Re: [v2] hwmon/tmp401: use smb word operations instead of 2 smb byte operations

From: Guenter Roeck
Date: Tue Jan 10 2017 - 12:03:37 EST


On Mon, Jan 09, 2017 at 06:55:00PM +0100, jeroen.de_wachter.ext@xxxxxxxxx wrote:
> From: Jeroen De Wachter <jeroen.de_wachter.ext@xxxxxxxxx>
>
> 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@xxxxxxxxx>

Applied to -next.

Thanks,
Guenter

> ---
> 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;
>