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
  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
  62 static u8 sja1000_ofp_read_reg(const struct sja1000_priv *priv, int reg)
  63 {
  64         return ioread8(priv->reg_base + reg);
  65 }
  66
  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
  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
  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);