sja1000_of_platform.c

Go to the documentation of this file.

/*
 * Driver for SJA1000 CAN controllers on the OpenFirmware platform bus
 *
 * Copyright (C) 2008-2009 Wolfgang Grandegger <[email protected]>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* This is a generic driver for SJA1000 chips on the OpenFirmware platform
 * bus found on embedded PowerPC systems. You need a SJA1000 CAN node
 * definition in your flattened device tree source (DTS) file similar to:
 *
 *   can@3,100 {
 *           compatible = "nxp,sja1000";
 *           reg = <3 0x100 0x80>;
 *           interrupts = <2 0>;
 *           interrupt-parent = <&mpic>;
 *           nxp,external-clock-frequency = <16000000>;
 *   };
 *
 * See "Documentation/devicetree/bindings/net/can/sja1000.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/io.h>
#include <linux/can/dev.h>

#include <linux/of_platform.h>
#include <asm/prom.h>

#include "sja1000.h"

#define DRV_NAME "sja1000_of_platform"

MODULE_AUTHOR("Wolfgang Grandegger <[email protected]>");
MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the OF platform bus");
MODULE_LICENSE("GPL v2");

#define SJA1000_OFP_CAN_CLOCK  (16000000 / 2)

#define SJA1000_OFP_OCR        OCR_TX0_PULLDOWN
#define SJA1000_OFP_CDR        (CDR_CBP | CDR_CLK_OFF)

static u8 sja1000_ofp_read_reg(const struct sja1000_priv *priv, int reg)
{
    return in_8(priv->reg_base + reg);
}

static void sja1000_ofp_write_reg(const struct sja1000_priv *priv,
                  int reg, u8 val)
{
    out_8(priv->reg_base + reg, val);
}

static int __devexit sja1000_ofp_remove(struct platform_device *ofdev)
{
    struct net_device *dev = dev_get_drvdata(&ofdev->dev);
    struct sja1000_priv *priv = netdev_priv(dev);
    struct device_node *np = ofdev->dev.of_node;
    struct resource res;

    dev_set_drvdata(&ofdev->dev, NULL);

    unregister_sja1000dev(dev);
    free_sja1000dev(dev);
    iounmap(priv->reg_base);
    irq_dispose_mapping(dev->irq);

    of_address_to_resource(np, 0, &res);
    release_mem_region(res.start, resource_size(&res));

    return 0;
}

static int __devinit sja1000_ofp_probe(struct platform_device *ofdev)
{
    struct device_node *np = ofdev->dev.of_node;
    struct net_device *dev;
    struct sja1000_priv *priv;
    struct resource res;
    const u32 *prop;
    int err, irq, res_size, prop_size;
    void __iomem *base;

    err = of_address_to_resource(np, 0, &res);
    if (err) {
        dev_err(&ofdev->dev, "invalid address\n");
        return err;
    }

    res_size = resource_size(&res);

    if (!request_mem_region(res.start, res_size, DRV_NAME)) {
        dev_err(&ofdev->dev, "couldn't request %pR\n", &res);
        return -EBUSY;
    }

    base = ioremap_nocache(res.start, res_size);
    if (!base) {
        dev_err(&ofdev->dev, "couldn't ioremap %pR\n", &res);
        err = -ENOMEM;
        goto exit_release_mem;
    }

    irq = irq_of_parse_and_map(np, 0);
    if (irq == NO_IRQ) {
        dev_err(&ofdev->dev, "no irq found\n");
        err = -ENODEV;
        goto exit_unmap_mem;
    }

    dev = alloc_sja1000dev(0);
    if (!dev) {
        err = -ENOMEM;
        goto exit_dispose_irq;
    }

    priv = netdev_priv(dev);

    priv->read_reg = sja1000_ofp_read_reg;
    priv->write_reg = sja1000_ofp_write_reg;

    prop = of_get_property(np, "nxp,external-clock-frequency", &prop_size);
    if (prop && (prop_size ==  sizeof(u32)))
        priv->can.clock.freq = *prop / 2;
    else
        priv->can.clock.freq = SJA1000_OFP_CAN_CLOCK; /* default */

    prop = of_get_property(np, "nxp,tx-output-mode", &prop_size);
    if (prop && (prop_size == sizeof(u32)))
        priv->ocr |= *prop & OCR_MODE_MASK;
    else
        priv->ocr |= OCR_MODE_NORMAL; /* default */

    prop = of_get_property(np, "nxp,tx-output-config", &prop_size);
    if (prop && (prop_size == sizeof(u32)))
        priv->ocr |= (*prop << OCR_TX_SHIFT) & OCR_TX_MASK;
    else
        priv->ocr |= OCR_TX0_PULLDOWN; /* default */

    prop = of_get_property(np, "nxp,clock-out-frequency", &prop_size);
    if (prop && (prop_size == sizeof(u32)) && *prop) {
        u32 divider = priv->can.clock.freq * 2 / *prop;

        if (divider > 1)
            priv->cdr |= divider / 2 - 1;
        else
            priv->cdr |= CDR_CLKOUT_MASK;
    } else {
        priv->cdr |= CDR_CLK_OFF; /* default */
    }

    prop = of_get_property(np, "nxp,no-comparator-bypass", NULL);
    if (!prop)
        priv->cdr |= CDR_CBP; /* default */

    priv->irq_flags = IRQF_SHARED;
    priv->reg_base = base;

    dev->irq = irq;

    dev_info(&ofdev->dev,
         "reg_base=0x%p irq=%d clock=%d ocr=0x%02x cdr=0x%02x\n",
         priv->reg_base, dev->irq, priv->can.clock.freq,
         priv->ocr, priv->cdr);

    dev_set_drvdata(&ofdev->dev, dev);
    SET_NETDEV_DEV(dev, &ofdev->dev);

    err = register_sja1000dev(dev);
    if (err) {
        dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
            DRV_NAME, err);
        goto exit_free_sja1000;
    }

    return 0;

exit_free_sja1000:
    free_sja1000dev(dev);
exit_dispose_irq:
    irq_dispose_mapping(irq);
exit_unmap_mem:
    iounmap(base);
exit_release_mem:
    release_mem_region(res.start, res_size);

    return err;
}

static struct of_device_id __devinitdata sja1000_ofp_table[] = {
    {.compatible = "nxp,sja1000"},
    {},
};
MODULE_DEVICE_TABLE(of, sja1000_ofp_table);

static struct platform_driver sja1000_ofp_driver = {
    .driver = {
        .owner = THIS_MODULE,
        .name = DRV_NAME,
        .of_match_table = sja1000_ofp_table,
    },
    .probe = sja1000_ofp_probe,
    .remove = __devexit_p(sja1000_ofp_remove),
};

module_platform_driver(sja1000_ofp_driver);