@@ -48,6 +48,55 @@ enum max31785_regs {
#define MAX31785_NR_PAGES 23
+/*
+ * MAX31785 dragons ahead
+ *
+ * It seems there's an undocumented timing constraint when performing
+ * back-to-back writes where the first write is to FAN_CONFIG_1_2. The device
+ * provides no indication of this besides NACK'ing master Txs; no bits are set
+ * in STATUS_BYTE to suggest anything has gone wrong.
+ *
+ * Given that, do a one-shot retry of the write.
+ *
+ * The max31785_*_write_*_data() functions should be used at any point where
+ * the prior write is to FAN_CONFIG_1_2.
+ */
+static int max31785_i2c_smbus_write_byte_data(struct i2c_client *client,
+ int command, u8 data)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(client, command, data);
+ if (ret == -EIO)
+ ret = i2c_smbus_write_byte_data(client, command, data);
+
+ return ret;
+}
+
+static int max31785_i2c_smbus_write_word_data(struct i2c_client *client,
+ int command, u16 data)
+{
+ int ret;
+
+ ret = i2c_smbus_write_word_data(client, command, data);
+ if (ret == -EIO)
+ ret = i2c_smbus_write_word_data(client, command, data);
+
+ return ret;
+}
+
+static int max31785_pmbus_write_word_data(struct i2c_client *client, int page,
+ int command, u16 data)
+{
+ int ret;
+
+ ret = pmbus_write_word_data(client, page, command, data);
+ if (ret == -EIO)
+ ret = pmbus_write_word_data(client, page, command, data);
+
+ return ret;
+}
+
static int max31785_read_byte_data(struct i2c_client *client, int page,
int reg)
{
@@ -210,6 +259,31 @@ static int max31785_read_word_data(struct i2c_client *client, int page,
return rv;
}
+static int max31785_update_fan(struct i2c_client *client, int page,
+ u8 config, u8 mask, u16 command)
+{
+ int from, rv;
+ u8 to;
+
+ from = pmbus_read_byte_data(client, page, PMBUS_FAN_CONFIG_12);
+ if (from < 0)
+ return from;
+
+ to = (from & ~mask) | (config & mask);
+
+ if (to != from) {
+ rv = pmbus_write_byte_data(client, page, PMBUS_FAN_CONFIG_12,
+ to);
+ if (rv < 0)
+ return rv;
+ }
+
+ rv = max31785_pmbus_write_word_data(client, page, PMBUS_FAN_COMMAND_1,
+ command);
+
+ return rv;
+}
+
static const int max31785_pwm_modes[] = { 0x7fff, 0x2710, 0xffff };
static int max31785_write_word_data(struct i2c_client *client, int page,
@@ -219,12 +293,24 @@ static int max31785_write_word_data(struct i2c_client *client, int page,
return -ENXIO;
switch (reg) {
+ case PMBUS_VIRT_FAN_TARGET_1:
+ return max31785_update_fan(client, page, PB_FAN_1_RPM,
+ PB_FAN_1_RPM, word);
+ case PMBUS_VIRT_PWM_1:
+ {
+ u32 command = word;
+
+ command *= 100;
+ command /= 255;
+ return max31785_update_fan(client, page, 0, PB_FAN_1_RPM,
+ command);
+ }
case PMBUS_VIRT_PWM_ENABLE_1:
if (word >= ARRAY_SIZE(max31785_pwm_modes))
return -EINVAL;
- return pmbus_update_fan(client, page, 0, 0, PB_FAN_1_RPM,
- max31785_pwm_modes[word]);
+ return max31785_update_fan(client, page, 0, PB_FAN_1_RPM,
+ max31785_pwm_modes[word]);
default:
break;
}
@@ -262,7 +348,7 @@ static int max31785_of_fan_config(struct i2c_client *client,
return -ENXIO;
}
- ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+ ret = max31785_i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
if (ret < 0)
return ret;
@@ -419,7 +505,8 @@ static int max31785_of_fan_config(struct i2c_client *client,
if (ret < 0)
return ret;
- ret = i2c_smbus_write_word_data(client, MFR_FAN_CONFIG, mfr_cfg);
+ ret = max31785_i2c_smbus_write_word_data(client, MFR_FAN_CONFIG,
+ mfr_cfg);
if (ret < 0)
return ret;
@@ -473,7 +560,7 @@ static int max31785_of_tmp_config(struct i2c_client *client,
return -ENXIO;
}
- ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+ ret = max31785_i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
if (ret < 0)
return ret;
@@ -631,7 +718,8 @@ static int max31785_probe(struct i2c_client *client,
if (!have_fan || fan_configured)
continue;
- ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
+ ret = max31785_i2c_smbus_write_byte_data(client, PMBUS_PAGE,
+ i);
if (ret < 0)
return ret;
@@ -640,8 +728,9 @@ static int max31785_probe(struct i2c_client *client,
return ret;
ret &= ~PB_FAN_1_INSTALLED;
- ret = i2c_smbus_write_word_data(client, PMBUS_FAN_CONFIG_12,
- ret);
+ ret = max31785_i2c_smbus_write_word_data(client,
+ PMBUS_FAN_CONFIG_12,
+ ret);
if (ret < 0)
return ret;
}