Linux-2.6.12-rc2

[linux-2.6/kvm.git] / drivers / i2c / busses / i2c-au1550.c

/*
 * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
 * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
 *
 * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
 *
 * The documentation describes this as an SMBus controller, but it doesn't
 * understand any of the SMBus protocol in hardware.  It's really an I2C
 * controller that could emulate most of the SMBus in software.
 *
 * This is just a skeleton adapter to use with the Au1550 PSC
 * algorithm.  It was developed for the Pb1550, but will work with
 * any Au1550 board that has a similar PSC configuration.
 *
 * 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
 * of the License, or (at your option) any later version.
 *
 * 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.
 */

#include <linux/config.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/i2c.h>

#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-pb1x00/pb1550.h>
#include <asm/mach-au1x00/au1xxx_psc.h>

#include "i2c-au1550.h"

static int
wait_xfer_done(struct i2c_au1550_data *adap)
{
        u32     stat;
        int     i;
        volatile psc_smb_t      *sp;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        /* Wait for Tx FIFO Underflow.
        */
        for (i = 0; i < adap->xfer_timeout; i++) {
                stat = sp->psc_smbevnt;
                au_sync();
                if ((stat & PSC_SMBEVNT_TU) != 0) {
                        /* Clear it.  */
                        sp->psc_smbevnt = PSC_SMBEVNT_TU;
                        au_sync();
                        return 0;
                }
                udelay(1);
        }

        return -ETIMEDOUT;
}

static int
wait_ack(struct i2c_au1550_data *adap)
{
        u32     stat;
        volatile psc_smb_t      *sp;

        if (wait_xfer_done(adap))
                return -ETIMEDOUT;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        stat = sp->psc_smbevnt;
        au_sync();

        if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
                return -ETIMEDOUT;

        return 0;
}

static int
wait_master_done(struct i2c_au1550_data *adap)
{
        u32     stat;
        int     i;
        volatile psc_smb_t      *sp;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        /* Wait for Master Done.
        */
        for (i = 0; i < adap->xfer_timeout; i++) {
                stat = sp->psc_smbevnt;
                au_sync();
                if ((stat & PSC_SMBEVNT_MD) != 0)
                        return 0;
                udelay(1);
        }

        return -ETIMEDOUT;
}

static int
do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd)
{
        volatile psc_smb_t      *sp;
        u32                     stat;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        /* Reset the FIFOs, clear events.
        */
        sp->psc_smbpcr = PSC_SMBPCR_DC;
        sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR;
        au_sync();
        do {
                stat = sp->psc_smbpcr;
                au_sync();
        } while ((stat & PSC_SMBPCR_DC) != 0);

        /* Write out the i2c chip address and specify operation
        */
        addr <<= 1;
        if (rd)
                addr |= 1;

        /* Put byte into fifo, start up master.
        */
        sp->psc_smbtxrx = addr;
        au_sync();
        sp->psc_smbpcr = PSC_SMBPCR_MS;
        au_sync();
        if (wait_ack(adap))
                return -EIO;
        return 0;
}

static u32
wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data)
{
        int     j;
        u32     data, stat;
        volatile psc_smb_t      *sp;

        if (wait_xfer_done(adap))
                return -EIO;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        j =  adap->xfer_timeout * 100;
        do {
                j--;
                if (j <= 0)
                        return -EIO;

                stat = sp->psc_smbstat;
                au_sync();
                if ((stat & PSC_SMBSTAT_RE) == 0)
                        j = 0;
                else
                        udelay(1);
        } while (j > 0);
        data = sp->psc_smbtxrx;
        au_sync();
        *ret_data = data;

        return 0;
}

static int
i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
                    unsigned int len)
{
        int     i;
        u32     data;
        volatile psc_smb_t      *sp;

        if (len == 0)
                return 0;

        /* A read is performed by stuffing the transmit fifo with
         * zero bytes for timing, waiting for bytes to appear in the
         * receive fifo, then reading the bytes.
         */

        sp = (volatile psc_smb_t *)(adap->psc_base);

        i = 0;
        while (i < (len-1)) {
                sp->psc_smbtxrx = 0;
                au_sync();
                if (wait_for_rx_byte(adap, &data))
                        return -EIO;

                buf[i] = data;
                i++;
        }

        /* The last byte has to indicate transfer done.
        */
        sp->psc_smbtxrx = PSC_SMBTXRX_STP;
        au_sync();
        if (wait_master_done(adap))
                return -EIO;

        data = sp->psc_smbtxrx;
        au_sync();
        buf[i] = data;
        return 0;
}

static int
i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
                     unsigned int len)
{
        int     i;
        u32     data;
        volatile psc_smb_t      *sp;

        if (len == 0)
                return 0;

        sp = (volatile psc_smb_t *)(adap->psc_base);

        i = 0;
        while (i < (len-1)) {
                data = buf[i];
                sp->psc_smbtxrx = data;
                au_sync();
                if (wait_ack(adap))
                        return -EIO;
                i++;
        }

        /* The last byte has to indicate transfer done.
        */
        data = buf[i];
        data |= PSC_SMBTXRX_STP;
        sp->psc_smbtxrx = data;
        au_sync();
        if (wait_master_done(adap))
                return -EIO;
        return 0;
}

static int
au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
        struct i2c_au1550_data *adap = i2c_adap->algo_data;
        struct i2c_msg *p;
        int i, err = 0;

        for (i = 0; !err && i < num; i++) {
                p = &msgs[i];
                err = do_address(adap, p->addr, p->flags & I2C_M_RD);
                if (err || !p->len)
                        continue;
                if (p->flags & I2C_M_RD)
                        err = i2c_read(adap, p->buf, p->len);
                else
                        err = i2c_write(adap, p->buf, p->len);
        }

        /* Return the number of messages processed, or the error code.
        */
        if (err == 0)
                err = num;
        return err;
}

static u32
au1550_func(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C;
}

static struct i2c_algorithm au1550_algo = {
        .name           = "Au1550 algorithm",
        .id             = I2C_ALGO_AU1550,
        .master_xfer    = au1550_xfer,
        .functionality  = au1550_func,
};

/*
 * registering functions to load algorithms at runtime
 * Prior to calling us, the 50MHz clock frequency and routing
 * must have been set up for the PSC indicated by the adapter.
 */
int
i2c_au1550_add_bus(struct i2c_adapter *i2c_adap)
{
        struct i2c_au1550_data *adap = i2c_adap->algo_data;
        volatile psc_smb_t      *sp;
        u32     stat;

        i2c_adap->algo = &au1550_algo;

        /* Now, set up the PSC for SMBus PIO mode.
        */
        sp = (volatile psc_smb_t *)(adap->psc_base);
        sp->psc_ctrl = PSC_CTRL_DISABLE;
        au_sync();
        sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
        sp->psc_smbcfg = 0;
        au_sync();
        sp->psc_ctrl = PSC_CTRL_ENABLE;
        au_sync();
        do {
                stat = sp->psc_smbstat;
                au_sync();
        } while ((stat & PSC_SMBSTAT_SR) == 0);

        sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
                                PSC_SMBCFG_DD_DISABLE);

        /* Divide by 8 to get a 6.25 MHz clock.  The later protocol
         * timings are based on this clock.
         */
        sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
        sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
        au_sync();

        /* Set the protocol timer values.  See Table 71 in the
         * Au1550 Data Book for standard timing values.
         */
        sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
                PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
                PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
                PSC_SMBTMR_SET_CH(15);
        au_sync();

        sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
        do {
                stat = sp->psc_smbstat;
                au_sync();
        } while ((stat & PSC_SMBSTAT_DR) == 0);

        return i2c_add_adapter(i2c_adap);
}


int
i2c_au1550_del_bus(struct i2c_adapter *adap)
{
        return i2c_del_adapter(adap);
}

static int
pb1550_reg(struct i2c_client *client)
{
        return 0;
}

static int
pb1550_unreg(struct i2c_client *client)
{
        return 0;
}

static struct i2c_au1550_data pb1550_i2c_info = {
        SMBUS_PSC_BASE, 200, 200
};

static struct i2c_adapter pb1550_board_adapter = {
        name:              "pb1550 adapter",
        id:                I2C_HW_AU1550_PSC,
        algo:              NULL,
        algo_data:         &pb1550_i2c_info,
        client_register:   pb1550_reg,
        client_unregister: pb1550_unreg,
};

/* BIG hack to support the control interface on the Wolfson WM8731
 * audio codec on the Pb1550 board.  We get an address and two data
 * bytes to write, create an i2c message, and send it across the
 * i2c transfer function.  We do this here because we have access to
 * the i2c adapter structure.
 */
static struct i2c_msg wm_i2c_msg;  /* We don't want this stuff on the stack */
static  u8 i2cbuf[2];

int
pb1550_wm_codec_write(u8 addr, u8 reg, u8 val)
{
        wm_i2c_msg.addr = addr;
        wm_i2c_msg.flags = 0;
        wm_i2c_msg.buf = i2cbuf;
        wm_i2c_msg.len = 2;
        i2cbuf[0] = reg;
        i2cbuf[1] = val;

        return pb1550_board_adapter.algo->master_xfer(&pb1550_board_adapter, &wm_i2c_msg, 1);
}

static int __init
i2c_au1550_init(void)
{
        printk(KERN_INFO "Au1550 I2C: ");

        /* This is where we would set up a 50MHz clock source
         * and routing.  On the Pb1550, the SMBus is PSC2, which
         * uses a shared clock with USB.  This has been already
         * configured by Yamon as a 48MHz clock, close enough
         * for our work.
         */
        if (i2c_au1550_add_bus(&pb1550_board_adapter) < 0) {
                printk("failed to initialize.\n");
                return -ENODEV;
        }

        printk("initialized.\n");
        return 0;
}

static void __exit
i2c_au1550_exit(void)
{
        i2c_au1550_del_bus(&pb1550_board_adapter);
}

MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
MODULE_LICENSE("GPL");

module_init (i2c_au1550_init);
module_exit (i2c_au1550_exit);