hwmon: (lm80) Add detection of NatSemi/TI LM96080

Add detection of the National Semiconductor (now Texas Instruments)
LM96080. It is functionally compatible with the LM80 but detection is
completely different.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Frans Meulenbroeks <fransmeulenbroeks@gmail.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

2 files changed, 37 insertions, 11 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index dad895fec62a..1cd0e201819c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -598,11 +598,11 @@ config SENSORS_LM78
           will be called lm78.
 
 config SENSORS_LM80
-        tristate "National Semiconductor LM80"
+        tristate "National Semiconductor LM80 and LM96080"
         depends on I2C
         help
           If you say yes here you get support for National Semiconductor
-          LM80 sensor chips.
+          LM80 and LM96080 sensor chips.
 
           This driver can also be built as a module.  If so, the module
           will be called lm80.
diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c
index a996f2795db0..e2c43e1774be 100644
--- a/drivers/hwmon/lm80.c
+++ b/drivers/hwmon/lm80.c
@@ -60,6 +60,10 @@ static const unsigned short normal_i2c[] = { 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d,
 #define LM80_REG_FANDIV                 0x05
 #define LM80_REG_RES                    0x06
 
+#define LM96080_REG_CONV_RATE           0x07
+#define LM96080_REG_MAN_ID              0x3e
+#define LM96080_REG_DEV_ID              0x3f
+
 
 /*
  * Conversions. Rounding and limit checking is only done on the TO_REG
@@ -147,6 +151,7 @@ static int lm80_write_value(struct i2c_client *client, u8 reg, u8 value);
 
 static const struct i2c_device_id lm80_id[] = {
         { "lm80", 0 },
+        { "lm96080", 1 },
         { }
 };
 MODULE_DEVICE_TABLE(i2c, lm80_id);
@@ -490,23 +495,44 @@ static const struct attribute_group lm80_group = {
 static int lm80_detect(struct i2c_client *client, struct i2c_board_info *info)
 {
         struct i2c_adapter *adapter = client->adapter;
-        int i, cur;
+        int i, cur, man_id, dev_id;
+        const char *name = NULL;
 
         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                 return -ENODEV;
 
-        /* Now, we do the remaining detection. It is lousy. */
-        if (lm80_read_value(client, LM80_REG_ALARM2) & 0xc0)
+        /* First check for unused bits, common to both chip types */
+        if ((lm80_read_value(client, LM80_REG_ALARM2) & 0xc0)
+         || (lm80_read_value(client, LM80_REG_CONFIG) & 0x80))
                 return -ENODEV;
-        for (i = 0x2a; i <= 0x3d; i++) {
-                cur = i2c_smbus_read_byte_data(client, i);
-                if ((i2c_smbus_read_byte_data(client, i + 0x40) != cur)
-                 || (i2c_smbus_read_byte_data(client, i + 0x80) != cur)
-                 || (i2c_smbus_read_byte_data(client, i + 0xc0) != cur))
+
+        /*
+         * The LM96080 has manufacturer and stepping/die rev registers so we
+         * can just check that. The LM80 does not have such registers so we
+         * have to use a more expensive trick.
+         */
+        man_id = lm80_read_value(client, LM96080_REG_MAN_ID);
+        dev_id = lm80_read_value(client, LM96080_REG_DEV_ID);
+        if (man_id == 0x01 && dev_id == 0x08) {
+                /* Check more unused bits for confirmation */
+                if (lm80_read_value(client, LM96080_REG_CONV_RATE) & 0xfe)
                         return -ENODEV;
+
+                name = "lm96080";
+        } else {
+                /* Check 6-bit addressing */
+                for (i = 0x2a; i <= 0x3d; i++) {
+                        cur = i2c_smbus_read_byte_data(client, i);
+                        if ((i2c_smbus_read_byte_data(client, i + 0x40) != cur)
+                         || (i2c_smbus_read_byte_data(client, i + 0x80) != cur)
+                         || (i2c_smbus_read_byte_data(client, i + 0xc0) != cur))
+                                return -ENODEV;
+                }
+
+                name = "lm80";
         }
 
-        strlcpy(info->type, "lm80", I2C_NAME_SIZE);
+        strlcpy(info->type, name, I2C_NAME_SIZE);
 
         return 0;
 }