spi_ks8995.c

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/*
 * SPI driver for Micrel/Kendin KS8995M ethernet switch
 *
 * Copyright (C) 2008 Gabor Juhos <juhosg at openwrt.org>
 *
 * This file was based on: drivers/spi/at25.c
 *     Copyright (C) 2006 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/device.h>

#include <linux/spi/spi.h>

#define DRV_VERSION     "0.1.1"
#define DRV_DESC        "Micrel KS8995 Ethernet switch SPI driver"

/* ------------------------------------------------------------------------ */

#define KS8995_REG_ID0      0x00    /* Chip ID0 */
#define KS8995_REG_ID1      0x01    /* Chip ID1 */

#define KS8995_REG_GC0      0x02    /* Global Control 0 */
#define KS8995_REG_GC1      0x03    /* Global Control 1 */
#define KS8995_REG_GC2      0x04    /* Global Control 2 */
#define KS8995_REG_GC3      0x05    /* Global Control 3 */
#define KS8995_REG_GC4      0x06    /* Global Control 4 */
#define KS8995_REG_GC5      0x07    /* Global Control 5 */
#define KS8995_REG_GC6      0x08    /* Global Control 6 */
#define KS8995_REG_GC7      0x09    /* Global Control 7 */
#define KS8995_REG_GC8      0x0a    /* Global Control 8 */
#define KS8995_REG_GC9      0x0b    /* Global Control 9 */

#define KS8995_REG_PC(p, r) ((0x10 * p) + r)     /* Port Control */
#define KS8995_REG_PS(p, r) ((0x10 * p) + r + 0xe)  /* Port Status */

#define KS8995_REG_TPC0     0x60    /* TOS Priority Control 0 */
#define KS8995_REG_TPC1     0x61    /* TOS Priority Control 1 */
#define KS8995_REG_TPC2     0x62    /* TOS Priority Control 2 */
#define KS8995_REG_TPC3     0x63    /* TOS Priority Control 3 */
#define KS8995_REG_TPC4     0x64    /* TOS Priority Control 4 */
#define KS8995_REG_TPC5     0x65    /* TOS Priority Control 5 */
#define KS8995_REG_TPC6     0x66    /* TOS Priority Control 6 */
#define KS8995_REG_TPC7     0x67    /* TOS Priority Control 7 */

#define KS8995_REG_MAC0     0x68    /* MAC address 0 */
#define KS8995_REG_MAC1     0x69    /* MAC address 1 */
#define KS8995_REG_MAC2     0x6a    /* MAC address 2 */
#define KS8995_REG_MAC3     0x6b    /* MAC address 3 */
#define KS8995_REG_MAC4     0x6c    /* MAC address 4 */
#define KS8995_REG_MAC5     0x6d    /* MAC address 5 */

#define KS8995_REG_IAC0     0x6e    /* Indirect Access Control 0 */
#define KS8995_REG_IAC1     0x6f    /* Indirect Access Control 0 */
#define KS8995_REG_IAD7     0x70    /* Indirect Access Data 7 */
#define KS8995_REG_IAD6     0x71    /* Indirect Access Data 6 */
#define KS8995_REG_IAD5     0x72    /* Indirect Access Data 5 */
#define KS8995_REG_IAD4     0x73    /* Indirect Access Data 4 */
#define KS8995_REG_IAD3     0x74    /* Indirect Access Data 3 */
#define KS8995_REG_IAD2     0x75    /* Indirect Access Data 2 */
#define KS8995_REG_IAD1     0x76    /* Indirect Access Data 1 */
#define KS8995_REG_IAD0     0x77    /* Indirect Access Data 0 */

#define KS8995_REGS_SIZE    0x80

#define ID1_CHIPID_M        0xf
#define ID1_CHIPID_S        4
#define ID1_REVISION_M      0x7
#define ID1_REVISION_S      1
#define ID1_START_SW        1   /* start the switch */

#define FAMILY_KS8995       0x95
#define CHIPID_M        0

#define KS8995_CMD_WRITE    0x02U
#define KS8995_CMD_READ     0x03U

#define KS8995_RESET_DELAY  10 /* usec */

struct ks8995_pdata {
    /* not yet implemented */
};

struct ks8995_switch {
    struct spi_device   *spi;
    struct mutex        lock;
    struct ks8995_pdata *pdata;
};

static inline u8 get_chip_id(u8 val)
{
    return (val >> ID1_CHIPID_S) & ID1_CHIPID_M;
}

static inline u8 get_chip_rev(u8 val)
{
    return (val >> ID1_REVISION_S) & ID1_REVISION_M;
}

/* ------------------------------------------------------------------------ */
static int ks8995_read(struct ks8995_switch *ks, char *buf,
         unsigned offset, size_t count)
{
    u8 cmd[2];
    struct spi_transfer t[2];
    struct spi_message m;
    int err;

    spi_message_init(&m);

    memset(&t, 0, sizeof(t));

    t[0].tx_buf = cmd;
    t[0].len = sizeof(cmd);
    spi_message_add_tail(&t[0], &m);

    t[1].rx_buf = buf;
    t[1].len = count;
    spi_message_add_tail(&t[1], &m);

    cmd[0] = KS8995_CMD_READ;
    cmd[1] = offset;

    mutex_lock(&ks->lock);
    err = spi_sync(ks->spi, &m);
    mutex_unlock(&ks->lock);

    return err ? err : count;
}


static int ks8995_write(struct ks8995_switch *ks, char *buf,
         unsigned offset, size_t count)
{
    u8 cmd[2];
    struct spi_transfer t[2];
    struct spi_message m;
    int err;

    spi_message_init(&m);

    memset(&t, 0, sizeof(t));

    t[0].tx_buf = cmd;
    t[0].len = sizeof(cmd);
    spi_message_add_tail(&t[0], &m);

    t[1].tx_buf = buf;
    t[1].len = count;
    spi_message_add_tail(&t[1], &m);

    cmd[0] = KS8995_CMD_WRITE;
    cmd[1] = offset;

    mutex_lock(&ks->lock);
    err = spi_sync(ks->spi, &m);
    mutex_unlock(&ks->lock);

    return err ? err : count;
}

static inline int ks8995_read_reg(struct ks8995_switch *ks, u8 addr, u8 *buf)
{
    return (ks8995_read(ks, buf, addr, 1) != 1);
}

static inline int ks8995_write_reg(struct ks8995_switch *ks, u8 addr, u8 val)
{
    char buf = val;

    return (ks8995_write(ks, &buf, addr, 1) != 1);
}

/* ------------------------------------------------------------------------ */

static int ks8995_stop(struct ks8995_switch *ks)
{
    return ks8995_write_reg(ks, KS8995_REG_ID1, 0);
}

static int ks8995_start(struct ks8995_switch *ks)
{
    return ks8995_write_reg(ks, KS8995_REG_ID1, 1);
}

static int ks8995_reset(struct ks8995_switch *ks)
{
    int err;

    err = ks8995_stop(ks);
    if (err)
        return err;

    udelay(KS8995_RESET_DELAY);

    return ks8995_start(ks);
}

/* ------------------------------------------------------------------------ */

static ssize_t ks8995_registers_read(struct file *filp, struct kobject *kobj,
    struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
{
    struct device *dev;
    struct ks8995_switch *ks8995;

    dev = container_of(kobj, struct device, kobj);
    ks8995 = dev_get_drvdata(dev);

    if (unlikely(off > KS8995_REGS_SIZE))
        return 0;

    if ((off + count) > KS8995_REGS_SIZE)
        count = KS8995_REGS_SIZE - off;

    if (unlikely(!count))
        return count;

    return ks8995_read(ks8995, buf, off, count);
}


static ssize_t ks8995_registers_write(struct file *filp, struct kobject *kobj,
    struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
{
    struct device *dev;
    struct ks8995_switch *ks8995;

    dev = container_of(kobj, struct device, kobj);
    ks8995 = dev_get_drvdata(dev);

    if (unlikely(off >= KS8995_REGS_SIZE))
        return -EFBIG;

    if ((off + count) > KS8995_REGS_SIZE)
        count = KS8995_REGS_SIZE - off;

    if (unlikely(!count))
        return count;

    return ks8995_write(ks8995, buf, off, count);
}


static struct bin_attribute ks8995_registers_attr = {
    .attr = {
        .name   = "registers",
        .mode   = S_IRUSR | S_IWUSR,
    },
    .size   = KS8995_REGS_SIZE,
    .read   = ks8995_registers_read,
    .write  = ks8995_registers_write,
};

/* ------------------------------------------------------------------------ */

static int __devinit ks8995_probe(struct spi_device *spi)
{
    struct ks8995_switch    *ks;
    struct ks8995_pdata     *pdata;
    u8      ids[2];
    int     err;

    /* Chip description */
    pdata = spi->dev.platform_data;

    ks = kzalloc(sizeof(*ks), GFP_KERNEL);
    if (!ks) {
        dev_err(&spi->dev, "no memory for private data\n");
        return -ENOMEM;
    }

    mutex_init(&ks->lock);
    ks->pdata = pdata;
    ks->spi = spi_dev_get(spi);
    dev_set_drvdata(&spi->dev, ks);

    spi->mode = SPI_MODE_0;
    spi->bits_per_word = 8;
    err = spi_setup(spi);
    if (err) {
        dev_err(&spi->dev, "spi_setup failed, err=%d\n", err);
        goto err_drvdata;
    }

    err = ks8995_read(ks, ids, KS8995_REG_ID0, sizeof(ids));
    if (err < 0) {
        dev_err(&spi->dev, "unable to read id registers, err=%d\n",
                err);
        goto err_drvdata;
    }

    switch (ids[0]) {
    case FAMILY_KS8995:
        break;
    default:
        dev_err(&spi->dev, "unknown family id:%02x\n", ids[0]);
        err = -ENODEV;
        goto err_drvdata;
    }

    err = ks8995_reset(ks);
    if (err)
        goto err_drvdata;

    err = sysfs_create_bin_file(&spi->dev.kobj, &ks8995_registers_attr);
    if (err) {
        dev_err(&spi->dev, "unable to create sysfs file, err=%d\n",
                    err);
        goto err_drvdata;
    }

    dev_info(&spi->dev, "KS89%02X device found, Chip ID:%01x, "
            "Revision:%01x\n", ids[0],
            get_chip_id(ids[1]), get_chip_rev(ids[1]));

    return 0;

err_drvdata:
    dev_set_drvdata(&spi->dev, NULL);
    kfree(ks);
    return err;
}

static int __devexit ks8995_remove(struct spi_device *spi)
{
    struct ks8995_data      *ks8995;

    ks8995 = dev_get_drvdata(&spi->dev);
    sysfs_remove_bin_file(&spi->dev.kobj, &ks8995_registers_attr);

    dev_set_drvdata(&spi->dev, NULL);
    kfree(ks8995);

    return 0;
}

/* ------------------------------------------------------------------------ */

static struct spi_driver ks8995_driver = {
    .driver = {
        .name       = "spi-ks8995",
        .owner     = THIS_MODULE,
    },
    .probe    = ks8995_probe,
    .remove   = __devexit_p(ks8995_remove),
};

static int __init ks8995_init(void)
{
    pr_info(DRV_DESC " version " DRV_VERSION "\n");

    return spi_register_driver(&ks8995_driver);
}
module_init(ks8995_init);

static void __exit ks8995_exit(void)
{
    spi_unregister_driver(&ks8995_driver);
}
module_exit(ks8995_exit);

MODULE_DESCRIPTION(DRV_DESC);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
MODULE_LICENSE("GPL v2");