ivtv-i2c.c

linux内核源码

		IVTV_DEBUG_I2C("resetting I2C\n");
		for (i = 0; i < 16; ++i) {
			ivtv_setscl(itv, 0);
			ivtv_scldelay(itv);
			ivtv_setscl(itv, 1);
			ivtv_scldelay(itv);
			ivtv_setsda(itv, 1);
		}
		ivtv_waitsda(itv, 1);
		return -EREMOTEIO;
	}
	return 0;
}

/* Write a message to the given i2c slave.  do_stop may be 0 to prevent
   issuing the i2c stop condition (when following with a read) */
static int ivtv_write(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len, int do_stop)
{
	int retry, ret = -EREMOTEIO;
	u32 i;

	for (retry = 0; ret != 0 && retry < 8; ++retry) {
		ret = ivtv_start(itv);

		if (ret == 0) {
			ret = ivtv_sendbyte(itv, addr<<1);
			for (i = 0; ret == 0 && i < len; ++i)
				ret = ivtv_sendbyte(itv, data[i]);
		}
		if (ret != 0 || do_stop) {
			ivtv_stop(itv);
		}
	}
	if (ret)
		IVTV_DEBUG_I2C("i2c write to %x failed\n", addr);
	return ret;
}

/* Read data from the given i2c slave.  A stop condition is always issued. */
static int ivtv_read(struct ivtv *itv, unsigned char addr, unsigned char *data, u32 len)
{
	int retry, ret = -EREMOTEIO;
	u32 i;

	for (retry = 0; ret != 0 && retry < 8; ++retry) {
		ret = ivtv_start(itv);
		if (ret == 0)
			ret = ivtv_sendbyte(itv, (addr << 1) | 1);
		for (i = 0; ret == 0 && i < len; ++i) {
			ret = ivtv_readbyte(itv, &data[i], i == len - 1);
		}
		ivtv_stop(itv);
	}
	if (ret)
		IVTV_DEBUG_I2C("i2c read from %x failed\n", addr);
	return ret;
}

/* Kernel i2c transfer implementation.  Takes a number of messages to be read
   or written.  If a read follows a write, this will occur without an
   intervening stop condition */
static int ivtv_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
	struct ivtv *itv = i2c_get_adapdata(i2c_adap);
	int retval;
	int i;

	mutex_lock(&itv->i2c_bus_lock);
	for (i = retval = 0; retval == 0 && i < num; i++) {
		if (msgs[i].flags & I2C_M_RD)
			retval = ivtv_read(itv, msgs[i].addr, msgs[i].buf, msgs[i].len);
		else {
			/* if followed by a read, don't stop */
			int stop = !(i + 1 < num && msgs[i + 1].flags == I2C_M_RD);

			retval = ivtv_write(itv, msgs[i].addr, msgs[i].buf, msgs[i].len, stop);
		}
	}
	mutex_unlock(&itv->i2c_bus_lock);
	return retval ? retval : num;
}

/* Kernel i2c capabilities */
static u32 ivtv_functionality(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static struct i2c_algorithm ivtv_algo = {
	.master_xfer   = ivtv_xfer,
	.functionality = ivtv_functionality,
};

/* template for our-bit banger */
static struct i2c_adapter ivtv_i2c_adap_hw_template = {
	.name = "ivtv i2c driver",
	.id = I2C_HW_B_CX2341X,
	.algo = &ivtv_algo,
	.algo_data = NULL,			/* filled from template */
	.client_register = attach_inform,
	.client_unregister = detach_inform,
	.owner = THIS_MODULE,
#ifdef I2C_ADAP_CLASS_TV_ANALOG
	.class = I2C_ADAP_CLASS_TV_ANALOG,
#endif
};

static void ivtv_setscl_old(void *data, int state)
{
	struct ivtv *itv = (struct ivtv *)data;

	if (state)
		itv->i2c_state |= 0x01;
	else
		itv->i2c_state &= ~0x01;

	/* write them out */
	/* write bits are inverted */
	write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSCL_OFFSET);
}

static void ivtv_setsda_old(void *data, int state)
{
	struct ivtv *itv = (struct ivtv *)data;

	if (state)
		itv->i2c_state |= 0x01;
	else
		itv->i2c_state &= ~0x01;

	/* write them out */
	/* write bits are inverted */
	write_reg(~itv->i2c_state, IVTV_REG_I2C_SETSDA_OFFSET);
}

static int ivtv_getscl_old(void *data)
{
	struct ivtv *itv = (struct ivtv *)data;

	return read_reg(IVTV_REG_I2C_GETSCL_OFFSET) & 1;
}

static int ivtv_getsda_old(void *data)
{
	struct ivtv *itv = (struct ivtv *)data;

	return read_reg(IVTV_REG_I2C_GETSDA_OFFSET) & 1;
}

/* template for i2c-bit-algo */
static struct i2c_adapter ivtv_i2c_adap_template = {
	.name = "ivtv i2c driver",
	.id = I2C_HW_B_CX2341X,  	/* algo-bit is OR'd with this */
	.algo = NULL,                   /* set by i2c-algo-bit */
	.algo_data = NULL,              /* filled from template */
	.client_register = attach_inform,
	.client_unregister = detach_inform,
	.owner = THIS_MODULE,
#ifdef I2C_ADAP_CLASS_TV_ANALOG
	.class = I2C_ADAP_CLASS_TV_ANALOG,
#endif
};

static const struct i2c_algo_bit_data ivtv_i2c_algo_template = {
	.setsda		= ivtv_setsda_old,
	.setscl		= ivtv_setscl_old,
	.getsda		= ivtv_getsda_old,
	.getscl		= ivtv_getscl_old,
	.udelay		= 10,
	.timeout	= 200,
};

static struct i2c_client ivtv_i2c_client_template = {
	.name = "ivtv internal",
};

int ivtv_call_i2c_client(struct ivtv *itv, int addr, unsigned int cmd, void *arg)
{
	struct i2c_client *client;
	int retval;
	int i;

	IVTV_DEBUG_I2C("call_i2c_client addr=%02x\n", addr);
	for (i = 0; i < I2C_CLIENTS_MAX; i++) {
		client = itv->i2c_clients[i];
		if (client == NULL) {
			continue;
		}
		if (client->driver->command == NULL) {
			continue;
		}
		if (addr == client->addr) {
			retval = client->driver->command(client, cmd, arg);
			return retval;
		}
	}
	if (cmd != VIDIOC_G_CHIP_IDENT)
		IVTV_ERR("i2c addr 0x%02x not found for command 0x%x\n", addr, cmd);
	return -ENODEV;
}

/* Find the i2c device based on the driver ID and return
   its i2c address or -ENODEV if no matching device was found. */
static int ivtv_i2c_id_addr(struct ivtv *itv, u32 id)
{
	struct i2c_client *client;
	int retval = -ENODEV;
	int i;

	for (i = 0; i < I2C_CLIENTS_MAX; i++) {
		client = itv->i2c_clients[i];
		if (client == NULL)
			continue;
		if (id == client->driver->id) {
			retval = client->addr;
			break;
		}
	}
	return retval;
}

/* Find the i2c device name matching the DRIVERID */
static const char *ivtv_i2c_id_name(u32 id)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(hw_driverids); i++)
		if (hw_driverids[i] == id)
			return hw_drivernames[i];
	return "unknown device";
}

/* Find the i2c device name matching the IVTV_HW_ flag */
static const char *ivtv_i2c_hw_name(u32 hw)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(hw_driverids); i++)
		if (1 << i == hw)
			return hw_drivernames[i];
	return "unknown device";
}

/* Find the i2c device matching the IVTV_HW_ flag and return
   its i2c address or -ENODEV if no matching device was found. */
int ivtv_i2c_hw_addr(struct ivtv *itv, u32 hw)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(hw_driverids); i++)
		if (1 << i == hw)
			return ivtv_i2c_id_addr(itv, hw_driverids[i]);
	return -ENODEV;
}

/* Calls i2c device based on IVTV_HW_ flag. If hw == 0, then do nothing.
   If hw == IVTV_HW_GPIO then call the gpio handler. */
int ivtv_i2c_hw(struct ivtv *itv, u32 hw, unsigned int cmd, void *arg)
{
	int addr;

	if (hw == IVTV_HW_GPIO)
		return ivtv_gpio(itv, cmd, arg);
	if (hw == 0)
		return 0;

	addr = ivtv_i2c_hw_addr(itv, hw);
	if (addr < 0) {
		IVTV_ERR("i2c hardware 0x%08x (%s) not found for command 0x%x\n",
			       hw, ivtv_i2c_hw_name(hw), cmd);
		return addr;
	}
	return ivtv_call_i2c_client(itv, addr, cmd, arg);
}

/* Calls i2c device based on I2C driver ID. */
int ivtv_i2c_id(struct ivtv *itv, u32 id, unsigned int cmd, void *arg)
{
	int addr;

	addr = ivtv_i2c_id_addr(itv, id);
	if (addr < 0) {
		if (cmd != VIDIOC_G_CHIP_IDENT)
			IVTV_ERR("i2c ID 0x%08x (%s) not found for command 0x%x\n",
				id, ivtv_i2c_id_name(id), cmd);
		return addr;
	}
	return ivtv_call_i2c_client(itv, addr, cmd, arg);
}

int ivtv_cx25840(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_CX25840_I2C_ADDR, cmd, arg);
}

int ivtv_saa7115(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_SAA7115_I2C_ADDR, cmd, arg);
}

int ivtv_saa7127(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_SAA7127_I2C_ADDR, cmd, arg);
}

int ivtv_saa717x(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_SAA717x_I2C_ADDR, cmd, arg);
}

int ivtv_upd64031a(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_UPD64031A_I2C_ADDR, cmd, arg);
}

int ivtv_upd64083(struct ivtv *itv, unsigned int cmd, void *arg)
{
	return ivtv_call_i2c_client(itv, IVTV_UPD64083_I2C_ADDR, cmd, arg);
}

/* broadcast cmd for all I2C clients and for the gpio subsystem */
void ivtv_call_i2c_clients(struct ivtv *itv, unsigned int cmd, void *arg)
{
	if (itv->i2c_adap.algo == NULL) {
		IVTV_ERR("Adapter is not set");
		return;
	}
	i2c_clients_command(&itv->i2c_adap, cmd, arg);
	if (itv->hw_flags & IVTV_HW_GPIO)
		ivtv_gpio(itv, cmd, arg);
}

/* init + register i2c algo-bit adapter */
int init_ivtv_i2c(struct ivtv *itv)
{
	IVTV_DEBUG_I2C("i2c init\n");

	if (itv->options.newi2c > 0) {
		memcpy(&itv->i2c_adap, &ivtv_i2c_adap_hw_template,
		       sizeof(struct i2c_adapter));
	} else {
		memcpy(&itv->i2c_adap, &ivtv_i2c_adap_template,
		       sizeof(struct i2c_adapter));
		memcpy(&itv->i2c_algo, &ivtv_i2c_algo_template,
		       sizeof(struct i2c_algo_bit_data));
		itv->i2c_algo.data = itv;
		itv->i2c_adap.algo_data = &itv->i2c_algo;
	}

	sprintf(itv->i2c_adap.name + strlen(itv->i2c_adap.name), " #%d",
		itv->num);
	i2c_set_adapdata(&itv->i2c_adap, itv);

	memcpy(&itv->i2c_client, &ivtv_i2c_client_template,
	       sizeof(struct i2c_client));
	itv->i2c_client.adapter = &itv->i2c_adap;
	itv->i2c_adap.dev.parent = &itv->dev->dev;

	IVTV_DEBUG_I2C("setting scl and sda to 1\n");
	ivtv_setscl(itv, 1);
	ivtv_setsda(itv, 1);

	if (itv->options.newi2c > 0)
		return i2c_add_adapter(&itv->i2c_adap);
	else
		return i2c_bit_add_bus(&itv->i2c_adap);
}

void exit_ivtv_i2c(struct ivtv *itv)
{
	IVTV_DEBUG_I2C("i2c exit\n");

	i2c_del_adapter(&itv->i2c_adap);
}