Re: [Patch v5 08/13] ARM: imx6q: add config-on-boot gpios

[Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 06/13/2012 10:28 AM, Richard Zhao wrote:
> On Wed, Jun 13, 2012 at 10:09:54AM -0500, Rob Herring wrote:
>> On 06/13/2012 07:34 AM, Richard Zhao wrote:
>>> Sometimes, boards have gpios that don't own by any driver or owner
>>> by a generic driver that don't like hacks. Such gpios is normally
>>> output and need setup once on boot. So I introduce the config-on-boot
>>> gpios.
>>>
>>> Signed-off-by: Richard Zhao <richard.zhao-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
>>> Cc: Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> Cc: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
>>> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
>>> ---
>>>  .../devicetree/bindings/arm/config-on-boot.txt     |   12 +++++++
>>>  arch/arm/boot/dts/imx6q-sabrelite.dts              |    7 ++++
>>>  arch/arm/mach-imx/mach-imx6q.c                     |   35 ++++++++++++++++++++
>>>  3 files changed, 54 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/arm/config-on-boot.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/config-on-boot.txt b/Documentation/devicetree/bindings/arm/config-on-boot.txt
>>> new file mode 100644
>>> index 0000000..f98ed74
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/config-on-boot.txt
>>> @@ -0,0 +1,12 @@
>>> +* Configure on Boot
>>> +
>>> +Node name: config-on-boot
>>> +  It must be in root node. config-on-boot means to describe settings that needs
>>> +  to be set one time on boot but aren't owned by any driver, or the owned driver
>>> +  is too generic to handle such settings. For example, usb hub uses generic
>>> +  driver in usb core code, a on-board usb may need deassert reset pin.
>>
>> NAK. This is not a h/w description
> It's misc things, but is hw description.

You are defining something based on whether linux has a driver or not.
That should not matter to DT. That's backwards.

>> and should be solved within the
>> kernel or bootloader. Either fix this in u-boot,
> Kernel might be better not to depend on uboot.
>> the platform code, or
> How do I get gpio in platfrom code without dts description?
>> make the generic driver support this in a generic way.
> It's called just after populate devices. It's hard for generic driver to
> decide when it's called.

You need to describe that you have a hub on the usb bus and add the gpio
line to that node. Just like PCI is probe-able, you still need DT nodes
sometimes for cases like this. A simpler approach would be to just add
the gpio to the ehci controller node, but that's not exactly correct.

Rob


> 
> Thanks
> Richard
>>
>> Rob
>>
>>> +
>>> +Optional properties:
>>> +- output-gpios: Output gpio array that needs to set.
>>> +- output-gpio-values: This property is required if output-gpios is set.
>>> +  The value is a array of 0 or 1. Total count eaquals the number of gpios.
>>> diff --git a/arch/arm/boot/dts/imx6q-sabrelite.dts b/arch/arm/boot/dts/imx6q-sabrelite.dts
>>> index e0ec929..1dd2261 100644
>>> --- a/arch/arm/boot/dts/imx6q-sabrelite.dts
>>> +++ b/arch/arm/boot/dts/imx6q-sabrelite.dts
>>> @@ -17,6 +17,13 @@
>>>  	model = "Freescale i.MX6 Quad SABRE Lite Board";
>>>  	compatible = "fsl,imx6q-sabrelite", "fsl,imx6q";
>>>  
>>> +	config-on-boot {
>>> +		output-gpios = <
>>> +				&gpio3 22 0>;	/* vbus reset */
>>> +		output-gpio-values = <
>>> +				1>;		/* vbus reset */
>>> +	};
>>> +
>>>  	memory {
>>>  		reg = <0x10000000 0x40000000>;
>>>  	};
>>> diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
>>> index b47e98b..577cf19 100644
>>> --- a/arch/arm/mach-imx/mach-imx6q.c
>>> +++ b/arch/arm/mach-imx/mach-imx6q.c
>>> @@ -19,6 +19,7 @@
>>>  #include <linux/irqdomain.h>
>>>  #include <linux/of.h>
>>>  #include <linux/of_address.h>
>>> +#include <linux/of_gpio.h>
>>>  #include <linux/of_irq.h>
>>>  #include <linux/of_platform.h>
>>>  #include <linux/pinctrl/machine.h>
>>> @@ -113,6 +114,38 @@ static void __init imx6q_sabrelite_init(void)
>>>  	imx6q_sabrelite_cko1_setup();
>>>  }
>>>  
>>> +static void __init imx6q_config_on_boot(void)
>>> +{
>>> +	struct device_node *np;
>>> +	struct property *pp;
>>> +	int cnt, len, i;
>>> +	int gpio;
>>> +
>>> +	np = of_find_node_by_path("/config-on-boot");
>>> +	if (!np)
>>> +		return;
>>> +	cnt = of_gpio_named_count(np, "output-gpios");
>>> +	pp = of_find_property(np, "output-gpio-values", &len);
>>> +	if (!pp || cnt != len / sizeof(u32)) {
>>> +		pr_err("Invalid config-on-boot gpios!\n");
>>> +		of_node_put(np);
>>> +		return;
>>> +	}
>>> +	for (i = 0; i < cnt; i++) {
>>> +		gpio = of_get_named_gpio(np, "output-gpios", i);
>>> +		if (gpio_is_valid(gpio))
>>> +			gpio_request_one(gpio, GPIOF_OUT_INIT_HIGH,
>>> +					"config-on-boot");
>>> +	}
>>> +
>>> +	of_node_put(np);
>>> +}
>>> +
>>> +static void __init imx6q_post_populate(void)
>>> +{
>>> +	imx6q_config_on_boot();
>>> +}
>>> +
>>>  static void __init imx6q_init_machine(void)
>>>  {
>>>  	/*
>>> @@ -126,6 +159,8 @@ static void __init imx6q_init_machine(void)
>>>  
>>>  	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
>>>  
>>> +	imx6q_post_populate();
>>> +
>>>  	imx6q_pm_init();
>>>  }
>>>  
>>

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