[1/2] rtc: pcf8563: Refactor to use SMBUS api instead of raw I2C.

[Martin Fuzzey <mfuzzey@parkeon.com>]

This is simpler and supported by more bus drivers.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
---
 drivers/rtc/rtc-pcf8563.c |   72 +++++++++++++++++++++------------------------
 1 file changed, 33 insertions(+), 39 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 63b558c..88b5c99 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -69,6 +69,28 @@ struct pcf8563 {
 	int voltage_low; /* incicates if a low_voltage was detected */
 };
 
+static int  pcf8563_read_regs(struct i2c_client *client,
+			const uint8_t first_reg,
+			int num_regs, uint8_t *buf)
+{
+	s32 count;
+
+	count = i2c_smbus_read_i2c_block_data(client, first_reg, num_regs, buf);
+
+	if (count == num_regs)
+		return 0;
+
+	if (count < 0) {
+		dev_err(&client->dev, "%s: reg=%d err=%d\n", __func__,
+				first_reg, count);
+		return count;
+	}
+
+	dev_err(&client->dev, "%s: partial reg=%d wanted=%d got=%d\n", __func__,
+				first_reg, num_regs, count);
+	return -EIO;
+}
+
 /*
  * In the routines that deal directly with the pcf8563 hardware, we use
  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
@@ -76,27 +98,12 @@ struct pcf8563 {
 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 {
 	struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
-	unsigned char buf[13] = { PCF8563_REG_ST1 };
-
-	struct i2c_msg msgs[] = {
-		{/* setup read ptr */
-			.addr = client->addr,
-			.len = 1,
-			.buf = buf
-		},
-		{/* read status + date */
-			.addr = client->addr,
-			.flags = I2C_M_RD,
-			.len = 13,
-			.buf = buf
-		},
-	};
-
-	/* read registers */
-	if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
-		dev_err(&client->dev, "%s: read error\n", __func__);
-		return -EIO;
-	}
+	uint8_t buf[PCF8563_REG_YR + 1];
+	int ret;
+
+	ret = pcf8563_read_regs(client, PCF8563_REG_ST1, sizeof(buf), buf);
+	if (ret)
+		return ret;
 
 	if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
 		pcf8563->voltage_low = 1;
@@ -144,8 +151,7 @@ static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 {
 	struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
-	int i, err;
-	unsigned char buf[9];
+	unsigned char buf[PCF8563_REG_YR + 1];
 
 	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
 		"mday=%d, mon=%d, year=%d, wday=%d\n",
@@ -170,21 +176,9 @@ static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 
 	buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
 
-	/* write register's data */
-	for (i = 0; i < 7; i++) {
-		unsigned char data[2] = { PCF8563_REG_SC + i,
-						buf[PCF8563_REG_SC + i] };
-
-		err = i2c_master_send(client, data, sizeof(data));
-		if (err != sizeof(data)) {
-			dev_err(&client->dev,
-				"%s: err=%d addr=%02x, data=%02x\n",
-				__func__, err, data[0], data[1]);
-			return -EIO;
-		}
-	}
-
-	return 0;
+	return i2c_smbus_write_i2c_block_data(client, PCF8563_REG_SC,
+						sizeof(buf) - PCF8563_REG_SC,
+						&buf[PCF8563_REG_SC]);
 }
 
 #ifdef CONFIG_RTC_INTF_DEV
@@ -248,7 +242,7 @@ static int pcf8563_probe(struct i2c_client *client,
 
 	dev_dbg(&client->dev, "%s\n", __func__);
 
-	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 		return -ENODEV;
 
 	pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),