via_i2c.c

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/*
 * Copyright 1998-2009 VIA Technologies, Inc. All Rights Reserved.
 * Copyright 2001-2008 S3 Graphics, Inc. All Rights Reserved.

 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation;
 * either version 2, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTIES OR REPRESENTATIONS; 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.
 */

#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/via-core.h>
#include <linux/via_i2c.h>

/*
 * There can only be one set of these, so there's no point in having
 * them be dynamically allocated...
 */
#define VIAFB_NUM_I2C       5
static struct via_i2c_stuff via_i2c_par[VIAFB_NUM_I2C];
static struct viafb_dev *i2c_vdev;  /* Passed in from core */

static void via_i2c_setscl(void *data, int state)
{
    u8 val;
    struct via_port_cfg *adap_data = data;
    unsigned long flags;

    spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
    val = via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0xF0;
    if (state)
        val |= 0x20;
    else
        val &= ~0x20;
    switch (adap_data->type) {
    case VIA_PORT_I2C:
        val |= 0x01;
        break;
    case VIA_PORT_GPIO:
        val |= 0x82;
        break;
    default:
        printk(KERN_ERR "viafb_i2c: specify wrong i2c type.\n");
    }
    via_write_reg(adap_data->io_port, adap_data->ioport_index, val);
    spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
}

static int via_i2c_getscl(void *data)
{
    struct via_port_cfg *adap_data = data;
    unsigned long flags;
    int ret = 0;

    spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
    if (adap_data->type == VIA_PORT_GPIO)
        via_write_reg_mask(adap_data->io_port, adap_data->ioport_index,
            0, 0x80);
    if (via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0x08)
        ret = 1;
    spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
    return ret;
}

static int via_i2c_getsda(void *data)
{
    struct via_port_cfg *adap_data = data;
    unsigned long flags;
    int ret = 0;

    spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
    if (adap_data->type == VIA_PORT_GPIO)
        via_write_reg_mask(adap_data->io_port, adap_data->ioport_index,
            0, 0x40);
    if (via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0x04)
        ret = 1;
    spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
    return ret;
}

static void via_i2c_setsda(void *data, int state)
{
    u8 val;
    struct via_port_cfg *adap_data = data;
    unsigned long flags;

    spin_lock_irqsave(&i2c_vdev->reg_lock, flags);
    val = via_read_reg(adap_data->io_port, adap_data->ioport_index) & 0xF0;
    if (state)
        val |= 0x10;
    else
        val &= ~0x10;
    switch (adap_data->type) {
    case VIA_PORT_I2C:
        val |= 0x01;
        break;
    case VIA_PORT_GPIO:
        val |= 0x42;
        break;
    default:
        printk(KERN_ERR "viafb_i2c: specify wrong i2c type.\n");
    }
    via_write_reg(adap_data->io_port, adap_data->ioport_index, val);
    spin_unlock_irqrestore(&i2c_vdev->reg_lock, flags);
}

int viafb_i2c_readbyte(u8 adap, u8 slave_addr, u8 index, u8 *pdata)
{
    int ret;
    u8 mm1[] = {0x00};
    struct i2c_msg msgs[2];

    if (!via_i2c_par[adap].is_active)
        return -ENODEV;
    *pdata = 0;
    msgs[0].flags = 0;
    msgs[1].flags = I2C_M_RD;
    msgs[0].addr = msgs[1].addr = slave_addr / 2;
    mm1[0] = index;
    msgs[0].len = 1; msgs[1].len = 1;
    msgs[0].buf = mm1; msgs[1].buf = pdata;
    ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2);
    if (ret == 2)
        ret = 0;
    else if (ret >= 0)
        ret = -EIO;

    return ret;
}

int viafb_i2c_writebyte(u8 adap, u8 slave_addr, u8 index, u8 data)
{
    int ret;
    u8 msg[2] = { index, data };
    struct i2c_msg msgs;

    if (!via_i2c_par[adap].is_active)
        return -ENODEV;
    msgs.flags = 0;
    msgs.addr = slave_addr / 2;
    msgs.len = 2;
    msgs.buf = msg;
    ret = i2c_transfer(&via_i2c_par[adap].adapter, &msgs, 1);
    if (ret == 1)
        ret = 0;
    else if (ret >= 0)
        ret = -EIO;

    return ret;
}

int viafb_i2c_readbytes(u8 adap, u8 slave_addr, u8 index, u8 *buff, int buff_len)
{
    int ret;
    u8 mm1[] = {0x00};
    struct i2c_msg msgs[2];

    if (!via_i2c_par[adap].is_active)
        return -ENODEV;
    msgs[0].flags = 0;
    msgs[1].flags = I2C_M_RD;
    msgs[0].addr = msgs[1].addr = slave_addr / 2;
    mm1[0] = index;
    msgs[0].len = 1; msgs[1].len = buff_len;
    msgs[0].buf = mm1; msgs[1].buf = buff;
    ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2);
    if (ret == 2)
        ret = 0;
    else if (ret >= 0)
        ret = -EIO;

    return ret;
}

/*
 * Allow other viafb subdevices to look up a specific adapter
 * by port name.
 */
struct i2c_adapter *viafb_find_i2c_adapter(enum viafb_i2c_adap which)
{
    struct via_i2c_stuff *stuff = &via_i2c_par[which];

    return &stuff->adapter;
}
EXPORT_SYMBOL_GPL(viafb_find_i2c_adapter);


static int create_i2c_bus(struct i2c_adapter *adapter,
              struct i2c_algo_bit_data *algo,
              struct via_port_cfg *adap_cfg,
              struct pci_dev *pdev)
{
    algo->setsda = via_i2c_setsda;
    algo->setscl = via_i2c_setscl;
    algo->getsda = via_i2c_getsda;
    algo->getscl = via_i2c_getscl;
    algo->udelay = 10;
    algo->timeout = 2;
    algo->data = adap_cfg;

    sprintf(adapter->name, "viafb i2c io_port idx 0x%02x",
        adap_cfg->ioport_index);
    adapter->owner = THIS_MODULE;
    adapter->class = I2C_CLASS_DDC;
    adapter->algo_data = algo;
    if (pdev)
        adapter->dev.parent = &pdev->dev;
    else
        adapter->dev.parent = NULL;
    /* i2c_set_adapdata(adapter, adap_cfg); */

    /* Raise SCL and SDA */
    via_i2c_setsda(adap_cfg, 1);
    via_i2c_setscl(adap_cfg, 1);
    udelay(20);

    return i2c_bit_add_bus(adapter);
}

static int viafb_i2c_probe(struct platform_device *platdev)
{
    int i, ret;
    struct via_port_cfg *configs;

    i2c_vdev = platdev->dev.platform_data;
    configs = i2c_vdev->port_cfg;

    for (i = 0; i < VIAFB_NUM_PORTS; i++) {
        struct via_port_cfg *adap_cfg = configs++;
        struct via_i2c_stuff *i2c_stuff = &via_i2c_par[i];

        i2c_stuff->is_active = 0;
        if (adap_cfg->type == 0 || adap_cfg->mode != VIA_MODE_I2C)
            continue;
        ret = create_i2c_bus(&i2c_stuff->adapter,
                     &i2c_stuff->algo, adap_cfg,
                NULL); /* FIXME: PCIDEV */
        if (ret < 0) {
            printk(KERN_ERR "viafb: cannot create i2c bus %u:%d\n",
                i, ret);
            continue;  /* Still try to make the rest */
        }
        i2c_stuff->is_active = 1;
    }

    return 0;
}

static int viafb_i2c_remove(struct platform_device *platdev)
{
    int i;

    for (i = 0; i < VIAFB_NUM_PORTS; i++) {
        struct via_i2c_stuff *i2c_stuff = &via_i2c_par[i];
        /*
         * Only remove those entries in the array that we've
         * actually used (and thus initialized algo_data)
         */
        if (i2c_stuff->is_active)
            i2c_del_adapter(&i2c_stuff->adapter);
    }
    return 0;
}

static struct platform_driver via_i2c_driver = {
    .driver = {
        .name = "viafb-i2c",
    },
    .probe = viafb_i2c_probe,
    .remove = viafb_i2c_remove,
};

int viafb_i2c_init(void)
{
    return platform_driver_register(&via_i2c_driver);
}

void viafb_i2c_exit(void)
{
    platform_driver_unregister(&via_i2c_driver);
}