Re: [PATCH 3/3] usb: phy-generic: Add ULPI VBUS support

[Chris Ruehl <chris.ruehl@gtsys.com.hk>]

On Tuesday, December 03, 2013 02:22 AM, Mark Rutland wrote:
> On Mon, Dec 02, 2013 at 07:05:19AM +0000, Chris Ruehl wrote:
>> usb: phy-generic: Add ULPI VBUS support
>>
>> Some platforms need to set the VBUS parameters of the ULPI
>> like ISP1504 which interact with overcurrent protection and
>> power switch MIC2575. Therefore it requires to set
>> * DRVVBUS
>> * DRVVBUS_EXT
>> * EXTVBUSIND
>> * CHRGVBUS
>> of the ULPI.
>> This patch add support for it.
>
> Could you elaborate on when we need to do this and why?
>
>>
>> Devicetree configuration example:
>>
>> usbphy0: usbphy@0x10024170 {
>>   compatible = "usb-nop-xceiv";
>>   reg =<0x10024170 0x4>; /* ULPI Viewport OTG */
>>   clocks =<&clks 75>;
>>   clock-names = "main_clk";
>> };
>>
>> &usbphy0 {
>>          reset-gpios =<&gpio1 31 1>;
>>          pinctrl-names = "default";
>>          pinctrl-0 =<&pinctrl_usbphy0&pinctrl_usbotg1>;
>>          ulpi_set_vbus =<0x0f>;
>> };
>>
>> Please refer to the phy-bindings.txt for the value of ulpi_set_vbus commit
>> with this patch.
>>
>> Signed-off-by: Chris Ruehl<chris.ruehl@gtsys.com.hk>
>> ---
>>   .../devicetree/bindings/phy/phy-bindings.txt       |   15 ++++++
>>   drivers/usb/phy/phy-generic.c                      |   50 +++++++++++++++++++-
>>   drivers/usb/phy/phy-generic.h                      |    3 ++
>>   3 files changed, 67 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/phy/phy-bindings.txt b/Documentation/devicetree/bindings/phy/phy-bindings.txt
>> index 8ae844f..b109b2f 100644
>> --- a/Documentation/devicetree/bindings/phy/phy-bindings.txt
>> +++ b/Documentation/devicetree/bindings/phy/phy-bindings.txt
>> @@ -34,6 +34,18 @@ phys : the phandle for the PHY device (used by the PHY subsystem)
>>   phy-names : the names of the PHY corresponding to the PHYs present in the
>>   	    *phys* phandle
>>
>> +Optional Properties:
>> +reset-gpios :	GPIO used to reset ULPI like ISP1504 with
>> +		0 = reset active high ; 1 = reset active low.
>
> The format of the gpio-specifier doesn't matter here.
>
> Why do you need to mention the ISP1504? Either this is generic, or it
> doesn't belong here.
>
> Perhaps we need a ulpi-phy binding document. This and the rest of the
> patch is strongly tied to ULPI.
>
>> +cs-gpios :	GPIO used to activate a ULPI like ISP1504 with
>> +		0 = reset acitive high; 1 = reset active low.
>
> Again, the format of the gpio-specifier is not a concern here. I'm also
> a little confused as to the name "cs-gpios" for something that activates
> the ULPI.
>
>> +ulpi_set_vbus :	ULPI configuation parameter to program the VBUS signaling of
>> +		ISP1504 or similar chipsets.
>
> Could you elaborate on this? Is this applicable to any ULPI PHY? The
> description implies that it's somewhat tied to ISP1504 (if it's not,
> drop the mention of ISP1504).
>
> Why exactly do we need this, and why should it live in the DT?
>
> Why can se not figure this out automatically, or have defaults that work
> in more places?
>
> Also, s/_/-/ on property names please.
>
>> +		Set the parameter:
>> +		DRVVBUS = (1) DRVVBUS_EXT = (1<<1) EXTVBUSIND = (1<<2) CHRGVBUS = (1<<3)
>> +		eg: DRVVBUS | DRVVBUS_EXT = 0x03
>> +		    ulpi_set_vbus =<0x03>
>
> I don't like putting arbitrary bitfields like this in DT. They're
> illegible and easy to abuse.
>
> Boolean properties are nicer for flags.
>
> What exactly do these flags mean?
>
> [...]
>
>> @@ -253,14 +284,15 @@ static int usb_phy_gen_xceiv_probe(struct platform_device *pdev)
>>
>>   	if (dev->of_node) {
>>   		struct device_node *node = dev->of_node;
>> +		struct resource	*res;
>>   		enum of_gpio_flags flags;
>>   		enum of_gpio_flags csflags;
>> +		u32 ulpi_vbus;
>>
>>   		if (of_property_read_u32(node, "clock-frequency",&clk_rate))
>>   			clk_rate = 0;
>>
>>   		needs_vcc = of_property_read_bool(node, "vcc-supply");
>> -
>>   		nop->gpio_reset = of_get_named_gpio_flags(node, "reset-gpios",
>>   								0,&flags);
>
> Why the random line deletion?
>
>>
>> @@ -274,6 +306,22 @@ static int usb_phy_gen_xceiv_probe(struct platform_device *pdev)
>>   		if (gpio_is_valid(nop->gpio_chipselect))
>>   			nop->cs_active_low = csflags&  OF_GPIO_ACTIVE_LOW;
>>
>> +		err = of_property_read_u32(node, "ulpi_set_vbus",&ulpi_vbus);
>> +		if (err) {
>> +			nop->ulpi_vbus = -1;
>> +			nop->viewport = NULL;
>> +			ulpi_vbus = 0;
>> +		} else {
>> +			dev_dbg(dev,"ULPI ulpi_set_vbus 0x%02x",ulpi_vbus);
>> +			nop->ulpi_vbus = ulpi_vbus;
>> +			res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
> This wasn't described in the binding document, and it's ULPI specific. I
> think we need a separate ulpi-phy binding that builds upon the generic
> one.
>
Mark, before commit an other patch, is it this what you looking for?
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/phy-ulpi.txt
@@ -0,0 +1,36 @@
+This document explains only the device tree data binding for phy-ulpi nodes. 
For general
+information about PHY subsystem refer to Documentation/phy.txt
+
+PHY device node
+===============
+
+Required Properties:
+reg:           ULPI Viewport
+reset-gpios :  GPIO used to reset ULPI chipset
+
+Optional Properties:
+cs-gpios :     GPIO used to activate a ULPI chipset
+ulpi-set-vbus :        ULPI configuation parameter to program the VBUS logic
+               Set the parameter:
+               DRVVBUS         = (1<<0)        Enable VBUS logic
+               DRVVBUS_EXT     = (1<<1)        Enable External VBUS logic
+               EXTVBUSIND      = (1<<2)        Enable Ext. VBUS indication and 
fault handler
+               CHRGVBUS        = (1<<3)        Enable VBUS charge pump logic
+               eg: DRVVBUS | DRVVBUS_EXT = 0x03
+                   ulpi_set_vbus = <0x03>
+
+For example:
+
+phys: phy@p {
+    compatible = "xxx";
+    reg = <p>;
+    .
+    .
+    #phy-cells = <1>;
+    .
+    .
+    reset-gpios = <&gpioX nn n>
+    cs-gpios = <&gpioX nn n>
+    ulpi-set-vbus = <0xXX>;
+};
+


Thanks
Chris




> Thanks,
> Mark.
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