hwmon: (tmp401) use smb word operations instead of 2 smb byte operations

tmp401 separately read/wrote high and low bytes of temperature values while
the hardware supports reading/writing those values in one operation. Driver
has been modified to use word operations where possible.

Tested with a tmp432 sensor on a mips64 platform.

Signed-off-by: Jeroen De Wachter <jeroen.de_wachter.ext@nokia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
index 6276003fdcb3ddd5dfee0e1beffc7d44aff41ece..1f2d13dc94396f87a779e665eb6a51f1aee656fe 100644 (file)
--- a/drivers/hwmon/tmp401.c
+++ b/drivers/hwmon/tmp401.c
@@ -82,16 +82,6 @@ static const u8 TMP401_TEMP_MSB_WRITE[7][2] = {
        { 0, 0x11 },    /* offset */
 };
 
-static const u8 TMP401_TEMP_LSB[7][2] = {
-       { 0x15, 0x10 }, /* temp */
-       { 0x17, 0x14 }, /* low limit */
-       { 0x16, 0x13 }, /* high limit */
-       { 0, 0 },       /* therm (crit) limit (unused) */
-       { 0x31, 0x35 }, /* lowest */
-       { 0x33, 0x37 }, /* highest */
-       { 0, 0x12 },    /* offset */
-};
-
 static const u8 TMP432_TEMP_MSB_READ[4][3] = {
        { 0x00, 0x01, 0x23 },   /* temp */
        { 0x06, 0x08, 0x16 },   /* low limit */
@@ -106,12 +96,6 @@ static const u8 TMP432_TEMP_MSB_WRITE[4][3] = {
        { 0x20, 0x19, 0x1A },   /* therm (crit) limit */
 };
 
-static const u8 TMP432_TEMP_LSB[3][3] = {
-       { 0x29, 0x10, 0x24 },   /* temp */
-       { 0x3E, 0x14, 0x18 },   /* low limit */
-       { 0x3D, 0x13, 0x17 },   /* high limit */
-};
-
 /* [0] = fault, [1] = low, [2] = high, [3] = therm/crit */
 static const u8 TMP432_STATUS_REG[] = {
        0x1b, 0x36, 0x35, 0x37 };
@@ -213,25 +197,20 @@ static int tmp401_update_device_reg16(struct i2c_client *client,
        for (i = 0; i < num_sensors; i++) {             /* local / r1 / r2 */
                for (j = 0; j < num_regs; j++) {        /* temp / low / ... */
                        u8 regaddr;
-                       /*
-                        * High byte must be read first immediately followed
-                        * by the low byte
-                        */
+
                        regaddr = data->kind == tmp432 ?
                                                TMP432_TEMP_MSB_READ[j][i] :
                                                TMP401_TEMP_MSB_READ[j][i];
-                       val = i2c_smbus_read_byte_data(client, regaddr);
-                       if (val < 0)
-                               return val;
-                       data->temp[j][i] = val << 8;
-                       if (j == 3)             /* crit is msb only */
-                               continue;
-                       regaddr = data->kind == tmp432 ? TMP432_TEMP_LSB[j][i]
-                                                      : TMP401_TEMP_LSB[j][i];
-                       val = i2c_smbus_read_byte_data(client, regaddr);
+                       if (j == 3) { /* crit is msb only */
+                               val = i2c_smbus_read_byte_data(client, regaddr);
+                       } else {
+                               val = i2c_smbus_read_word_swapped(client,
+                                                                 regaddr);
+                       }
                        if (val < 0)
                                return val;
-                       data->temp[j][i] |= val;
+
+                       data->temp[j][i] = j == 3 ? val << 8 : val;
                }
        }
        return 0;
@@ -373,11 +352,11 @@ static ssize_t store_temp(struct device *dev, struct device_attribute *devattr,
 
        regaddr = data->kind == tmp432 ? TMP432_TEMP_MSB_WRITE[nr][index]
                                       : TMP401_TEMP_MSB_WRITE[nr][index];
-       i2c_smbus_write_byte_data(client, regaddr, reg >> 8);
-       if (nr != 3) {
-               regaddr = data->kind == tmp432 ? TMP432_TEMP_LSB[nr][index]
-                                              : TMP401_TEMP_LSB[nr][index];
-               i2c_smbus_write_byte_data(client, regaddr, reg & 0xFF);
+       if (nr == 3) { /* crit is msb only */
+               i2c_smbus_write_byte_data(client, regaddr, reg >> 8);
+       } else {
+               /* Hardware expects big endian data --> use _swapped */
+               i2c_smbus_write_word_swapped(client, regaddr, reg);
        }
        data->temp[nr][index] = reg;