RTC: make m41t80 driver can work with the SMBus adapters

@@ -105,6 +105,51 @@ struct m41t80_data {
 	struct rtc_device *rtc;
 };
 
+static int m41t80_i2c_read(struct i2c_client *client, struct i2c_msg *msgs, int num)
+{
+	int i, rc;
+	u8 dt_addr = msgs[0].buf[0];
+
+	if (num < 2)
+		return -1;
+
+	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C) &&
+		i2c_transfer(client->adapter, msgs, 2) < 0) {
+		dev_err(&client->dev, "read error\n");
+		return -EIO;
+	} else {
+		for (i = 0; i < msgs[1].len; i++) {
+			rc = i2c_smbus_read_byte_data(client, dt_addr + i);
+			if (rc < 0)
+				return -EIO;
+			msgs[1].buf[i] = (u8)rc;
+		}
+	}
+
+	return 0;
+}
+
+static int m41t80_i2c_write(struct i2c_client *client, struct i2c_msg *msg)
+{
+	int i, rc;
+	u8 *wbuf = msg->buf;
+	u8 *buf = wbuf + 1;
+
+	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C) &&
+	    i2c_transfer(client->adapter, msg, 1) < 0) {
+		dev_err(&client->dev, "write error\n");
+		return -EIO;
+	} else {
+		for (i = 0; i < msg[0].len - 1; i++) {
+			rc = i2c_smbus_write_byte_data(client, wbuf[0]+i, buf[i]);
+			if (rc < 0)
+				return -EIO;
+		}
+	}
+
+	return 0;
+}
+
 static int m41t80_get_datetime(struct i2c_client *client,
 			       struct rtc_time *tm)
 {

@@ -124,10 +169,8 @@ static int m41t80_get_datetime(struct i2
 		},
 	};
 
-	if (i2c_transfer(client->adapter, msgs, 2) < 0) {
-		dev_err(&client->dev, "read error\n");
+	if (m41t80_i2c_read(client, msgs, 2))
 		return -EIO;
-	}
 
 	tm->tm_sec = BCD2BIN(buf[M41T80_REG_SEC] & 0x7f);
 	tm->tm_min = BCD2BIN(buf[M41T80_REG_MIN] & 0x7f);

@@ -171,10 +214,8 @@ static int m41t80_set_datetime(struct i2
 	};
 
 	/* Read current reg values into buf[1..7] */
-	if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
-		dev_err(&client->dev, "read error\n");
+	if (m41t80_i2c_read(client, msgs_in, 2))
 		return -EIO;
-	}
 
 	wbuf[0] = 0; /* offset into rtc's regs */
 	/* Merge time-data and register flags into buf[0..7] */

@@ -194,10 +235,9 @@ static int m41t80_set_datetime(struct i2
 	/* assume 20YY not 19YY */
 	buf[M41T80_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
 
-	if (i2c_transfer(client->adapter, msgs, 1) != 1) {
-		dev_err(&client->dev, "write error\n");
+	if (m41t80_i2c_write(client, msgs))
 		return -EIO;
-	}
+
 	return 0;
 }
 

@@ -295,10 +335,9 @@ static int m41t80_rtc_set_alarm(struct d
 		 },
 	};
 
-	if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
-		dev_err(&client->dev, "read error\n");
+	if (m41t80_i2c_read(client, msgs_in, 2))
 		return -EIO;
-	}
+
 	reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
 	reg[M41T80_REG_ALARM_DAY] = 0;
 	reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);

@@ -319,10 +358,8 @@ static int m41t80_rtc_set_alarm(struct d
 	else
 		reg[M41T80_REG_ALARM_DAY] |= 0x40;
 
-	if (i2c_transfer(client->adapter, msgs, 1) != 1) {
-		dev_err(&client->dev, "write error\n");
+	if (m41t80_i2c_write(client, msgs))
 		return -EIO;
-	}
 
 	if (t->enabled) {
 		reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;

@@ -356,10 +393,9 @@ static int m41t80_rtc_read_alarm(struct
 		},
 	};
 
-	if (i2c_transfer(client->adapter, msgs, 2) < 0) {
-		dev_err(&client->dev, "read error\n");
+	if (m41t80_i2c_read(client, msgs, 2))
 		return -EIO;
-	}
+
 	t->time.tm_sec = -1;
 	t->time.tm_min = -1;
 	t->time.tm_hour = -1;

@@ -516,14 +552,7 @@ static int boot_flag;
 static void wdt_ping(void)
 {
 	unsigned char i2c_data[2];
-	struct i2c_msg msgs1[1] = {
-		{
-			.addr	= save_client->addr,
-			.flags	= 0,
-			.len	= 2,
-			.buf	= i2c_data,
-		},
-	};
+
 	i2c_data[0] = 0x09;		/* watchdog register */
 
 	if (wdt_margin > 31)

@@ -534,7 +563,7 @@ static void wdt_ping(void)
 		 */
 		i2c_data[1] = wdt_margin<<2 | 0x82;
 
-	i2c_transfer(save_client->adapter, msgs1, 1);
+	i2c_smbus_write_byte_data(save_client, i2c_data[0], i2c_data[1]);
 }
 
 /**

@@ -544,36 +573,14 @@ static void wdt_ping(void)
  */
 static void wdt_disable(void)
 {
-	unsigned char i2c_data[2], i2c_buf[0x10];
-	struct i2c_msg msgs0[2] = {
-		{
-			.addr	= save_client->addr,
-			.flags	= 0,
-			.len	= 1,
-			.buf	= i2c_data,
-		},
-		{
-			.addr	= save_client->addr,
-			.flags	= I2C_M_RD,
-			.len	= 1,
-			.buf	= i2c_buf,
-		},
-	};
-	struct i2c_msg msgs1[1] = {
-		{
-			.addr	= save_client->addr,
-			.flags	= 0,
-			.len	= 2,
-			.buf	= i2c_data,
-		},
-	};
+	unsigned char i2c_data[2];
 
-	i2c_data[0] = 0x09;
-	i2c_transfer(save_client->adapter, msgs0, 2);
+	i2c_data[0] = 0x09; /* watchdog register */
+	i2c_data[1] = i2c_smbus_read_byte_data(save_client, i2c_data[0]);
 
-	i2c_data[0] = 0x09;
+	/* write 0x00 to disable WDT until it is programmed again. */
 	i2c_data[1] = 0x00;
-	i2c_transfer(save_client->adapter, msgs1, 1);
+	i2c_smbus_read_byte_datasave_client, i2c_data[0], i2c_data[1]);
 }
 
 /**

@@ -764,8 +771,7 @@ static int m41t80_probe(struct i2c_clien
 	const struct m41t80_chip_info *chip;
 	struct m41t80_data *clientdata = NULL;
 
-	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
-				     | I2C_FUNC_SMBUS_BYTE_DATA)) {
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
 		rc = -ENODEV;
 		goto exit;
 	}