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Subject[PATCH v2] hwmon/tmp401: use smb word operations instead of 2 smb byte operations
Date
From: Jeroen De Wachter <jeroen.de_wachter.ext@nokia.com>

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>
---
drivers/hwmon/tmp401.c | 49 ++++++++++++++-----------------------------------
1 file changed, 14 insertions(+), 35 deletions(-)

diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
index eeeed2c..0af6b86 100644
--- a/drivers/hwmon/tmp401.c
+++ b/drivers/hwmon/tmp401.c
@@ -82,16 +82,6 @@
{ 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 @@
{ 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;

--
1.8.3.1
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