	if (!strcmp(of_id->compatible, "rockchip,vop-pwm"))
>>>> +		pc->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
>>>> +	else
>>>> +		pc->base = devm_ioremap_resource(&pdev->dev, r);
>>> Sorry, this still isn't an option. You really shouldn't remap I/O
>>> regions that other drivers may be using. You hinted at a shared register
>>> space during the review of the initial version. Can you provide more
>>> detail about what exactly the memory map looks like of the rk3288? Is
>>> there some kind of technical reference manual that I could look at? Or
>>> do you have a device tree extract that shows what the memory map looks
>>> like?
>>>
>>> Thierry
>> Maybe,you can look at the ARM: dts: rk3288:
>> https://github.com/rkchrome/kernel/blob/master/arch/arm/boot/dts/rk3288.dtsi
>> There is some lcdc and vop-pwm map address for rk3288.
>>
>> ,and you can look at the vop-introduce.pdf and vop-register.pdf in Annex.
>>
>> Maybe,I should put the vop-pwm in lcdc driver,but I don't hope do so it.
>>
>> Could you give a suggestion to solve it? Thanks.
> It looks like you could turn the lcdc device into an MFD device so that
> it can instantiate two devices, one for the display controller, the
> other for the PWM. Or perhaps it would even work with only a single
> child device.
>
> The device tree would become something like this:
>
> 	lcdc@...30000 {
> 		compatible = "rockchip,rk3288-lcdc";
> 		...
>
> 		pwm@...301a0 {
> 			compatible = "rockchip,vop-pwm";
> 			...
> 		};
> 	};
>
> And your driver would do something like:
>
> 	static const struct resource pwm_resources[] = {
> 		{
> 			.start = 0x1a0,
> 			.end = 0x1af,
> 			.flags = IORESOURCE_MEM,
> 		},
> 	};
>
> 	static const struct mfd_cell subdevices[] = {
> 		{
> 			.name = "pwm",
> 			.id = 1,
> 			.of_compatible = "rockchip,vop-pwm",
> 			.num_resources = ARRAY_SIZE(pwm_resources),
> 			.resources = pwm_resources,
> 		},
> 	};
>
> 	static int lcdc_probe(struct platform_device *pdev)
> 	{
> 		struct resource *regs;
> 		...
>
> 		regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
> 		...
>
> 		err = mfd_add_devices(&pdev->dev, 0, subdevices, ARRAY_SIZE(subdevices),
> 				      regs, NULL, NULL);
> 		...
> 	}
>
> Thierry
Sorry,I might a little trouble for the changes.

The driver changes only for lcdc? If that is the case,I suddenly don't 
know how to do it ?

Maybe,I didn't say it clearly.

lcdc0: lcdc@...30000                   |     vop0pwm: pwm@...301a0
reg = <0xff930000 0x10000>     |      reg = <0xff9301a0 0x10>;

The lcdc has to add resource's address  from  0xff930000 to 0xff93ffff.

When the  pwm driver is loading vop0pwm. the "devm_ioremap_resource()" 
will be used in probe();

I think it will be occur a fail. because the resource [mem 
0xff9301a0-0xff9301af] has be requested by lcdc.
=>rockchip-pwm ff9301a0.pwm: can't request region for resource [mem 
0xff9301a0-0xff9301af]

If I do the changes in pwm driver,do you have a other suggestion for 
it?    thanks.:-)


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