Tested successfully with an ADM1032 chip on its evaluation board. It
should work fine with all other chips as well.
At this point this is more of a proof-of-concept, we don't do anything
terribly useful on SMBus alert: we simply log the event. But this could
later evolve into libsensors signaling so that user-space applications
can take an appropriate action.
Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: Trent Piepho <tpiepho@xxxxxxxxxxxxx>
---
Documentation/hwmon/lm90 | 12 ++++++++
drivers/hwmon/lm90.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+)
--- linux-2.6.33-rc8.orig/Documentation/hwmon/lm90 2010-02-13 16:24:06.000000000 +0100
+++ linux-2.6.33-rc8/Documentation/hwmon/lm90 2010-02-13 16:24:41.000000000 +0100
@@ -173,6 +173,18 @@ The lm90 driver will not update its valu
other second; reading them more often will do no harm, but will return
'old' values.
+SMBus Alert Support
+-------------------
+
+This driver has basic support for SMBus alert. When an alert is received,
+the status register is read and the faulty temperature channel is logged.
+
+The Analog Devices chips (ADM1032 and ADT7461) do not implement the SMBus
+alert protocol properly so additional care is needed: the ALERT output is
+disabled when an alert is received, and is re-enabled only when the alarm
+is gone. Otherwise the chip would block alerts from other chips in the bus
+as long as the alarm is active.
+
PEC Support
-----------
--- linux-2.6.33-rc8.orig/drivers/hwmon/lm90.c 2010-02-13 16:24:17.000000000 +0100
+++ linux-2.6.33-rc8/drivers/hwmon/lm90.c 2010-02-13 15:50:53.000000000 +0100
@@ -152,6 +152,7 @@ static int lm90_detect(struct i2c_client
static int lm90_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static void lm90_init_client(struct i2c_client *client);
+static void lm90_alert(struct i2c_client *client, unsigned int flag);
static int lm90_remove(struct i2c_client *client);
static struct lm90_data *lm90_update_device(struct device *dev);
@@ -186,6 +187,7 @@ static struct i2c_driver lm90_driver = {
},
.probe = lm90_probe,
.remove = lm90_remove,
+ .alert = lm90_alert,
.id_table = lm90_id,
.detect = lm90_detect,
.address_list = normal_i2c,
@@ -204,6 +206,7 @@ struct lm90_data {
int flags;
u8 config_orig; /* Original configuration register value */
+ u8 alert_alarms; /* Which alarm bits trigger ALERT# */
/* registers values */
s8 temp8[4]; /* 0: local low limit
@@ -806,6 +809,19 @@ static int lm90_probe(struct i2c_client
new_client->flags &= ~I2C_CLIENT_PEC;
}
+ /* Different devices have different alarm bits triggering the
+ * ALERT# output */
+ switch (data->kind) {
+ case lm90:
+ case lm99:
+ case lm86:
+ data->alert_alarms = 0x7b;
+ break;
+ default:
+ data->alert_alarms = 0x7c;
+ break;
+ }
+
/* Initialize the LM90 chip */
lm90_init_client(new_client);
@@ -895,6 +911,38 @@ static int lm90_remove(struct i2c_client
return 0;
}
+static void lm90_alert(struct i2c_client *client, unsigned int flag)
+{
+ struct lm90_data *data = i2c_get_clientdata(client);
+ u8 config, alarms;
+
+ lm90_read_reg(client, LM90_REG_R_STATUS, &alarms);
+ if ((alarms & 0x7f) == 0) {
+ dev_info(&client->dev, "Everything OK\n");
+ } else {
+ if (alarms & 0x61)
+ dev_warn(&client->dev,
+ "temp%d out of range, please check!\n", 1);
+ if (alarms & 0x1a)
+ dev_warn(&client->dev,
+ "temp%d out of range, please check!\n", 2);
+ if (alarms & 0x04)
+ dev_warn(&client->dev,
+ "temp%d diode open, please check!\n", 2);
+
+ /* Disable ALERT# output, because these chips don't implement
+ SMBus alert correctly; they should only hold the alert line
+ low briefly. */
+ if ((data->kind == adm1032 || data->kind == adt7461)
+ && (alarms & data->alert_alarms)) {
+ dev_dbg(&client->dev, "Disabling ALERT#\n");
+ lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
+ i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
+ config | 0x80);
+ }
+ }
+}
+
static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
{
int err;
@@ -982,6 +1030,21 @@ static struct lm90_data *lm90_update_dev
}
lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
+ /* Re-enable ALERT# output if it was originally enabled and
+ * relevant alarms are all clear */
+ if ((data->config_orig & 0x80) == 0
+ && (data->alarms & data->alert_alarms) == 0) {
+ u8 config;
+
+ lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
+ if (config & 0x80) {
+ dev_dbg(&client->dev, "Re-enabling ALERT#\n");
+ i2c_smbus_write_byte_data(client,
+ LM90_REG_W_CONFIG1,
+ config & ~0x80);
+ }
+ }
+
data->last_updated = jiffies;
data->valid = 1;
}
--
Jean Delvare
--
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