xref: /kernel/linux/linux-5.10/drivers/media/pci/cx23885/cx23885-i2c.c

// 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);
}