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
53 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
54 MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the OF platform bus");
55 MODULE_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
sja1000_ofp_read_reg(const struct sja1000_priv * priv,int reg)62 static u8 sja1000_ofp_read_reg(const struct sja1000_priv *priv, int reg)
63 {
64 return ioread8(priv->reg_base + reg);
65 }
66
sja1000_ofp_write_reg(const struct sja1000_priv * priv,int reg,u8 val)67 static 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
sja1000_ofp_remove(struct platform_device * ofdev)73 static int sja1000_ofp_remove(struct platform_device *ofdev)
74 {
75 struct net_device *dev = dev_get_drvdata(&ofdev->dev);
76 struct sja1000_priv *priv = netdev_priv(dev);
77 struct device_node *np = ofdev->dev.of_node;
78 struct resource res;
79
80 dev_set_drvdata(&ofdev->dev, NULL);
81
82 unregister_sja1000dev(dev);
83 free_sja1000dev(dev);
84 iounmap(priv->reg_base);
85 irq_dispose_mapping(dev->irq);
86
87 of_address_to_resource(np, 0, &res);
88 release_mem_region(res.start, resource_size(&res));
89
90 return 0;
91 }
92
sja1000_ofp_probe(struct platform_device * ofdev)93 static int sja1000_ofp_probe(struct platform_device *ofdev)
94 {
95 struct device_node *np = ofdev->dev.of_node;
96 struct net_device *dev;
97 struct sja1000_priv *priv;
98 struct resource res;
99 u32 prop;
100 int err, irq, res_size;
101 void __iomem *base;
102
103 err = of_address_to_resource(np, 0, &res);
104 if (err) {
105 dev_err(&ofdev->dev, "invalid address\n");
106 return err;
107 }
108
109 res_size = resource_size(&res);
110
111 if (!request_mem_region(res.start, res_size, DRV_NAME)) {
112 dev_err(&ofdev->dev, "couldn't request %pR\n", &res);
113 return -EBUSY;
114 }
115
116 base = ioremap_nocache(res.start, res_size);
117 if (!base) {
118 dev_err(&ofdev->dev, "couldn't ioremap %pR\n", &res);
119 err = -ENOMEM;
120 goto exit_release_mem;
121 }
122
123 irq = irq_of_parse_and_map(np, 0);
124 if (irq == 0) {
125 dev_err(&ofdev->dev, "no irq found\n");
126 err = -ENODEV;
127 goto exit_unmap_mem;
128 }
129
130 dev = alloc_sja1000dev(0);
131 if (!dev) {
132 err = -ENOMEM;
133 goto exit_dispose_irq;
134 }
135
136 priv = netdev_priv(dev);
137
138 priv->read_reg = sja1000_ofp_read_reg;
139 priv->write_reg = sja1000_ofp_write_reg;
140
141 err = of_property_read_u32(np, "nxp,external-clock-frequency", &prop);
142 if (!err)
143 priv->can.clock.freq = prop / 2;
144 else
145 priv->can.clock.freq = SJA1000_OFP_CAN_CLOCK; /* default */
146
147 err = of_property_read_u32(np, "nxp,tx-output-mode", &prop);
148 if (!err)
149 priv->ocr |= prop & OCR_MODE_MASK;
150 else
151 priv->ocr |= OCR_MODE_NORMAL; /* default */
152
153 err = of_property_read_u32(np, "nxp,tx-output-config", &prop);
154 if (!err)
155 priv->ocr |= (prop << OCR_TX_SHIFT) & OCR_TX_MASK;
156 else
157 priv->ocr |= OCR_TX0_PULLDOWN; /* default */
158
159 err = of_property_read_u32(np, "nxp,clock-out-frequency", &prop);
160 if (!err && prop) {
161 u32 divider = priv->can.clock.freq * 2 / prop;
162
163 if (divider > 1)
164 priv->cdr |= divider / 2 - 1;
165 else
166 priv->cdr |= CDR_CLKOUT_MASK;
167 } else {
168 priv->cdr |= CDR_CLK_OFF; /* default */
169 }
170
171 if (!of_property_read_bool(np, "nxp,no-comparator-bypass"))
172 priv->cdr |= CDR_CBP; /* default */
173
174 priv->irq_flags = IRQF_SHARED;
175 priv->reg_base = base;
176
177 dev->irq = irq;
178
179 dev_info(&ofdev->dev,
180 "reg_base=0x%p irq=%d clock=%d ocr=0x%02x cdr=0x%02x\n",
181 priv->reg_base, dev->irq, priv->can.clock.freq,
182 priv->ocr, priv->cdr);
183
184 dev_set_drvdata(&ofdev->dev, dev);
185 SET_NETDEV_DEV(dev, &ofdev->dev);
186
187 err = register_sja1000dev(dev);
188 if (err) {
189 dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
190 DRV_NAME, err);
191 goto exit_free_sja1000;
192 }
193
194 return 0;
195
196 exit_free_sja1000:
197 free_sja1000dev(dev);
198 exit_dispose_irq:
199 irq_dispose_mapping(irq);
200 exit_unmap_mem:
201 iounmap(base);
202 exit_release_mem:
203 release_mem_region(res.start, res_size);
204
205 return err;
206 }
207
208 static struct of_device_id sja1000_ofp_table[] = {
209 {.compatible = "nxp,sja1000"},
210 {},
211 };
212 MODULE_DEVICE_TABLE(of, sja1000_ofp_table);
213
214 static struct platform_driver sja1000_ofp_driver = {
215 .driver = {
216 .owner = THIS_MODULE,
217 .name = DRV_NAME,
218 .of_match_table = sja1000_ofp_table,
219 },
220 .probe = sja1000_ofp_probe,
221 .remove = sja1000_ofp_remove,
222 };
223
224 module_platform_driver(sja1000_ofp_driver);
225