[PATCH v4] hwmon:max6697: Allow max6581 to create tempX_offset

From: Chu Lin
Date: Tue Jul 07 2020 - 13:15:40 EST

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Testing:
echo 16250 > temp2_offset
cat temp2_offset
16250

echo 17500 > temp3_offset
cat temp3_offset
17500
cat temp4_offset
0
cat temp2_offset
17500

echo 0 > temp2_offset
cat temp2_offset
0
cat temp3_offset
17500

echo -0 > temp2_offset
cat temp2_offset
0

echo -100000 > temp2_offset
cat temp2_input
4875

echo 10000 > temp2_offset
cat temp2_input
47125

echo -2000 > temp2_offset
cat temp2_input
34875

echo -0 > temp2_offset
cat temp2_input
37000

Signed-off-by: Chu Lin <linchuyuan@xxxxxxxxxx>
---
ChangeLog v3 -> v4:
- Check if a particular channel is disabled/enabled before flipping
state
- Make sure the RW operation is mux protected to avoid the situation
where the user is able to modify the offset select value after it is
read
- indentation cleanup
- Use label to make sure the lock is released
- Fix a typo where the channel index should be /7 instead of /8

ChangeLog v2 -> v3:
- Use reverse christmas tree order convension
- Fix the type issue where comparision is always true
- Change the line limit to 100 char instead of 80 char

ChangeLog v1 -> v2:
- Simplify the offset reg raw value to milli ceisus conversion
- Substitute the temp1_offset with dummy attr
- Avoid using double negative in the macro definition
- Return the actual error when i2c read/write is failed
- clamp the value to MAX or MIN respectively if an out of range input is given
- Provide mux protection when multiple i2c accesses is required

drivers/hwmon/max6697.c | 97 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 95 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/max6697.c b/drivers/hwmon/max6697.c
index 64122eb38060..5b4e72d8df00 100644
--- a/drivers/hwmon/max6697.c
+++ b/drivers/hwmon/max6697.c
@@ -57,6 +57,8 @@ static const u8 MAX6697_REG_CRIT[] = {
#define MAX6581_REG_IDEALITY_SELECT 0x4c
#define MAX6581_REG_OFFSET 0x4d
#define MAX6581_REG_OFFSET_SELECT 0x4e
+#define MAX6581_OFFSET_MIN -31750
+#define MAX6581_OFFSET_MAX 31750

#define MAX6697_CONV_TIME 156 /* ms per channel, worst case */

@@ -172,6 +174,11 @@ static const struct max6697_chip_data max6697_chip_data[] = {
},
};

+static inline int max6581_offset_to_millic(int val)
+{
+ return sign_extend32(val, 7) * 250;
+}
+
static struct max6697_data *max6697_update_device(struct device *dev)
{
struct max6697_data *data = dev_get_drvdata(dev);
@@ -317,6 +324,71 @@ static ssize_t temp_store(struct device *dev,
return ret < 0 ? ret : count;
}

+static ssize_t offset_store(struct device *dev, struct device_attribute *devattr, const char *buf,
+ size_t count)
+{
+ int val, ret, index, select;
+ struct max6697_data *data;
+ bool channel_enabled;
+ long temp;
+
+ index = to_sensor_dev_attr(devattr)->index;
+ data = dev_get_drvdata(dev);
+ ret = kstrtol(buf, 10, &temp);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&data->update_lock);
+ select = i2c_smbus_read_byte_data(data->client, MAX6581_REG_OFFSET_SELECT);
+ if (select < 0) {
+ ret = select;
+ goto abort;
+ }
+ channel_enabled = (select & (1 << (index - 1)));
+ temp = clamp_val(temp, MAX6581_OFFSET_MIN, MAX6581_OFFSET_MAX);
+ val = DIV_ROUND_CLOSEST(temp, 250);
+ /* disable the offset for channel if the new offset is 0 */
+ if (val == 0) {
+ if (channel_enabled)
+ ret = i2c_smbus_write_byte_data(data->client, MAX6581_REG_OFFSET_SELECT,
+ select & ~(1 << (index - 1)));
+ ret = ret < 0 ? ret : count;
+ goto abort;
+ }
+ if (!channel_enabled) {
+ ret = i2c_smbus_write_byte_data(data->client, MAX6581_REG_OFFSET_SELECT,
+ select | (1 << (index - 1)));
+ if (ret < 0)
+ goto abort;
+ }
+ ret = i2c_smbus_write_byte_data(data->client, MAX6581_REG_OFFSET, val);
+ ret = ret < 0 ? ret : count;
+
+abort:
+ mutex_unlock(&data->update_lock);
+ return ret;
+}
+
+static ssize_t offset_show(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+ struct max6697_data *data;
+ int select, ret, index;
+
+ index = to_sensor_dev_attr(devattr)->index;
+ data = dev_get_drvdata(dev);
+ mutex_lock(&data->update_lock);
+ select = i2c_smbus_read_byte_data(data->client, MAX6581_REG_OFFSET_SELECT);
+ if (select < 0) {
+ ret = select;
+ } else if (select & (1 << (index - 1))) {
+ ret = i2c_smbus_read_byte_data(data->client, MAX6581_REG_OFFSET);
+ } else {
+ ret = 0;
+ }
+ mutex_unlock(&data->update_lock);
+ return ret < 0 ? ret : sprintf(buf, "%d\n", max6581_offset_to_millic(ret));
+}
+
static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_input, 0);
static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp, 0, MAX6697_TEMP_MAX);
static SENSOR_DEVICE_ATTR_2_RW(temp1_crit, temp, 0, MAX6697_TEMP_CRIT);
@@ -375,6 +447,15 @@ static SENSOR_DEVICE_ATTR_RO(temp6_fault, alarm, 5);
static SENSOR_DEVICE_ATTR_RO(temp7_fault, alarm, 6);
static SENSOR_DEVICE_ATTR_RO(temp8_fault, alarm, 7);

+/* There is no offset for local temperature so starting from temp2 */
+static SENSOR_DEVICE_ATTR_RW(temp2_offset, offset, 1);
+static SENSOR_DEVICE_ATTR_RW(temp3_offset, offset, 2);
+static SENSOR_DEVICE_ATTR_RW(temp4_offset, offset, 3);
+static SENSOR_DEVICE_ATTR_RW(temp5_offset, offset, 4);
+static SENSOR_DEVICE_ATTR_RW(temp6_offset, offset, 5);
+static SENSOR_DEVICE_ATTR_RW(temp7_offset, offset, 6);
+static SENSOR_DEVICE_ATTR_RW(temp8_offset, offset, 7);
+
static DEVICE_ATTR(dummy, 0, NULL, NULL);

static umode_t max6697_is_visible(struct kobject *kobj, struct attribute *attr,
@@ -383,8 +464,8 @@ static umode_t max6697_is_visible(struct kobject *kobj, struct attribute *attr,
struct device *dev = container_of(kobj, struct device, kobj);
struct max6697_data *data = dev_get_drvdata(dev);
const struct max6697_chip_data *chip = data->chip;
- int channel = index / 6; /* channel number */
- int nr = index % 6; /* attribute index within channel */
+ int channel = index / 7; /* channel number */
+ int nr = index % 7; /* attribute index within channel */

if (channel >= chip->channels)
return 0;
@@ -393,6 +474,10 @@ static umode_t max6697_is_visible(struct kobject *kobj, struct attribute *attr,
return 0;
if (nr == 5 && !(chip->have_fault & (1 << channel)))
return 0;
+ /* offset reg is only supported on max6581 remote channels */
+ if (nr == 6)
+ if (data->type != max6581 || channel == 0)
+ return 0;

return attr->mode;
}
@@ -409,6 +494,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp1_crit.dev_attr.attr,
&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
&dev_attr_dummy.attr,
+ &dev_attr_dummy.attr,

&sensor_dev_attr_temp2_input.dev_attr.attr,
&sensor_dev_attr_temp2_max.dev_attr.attr,
@@ -416,6 +502,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp2_crit.dev_attr.attr,
&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_fault.dev_attr.attr,
+ &sensor_dev_attr_temp2_offset.dev_attr.attr,

&sensor_dev_attr_temp3_input.dev_attr.attr,
&sensor_dev_attr_temp3_max.dev_attr.attr,
@@ -423,6 +510,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp3_crit.dev_attr.attr,
&sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp3_fault.dev_attr.attr,
+ &sensor_dev_attr_temp3_offset.dev_attr.attr,

&sensor_dev_attr_temp4_input.dev_attr.attr,
&sensor_dev_attr_temp4_max.dev_attr.attr,
@@ -430,6 +518,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp4_crit.dev_attr.attr,
&sensor_dev_attr_temp4_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp4_fault.dev_attr.attr,
+ &sensor_dev_attr_temp4_offset.dev_attr.attr,

&sensor_dev_attr_temp5_input.dev_attr.attr,
&sensor_dev_attr_temp5_max.dev_attr.attr,
@@ -437,6 +526,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp5_crit.dev_attr.attr,
&sensor_dev_attr_temp5_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp5_fault.dev_attr.attr,
+ &sensor_dev_attr_temp5_offset.dev_attr.attr,

&sensor_dev_attr_temp6_input.dev_attr.attr,
&sensor_dev_attr_temp6_max.dev_attr.attr,
@@ -444,6 +534,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp6_crit.dev_attr.attr,
&sensor_dev_attr_temp6_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp6_fault.dev_attr.attr,
+ &sensor_dev_attr_temp6_offset.dev_attr.attr,

&sensor_dev_attr_temp7_input.dev_attr.attr,
&sensor_dev_attr_temp7_max.dev_attr.attr,
@@ -451,6 +542,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp7_crit.dev_attr.attr,
&sensor_dev_attr_temp7_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp7_fault.dev_attr.attr,
+ &sensor_dev_attr_temp7_offset.dev_attr.attr,

&sensor_dev_attr_temp8_input.dev_attr.attr,
&sensor_dev_attr_temp8_max.dev_attr.attr,
@@ -458,6 +550,7 @@ static struct attribute *max6697_attributes[] = {
&sensor_dev_attr_temp8_crit.dev_attr.attr,
&sensor_dev_attr_temp8_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp8_fault.dev_attr.attr,
+ &sensor_dev_attr_temp8_offset.dev_attr.attr,
NULL
};

--
2.27.0.383.g050319c2ae-goog

Next message: Gustavo A. R. Silva: "[PATCH][next] net/sched: Use fallthrough pseudo-keyword"
Previous message: Sven Schnelle: "[PATCH] perf: add psw_idle and psw_idle_exit to list of idle symbols"
Next in thread: Guenter Roeck: "Re: [PATCH v4] hwmon:max6697: Allow max6581 to create tempX_offset"
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