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

Dear Rob Herring,

On 06/13/2012 10:19 AM, Marek Vasut wrote:

quoted

Dear Rob Herring,

quoted

On 06/13/2012 07:34 AM, Richard Zhao wrote:

quoted

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 <redacted>
Cc: Shawn Guo <redacted>
Cc: Rob Herring <redacted>
Cc: Grant Likely <redacted>
---

 .../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 and should be solved within the
kernel or bootloader. Either fix this in u-boot

I don't want to be the bastard here, but this shouldn't go into uboot.

Just listing possible options. Obviously, no one wants the dirty stuff
in their code...

There would never be a need in u-boot to support boot from USB mass
storage?

We already support that obviously ;-)

In which case you would have to handle this reset line leaving
it deasserted and linux would likely never know. (Yes, I know we can't
rely on bootloader setup.)

But we defer the initialization of USB to a point where user really needs it. 
Therefore if you boot from ie. NAND, you won't have the USB inited anyway.

quoted

quoted

the platform code

Yes, it should be here. But then, it's some usb reset, so maybe the PHY
should somehow handle it?

quoted

, or
make the generic driver support this in a generic way.

Well, this is platform specific stuff, so it shouldn't be in any way part
of the driver.

An embedded hub with gpio controlled reset line sounds fairly generic to
me. The only platform specific part is which gpio line which is nothing
new to deal with.

And what about embedded hub that has two distinct power GPIOs? And we can go 
forever with this discussion.

On the other hand, this is really a flaw in the h/w design as whether
the hub is integrated on board or a separate hub should be transparent
to s/w.

I don't think so. You might want to minimize the power consumption by disabling 
the hub power completely.

So just keeping it contained in platform code may be the best
option.

Agreed

Rob

quoted

quoted

Rob

quoted

+
+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();
 
 }

Best regards,
Marek Vasut