[PATCH] net: smc91x: Fix gpios for device tree based booting

[PATCH] net: smc91x: Fix gpios for device tree based booting

[Tony Lindgren]

With legacy booting, the platform init code was taking care of
the configuring of GPIOs. With device tree based booting, things
may or may not work depending what bootloader has configured or
if the legacy platform code gets called.

Let's add support for the pwrdn and reset GPIOs to the smc91x
driver to fix the issues of smc91x not working properly when
booted in device tree mode.

And let's change n900 to use these settings as some versions
of the bootloader do not configure things properly causing
errors.

Reported-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

--- a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt
+++ b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt
@@ -11,3 +11,5 @@ Optional properties:
   are supported on the device.  Valid value for SMSC LAN91c111 are
   1, 2 or 4.  If it's omitted or invalid, the size would be 2 meaning
   16-bit access only.
+- power-gpios: GPIO to control the PWRDWN pin
+- reset-gpios: GPIO to control the RESET pin
--- a/arch/arm/boot/dts/omap3-n900.dts
+++ b/arch/arm/boot/dts/omap3-n900.dts
@@ -697,6 +697,8 @@
 		bank-width = <2>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&ethernet_pins>;
+		power-gpios = <&gpio3 22 GPIO_ACTIVE_HIGH>;	/* gpio86 */
+		reset-gpios = <&gpio6 4 GPIO_ACTIVE_HIGH>;	/* gpio164 */
 		gpmc,device-width = <2>;
 		gpmc,sync-clk-ps = <0>;
 		gpmc,cs-on-ns = <0>;
--- a/arch/arm/mach-omap2/pdata-quirks.c
+++ b/arch/arm/mach-omap2/pdata-quirks.c
@@ -253,9 +253,6 @@ static void __init nokia_n900_legacy_init(void)
 		platform_device_register(&omap3_rom_rng_device);
 
 	}
-
-	/* Only on some development boards */
-	gpio_request_one(164, GPIOF_OUT_INIT_LOW, "smc91x reset");
 }
 
 static void __init omap3_tao3530_legacy_init(void)
--- a/drivers/net/ethernet/smsc/smc91x.c
+++ b/drivers/net/ethernet/smsc/smc91x.c
@@ -81,6 +81,7 @@ static const char version[] =
 #include <linux/workqueue.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
@@ -2190,6 +2191,41 @@ static const struct of_device_id smc91x_match[] = {
 MODULE_DEVICE_TABLE(of, smc91x_match);
 #endif
 
+/**
+ * of_try_set_control_gpio - configure a gpio if it exists
+ */
+static int try_toggle_control_gpio(struct device *dev,
+				   struct gpio_desc **desc,
+				   const char *name, int index,
+				   int value, unsigned int nsdelay)
+{
+	struct gpio_desc *gpio = *desc;
+	int res;
+
+	gpio = devm_gpiod_get_index(dev, name, index);
+	if (IS_ERR(gpio)) {
+		if (PTR_ERR(gpio) == -ENOENT) {
+			*desc = NULL;
+			return 0;
+		}
+
+		return PTR_ERR(gpio);
+	}
+	res = gpiod_direction_output(gpio, !value);
+	if (res) {
+		dev_err(dev, "unable to toggle gpio %s: %i\n", name, res);
+		devm_gpiod_put(dev, gpio);
+		gpio = NULL;
+		return res;
+	}
+	if (nsdelay)
+		usleep_range(nsdelay, 2 * nsdelay);
+	gpiod_set_value_cansleep(gpio, value);
+	*desc = gpio;
+
+	return 0;
+}
+
 /*
  * smc_init(void)
  *   Input parameters:
@@ -2237,6 +2273,28 @@ static int smc_drv_probe(struct platform_device *pdev)
 		struct device_node *np = pdev->dev.of_node;
 		u32 val;
 
+		/* Optional pwrdwn GPIO configured? */
+		ret = try_toggle_control_gpio(&pdev->dev, &lp->power_gpio,
+					      "power", 0, 0, 100);
+		if (ret)
+			return ret;
+
+		/*
+		 * Optional reset GPIO configured? Minimum 100 ns reset needed
+		 * according to LAN91C96 datasheet page 14.
+		 */
+		ret = try_toggle_control_gpio(&pdev->dev, &lp->reset_gpio,
+					      "reset", 0, 0, 100);
+		if (ret)
+			return ret;
+
+		/*
+		 * Need to wait for optional EEPROM to load, max 750 us according
+		 * to LAN91C96 datasheet page 55.
+		 */
+		if (lp->reset_gpio)
+			usleep_range(750, 1000);
+
 		/* Combination of IO widths supported, default to 16-bit */
 		if (!of_property_read_u32(np, "reg-io-width", &val)) {
 			if (val & 1)
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -298,6 +298,9 @@ struct smc_local {
 	struct sk_buff *pending_tx_skb;
 	struct tasklet_struct tx_task;
 
+	struct gpio_desc *power_gpio;
+	struct gpio_desc *reset_gpio;
+
 	/* version/revision of the SMC91x chip */
 	int	version;
 

Re: [PATCH] net: smc91x: Fix gpios for device tree based booting

[David Miller]

From: Tony Lindgren <tony@atomide.com>
Date: Mon, 27 Oct 2014 13:25:56 -0700

> +/**
> + * of_try_set_control_gpio - configure a gpio if it exists
> + */
> +static int try_toggle_control_gpio(struct device *dev,
> +				   struct gpio_desc **desc,
> +				   const char *name, int index,
> +				   int value, unsigned int nsdelay)

This needs to be under CONFIG_OF cpp protection just like the code that
calls it.

Re: [PATCH] net: smc91x: Fix gpios for device tree based booting

[Tony Lindgren]

* David Miller <davem@davemloft.net> [141029 11:53]:
> From: Tony Lindgren <tony@atomide.com>
> Date: Mon, 27 Oct 2014 13:25:56 -0700
> 
> > +/**
> > + * of_try_set_control_gpio - configure a gpio if it exists
> > + */
> > +static int try_toggle_control_gpio(struct device *dev,
> > +				   struct gpio_desc **desc,
> > +				   const char *name, int index,
> > +				   int value, unsigned int nsdelay)
> 
> This needs to be under CONFIG_OF cpp protection just like the code that
> calls it.

Oops thanks for catching that, updated patch below. The code
for try_toggle_control_gpio() is now within the existing
IS_BUILTIN(CONFIG_OF) block. Compile and boot tested on omap1
that's not yet booting with device tree.

Regards,

Tony

8< ----------------------
From: Tony Lindgren <tony@atomide.com>
Date: Wed, 29 Oct 2014 16:06:11 -0700
Subject: [PATCH] net: smc91x: Fix gpios for device tree based booting

With legacy booting, the platform init code was taking care of
the configuring of GPIOs. With device tree based booting, things
may or may not work depending what bootloader has configured or
if the legacy platform code gets called.

Let's add support for the pwrdn and reset GPIOs to the smc91x
driver to fix the issues of smc91x not working properly when
booted in device tree mode.

And let's change n900 to use these settings as some versions
of the bootloader do not configure things properly causing
errors.

Reported-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

--- a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt
+++ b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt
@@ -11,3 +11,5 @@ Optional properties:
   are supported on the device.  Valid value for SMSC LAN91c111 are
   1, 2 or 4.  If it's omitted or invalid, the size would be 2 meaning
   16-bit access only.
+- power-gpios: GPIO to control the PWRDWN pin
+- reset-gpios: GPIO to control the RESET pin
--- a/arch/arm/boot/dts/omap3-n900.dts
+++ b/arch/arm/boot/dts/omap3-n900.dts
@@ -668,6 +668,8 @@
 		bank-width = <2>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&ethernet_pins>;
+		power-gpios = <&gpio3 22 GPIO_ACTIVE_HIGH>;	/* gpio86 */
+		reset-gpios = <&gpio6 4 GPIO_ACTIVE_HIGH>;	/* gpio164 */
 		gpmc,device-width = <2>;
 		gpmc,sync-clk-ps = <0>;
 		gpmc,cs-on-ns = <0>;
--- a/arch/arm/mach-omap2/pdata-quirks.c
+++ b/arch/arm/mach-omap2/pdata-quirks.c
@@ -252,9 +252,6 @@ static void __init nokia_n900_legacy_init(void)
 		platform_device_register(&omap3_rom_rng_device);
 
 	}
-
-	/* Only on some development boards */
-	gpio_request_one(164, GPIOF_OUT_INIT_LOW, "smc91x reset");
 }
 
 static void __init omap3_tao3530_legacy_init(void)
--- a/drivers/net/ethernet/smsc/smc91x.c
+++ b/drivers/net/ethernet/smsc/smc91x.c
@@ -81,6 +81,7 @@ static const char version[] =
 #include <linux/workqueue.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
@@ -2188,6 +2189,41 @@ static const struct of_device_id smc91x_match[] = {
 	{},
 };
 MODULE_DEVICE_TABLE(of, smc91x_match);
+
+/**
+ * of_try_set_control_gpio - configure a gpio if it exists
+ */
+static int try_toggle_control_gpio(struct device *dev,
+				   struct gpio_desc **desc,
+				   const char *name, int index,
+				   int value, unsigned int nsdelay)
+{
+	struct gpio_desc *gpio = *desc;
+	int res;
+
+	gpio = devm_gpiod_get_index(dev, name, index);
+	if (IS_ERR(gpio)) {
+		if (PTR_ERR(gpio) == -ENOENT) {
+			*desc = NULL;
+			return 0;
+		}
+
+		return PTR_ERR(gpio);
+	}
+	res = gpiod_direction_output(gpio, !value);
+	if (res) {
+		dev_err(dev, "unable to toggle gpio %s: %i\n", name, res);
+		devm_gpiod_put(dev, gpio);
+		gpio = NULL;
+		return res;
+	}
+	if (nsdelay)
+		usleep_range(nsdelay, 2 * nsdelay);
+	gpiod_set_value_cansleep(gpio, value);
+	*desc = gpio;
+
+	return 0;
+}
 #endif
 
 /*
@@ -2237,6 +2273,28 @@ static int smc_drv_probe(struct platform_device *pdev)
 		struct device_node *np = pdev->dev.of_node;
 		u32 val;
 
+		/* Optional pwrdwn GPIO configured? */
+		ret = try_toggle_control_gpio(&pdev->dev, &lp->power_gpio,
+					      "power", 0, 0, 100);
+		if (ret)
+			return ret;
+
+		/*
+		 * Optional reset GPIO configured? Minimum 100 ns reset needed
+		 * according to LAN91C96 datasheet page 14.
+		 */
+		ret = try_toggle_control_gpio(&pdev->dev, &lp->reset_gpio,
+					      "reset", 0, 0, 100);
+		if (ret)
+			return ret;
+
+		/*
+		 * Need to wait for optional EEPROM to load, max 750 us according
+		 * to LAN91C96 datasheet page 55.
+		 */
+		if (lp->reset_gpio)
+			usleep_range(750, 1000);
+
 		/* Combination of IO widths supported, default to 16-bit */
 		if (!of_property_read_u32(np, "reg-io-width", &val)) {
 			if (val & 1)
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -298,6 +298,9 @@ struct smc_local {
 	struct sk_buff *pending_tx_skb;
 	struct tasklet_struct tx_task;
 
+	struct gpio_desc *power_gpio;
+	struct gpio_desc *reset_gpio;
+
 	/* version/revision of the SMC91x chip */
 	int	version;