Thread (27 messages) 27 messages, 5 authors, 2014-08-02

Re: [PATCH v4 4/4] ARM: dts: Add exynos5250-spring device tree

From: Tomasz Figa <hidden>
Date: 2014-07-31 19:05:25
Also in: linux-arm-kernel, linux-samsung-soc, lkml

Hi Andreas,

Sorry for joining the party a bit late, but there were patches with less
people involved so I preferred to review them first.

You can find my comments inline.

On 31.07.2014 18:08, Andreas Färber wrote:
Adds initial support for the HP Chromebook 11.
[snip]
+	gpio-keys {
+		compatible = "gpio-keys";
+		pinctrl-names = "default";
+		pinctrl-0 = <&power_key_irq>, <&lid_irq>;
+
+		power {
+			label = "Power";
+			gpios = <&gpx1 3 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_POWER>;
I assume the key is debounced in hardware, so there is no need for
debounce-interval here. Is this correct?
+			gpio-key,wakeup;
+		};
+
+		lid-switch {
+			label = "Lid";
+			gpios = <&gpx3 5 GPIO_ACTIVE_LOW>;
+			linux,input-type = <5>; /* EV_SW */
+			linux,code = <0>; /* SW_LID */
+			debounce-interval = <1>;
+			gpio-key,wakeup;
+		};
+	};
+
+	usb3_vbus_reg: regulator-usb3 {
+		compatible = "regulator-fixed";
+		regulator-name = "P5.0V_USB3CON";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		gpio = <&gpe1 0 GPIO_ACTIVE_LOW>;
+		enable-active-high;
+	};
+
+	usb@12110000 {
Since this is a brand new dts file, it should use the reference based
syntax, which would be something like

&usbhost {
	...
};

below the / { ... }; block.
+		samsung,vbus-gpio = <&gpx1 1 GPIO_ACTIVE_HIGH>;
+	};
+
+	usb-hub {
+		compatible = "smsc,usb3503a";
+		reset-gpios = <&hsic_reset>;
Hmm, why a -gpios property points to a pinctrl node? Shouldn't there be
a phandle to GPIO bank + GPIO specifier instead?
+	};
+
+	fixed-rate-clocks {
+		xxti {
+			compatible = "samsung,clock-xxti";
+			clock-frequency = <24000000>;
+		};
+	};
This is also referencing a node from higher level, so it should be done
using a reference.
+
+	hdmi {
+		hpd-gpio = <&gpx3 7 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&hdmi_hpd_irq>;
+		phy = <&hdmiphy>;
+		ddc = <&i2c_2>;
+		hdmi-en-supply = <&s5m_ldo8_reg>;
+		vdd-supply = <&s5m_ldo8_reg>;
+		vdd_osc-supply = <&s5m_ldo10_reg>;
+		vdd_pll-supply = <&s5m_ldo8_reg>;
+	};
Ditto.
+
+	fimd@14400000 {
+		status = "okay";
+		samsung,invert-vclk;
+	};
Ditto.
+
+	dp-controller@145B0000 {
+		status = "okay";
+		pinctrl-names = "default";
+		pinctrl-0 = <&dp_hpd>;
+		samsung,color-space = <0>;
+		samsung,dynamic-range = <0>;
+		samsung,ycbcr-coeff = <0>;
+		samsung,color-depth = <1>;
+		samsung,link-rate = <0x0a>;
+		samsung,lane-count = <1>;
+		samsung,hpd-gpio = <&gpc3 0 GPIO_ACTIVE_HIGH>;
+	};
Ditto.
+};
+
+&dp_hpd {
+	samsung,pins = "gpc3-0";
+	samsung,pin-function = <0>;
+	samsung,pin-pud = <3>;
+	samsung,pin-drv = <0>;
+};
Hmm, what node is this referencing? I believe this should rather
reference the pin controller and add a new board-specific pinconf/pinmux
group instead....
+
+&i2c_0 {
+	status = "okay";
+	samsung,i2c-sda-delay = <100>;
+	samsung,i2c-max-bus-freq = <378000>;
[snip]
+/*
+ * Disabled pullups since external part has its own pullups and
+ * double-pulling gets us out of spec in some cases.
+ */
+&i2c2_bus {
+	samsung,pin-pud = <0>;
+};
OK, here overriding a generic pinconf group is justified and nicely
explained by a comment.
+
+&i2c_2 {
+	status = "okay";
+	samsung,i2c-sda-delay = <100>;
+	samsung,i2c-max-bus-freq = <66000>;
+
+	hdmiddc@50 {
+		compatible = "samsung,exynos4210-hdmiddc";
+		reg = <0x50>;
+	};
I don't think this matches current Exynos HDMI bindings, which I believe
have been changed to just take a phandle to i2c bus instead.
+};
+
+&i2c_3 {
+	status = "okay";
+	samsung,i2c-sda-delay = <100>;
+	samsung,i2c-max-bus-freq = <66000>;
+};
[snip]
+&sd1_clk {
+	samsung,pin-drv = <0>;
+};
+
+&sd1_cmd {
+	samsung,pin-pud = <3>;
+	samsung,pin-drv = <0>;
+};
+
+&sd1_cd {
+	samsung,pin-drv = <0>;
+};
+
+&sd1_bus4 {
+	samsung,pin-drv = <0>;
+};
Here generic settings are being overridden, so it might be a good idea
to explain why, like with i2c pull-up above.

Best regards,
Tomasz
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