cc770_platform.c

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/*
 * Driver for CC770 and AN82527 CAN controllers on the platform bus
 *
 * Copyright (C) 2009, 2011 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.
 */

/*
 * 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 <[email protected]>");
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);