can: cc770: add platform bus driver for the CC770 and AN82527

This driver works with both, static platform data and device tree
bindings. It has been tested on a TQM855L board with two AN82527
CAN controllers on the local bus.

CC: [e-mail]
CC: [e-mail]
CC: Kumar Gala <[e-mail]>
Signed-off-by: Wolfgang Grandegger <[e-mail]>
Acked-by: Marc Kleine-Budde <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/can/cc770.txt

···
+Memory mapped Bosch CC770 and Intel AN82527 CAN controller
+
+Note: The CC770 is a CAN controller from Bosch, which is 100%
+compatible with the old AN82527 from Intel, but with "bugs" being fixed.
+
+Required properties:
+
+- compatible : should be "bosch,cc770" for the CC770 and "intc,82527"
+	for the AN82527.
+
+- reg : should specify the chip select, address offset and size required
+	to map the registers of the controller. The size is usually 0x80.
+
+- interrupts : property with a value describing the interrupt source
+	(number and sensitivity) required for the controller.
+
+Optional properties:
+
+- bosch,external-clock-frequency : frequency of the external oscillator
+	clock in Hz. Note that the internal clock frequency used by the
+	controller is half of that value. If not specified, a default
+	value of 16000000 (16 MHz) is used.
+
+- bosch,clock-out-frequency : slock frequency in Hz on the CLKOUT pin.
+	If not specified or if the specified value is 0, the CLKOUT pin
+	will be disabled.
+
+- bosch,slew-rate : slew rate of the CLKOUT signal. If not specified,
+	a resonable value will be calculated.
+
+- bosch,disconnect-rx0-input : see data sheet.
+
+- bosch,disconnect-rx1-input : see data sheet.
+
+- bosch,disconnect-tx1-output : see data sheet.
+
+- bosch,polarity-dominant : see data sheet.
+
+- bosch,divide-memory-clock : see data sheet.
+
+- bosch,iso-low-speed-mux : see data sheet.
+
+For further information, please have a look to the CC770 or AN82527.
+
+Examples:
+
+can@3,100 {
+	compatible = "bosch,cc770";
+	reg = <3 0x100 0x80>;
+	interrupts = <2 0>;
+	interrupt-parent = <&mpic>;
+	bosch,external-clock-frequency = <16000000>;
+};

drivers/net/can/cc770/Kconfig

···
 	  connected to the ISA bus using I/O port, memory mapped or
 	  indirect access.
 
+config CAN_CC770_PLATFORM
+	tristate "Generic Platform Bus based CC770 driver"
+	---help---
+	  This driver adds support for the CC770 and AN82527 chips
+	  connected to the "platform bus" (Linux abstraction for directly
+	  to the processor attached devices).
+
 endif

drivers/net/can/cc770/Makefile

···
 
 obj-$(CONFIG_CAN_CC770) += cc770.o
 obj-$(CONFIG_CAN_CC770_ISA) += cc770_isa.o
+obj-$(CONFIG_CAN_CC770_PLATFORM) += cc770_platform.o
 
 ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG

drivers/net/can/cc770/cc770_platform.c

···
+/*
+ * Driver for CC770 and AN82527 CAN controllers on the platform bus
+ *
+ * Copyright (C) 2009, 2011 Wolfgang Grandegger <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * If platform data are used you should have similar definitions
+ * in your board-specific code:
+ *
+ *   static struct cc770_platform_data myboard_cc770_pdata = {
+ *           .osc_freq = 16000000,
+ *           .cir = 0x41,
+ *           .cor = 0x20,
+ *           .bcr = 0x40,
+ *   };
+ *
+ * Please see include/linux/can/platform/cc770.h for description of
+ * above fields.
+ *
+ * If the device tree is used, you need a CAN node definition in your
+ * DTS file similar to:
+ *
+ *   can@3,100 {
+ *           compatible = "bosch,cc770";
+ *           reg = <3 0x100 0x80>;
+ *           interrupts = <2 0>;
+ *           interrupt-parent = <&mpic>;
+ *           bosch,external-clock-frequency = <16000000>;
+ *   };
+ *
+ * See "Documentation/devicetree/bindings/net/can/cc770.txt" for further
+ * information.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/platform/cc770.h>
+
+#include "cc770.h"
+
+#define DRV_NAME "cc770_platform"
+
+MODULE_AUTHOR("Wolfgang Grandegger <[e-mail]>");
+MODULE_DESCRIPTION("Socket-CAN driver for CC770 on the platform bus");
+MODULE_LICENSE("GPL v2");
+
+#define CC770_PLATFORM_CAN_CLOCK  16000000
+
+static u8 cc770_platform_read_reg(const struct cc770_priv *priv, int reg)
+{
+	return ioread8(priv->reg_base + reg);
+}
+
+static void cc770_platform_write_reg(const struct cc770_priv *priv, int reg,
+				     u8 val)
+{
+	iowrite8(val, priv->reg_base + reg);
+}
+
+static int __devinit cc770_get_of_node_data(struct platform_device *pdev,
+					    struct cc770_priv *priv)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const u32 *prop;
+	int prop_size;
+	u32 clkext;
+
+	prop = of_get_property(np, "bosch,external-clock-frequency",
+			       &prop_size);
+	if (prop && (prop_size ==  sizeof(u32)))
+		clkext = *prop;
+	else
+		clkext = CC770_PLATFORM_CAN_CLOCK; /* default */
+	priv->can.clock.freq = clkext;
+
+	/* The system clock may not exceed 10 MHz */
+	if (priv->can.clock.freq > 10000000) {
+		priv->cpu_interface |= CPUIF_DSC;
+		priv->can.clock.freq /= 2;
+	}
+
+	/* The memory clock may not exceed 8 MHz */
+	if (priv->can.clock.freq > 8000000)
+		priv->cpu_interface |= CPUIF_DMC;
+
+	if (of_get_property(np, "bosch,divide-memory-clock", NULL))
+		priv->cpu_interface |= CPUIF_DMC;
+	if (of_get_property(np, "bosch,iso-low-speed-mux", NULL))
+		priv->cpu_interface |= CPUIF_MUX;
+
+	if (!of_get_property(np, "bosch,no-comperator-bypass", NULL))
+		priv->bus_config |= BUSCFG_CBY;
+	if (of_get_property(np, "bosch,disconnect-rx0-input", NULL))
+		priv->bus_config |= BUSCFG_DR0;
+	if (of_get_property(np, "bosch,disconnect-rx1-input", NULL))
+		priv->bus_config |= BUSCFG_DR1;
+	if (of_get_property(np, "bosch,disconnect-tx1-output", NULL))
+		priv->bus_config |= BUSCFG_DT1;
+	if (of_get_property(np, "bosch,polarity-dominant", NULL))
+		priv->bus_config |= BUSCFG_POL;
+
+	prop = of_get_property(np, "bosch,clock-out-frequency", &prop_size);
+	if (prop && (prop_size == sizeof(u32)) && *prop > 0) {
+		u32 cdv = clkext / *prop;
+		int slew;
+
+		if (cdv > 0 && cdv < 16) {
+			priv->cpu_interface |= CPUIF_CEN;
+			priv->clkout |= (cdv - 1) & CLKOUT_CD_MASK;
+
+			prop = of_get_property(np, "bosch,slew-rate",
+					       &prop_size);
+			if (prop && (prop_size == sizeof(u32))) {
+				slew = *prop;
+			} else {
+				/* Determine default slew rate */
+				slew = (CLKOUT_SL_MASK >>
+					CLKOUT_SL_SHIFT) -
+					((cdv * clkext - 1) / 8000000);
+				if (slew < 0)
+					slew = 0;
+			}
+			priv->clkout |= (slew << CLKOUT_SL_SHIFT) &
+				CLKOUT_SL_MASK;
+		} else {
+			dev_dbg(&pdev->dev, "invalid clock-out-frequency\n");
+		}
+	}
+
+	return 0;
+}
+
+static int __devinit cc770_get_platform_data(struct platform_device *pdev,
+					     struct cc770_priv *priv)
+{
+
+	struct cc770_platform_data *pdata = pdev->dev.platform_data;
+
+	priv->can.clock.freq = pdata->osc_freq;
+	if (priv->cpu_interface | CPUIF_DSC)
+		priv->can.clock.freq /= 2;
+	priv->clkout = pdata->cor;
+	priv->bus_config = pdata->bcr;
+	priv->cpu_interface = pdata->cir;
+
+	return 0;
+}
+
+static int __devinit cc770_platform_probe(struct platform_device *pdev)
+{
+	struct net_device *dev;
+	struct cc770_priv *priv;
+	struct resource *mem;
+	resource_size_t mem_size;
+	void __iomem *base;
+	int err, irq;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	irq = platform_get_irq(pdev, 0);
+	if (!mem || irq <= 0)
+		return -ENODEV;
+
+	mem_size = resource_size(mem);
+	if (!request_mem_region(mem->start, mem_size, pdev->name))
+		return -EBUSY;
+
+	base = ioremap(mem->start, mem_size);
+	if (!base) {
+		err = -ENOMEM;
+		goto exit_release_mem;
+	}
+
+	dev = alloc_cc770dev(0);
+	if (!dev) {
+		err = -ENOMEM;
+		goto exit_unmap_mem;
+	}
+
+	dev->irq = irq;
+	priv = netdev_priv(dev);
+	priv->read_reg = cc770_platform_read_reg;
+	priv->write_reg = cc770_platform_write_reg;
+	priv->irq_flags = IRQF_SHARED;
+	priv->reg_base = base;
+
+	if (pdev->dev.of_node)
+		err = cc770_get_of_node_data(pdev, priv);
+	else if (pdev->dev.platform_data)
+		err = cc770_get_platform_data(pdev, priv);
+	else
+		err = -ENODEV;
+	if (err)
+		goto exit_free_cc770;
+
+	dev_dbg(&pdev->dev,
+		 "reg_base=0x%p irq=%d clock=%d cpu_interface=0x%02x "
+		 "bus_config=0x%02x clkout=0x%02x\n",
+		 priv->reg_base, dev->irq, priv->can.clock.freq,
+		 priv->cpu_interface, priv->bus_config, priv->clkout);
+
+	dev_set_drvdata(&pdev->dev, dev);
+	SET_NETDEV_DEV(dev, &pdev->dev);
+
+	err = register_cc770dev(dev);
+	if (err) {
+		dev_err(&pdev->dev,
+			"couldn't register CC700 device (err=%d)\n", err);
+		goto exit_free_cc770;
+	}
+
+	return 0;
+
+exit_free_cc770:
+	free_cc770dev(dev);
+exit_unmap_mem:
+	iounmap(base);
+exit_release_mem:
+	release_mem_region(mem->start, mem_size);
+
+	return err;
+}
+
+static int __devexit cc770_platform_remove(struct platform_device *pdev)
+{
+	struct net_device *dev = dev_get_drvdata(&pdev->dev);
+	struct cc770_priv *priv = netdev_priv(dev);
+	struct resource *mem;
+
+	unregister_cc770dev(dev);
+	iounmap(priv->reg_base);
+	free_cc770dev(dev);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(mem->start, resource_size(mem));
+
+	return 0;
+}
+
+static struct of_device_id __devinitdata cc770_platform_table[] = {
+	{.compatible = "bosch,cc770"}, /* CC770 from Bosch */
+	{.compatible = "intc,82527"},  /* AN82527 from Intel CP */
+	{},
+};
+
+static struct platform_driver cc770_platform_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = cc770_platform_table,
+	},
+	.probe = cc770_platform_probe,
+	.remove = __devexit_p(cc770_platform_remove),
+};
+
+module_platform_driver(cc770_platform_driver);