/drivers/net/can/sja1000/sja1000_of_platform.c

  1/*
  2 * Driver for SJA1000 CAN controllers on the OpenFirmware platform bus
  3 *
  4 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the version 2 of the GNU General Public License
  8 * as published by the Free Software Foundation
  9 *
 10 * This program is distributed in the hope that it will be useful,
 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 13 * GNU General Public License for more details.
 14 *
 15 * You should have received a copy of the GNU General Public License
 16 * along with this program; if not, write to the Free Software Foundation,
 17 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 18 */
 19
 20/* This is a generic driver for SJA1000 chips on the OpenFirmware platform
 21 * bus found on embedded PowerPC systems. You need a SJA1000 CAN node
 22 * definition in your flattened device tree source (DTS) file similar to:
 23 *
 24 *   can@3,100 {
 25 *           compatible = "nxp,sja1000";
 26 *           reg = <3 0x100 0x80>;
 27 *           interrupts = <2 0>;
 28 *           interrupt-parent = <&mpic>;
 29 *           nxp,external-clock-frequency = <16000000>;
 30 *   };
 31 *
 32 * See "Documentation/devicetree/bindings/net/can/sja1000.txt" for further
 33 * information.
 34 */
 35
 36#include <linux/kernel.h>
 37#include <linux/module.h>
 38#include <linux/interrupt.h>
 39#include <linux/netdevice.h>
 40#include <linux/delay.h>
 41#include <linux/io.h>
 42#include <linux/can/dev.h>
 43
 44#include <linux/of_platform.h>
 45#include <linux/of_address.h>
 46#include <linux/of_irq.h>
 47#include <asm/prom.h>
 48
 49#include "sja1000.h"
 50
 51#define DRV_NAME "sja1000_of_platform"
 52
 53MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 54MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the OF platform bus");
 55MODULE_LICENSE("GPL v2");
 56
 57#define SJA1000_OFP_CAN_CLOCK  (16000000 / 2)
 58
 59#define SJA1000_OFP_OCR        OCR_TX0_PULLDOWN
 60#define SJA1000_OFP_CDR        (CDR_CBP | CDR_CLK_OFF)
 61
 62static u8 sja1000_ofp_read_reg(const struct sja1000_priv *priv, int reg)
 63{
 64	return ioread8(priv->reg_base + reg);
 65}
 66
 67static void sja1000_ofp_write_reg(const struct sja1000_priv *priv,
 68				  int reg, u8 val)
 69{
 70	iowrite8(val, priv->reg_base + reg);
 71}
 72
 73static int sja1000_ofp_remove(struct platform_device *ofdev)
 74{
 75	struct net_device *dev = platform_get_drvdata(ofdev);
 76	struct sja1000_priv *priv = netdev_priv(dev);
 77	struct device_node *np = ofdev->dev.of_node;
 78	struct resource res;
 79
 80	unregister_sja1000dev(dev);
 81	free_sja1000dev(dev);
 82	iounmap(priv->reg_base);
 83	irq_dispose_mapping(dev->irq);
 84
 85	of_address_to_resource(np, 0, &res);
 86	release_mem_region(res.start, resource_size(&res));
 87
 88	return 0;
 89}
 90
 91static int sja1000_ofp_probe(struct platform_device *ofdev)
 92{
 93	struct device_node *np = ofdev->dev.of_node;
 94	struct net_device *dev;
 95	struct sja1000_priv *priv;
 96	struct resource res;
 97	u32 prop;
 98	int err, irq, res_size;
 99	void __iomem *base;
100
101	err = of_address_to_resource(np, 0, &res);
102	if (err) {
103		dev_err(&ofdev->dev, "invalid address\n");
104		return err;
105	}
106
107	res_size = resource_size(&res);
108
109	if (!request_mem_region(res.start, res_size, DRV_NAME)) {
110		dev_err(&ofdev->dev, "couldn't request %pR\n", &res);
111		return -EBUSY;
112	}
113
114	base = ioremap_nocache(res.start, res_size);
115	if (!base) {
116		dev_err(&ofdev->dev, "couldn't ioremap %pR\n", &res);
117		err = -ENOMEM;
118		goto exit_release_mem;
119	}
120
121	irq = irq_of_parse_and_map(np, 0);
122	if (irq == 0) {
123		dev_err(&ofdev->dev, "no irq found\n");
124		err = -ENODEV;
125		goto exit_unmap_mem;
126	}
127
128	dev = alloc_sja1000dev(0);
129	if (!dev) {
130		err = -ENOMEM;
131		goto exit_dispose_irq;
132	}
133
134	priv = netdev_priv(dev);
135
136	priv->read_reg = sja1000_ofp_read_reg;
137	priv->write_reg = sja1000_ofp_write_reg;
138
139	err = of_property_read_u32(np, "nxp,external-clock-frequency", &prop);
140	if (!err)
141		priv->can.clock.freq = prop / 2;
142	else
143		priv->can.clock.freq = SJA1000_OFP_CAN_CLOCK; /* default */
144
145	err = of_property_read_u32(np, "nxp,tx-output-mode", &prop);
146	if (!err)
147		priv->ocr |= prop & OCR_MODE_MASK;
148	else
149		priv->ocr |= OCR_MODE_NORMAL; /* default */
150
151	err = of_property_read_u32(np, "nxp,tx-output-config", &prop);
152	if (!err)
153		priv->ocr |= (prop << OCR_TX_SHIFT) & OCR_TX_MASK;
154	else
155		priv->ocr |= OCR_TX0_PULLDOWN; /* default */
156
157	err = of_property_read_u32(np, "nxp,clock-out-frequency", &prop);
158	if (!err && prop) {
159		u32 divider = priv->can.clock.freq * 2 / prop;
160
161		if (divider > 1)
162			priv->cdr |= divider / 2 - 1;
163		else
164			priv->cdr |= CDR_CLKOUT_MASK;
165	} else {
166		priv->cdr |= CDR_CLK_OFF; /* default */
167	}
168
169	if (!of_property_read_bool(np, "nxp,no-comparator-bypass"))
170		priv->cdr |= CDR_CBP; /* default */
171
172	priv->irq_flags = IRQF_SHARED;
173	priv->reg_base = base;
174
175	dev->irq = irq;
176
177	dev_info(&ofdev->dev,
178		 "reg_base=0x%p irq=%d clock=%d ocr=0x%02x cdr=0x%02x\n",
179		 priv->reg_base, dev->irq, priv->can.clock.freq,
180		 priv->ocr, priv->cdr);
181
182	platform_set_drvdata(ofdev, dev);
183	SET_NETDEV_DEV(dev, &ofdev->dev);
184
185	err = register_sja1000dev(dev);
186	if (err) {
187		dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
188			DRV_NAME, err);
189		goto exit_free_sja1000;
190	}
191
192	return 0;
193
194exit_free_sja1000:
195	free_sja1000dev(dev);
196exit_dispose_irq:
197	irq_dispose_mapping(irq);
198exit_unmap_mem:
199	iounmap(base);
200exit_release_mem:
201	release_mem_region(res.start, res_size);
202
203	return err;
204}
205
206static struct of_device_id sja1000_ofp_table[] = {
207	{.compatible = "nxp,sja1000"},
208	{},
209};
210MODULE_DEVICE_TABLE(of, sja1000_ofp_table);
211
212static struct platform_driver sja1000_ofp_driver = {
213	.driver = {
214		.owner = THIS_MODULE,
215		.name = DRV_NAME,
216		.of_match_table = sja1000_ofp_table,
217	},
218	.probe = sja1000_ofp_probe,
219	.remove = sja1000_ofp_remove,
220};
221
222module_platform_driver(sja1000_ofp_driver);