// SPDX-License-Identifier: GPL-2.0-or-later
/*

    bttv-i2c.c  --  all the i2c code is here

    bttv - Bt848 frame grabber driver

    Copyright (C) 1996,97,98 Ralph  Metzler (rjkm@thp.uni-koeln.de)
                           & Marcus Metzler (mocm@thp.uni-koeln.de)
    (c) 1999-2003 Gerd Knorr <kraxel@bytesex.org>

    (c) 2005 Mauro Carvalho Chehab <mchehab@kernel.org>
        - Multituner support and i2c address binding


*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>

#include "bttvp.h"
#include <media/v4l2-common.h>
#include <linux/jiffies.h>
#include <asm/io.h>

static int i2c_debug;
static int i2c_hw;
static int i2c_scan;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "configure i2c debug level");
module_param(i2c_hw,    int, 0444);
MODULE_PARM_DESC(i2c_hw, "force use of hardware i2c support, instead of software bitbang");
module_param(i2c_scan,  int, 0444);
MODULE_PARM_DESC(i2c_scan,"scan i2c bus at insmod time");

static unsigned int i2c_udelay = 5;
module_param(i2c_udelay, int, 0444);
MODULE_PARM_DESC(i2c_udelay, "soft i2c delay at insmod time, in usecs (should be 5 or higher). Lower value means higher bus speed.");

/* ----------------------------------------------------------------------- */
/* I2C functions - bitbanging adapter (software i2c)                       */

static void bttv_bit_setscl(void *data, int state)
{
        struct bttv *btv = (struct bttv*)data;

        if (state)
                btv->i2c_state |= 0x02;
        else
                btv->i2c_state &= ~0x02;
        btwrite(btv->i2c_state, BT848_I2C);
        btread(BT848_I2C);
}

static void bttv_bit_setsda(void *data, int state)
{
        struct bttv *btv = (struct bttv*)data;

        if (state)
                btv->i2c_state |= 0x01;
        else
                btv->i2c_state &= ~0x01;
        btwrite(btv->i2c_state, BT848_I2C);
        btread(BT848_I2C);
}

static int bttv_bit_getscl(void *data)
{
        struct bttv *btv = (struct bttv*)data;
        int state;

        state = btread(BT848_I2C) & 0x02 ? 1 : 0;
        return state;
}

static int bttv_bit_getsda(void *data)
{
        struct bttv *btv = (struct bttv*)data;
        int state;

        state = btread(BT848_I2C) & 0x01;
        return state;
}

static const struct i2c_algo_bit_data bttv_i2c_algo_bit_template = {
        .setsda  = bttv_bit_setsda,
        .setscl  = bttv_bit_setscl,
        .getsda  = bttv_bit_getsda,
        .getscl  = bttv_bit_getscl,
        .udelay  = 16,
        .timeout = 200,
};

/* ----------------------------------------------------------------------- */
/* I2C functions - hardware i2c                                            */

static u32 functionality(struct i2c_adapter *adap)
{
        return I2C_FUNC_SMBUS_EMUL;
}

static int
bttv_i2c_wait_done(struct bttv *btv)
{
        int rc = 0;

        /* timeout */
        if (wait_event_interruptible_timeout(btv->i2c_queue,
            btv->i2c_done, msecs_to_jiffies(85)) == -ERESTARTSYS)
                rc = -EIO;

        if (btv->i2c_done & BT848_INT_RACK)
                rc = 1;
        btv->i2c_done = 0;
        return rc;
}

#define I2C_HW (BT878_I2C_MODE  | BT848_I2C_SYNC |\
                BT848_I2C_SCL | BT848_I2C_SDA)

static int
bttv_i2c_sendbytes(struct bttv *btv, const struct i2c_msg *msg, int last)
{
        u32 xmit;
        int retval,cnt;

        /* sanity checks */
        if (0 == msg->len)
                return -EINVAL;

        /* start, address + first byte */
        xmit = (msg->addr << 25) | (msg->buf[0] << 16) | I2C_HW;
        if (msg->len > 1 || !last)
                xmit |= BT878_I2C_NOSTOP;
        btwrite(xmit, BT848_I2C);
        retval = bttv_i2c_wait_done(btv);
        if (retval < 0)
                goto err;
        if (retval == 0)
                goto eio;
        if (i2c_debug) {
                pr_cont(" <W %02x %02x", msg->addr << 1, msg->buf[0]);
        }

        for (cnt = 1; cnt < msg->len; cnt++ ) {
                /* following bytes */
                xmit = (msg->buf[cnt] << 24) | I2C_HW | BT878_I2C_NOSTART;
                if (cnt < msg->len-1 || !last)
                        xmit |= BT878_I2C_NOSTOP;
                btwrite(xmit, BT848_I2C);
                retval = bttv_i2c_wait_done(btv);
                if (retval < 0)
                        goto err;
                if (retval == 0)
                        goto eio;
                if (i2c_debug)
                        pr_cont(" %02x", msg->buf[cnt]);
        }
        if (i2c_debug && !(xmit & BT878_I2C_NOSTOP))
                pr_cont(">\n");
        return msg->len;

 eio:
        retval = -EIO;
 err:
        if (i2c_debug)
                pr_cont(" ERR: %d\n",retval);
        return retval;
}

static int
bttv_i2c_readbytes(struct bttv *btv, const struct i2c_msg *msg, int last)
{
        u32 xmit;
        u32 cnt;
        int retval;

        for (cnt = 0; cnt < msg->len; cnt++) {
                xmit = (msg->addr << 25) | (1 << 24) | I2C_HW;
                if (cnt < msg->len-1)
                        xmit |= BT848_I2C_W3B;
                if (cnt < msg->len-1 || !last)
                        xmit |= BT878_I2C_NOSTOP;
                if (cnt)
                        xmit |= BT878_I2C_NOSTART;

                if (i2c_debug) {
                        if (!(xmit & BT878_I2C_NOSTART))
                                pr_cont(" <R %02x", (msg->addr << 1) +1);
                }

                btwrite(xmit, BT848_I2C);
                retval = bttv_i2c_wait_done(btv);
                if (retval < 0)
                        goto err;
                if (retval == 0)
                        goto eio;
                msg->buf[cnt] = ((u32)btread(BT848_I2C) >> 8) & 0xff;
                if (i2c_debug) {
                        pr_cont(" =%02x", msg->buf[cnt]);
                }
                if (i2c_debug && !(xmit & BT878_I2C_NOSTOP))
                        pr_cont(" >\n");
        }


        return msg->len;

 eio:
        retval = -EIO;
 err:
        if (i2c_debug)
                pr_cont(" ERR: %d\n",retval);
        return retval;
}

static int bttv_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
        struct v4l2_device *v4l2_dev = i2c_get_adapdata(i2c_adap);
        struct bttv *btv = to_bttv(v4l2_dev);
        int retval = 0;
        int i;

        if (i2c_debug)
                pr_debug("bt-i2c:");

        btwrite(BT848_INT_I2CDONE|BT848_INT_RACK, BT848_INT_STAT);
        for (i = 0 ; i < num; i++) {
                if (msgs[i].flags & I2C_M_RD) {
                        /* read */
                        retval = bttv_i2c_readbytes(btv, &msgs[i], i+1 == num);
                        if (retval < 0)
                                goto err;
                } else {
                        /* write */
                        retval = bttv_i2c_sendbytes(btv, &msgs[i], i+1 == num);
                        if (retval < 0)
                                goto err;
                }
        }
        return num;

 err:
        return retval;
}

static const struct i2c_algorithm bttv_algo = {
        .master_xfer   = bttv_i2c_xfer,
        .functionality = functionality,
};

/* ----------------------------------------------------------------------- */
/* I2C functions - common stuff                                            */

/* read I2C */
int bttv_I2CRead(struct bttv *btv, unsigned char addr, char *probe_for)
{
        unsigned char buffer = 0;

        if (0 != btv->i2c_rc)
                return -1;
        if (bttv_verbose && NULL != probe_for)
                pr_info("%d: i2c: checking for %s @ 0x%02x... ",
                        btv->c.nr, probe_for, addr);
        btv->i2c_client.addr = addr >> 1;
        if (1 != i2c_master_recv(&btv->i2c_client, &buffer, 1)) {
                if (NULL != probe_for) {
                        if (bttv_verbose)
                                pr_cont("not found\n");
                } else
                        pr_warn("%d: i2c read 0x%x: error\n",
                                btv->c.nr, addr);
                return -1;
        }
        if (bttv_verbose && NULL != probe_for)
                pr_cont("found\n");
        return buffer;
}

/* write I2C */
int bttv_I2CWrite(struct bttv *btv, unsigned char addr, unsigned char b1,
                    unsigned char b2, int both)
{
        unsigned char buffer[2];
        int bytes = both ? 2 : 1;

        if (0 != btv->i2c_rc)
                return -1;
        btv->i2c_client.addr = addr >> 1;
        buffer[0] = b1;
        buffer[1] = b2;
        if (bytes != i2c_master_send(&btv->i2c_client, buffer, bytes))
                return -1;
        return 0;
}

/* read EEPROM content */
void bttv_readee(struct bttv *btv, unsigned char *eedata, int addr)
{
        memset(eedata, 0, 256);
        if (0 != btv->i2c_rc)
                return;
        btv->i2c_client.addr = addr >> 1;
        tveeprom_read(&btv->i2c_client, eedata, 256);
}

static char *i2c_devs[128] = {
        [ 0x1c >> 1 ] = "lgdt330x",
        [ 0x30 >> 1 ] = "IR (hauppauge)",
        [ 0x80 >> 1 ] = "msp34xx",
        [ 0x86 >> 1 ] = "tda9887",
        [ 0xa0 >> 1 ] = "eeprom",
        [ 0xc0 >> 1 ] = "tuner (analog)",
        [ 0xc2 >> 1 ] = "tuner (analog)",
};

static void do_i2c_scan(char *name, struct i2c_client *c)
{
        unsigned char buf;
        int i,rc;

        for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
                c->addr = i;
                rc = i2c_master_recv(c,&buf,0);
                if (rc < 0)
                        continue;
                pr_info("%s: i2c scan: found device @ 0x%x  [%s]\n",
                        name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
        }
}

/* init + register i2c adapter */
int init_bttv_i2c(struct bttv *btv)
{
        strscpy(btv->i2c_client.name, "bttv internal", I2C_NAME_SIZE);

        if (i2c_hw)
                btv->use_i2c_hw = 1;
        if (btv->use_i2c_hw) {
                /* bt878 */
                strscpy(btv->c.i2c_adap.name, "bt878",
                        sizeof(btv->c.i2c_adap.name));
                btv->c.i2c_adap.algo = &bttv_algo;
        } else {
                /* bt848 */
        /* Prevents usage of invalid delay values */
                if (i2c_udelay<5)
                        i2c_udelay=5;

                strscpy(btv->c.i2c_adap.name, "bttv",
                        sizeof(btv->c.i2c_adap.name));
                btv->i2c_algo = bttv_i2c_algo_bit_template;
                btv->i2c_algo.udelay = i2c_udelay;
                btv->i2c_algo.data = btv;
                btv->c.i2c_adap.algo_data = &btv->i2c_algo;
        }
        btv->c.i2c_adap.owner = THIS_MODULE;

        btv->c.i2c_adap.dev.parent = &btv->c.pci->dev;
        snprintf(btv->c.i2c_adap.name, sizeof(btv->c.i2c_adap.name),
                 "bt%d #%d [%s]", btv->id, btv->c.nr,
                 btv->use_i2c_hw ? "hw" : "sw");

        i2c_set_adapdata(&btv->c.i2c_adap, &btv->c.v4l2_dev);
        btv->i2c_client.adapter = &btv->c.i2c_adap;


        if (btv->use_i2c_hw) {
                btv->i2c_rc = i2c_add_adapter(&btv->c.i2c_adap);
        } else {
                bttv_bit_setscl(btv,1);
                bttv_bit_setsda(btv,1);
                btv->i2c_rc = i2c_bit_add_bus(&btv->c.i2c_adap);
        }
        if (0 == btv->i2c_rc && i2c_scan)
                do_i2c_scan(btv->c.v4l2_dev.name, &btv->i2c_client);

        return btv->i2c_rc;
}

int fini_bttv_i2c(struct bttv *btv)
{
        if (btv->i2c_rc == 0)
                i2c_del_adapter(&btv->c.i2c_adap);

        return 0;
}