On Wed, Sep 15, 2010 at 09:40:05AM -0400, Jean Delvare wrote:
> This is a new driver for the Winbond/Nuvoton W83795G/ADG hardware
> monitoring chips. The original code was contributed by Wei Song, a
> former employee of Nuvoton. I've fixed and improved a lot of things
> on top of his work.
>
Hi Jean,
highly unusual, I know, but I integrated all individual patches of this set
and then added my coments into the resulting file.
The result is a patch file with my comments.
I might be able to spend some more time on it, but this is what I have so far.
Hope it is useful.
Mostly nitpicks and suggested simplifications, but there may be one
real bug (see the comment about lsb).
Guenter
--
diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index 76c7f24..e19e6c9 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -124,6 +124,14 @@ static const u8 W83795_REG_IN_HL_LSB[] = {
0xa4, /* VSEN17 */
};
+/*
+ * type is either 1 or 2.
+ * 1: index := index --> could use index + type - 1
+ * 2: index := index + 1 --> could use index + type - 1
+ * Suggestion:
+ * #define IN_LSB_REG(index, type) W83795_REG_IN_HL_LSB[(index + type - 1)]
+ * or at least use type == IN_MAX instead of type == 1.
+ */
#define IN_LSB_REG(index, type) \
(((type) == 1) ? W83795_REG_IN_HL_LSB[(index)] \
: (W83795_REG_IN_HL_LSB[(index)] + 1))
@@ -161,6 +169,7 @@ static const u8 IN_LSB_SHIFT_IDX[][2] = {
#define W83795_REG_FAN_MIN_LSB(index) (0xC4 + (index) / 2)
#define W83795_REG_FAN_MIN_LSB_SHIFT(index) \
(((index) & 1) ? 4 : 0)
+/* could use ((index) & 1) << 2) */
#define W83795_REG_VID_CTRL 0x6A
@@ -349,6 +358,9 @@ struct w83795_data {
u8 dts_read_vrlsb[8]; /* Register value */
s8 dts_ext[4]; /* Register value */
+ /* something like pwm_count would be better here.
+ * All other has_xxx variables are bit masks.
+ */
u8 has_pwm; /* 795g supports 8 pwm, 795adg only supports 2,
* no config register, only affected by chip
* type */
@@ -470,6 +482,12 @@ static void w83795_update_limits(struct i2c_client *client)
/* Each register contains LSB for 2 fans, but we want to
* read it only once to save time */
+ /*
+ * But that causes lsb to be undefined across loop instances,
+ * doesn't it, since it is only defined inside the loop ?
+ * And what happens if an even fan does not exist
+ * but the odd one does ?
+ */
if ((i & 1) == 0 && (data->has_fan & (3 << i)))
lsb = w83795_read(client, W83795_REG_FAN_MIN_LSB(i));
@@ -491,6 +509,7 @@ static void w83795_update_limits(struct i2c_client *client)
}
/* Read the DTS limits */
+ /* != 0 isn't really needed */
if (data->enable_dts != 0) {
for (limit = DTS_CRIT; limit <= DTS_WARN_HYST; limit++)
data->dts_ext[limit] =
@@ -544,6 +563,7 @@ static struct w83795_data *w83795_update_pwm_config(struct device *dev)
data->pwm_temp[i][TEMP_PWM_CTFS] =
w83795_read(client, W83795_REG_CTFS(i));
tmp = w83795_read(client, W83795_REG_HT(i));
+ /* & 0x0f doesn't hurt but also isn't needed. */
data->pwm_temp[i][TEMP_PWM_HCT] = (tmp >> 4) & 0x0f;
data->pwm_temp[i][TEMP_PWM_HOT] = tmp & 0x0f;
}
@@ -620,6 +640,7 @@ static struct w83795_data *w83795_update_device(struct device *dev)
data->fan[i] = w83795_read(client, W83795_REG_FAN(i)) << 4;
data->fan[i] |=
(w83795_read(client, W83795_REG_VRLSB) >> 4) & 0x0F;
+ /* & 0x0f doesn't hurt but isn't needed either. */
}
/* Update temperature */
@@ -631,6 +652,7 @@ static struct w83795_data *w83795_update_device(struct device *dev)
}
/* Update dts temperature */
+ /* != 0 isn't really needed */
if (data->enable_dts != 0) {
for (i = 0; i < ARRAY_SIZE(data->dts); i++) {
if (!(data->has_dts & (1 << i)))
@@ -677,10 +699,11 @@ show_alarm_beep(struct device *dev, struct device_attribute *attr, char *buf)
int bit = sensor_attr->index & 0x07;
u8 val;
- if (ALARM_STATUS == nr) {
- val = (data->alarms[index] >> (bit)) & 1;
+ /* nr == ALARM_STATUS ? */
+ if (ALARM_STATUS == nr) { /* { } not needed ? */
+ val = (data->alarms[index] >> (bit)) & 1; /* (bit) --> bit */
} else { /* BEEP_ENABLE */
- val = (data->beeps[index] >> (bit)) & 1;
+ val = (data->beeps[index] >> (bit)) & 1; /* (bit) --> bit */
}
return sprintf(buf, "%u\n", val);
@@ -744,6 +767,18 @@ show_fan(struct device *dev, struct device_attribute *attr, char *buf)
struct w83795_data *data = w83795_update_device(dev);
u16 val;
+ /* Those reversed comparisons always confuse me.
+ * I think the compiler should refuse to compile
+ * such code to make me happy. And, no, I don't buy
+ * the argument that the compiler magically produces
+ * better code this way.
+ * They are used in this driver to compare variables against
+ * defined constants (though not all the time).
+ * Direct value comparisons are (most of the time) the other way.
+ * Any reason ?
+ * Maybe I shouldn't even ask since this one always create a lot of
+ * heated discussion. Let me know.
+ */
if (FAN_INPUT == nr)
val = data->fan[index] & 0x0fff;
else
@@ -855,6 +890,13 @@ show_pwm_enable(struct device *dev, struct device_attribute *attr, char *buf)
int index = sensor_attr->index;
u8 tmp;
+ /* so we are talking about
+ * (index == 0 && (data->pwm_fcms[0] & 1)),
+ * correct ? Or maybe
+ * (index == 0 && (data->pwm_fcms[0] & (1 << index))),
+ * Seems to me that would be less confusing and actually be less
+ * expensive.
+ */
if (1 == (data->pwm_fcms[0] & (1 << index))) {
tmp = 2;
goto out;
@@ -1011,6 +1053,7 @@ store_temp_pwm_enable(struct device *dev, struct device_attribute *attr,
switch (nr) {
case TEMP_PWM_ENABLE:
+ /* excessive () */
if ((tmp != 3) && (tmp != 4))
return -EINVAL;
tmp -= 3;
@@ -1075,6 +1118,7 @@ store_fanin(struct device *dev, struct device_attribute *attr,
case FANIN_TARGET:
val = fan_to_reg(SENSORS_LIMIT(val, 0, 0xfff));
w83795_write(client, W83795_REG_FTSH(index), (val >> 4) & 0xff);
+ /* & 0xff doesn't hurt but isn't needed either. */
w83795_write(client, W83795_REG_FTSL(index), (val << 4) & 0xf0);
data->target_speed[index] = val;
break;
@@ -1234,6 +1278,7 @@ show_temp(struct device *dev, struct device_attribute *attr, char *buf)
struct w83795_data *data = w83795_update_device(dev);
long temp = temp_from_reg(data->temp[index][nr]);
+ /* reverse order ? */
if (TEMP_READ == nr)
temp += (data->temp_read_vrlsb[index] >> 6) * 250;
return sprintf(buf, "%ld\n", temp);
@@ -1810,6 +1855,7 @@ static int w83795_detect(struct i2c_client *client,
/* If Nuvoton chip, address of chip and W83795_REG_I2C_ADDR
should match */
+ /* !((bank & 0x07) ? */
if ((bank & 0x07) == 0) {
i2c_addr = i2c_smbus_read_byte_data(client,
W83795_REG_I2C_ADDR);
@@ -1825,6 +1871,8 @@ static int w83795_detect(struct i2c_client *client,
Usually we don't write to chips during detection, but here we don't
quite have the choice; hopefully it's OK, we are about to return
success anyway */
+ /* != 0 isn't really needed.
+ * Also, looks like a candicate for an else statement. */
if ((bank & 0x07) != 0)
i2c_smbus_write_byte_data(client, W83795_REG_BANKSEL,
bank & ~0x07);
@@ -1891,6 +1939,7 @@ static int w83795_handle_files(struct device *dev, int (*fn)(struct device *,
}
}
+ /* != 0 isn't really needed */
if (data->enable_dts != 0) {
for (i = 0; i < ARRAY_SIZE(w83795_dts); i++) {
if (!(data->has_dts & (1 << i)))
@@ -1923,6 +1972,7 @@ static void w83795_check_dynamic_in_limits(struct i2c_client *client)
vid_ctl = w83795_read(client, W83795_REG_VID_CTRL);
/* Return immediately if VRM isn't configured */
+ /* !(vid_ctl & 0x07) ? */
if ((vid_ctl & 0x07) == 0x00 || (vid_ctl & 0x07) == 0x07)
return;
@@ -2021,6 +2071,8 @@ static int w83795_probe(struct i2c_client *client,
if (!(data->has_dts & (1 << i)))
continue;
tmp = w83795_read(client, W83795_REG_PECI_TBASE(i));
+ /* Is it common to report such values during boot ?
+ * Or is it just excessive noise ? */
dev_info(&client->dev,
"PECI agent %d Tbase temperature: %u\n",
i + 1, (unsigned int)tmp & 0x7f);
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