c_can_platform.c

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/*
 * Platform CAN bus driver for Bosch C_CAN controller
 *
 * Copyright (C) 2010 ST Microelectronics
 * Bhupesh Sharma <[email protected]>
 *
 * Borrowed heavily from the C_CAN driver originally written by:
 * Copyright (C) 2007
 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <[email protected]>
 * - Simon Kallweit, intefo AG <[email protected]>
 *
 * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
 * Bosch C_CAN user manual can be obtained from:
 * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
 * users_manual_c_can.pdf
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>

#include <linux/can/dev.h>

#include "c_can.h"

/*
 * 16-bit c_can registers can be arranged differently in the memory
 * architecture of different implementations. For example: 16-bit
 * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
 * Handle the same by providing a common read/write interface.
 */
static u16 c_can_plat_read_reg_aligned_to_16bit(struct c_can_priv *priv,
                        enum reg index)
{
    return readw(priv->base + priv->regs[index]);
}

static void c_can_plat_write_reg_aligned_to_16bit(struct c_can_priv *priv,
                        enum reg index, u16 val)
{
    writew(val, priv->base + priv->regs[index]);
}

static u16 c_can_plat_read_reg_aligned_to_32bit(struct c_can_priv *priv,
                        enum reg index)
{
    return readw(priv->base + 2 * priv->regs[index]);
}

static void c_can_plat_write_reg_aligned_to_32bit(struct c_can_priv *priv,
                        enum reg index, u16 val)
{
    writew(val, priv->base + 2 * priv->regs[index]);
}

static struct platform_device_id c_can_id_table[] = {
    [BOSCH_C_CAN_PLATFORM] = {
        .name = KBUILD_MODNAME,
        .driver_data = BOSCH_C_CAN,
    },
    [BOSCH_C_CAN] = {
        .name = "c_can",
        .driver_data = BOSCH_C_CAN,
    },
    [BOSCH_D_CAN] = {
        .name = "d_can",
        .driver_data = BOSCH_D_CAN,
    }, {
    }
};

static const struct of_device_id c_can_of_table[] = {
    { .compatible = "bosch,c_can", .data = &c_can_id_table[BOSCH_C_CAN] },
    { .compatible = "bosch,d_can", .data = &c_can_id_table[BOSCH_D_CAN] },
    { /* sentinel */ },
};

static int __devinit c_can_plat_probe(struct platform_device *pdev)
{
    int ret;
    void __iomem *addr;
    struct net_device *dev;
    struct c_can_priv *priv;
    const struct of_device_id *match;
    const struct platform_device_id *id;
    struct pinctrl *pinctrl;
    struct resource *mem;
    int irq;
    struct clk *clk;

    if (pdev->dev.of_node) {
        match = of_match_device(c_can_of_table, &pdev->dev);
        if (!match) {
            dev_err(&pdev->dev, "Failed to find matching dt id\n");
            ret = -EINVAL;
            goto exit;
        }
        id = match->data;
    } else {
        id = platform_get_device_id(pdev);
    }

    pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
    if (IS_ERR(pinctrl))
        dev_warn(&pdev->dev,
            "failed to configure pins from driver\n");

    /* get the appropriate clk */
    clk = clk_get(&pdev->dev, NULL);
    if (IS_ERR(clk)) {
        dev_err(&pdev->dev, "no clock defined\n");
        ret = -ENODEV;
        goto exit;
    }

    /* get the platform data */
    mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    irq = platform_get_irq(pdev, 0);
    if (!mem || irq <= 0) {
        ret = -ENODEV;
        goto exit_free_clk;
    }

    if (!request_mem_region(mem->start, resource_size(mem),
                KBUILD_MODNAME)) {
        dev_err(&pdev->dev, "resource unavailable\n");
        ret = -ENODEV;
        goto exit_free_clk;
    }

    addr = ioremap(mem->start, resource_size(mem));
    if (!addr) {
        dev_err(&pdev->dev, "failed to map can port\n");
        ret = -ENOMEM;
        goto exit_release_mem;
    }

    /* allocate the c_can device */
    dev = alloc_c_can_dev();
    if (!dev) {
        ret = -ENOMEM;
        goto exit_iounmap;
    }

    priv = netdev_priv(dev);
    switch (id->driver_data) {
    case BOSCH_C_CAN:
        priv->regs = reg_map_c_can;
        switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
        case IORESOURCE_MEM_32BIT:
            priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
            priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
            break;
        case IORESOURCE_MEM_16BIT:
        default:
            priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
            priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
            break;
        }
        break;
    case BOSCH_D_CAN:
        priv->regs = reg_map_d_can;
        priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
        priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
        priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
        break;
    default:
        ret = -EINVAL;
        goto exit_free_device;
    }

    dev->irq = irq;
    priv->base = addr;
    priv->device = &pdev->dev;
    priv->can.clock.freq = clk_get_rate(clk);
    priv->priv = clk;
    priv->type = id->driver_data;

    platform_set_drvdata(pdev, dev);
    SET_NETDEV_DEV(dev, &pdev->dev);

    ret = register_c_can_dev(dev);
    if (ret) {
        dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
            KBUILD_MODNAME, ret);
        goto exit_free_device;
    }

    dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
         KBUILD_MODNAME, priv->base, dev->irq);
    return 0;

exit_free_device:
    platform_set_drvdata(pdev, NULL);
    free_c_can_dev(dev);
exit_iounmap:
    iounmap(addr);
exit_release_mem:
    release_mem_region(mem->start, resource_size(mem));
exit_free_clk:
    clk_put(clk);
exit:
    dev_err(&pdev->dev, "probe failed\n");

    return ret;
}

static int __devexit c_can_plat_remove(struct platform_device *pdev)
{
    struct net_device *dev = platform_get_drvdata(pdev);
    struct c_can_priv *priv = netdev_priv(dev);
    struct resource *mem;

    unregister_c_can_dev(dev);
    platform_set_drvdata(pdev, NULL);

    free_c_can_dev(dev);
    iounmap(priv->base);

    mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    release_mem_region(mem->start, resource_size(mem));

    clk_put(priv->priv);

    return 0;
}

#ifdef CONFIG_PM
static int c_can_suspend(struct platform_device *pdev, pm_message_t state)
{
    int ret;
    struct net_device *ndev = platform_get_drvdata(pdev);
    struct c_can_priv *priv = netdev_priv(ndev);

    if (priv->type != BOSCH_D_CAN) {
        dev_warn(&pdev->dev, "Not supported\n");
        return 0;
    }

    if (netif_running(ndev)) {
        netif_stop_queue(ndev);
        netif_device_detach(ndev);
    }

    ret = c_can_power_down(ndev);
    if (ret) {
        netdev_err(ndev, "failed to enter power down mode\n");
        return ret;
    }

    priv->can.state = CAN_STATE_SLEEPING;

    return 0;
}

static int c_can_resume(struct platform_device *pdev)
{
    int ret;
    struct net_device *ndev = platform_get_drvdata(pdev);
    struct c_can_priv *priv = netdev_priv(ndev);

    if (priv->type != BOSCH_D_CAN) {
        dev_warn(&pdev->dev, "Not supported\n");
        return 0;
    }

    ret = c_can_power_up(ndev);
    if (ret) {
        netdev_err(ndev, "Still in power down mode\n");
        return ret;
    }

    priv->can.state = CAN_STATE_ERROR_ACTIVE;

    if (netif_running(ndev)) {
        netif_device_attach(ndev);
        netif_start_queue(ndev);
    }

    return 0;
}
#else
#define c_can_suspend NULL
#define c_can_resume NULL
#endif

static struct platform_driver c_can_plat_driver = {
    .driver = {
        .name = KBUILD_MODNAME,
        .owner = THIS_MODULE,
        .of_match_table = of_match_ptr(c_can_of_table),
    },
    .probe = c_can_plat_probe,
    .remove = __devexit_p(c_can_plat_remove),
    .suspend = c_can_suspend,
    .resume = c_can_resume,
    .id_table = c_can_id_table,
};

module_platform_driver(c_can_plat_driver);

MODULE_AUTHOR("Bhupesh Sharma <[email protected]>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");