// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for the Conexant CX23885 PCIe bridge
 *
 *  Copyright (c) 2006 Steven Toth <stoth@linuxtv.org>
 */

#include "cx23885.h"

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

#include <media/v4l2-common.h>

static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");

static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");

#define dprintk(level, fmt, arg...)\
        do { if (i2c_debug >= level)\
                printk(KERN_DEBUG pr_fmt("%s: i2c:" fmt), \
                        __func__, ##arg); \
        } while (0)

#define I2C_WAIT_DELAY 32
#define I2C_WAIT_RETRY 64

#define I2C_EXTEND  (1 << 3)
#define I2C_NOSTOP  (1 << 4)

static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
{
        struct cx23885_i2c *bus = i2c_adap->algo_data;
        struct cx23885_dev *dev = bus->dev;
        return cx_read(bus->reg_stat) & 0x01;
}

static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
{
        struct cx23885_i2c *bus = i2c_adap->algo_data;
        struct cx23885_dev *dev = bus->dev;
        return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
}

static int i2c_wait_done(struct i2c_adapter *i2c_adap)
{
        int count;

        for (count = 0; count < I2C_WAIT_RETRY; count++) {
                if (!i2c_is_busy(i2c_adap))
                        break;
                udelay(I2C_WAIT_DELAY);
        }

        if (I2C_WAIT_RETRY == count)
                return 0;

        return 1;
}

static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
                         const struct i2c_msg *msg, int joined_rlen)
{
        struct cx23885_i2c *bus = i2c_adap->algo_data;
        struct cx23885_dev *dev = bus->dev;
        u32 wdata, addr, ctrl;
        int retval, cnt;

        if (joined_rlen)
                dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
                        msg->len, joined_rlen);
        else
                dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);

        /* Deal with i2c probe functions with zero payload */
        if (msg->len == 0) {
                cx_write(bus->reg_addr, msg->addr << 25);
                cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
                if (!i2c_wait_done(i2c_adap))
                        return -EIO;
                if (!i2c_slave_did_ack(i2c_adap))
                        return -ENXIO;

                dprintk(1, "%s() returns 0\n", __func__);
                return 0;
        }


        /* dev, reg + first byte */
        addr = (msg->addr << 25) | msg->buf[0];
        wdata = msg->buf[0];
        ctrl = bus->i2c_period | (1 << 12) | (1 << 2);

        if (msg->len > 1)
                ctrl |= I2C_NOSTOP | I2C_EXTEND;
        else if (joined_rlen)
                ctrl |= I2C_NOSTOP;

        cx_write(bus->reg_addr, addr);
        cx_write(bus->reg_wdata, wdata);
        cx_write(bus->reg_ctrl, ctrl);

        if (!i2c_wait_done(i2c_adap))
                goto eio;
        if (i2c_debug) {
                printk(KERN_DEBUG " <W %02x %02x", msg->addr << 1, msg->buf[0]);
                if (!(ctrl & I2C_NOSTOP))
                        pr_cont(" >\n");
        }

        for (cnt = 1; cnt < msg->len; cnt++) {
                /* following bytes */
                wdata = msg->buf[cnt];
                ctrl = bus->i2c_period | (1 << 12) | (1 << 2);

                if (cnt < msg->len - 1)
                        ctrl |= I2C_NOSTOP | I2C_EXTEND;
                else if (joined_rlen)
                        ctrl |= I2C_NOSTOP;

                cx_write(bus->reg_addr, addr);
                cx_write(bus->reg_wdata, wdata);
                cx_write(bus->reg_ctrl, ctrl);

                if (!i2c_wait_done(i2c_adap))
                        goto eio;
                if (i2c_debug) {
                        pr_cont(" %02x", msg->buf[cnt]);
                        if (!(ctrl & I2C_NOSTOP))
                                pr_cont(" >\n");
                }
        }
        return msg->len;

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

static int i2c_readbytes(struct i2c_adapter *i2c_adap,
                         const struct i2c_msg *msg, int joined)
{
        struct cx23885_i2c *bus = i2c_adap->algo_data;
        struct cx23885_dev *dev = bus->dev;
        u32 ctrl, cnt;
        int retval;


        if (i2c_debug && !joined)
                dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);

        /* Deal with i2c probe functions with zero payload */
        if (msg->len == 0) {
                cx_write(bus->reg_addr, msg->addr << 25);
                cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
                if (!i2c_wait_done(i2c_adap))
                        return -EIO;
                if (!i2c_slave_did_ack(i2c_adap))
                        return -ENXIO;


                dprintk(1, "%s() returns 0\n", __func__);
                return 0;
        }

        if (i2c_debug) {
                if (joined)
                        dprintk(1, " R");
                else
                        dprintk(1, " <R %02x", (msg->addr << 1) + 1);
        }

        for (cnt = 0; cnt < msg->len; cnt++) {

                ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;

                if (cnt < msg->len - 1)
                        ctrl |= I2C_NOSTOP | I2C_EXTEND;

                cx_write(bus->reg_addr, msg->addr << 25);
                cx_write(bus->reg_ctrl, ctrl);

                if (!i2c_wait_done(i2c_adap))
                        goto eio;
                msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
                if (i2c_debug) {
                        dprintk(1, " %02x", msg->buf[cnt]);
                        if (!(ctrl & I2C_NOSTOP))
                                dprintk(1, " >\n");
                }
        }
        return msg->len;

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

static int i2c_xfer(struct i2c_adapter *i2c_adap,
                    struct i2c_msg *msgs, int num)
{
        int i, retval = 0;

        dprintk(1, "%s(num = %d)\n", __func__, num);

        for (i = 0 ; i < num; i++) {
                dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
                        __func__, num, msgs[i].addr, msgs[i].len);
                if (msgs[i].flags & I2C_M_RD) {
                        /* read */
                        retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
                } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
                           msgs[i].addr == msgs[i + 1].addr) {
                        /* write then read from same address */
                        retval = i2c_sendbytes(i2c_adap, &msgs[i],
                                               msgs[i + 1].len);
                        if (retval < 0)
                                goto err;
                        i++;
                        retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
                } else {
                        /* write */
                        retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
                }
                if (retval < 0)
                        goto err;
        }
        return num;

 err:
        return retval;
}

static u32 cx23885_functionality(struct i2c_adapter *adap)
{
        return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
}

static const struct i2c_algorithm cx23885_i2c_algo_template = {
        .master_xfer    = i2c_xfer,
        .functionality  = cx23885_functionality,
};

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

static const struct i2c_adapter cx23885_i2c_adap_template = {
        .name              = "cx23885",
        .owner             = THIS_MODULE,
        .algo              = &cx23885_i2c_algo_template,
};

static const struct i2c_client cx23885_i2c_client_template = {
        .name   = "cx23885 internal",
};

static char *i2c_devs[128] = {
        [0x10 >> 1] = "tda10048",
        [0x12 >> 1] = "dib7000pc",
        [0x1c >> 1] = "lgdt3303",
        [0x80 >> 1] = "cs3308",
        [0x82 >> 1] = "cs3308",
        [0x86 >> 1] = "tda9887",
        [0x32 >> 1] = "cx24227",
        [0x88 >> 1] = "cx25837",
        [0x84 >> 1] = "tda8295",
        [0x98 >> 1] = "flatiron",
        [0xa0 >> 1] = "eeprom",
        [0xc0 >> 1] = "tuner/mt2131/tda8275",
        [0xc2 >> 1] = "tuner/mt2131/tda8275/xc5000/xc3028",
        [0xc8 >> 1] = "tuner/xc3028L",
};

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

        for (i = 0; i < 128; i++) {
                c->addr = i;
                rc = i2c_master_recv(c, &buf, 0);
                if (rc < 0)
                        continue;
                pr_info("%s: i2c scan: found device @ 0x%04x  [%s]\n",
                       name, i, i2c_devs[i] ? i2c_devs[i] : "???");
        }
}

/* init + register i2c adapter */
int cx23885_i2c_register(struct cx23885_i2c *bus)
{
        struct cx23885_dev *dev = bus->dev;

        dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);

        bus->i2c_adap = cx23885_i2c_adap_template;
        bus->i2c_client = cx23885_i2c_client_template;
        bus->i2c_adap.dev.parent = &dev->pci->dev;

        strscpy(bus->i2c_adap.name, bus->dev->name,
                sizeof(bus->i2c_adap.name));

        bus->i2c_adap.algo_data = bus;
        i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
        i2c_add_adapter(&bus->i2c_adap);

        bus->i2c_client.adapter = &bus->i2c_adap;

        if (0 == bus->i2c_rc) {
                dprintk(1, "%s: i2c bus %d registered\n", dev->name, bus->nr);
                if (i2c_scan) {
                        pr_info("%s: scan bus %d:\n",
                                        dev->name, bus->nr);
                        do_i2c_scan(dev->name, &bus->i2c_client);
                }
        } else
                pr_warn("%s: i2c bus %d register FAILED\n",
                        dev->name, bus->nr);

        /* Instantiate the IR receiver device, if present */
        if (0 == bus->i2c_rc) {
                struct i2c_board_info info;
                static const unsigned short addr_list[] = {
                        0x6b, I2C_CLIENT_END
                };

                memset(&info, 0, sizeof(struct i2c_board_info));
                strscpy(info.type, "ir_video", I2C_NAME_SIZE);
                /* Use quick read command for probe, some IR chips don't
                 * support writes */
                i2c_new_scanned_device(&bus->i2c_adap, &info, addr_list,
                                       i2c_probe_func_quick_read);
        }

        return bus->i2c_rc;
}

int cx23885_i2c_unregister(struct cx23885_i2c *bus)
{
        i2c_del_adapter(&bus->i2c_adap);
        return 0;
}

void cx23885_av_clk(struct cx23885_dev *dev, int enable)
{
        /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
        char buffer[3];
        struct i2c_msg msg;
        dprintk(1, "%s(enabled = %d)\n", __func__, enable);

        /* Register 0x144 */
        buffer[0] = 0x01;
        buffer[1] = 0x44;
        if (enable == 1)
                buffer[2] = 0x05;
        else
                buffer[2] = 0x00;

        msg.addr = 0x44;
        msg.flags = I2C_M_TEN;
        msg.len = 3;
        msg.buf = buffer;

        i2c_xfer(&dev->i2c_bus[2].i2c_adap, &msg, 1);
}