root/drivers/media/dvb-frontends/dibx000_common.c
// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/module.h>

#include "dibx000_common.h"

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "turn on debugging (default: 0)");

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

static int dibx000_write_word(struct dibx000_i2c_master *mst, u16 reg, u16 val)
{
        int ret;

        if (mutex_lock_interruptible(&mst->i2c_buffer_lock) < 0) {
                dprintk("could not acquire lock\n");
                return -EINVAL;
        }

        mst->i2c_write_buffer[0] = (reg >> 8) & 0xff;
        mst->i2c_write_buffer[1] = reg & 0xff;
        mst->i2c_write_buffer[2] = (val >> 8) & 0xff;
        mst->i2c_write_buffer[3] = val & 0xff;

        memset(mst->msg, 0, sizeof(struct i2c_msg));
        mst->msg[0].addr = mst->i2c_addr;
        mst->msg[0].flags = 0;
        mst->msg[0].buf = mst->i2c_write_buffer;
        mst->msg[0].len = 4;

        ret = i2c_transfer(mst->i2c_adap, mst->msg, 1) != 1 ? -EREMOTEIO : 0;
        mutex_unlock(&mst->i2c_buffer_lock);

        return ret;
}

static u16 dibx000_read_word(struct dibx000_i2c_master *mst, u16 reg)
{
        u16 ret;

        if (mutex_lock_interruptible(&mst->i2c_buffer_lock) < 0) {
                dprintk("could not acquire lock\n");
                return 0;
        }

        mst->i2c_write_buffer[0] = reg >> 8;
        mst->i2c_write_buffer[1] = reg & 0xff;

        memset(mst->msg, 0, 2 * sizeof(struct i2c_msg));
        mst->msg[0].addr = mst->i2c_addr;
        mst->msg[0].flags = 0;
        mst->msg[0].buf = mst->i2c_write_buffer;
        mst->msg[0].len = 2;
        mst->msg[1].addr = mst->i2c_addr;
        mst->msg[1].flags = I2C_M_RD;
        mst->msg[1].buf = mst->i2c_read_buffer;
        mst->msg[1].len = 2;

        if (i2c_transfer(mst->i2c_adap, mst->msg, 2) != 2)
                dprintk("i2c read error on %d\n", reg);

        ret = (mst->i2c_read_buffer[0] << 8) | mst->i2c_read_buffer[1];
        mutex_unlock(&mst->i2c_buffer_lock);

        return ret;
}

static int dibx000_is_i2c_done(struct dibx000_i2c_master *mst)
{
        int i = 100;
        u16 status;

        while (((status = dibx000_read_word(mst, mst->base_reg + 2)) & 0x0100) == 0 && --i > 0)
                ;

        /* i2c timed out */
        if (i == 0)
                return -EREMOTEIO;

        /* no acknowledge */
        if ((status & 0x0080) == 0)
                return -EREMOTEIO;

        return 0;
}

static int dibx000_master_i2c_write(struct dibx000_i2c_master *mst, struct i2c_msg *msg, u8 stop)
{
        u16 data;
        u16 da;
        u16 i;
        u16 txlen = msg->len, len;
        const u8 *b = msg->buf;

        while (txlen) {
                dibx000_read_word(mst, mst->base_reg + 2);

                len = txlen > 8 ? 8 : txlen;
                for (i = 0; i < len; i += 2) {
                        data = *b++ << 8;
                        if (i+1 < len)
                                data |= *b++;
                        dibx000_write_word(mst, mst->base_reg, data);
                }
                da = (((u8) (msg->addr))  << 9) |
                        (1           << 8) |
                        (1           << 7) |
                        (0           << 6) |
                        (0           << 5) |
                        ((len & 0x7) << 2) |
                        (0           << 1) |
                        (0           << 0);

                if (txlen == msg->len)
                        da |= 1 << 5; /* start */

                if (txlen-len == 0 && stop)
                        da |= 1 << 6; /* stop */

                dibx000_write_word(mst, mst->base_reg+1, da);

                if (dibx000_is_i2c_done(mst) != 0)
                        return -EREMOTEIO;
                txlen -= len;
        }

        return 0;
}

static int dibx000_master_i2c_read(struct dibx000_i2c_master *mst, struct i2c_msg *msg)
{
        u16 da;
        u8 *b = msg->buf;
        u16 rxlen = msg->len, len;

        while (rxlen) {
                len = rxlen > 8 ? 8 : rxlen;
                da = (((u8) (msg->addr)) << 9) |
                        (1           << 8) |
                        (1           << 7) |
                        (0           << 6) |
                        (0           << 5) |
                        ((len & 0x7) << 2) |
                        (1           << 1) |
                        (0           << 0);

                if (rxlen == msg->len)
                        da |= 1 << 5; /* start */

                if (rxlen-len == 0)
                        da |= 1 << 6; /* stop */
                dibx000_write_word(mst, mst->base_reg+1, da);

                if (dibx000_is_i2c_done(mst) != 0)
                        return -EREMOTEIO;

                rxlen -= len;

                while (len) {
                        da = dibx000_read_word(mst, mst->base_reg);
                        *b++ = (da >> 8) & 0xff;
                        len--;
                        if (len >= 1) {
                                *b++ =  da   & 0xff;
                                len--;
                        }
                }
        }

        return 0;
}

int dibx000_i2c_set_speed(struct i2c_adapter *i2c_adap, u16 speed)
{
        struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);

        if (mst->device_rev < DIB7000MC && speed < 235)
                speed = 235;
        return dibx000_write_word(mst, mst->base_reg + 3, (u16)(60000 / speed));

}
EXPORT_SYMBOL(dibx000_i2c_set_speed);

static u32 dibx000_i2c_func(struct i2c_adapter *adapter)
{
        return I2C_FUNC_I2C;
}

static int dibx000_i2c_select_interface(struct dibx000_i2c_master *mst,
                                        enum dibx000_i2c_interface intf)
{
        if (mst->device_rev > DIB3000MC && mst->selected_interface != intf) {
                dprintk("selecting interface: %d\n", intf);
                mst->selected_interface = intf;
                return dibx000_write_word(mst, mst->base_reg + 4, intf);
        }
        return 0;
}

static int dibx000_i2c_master_xfer_gpio12(struct i2c_adapter *i2c_adap, struct i2c_msg msg[], int num)
{
        struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);
        int msg_index;
        int ret = 0;

        dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_GPIO_1_2);
        for (msg_index = 0; msg_index < num; msg_index++) {
                if (msg[msg_index].flags & I2C_M_RD) {
                        ret = dibx000_master_i2c_read(mst, &msg[msg_index]);
                        if (ret != 0)
                                return 0;
                } else {
                        ret = dibx000_master_i2c_write(mst, &msg[msg_index], 1);
                        if (ret != 0)
                                return 0;
                }
        }

        return num;
}

static int dibx000_i2c_master_xfer_gpio34(struct i2c_adapter *i2c_adap, struct i2c_msg msg[], int num)
{
        struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);
        int msg_index;
        int ret = 0;

        dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_GPIO_3_4);
        for (msg_index = 0; msg_index < num; msg_index++) {
                if (msg[msg_index].flags & I2C_M_RD) {
                        ret = dibx000_master_i2c_read(mst, &msg[msg_index]);
                        if (ret != 0)
                                return 0;
                } else {
                        ret = dibx000_master_i2c_write(mst, &msg[msg_index], 1);
                        if (ret != 0)
                                return 0;
                }
        }

        return num;
}

static const struct i2c_algorithm dibx000_i2c_master_gpio12_xfer_algo = {
        .master_xfer = dibx000_i2c_master_xfer_gpio12,
        .functionality = dibx000_i2c_func,
};

static const struct i2c_algorithm dibx000_i2c_master_gpio34_xfer_algo = {
        .master_xfer = dibx000_i2c_master_xfer_gpio34,
        .functionality = dibx000_i2c_func,
};

static int dibx000_i2c_gate_ctrl(struct dibx000_i2c_master *mst, u8 tx[4],
                                 u8 addr, int onoff)
{
        u16 val;


        if (onoff)
                val = addr << 8;        // bit 7 = use master or not, if 0, the gate is open
        else
                val = 1 << 7;

        if (mst->device_rev > DIB7000)
                val <<= 1;

        tx[0] = (((mst->base_reg + 1) >> 8) & 0xff);
        tx[1] = ((mst->base_reg + 1) & 0xff);
        tx[2] = val >> 8;
        tx[3] = val & 0xff;

        return 0;
}

static int dibx000_i2c_gated_gpio67_xfer(struct i2c_adapter *i2c_adap,
                                        struct i2c_msg msg[], int num)
{
        struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);
        int ret;

        if (num > 32) {
                dprintk("%s: too much I2C message to be transmitted (%i). Maximum is 32",
                        __func__, num);
                return -ENOMEM;
        }

        dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_GPIO_6_7);

        if (mutex_lock_interruptible(&mst->i2c_buffer_lock) < 0) {
                dprintk("could not acquire lock\n");
                return -EINVAL;
        }

        memset(mst->msg, 0, sizeof(struct i2c_msg) * (2 + num));

        /* open the gate */
        dibx000_i2c_gate_ctrl(mst, &mst->i2c_write_buffer[0], msg[0].addr, 1);
        mst->msg[0].addr = mst->i2c_addr;
        mst->msg[0].buf = &mst->i2c_write_buffer[0];
        mst->msg[0].len = 4;

        memcpy(&mst->msg[1], msg, sizeof(struct i2c_msg) * num);

        /* close the gate */
        dibx000_i2c_gate_ctrl(mst, &mst->i2c_write_buffer[4], 0, 0);
        mst->msg[num + 1].addr = mst->i2c_addr;
        mst->msg[num + 1].buf = &mst->i2c_write_buffer[4];
        mst->msg[num + 1].len = 4;

        ret = (i2c_transfer(mst->i2c_adap, mst->msg, 2 + num) == 2 + num ?
                        num : -EIO);

        mutex_unlock(&mst->i2c_buffer_lock);
        return ret;
}

static const struct i2c_algorithm dibx000_i2c_gated_gpio67_algo = {
        .master_xfer = dibx000_i2c_gated_gpio67_xfer,
        .functionality = dibx000_i2c_func,
};

static int dibx000_i2c_gated_tuner_xfer(struct i2c_adapter *i2c_adap,
                                        struct i2c_msg msg[], int num)
{
        struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);
        int ret;

        if (num > 32) {
                dprintk("%s: too much I2C message to be transmitted (%i). Maximum is 32",
                        __func__, num);
                return -ENOMEM;
        }

        dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_TUNER);

        if (mutex_lock_interruptible(&mst->i2c_buffer_lock) < 0) {
                dprintk("could not acquire lock\n");
                return -EINVAL;
        }
        memset(mst->msg, 0, sizeof(struct i2c_msg) * (2 + num));

        /* open the gate */
        dibx000_i2c_gate_ctrl(mst, &mst->i2c_write_buffer[0], msg[0].addr, 1);
        mst->msg[0].addr = mst->i2c_addr;
        mst->msg[0].buf = &mst->i2c_write_buffer[0];
        mst->msg[0].len = 4;

        memcpy(&mst->msg[1], msg, sizeof(struct i2c_msg) * num);

        /* close the gate */
        dibx000_i2c_gate_ctrl(mst, &mst->i2c_write_buffer[4], 0, 0);
        mst->msg[num + 1].addr = mst->i2c_addr;
        mst->msg[num + 1].buf = &mst->i2c_write_buffer[4];
        mst->msg[num + 1].len = 4;

        ret = (i2c_transfer(mst->i2c_adap, mst->msg, 2 + num) == 2 + num ?
                        num : -EIO);
        mutex_unlock(&mst->i2c_buffer_lock);
        return ret;
}

static const struct i2c_algorithm dibx000_i2c_gated_tuner_algo = {
        .master_xfer = dibx000_i2c_gated_tuner_xfer,
        .functionality = dibx000_i2c_func,
};

struct i2c_adapter *dibx000_get_i2c_adapter(struct dibx000_i2c_master *mst,
                                                enum dibx000_i2c_interface intf,
                                                int gating)
{
        struct i2c_adapter *i2c = NULL;

        switch (intf) {
        case DIBX000_I2C_INTERFACE_TUNER:
                if (gating)
                        i2c = &mst->gated_tuner_i2c_adap;
                break;
        case DIBX000_I2C_INTERFACE_GPIO_1_2:
                if (!gating)
                        i2c = &mst->master_i2c_adap_gpio12;
                break;
        case DIBX000_I2C_INTERFACE_GPIO_3_4:
                if (!gating)
                        i2c = &mst->master_i2c_adap_gpio34;
                break;
        case DIBX000_I2C_INTERFACE_GPIO_6_7:
                if (gating)
                        i2c = &mst->master_i2c_adap_gpio67;
                break;
        default:
                pr_err("incorrect I2C interface selected\n");
                break;
        }

        return i2c;
}

EXPORT_SYMBOL(dibx000_get_i2c_adapter);

void dibx000_reset_i2c_master(struct dibx000_i2c_master *mst)
{
        /* initialize the i2c-master by closing the gate */
        u8 tx[4];
        struct i2c_msg m = {.addr = mst->i2c_addr,.buf = tx,.len = 4 };

        dibx000_i2c_gate_ctrl(mst, tx, 0, 0);
        i2c_transfer(mst->i2c_adap, &m, 1);
        mst->selected_interface = 0xff; // the first time force a select of the I2C
        dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_TUNER);
}

EXPORT_SYMBOL(dibx000_reset_i2c_master);

static int i2c_adapter_init(struct i2c_adapter *i2c_adap,
                                const struct i2c_algorithm *algo, const char *name,
                                struct dibx000_i2c_master *mst)
{
        strscpy(i2c_adap->name, name, sizeof(i2c_adap->name));
        i2c_adap->algo = algo;
        i2c_adap->algo_data = NULL;
        i2c_set_adapdata(i2c_adap, mst);
        if (i2c_add_adapter(i2c_adap) < 0)
                return -ENODEV;
        return 0;
}

int dibx000_init_i2c_master(struct dibx000_i2c_master *mst, u16 device_rev,
                                struct i2c_adapter *i2c_adap, u8 i2c_addr)
{
        int ret;

        mutex_init(&mst->i2c_buffer_lock);
        if (mutex_lock_interruptible(&mst->i2c_buffer_lock) < 0) {
                dprintk("could not acquire lock\n");
                return -EINVAL;
        }
        memset(mst->msg, 0, sizeof(struct i2c_msg));
        mst->msg[0].addr = i2c_addr >> 1;
        mst->msg[0].flags = 0;
        mst->msg[0].buf = mst->i2c_write_buffer;
        mst->msg[0].len = 4;

        mst->device_rev = device_rev;
        mst->i2c_adap = i2c_adap;
        mst->i2c_addr = i2c_addr >> 1;

        if (device_rev == DIB7000P || device_rev == DIB8000)
                mst->base_reg = 1024;
        else
                mst->base_reg = 768;

        mst->gated_tuner_i2c_adap.dev.parent = mst->i2c_adap->dev.parent;
        if (i2c_adapter_init
                        (&mst->gated_tuner_i2c_adap, &dibx000_i2c_gated_tuner_algo,
                         "DiBX000 tuner I2C bus", mst) != 0)
                pr_err("could not initialize the tuner i2c_adapter\n");

        mst->master_i2c_adap_gpio12.dev.parent = mst->i2c_adap->dev.parent;
        if (i2c_adapter_init
                        (&mst->master_i2c_adap_gpio12, &dibx000_i2c_master_gpio12_xfer_algo,
                         "DiBX000 master GPIO12 I2C bus", mst) != 0)
                pr_err("could not initialize the master i2c_adapter\n");

        mst->master_i2c_adap_gpio34.dev.parent = mst->i2c_adap->dev.parent;
        if (i2c_adapter_init
                        (&mst->master_i2c_adap_gpio34, &dibx000_i2c_master_gpio34_xfer_algo,
                         "DiBX000 master GPIO34 I2C bus", mst) != 0)
                pr_err("could not initialize the master i2c_adapter\n");

        mst->master_i2c_adap_gpio67.dev.parent = mst->i2c_adap->dev.parent;
        if (i2c_adapter_init
                        (&mst->master_i2c_adap_gpio67, &dibx000_i2c_gated_gpio67_algo,
                         "DiBX000 master GPIO67 I2C bus", mst) != 0)
                pr_err("could not initialize the master i2c_adapter\n");

        /* initialize the i2c-master by closing the gate */
        dibx000_i2c_gate_ctrl(mst, mst->i2c_write_buffer, 0, 0);

        ret = (i2c_transfer(i2c_adap, mst->msg, 1) == 1);
        mutex_unlock(&mst->i2c_buffer_lock);

        return ret;
}

EXPORT_SYMBOL(dibx000_init_i2c_master);

void dibx000_exit_i2c_master(struct dibx000_i2c_master *mst)
{
        i2c_del_adapter(&mst->gated_tuner_i2c_adap);
        i2c_del_adapter(&mst->master_i2c_adap_gpio12);
        i2c_del_adapter(&mst->master_i2c_adap_gpio34);
        i2c_del_adapter(&mst->master_i2c_adap_gpio67);
}
EXPORT_SYMBOL(dibx000_exit_i2c_master);

MODULE_AUTHOR("Patrick Boettcher <patrick.boettcher@posteo.de>");
MODULE_DESCRIPTION("Common function the DiBcom demodulator family");
MODULE_LICENSE("GPL");