can: mcp251x: Add device tree support

This patch adds Device Tree support to the Microchip MCP251X driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/microchip,mcp251x.txt

+* Microchip MCP251X stand-alone CAN controller device tree bindings
+
+Required properties:
+ - compatible: Should be one of the following:
+   - "microchip,mcp2510" for MCP2510.
+   - "microchip,mcp2515" for MCP2515.
+ - reg: SPI chip select.
+ - clocks: The clock feeding the CAN controller.
+ - interrupt-parent: The parent interrupt controller.
+ - interrupts: Should contain IRQ line for the CAN controller.
+
+Optional properties:
+ - vdd-supply: Regulator that powers the CAN controller.
+ - xceiver-supply: Regulator that powers the CAN transceiver.
+
+Example:
+	can0: can@1 {
+		compatible = "microchip,mcp2515";
+		reg = <1>;
+		clocks = <&clk24m>;
+		interrupt-parent = <&gpio4>;
+		interrupts = <13 0x2>;
+		vdd-supply = <&reg5v0>;
+		xceiver-supply = <&reg5v0>;
+	};

drivers/net/can/mcp251x.c

@@ -58,6 +58,7 @@
 #include <linux/can/dev.h>
 #include <linux/can/led.h>
 #include <linux/can/platform/mcp251x.h>
+#include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -68,6 +69,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
@@ -263,6 +266,7 @@ struct mcp251x_priv {
 	int restart_tx;
 	struct regulator *power;
 	struct regulator *transceiver;
+	struct clk *clk;
 };
 
 #define MCP251X_IS(_model) \
@@ -994,22 +998,65 @@ static const struct net_device_ops mcp251x_netdev_ops = {
 	.ndo_start_xmit = mcp251x_hard_start_xmit,
 };
 
+static const struct of_device_id mcp251x_of_match[] = {
+	{
+		.compatible	= "microchip,mcp2510",
+		.data		= (void *)CAN_MCP251X_MCP2510,
+	},
+	{
+		.compatible	= "microchip,mcp2515",
+		.data		= (void *)CAN_MCP251X_MCP2515,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mcp251x_of_match);
+
+static const struct spi_device_id mcp251x_id_table[] = {
+	{
+		.name		= "mcp2510",
+		.driver_data	= (kernel_ulong_t)CAN_MCP251X_MCP2510,
+	},
+	{
+		.name		= "mcp2515",
+		.driver_data	= (kernel_ulong_t)CAN_MCP251X_MCP2515,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, mcp251x_id_table);
+
 static int mcp251x_can_probe(struct spi_device *spi)
 {
+	const struct of_device_id *of_id = of_match_device(mcp251x_of_match,
+							   &spi->dev);
+	struct mcp251x_platform_data *pdata = dev_get_platdata(&spi->dev);
 	struct net_device *net;
 	struct mcp251x_priv *priv;
-	struct mcp251x_platform_data *pdata = dev_get_platdata(&spi->dev);
-	int ret = -ENODEV;
+	int freq, ret = -ENODEV;
+	struct clk *clk;
+
+	clk = devm_clk_get(&spi->dev, NULL);
+	if (IS_ERR(clk)) {
+		if (pdata)
+			freq = pdata->oscillator_frequency;
+		else
+			return PTR_ERR(clk);
+	} else {
+		freq = clk_get_rate(clk);
+	}
 
-	if (!pdata)
-		/* Platform data is required for osc freq */
-		goto error_out;
+	/* Sanity check */
+	if (freq < 1000000 || freq > 25000000)
+		return -ERANGE;
 
 	/* Allocate can/net device */
 	net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);
-	if (!net) {
-		ret = -ENOMEM;
-		goto error_alloc;
+	if (!net)
+		return -ENOMEM;
+
+	if (!IS_ERR(clk)) {
+		ret = clk_prepare_enable(clk);
+		if (ret)
+			goto out_free;
 	}
 
 	net->netdev_ops = &mcp251x_netdev_ops;
@@ -1018,23 +1065,27 @@ static int mcp251x_can_probe(struct spi_device *spi)
 	priv = netdev_priv(net);
 	priv->can.bittiming_const = &mcp251x_bittiming_const;
 	priv->can.do_set_mode = mcp251x_do_set_mode;
-	priv->can.clock.freq = pdata->oscillator_frequency / 2;
+	priv->can.clock.freq = freq / 2;
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
 		CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;
-	priv->model = spi_get_device_id(spi)->driver_data;
+	if (of_id)
+		priv->model = (enum mcp251x_model)of_id->data;
+	else
+		priv->model = spi_get_device_id(spi)->driver_data;
 	priv->net = net;
+	priv->clk = clk;
 
 	priv->power = devm_regulator_get(&spi->dev, "vdd");
 	priv->transceiver = devm_regulator_get(&spi->dev, "xceiver");
 	if ((PTR_ERR(priv->power) == -EPROBE_DEFER) ||
 	    (PTR_ERR(priv->transceiver) == -EPROBE_DEFER)) {
 		ret = -EPROBE_DEFER;
-		goto error_power;
+		goto out_clk;
 	}
 
 	ret = mcp251x_power_enable(priv->power, 1);
 	if (ret)
-		goto error_power;
+		goto out_clk;
 
 	spi_set_drvdata(spi, priv);
 
@@ -1113,11 +1164,14 @@ static int mcp251x_can_probe(struct spi_device *spi)
 		dma_free_coherent(&spi->dev, PAGE_SIZE,
 				  priv->spi_tx_buf, priv->spi_tx_dma);
 	mcp251x_power_enable(priv->power, 0);
-error_power:
+
+out_clk:
+	if (!IS_ERR(clk))
+		clk_disable_unprepare(clk);
+
+out_free:
 	free_candev(net);
-error_alloc:
-	dev_err(&spi->dev, "probe failed\n");
-error_out:
+
 	return ret;
 }
 
@@ -1135,6 +1189,9 @@ static int mcp251x_can_remove(struct spi_device *spi)
 
 	mcp251x_power_enable(priv->power, 0);
 
+	if (!IS_ERR(priv->clk))
+		clk_disable_unprepare(priv->clk);
+
 	free_candev(net);
 
 	return 0;
@@ -1197,21 +1254,13 @@ static int mcp251x_can_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(mcp251x_can_pm_ops, mcp251x_can_suspend,
 	mcp251x_can_resume);
 
-static const struct spi_device_id mcp251x_id_table[] = {
-	{ "mcp2510",	CAN_MCP251X_MCP2510 },
-	{ "mcp2515",	CAN_MCP251X_MCP2515 },
-	{ },
-};
-
-MODULE_DEVICE_TABLE(spi, mcp251x_id_table);
-
 static struct spi_driver mcp251x_can_driver = {
 	.driver = {
 		.name = DEVICE_NAME,
 		.owner = THIS_MODULE,
+		.of_match_table = mcp251x_of_match,
 		.pm = &mcp251x_can_pm_ops,
 	},
-
 	.id_table = mcp251x_id_table,
 	.probe = mcp251x_can_probe,
 	.remove = mcp251x_can_remove,