hwmon: (lm75) cleanup/reorg

Minor cleanup and reorg of the lm75 code.

 - Kconfig provides a larger list of lm75-compatible chips

 - A top comment now says what the driver does (!) ... as in, just
   what sort of sensor is this??

 - Section comments now delineate the various sections of the driver:
   hwmon attributes, driver binding, register access, module glue.
   One driver binding function moved out of the attribute section,
   as did the driver struct itself.

 - Minor tweaks to legacy probe logic:  correct a comment, and
   remove a pointless variable.

 - Whitespace, linelength, and comment fixes.

This patch should include no functional changes.  It's preparation
for adding new-style (driver model) I2C driver binding.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

2 files changed, 64 insertions, 46 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 00ff53348491..86289c283dc8 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -394,13 +394,19 @@ config SENSORS_LM75
         tristate "National Semiconductor LM75 and compatibles"
         depends on I2C
         help
-          If you say yes here you get support for National Semiconductor LM75
-          sensor chips and clones: Dallas Semiconductor DS75 and DS1775 (in
-          9-bit precision mode), and TelCom (now Microchip) TCN75.
-
-          The DS75 and DS1775 in 10- to 12-bit precision modes will require
-          a force module parameter. The driver will not handle the extra
-          precision anyhow.
+          If you say yes here you get support for one common type of
+          temperature sensor chip, with models including:
+
+                - Dallas Semiconductor DS75 and DS1775
+                - Maxim MAX6625 and MAX6626
+                - Microchip MCP980x
+                - National Semiconductor LM75
+                - NXP's LM75A
+                - ST Microelectronics STDS75
+                - TelCom (now Microchip) TCN75
+                - Texas Instruments TMP100, TMP101, TMP75, TMP175, TMP275
+
+          Most of these chips will require a "force" module parameter.
 
           This driver can also be built as a module.  If so, the module
           will be called lm75.
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index de698dc73020..25ed26584100 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -30,14 +30,19 @@
 #include "lm75.h"
 
 
-/* Addresses to scan */
+/*
+ * This driver handles the LM75 and compatible digital temperature sensors.
+ * Compatibles include at least the DS75, DS1775, MCP980x, STDS75, TCN75,
+ * TMP100, TMP101, TMP75, TMP175, and TMP275.
+ */
+
+/* Addresses scanned by legacy style driver binding */
 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
 
-/* Insmod parameters */
+/* Insmod parameters (only for legacy style driver binding) */
 I2C_CLIENT_INSMOD_1(lm75);
 
-/* Many LM75 constants specified below */
 
 /* The LM75 registers */
 #define LM75_REG_CONF           0x01
@@ -50,9 +55,9 @@ static const u8 LM75_REG_TEMP[3] = {
 /* Each client has this additional data */
 struct lm75_data {
         struct i2c_client       client;
-        struct device *hwmon_dev;
+        struct device           *hwmon_dev;
         struct mutex            update_lock;
-        char                    valid;          /* !=0 if following fields are valid */
+        char                    valid;          /* !=0 if registers are valid */
         unsigned long           last_updated;   /* In jiffies */
         u16                     temp[3];        /* Register values,
                                                    0 = input
@@ -60,23 +65,15 @@ struct lm75_data {
                                                    2 = hyst */
 };
 
-static int lm75_attach_adapter(struct i2c_adapter *adapter);
-static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
 static void lm75_init_client(struct i2c_client *client);
-static int lm75_detach_client(struct i2c_client *client);
 static int lm75_read_value(struct i2c_client *client, u8 reg);
 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
 static struct lm75_data *lm75_update_device(struct device *dev);
 
 
-/* This is the driver that will be inserted */
-static struct i2c_driver lm75_driver = {
-        .driver = {
-                .name   = "lm75",
-        },
-        .attach_adapter = lm75_attach_adapter,
-        .detach_client  = lm75_detach_client,
-};
+/*-----------------------------------------------------------------------*/
+
+/* sysfs attributes for hwmon */
 
 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
                          char *buf)
@@ -109,13 +106,6 @@ static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
                         show_temp, set_temp, 2);
 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 
-static int lm75_attach_adapter(struct i2c_adapter *adapter)
-{
-        if (!(adapter->class & I2C_CLASS_HWMON))
-                return 0;
-        return i2c_probe(adapter, &addr_data, lm75_detect);
-}
-
 static struct attribute *lm75_attributes[] = {
         &sensor_dev_attr_temp1_input.dev_attr.attr,
         &sensor_dev_attr_temp1_max.dev_attr.attr,
@@ -128,6 +118,12 @@ static const struct attribute_group lm75_group = {
         .attrs = lm75_attributes,
 };
 
+/*-----------------------------------------------------------------------*/
+
+/* "Legacy" I2C driver binding */
+
+static struct i2c_driver lm75_driver;
+
 /* This function is called by i2c_probe */
 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
 {
@@ -135,15 +131,14 @@ static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
         struct i2c_client *new_client;
         struct lm75_data *data;
         int err = 0;
-        const char *name = "";
 
         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                                      I2C_FUNC_SMBUS_WORD_DATA))
                 goto exit;
 
-        /* OK. For now, we presume we have a valid client. We now create the
-           client structure, even though we cannot fill it completely yet.
-           But it allows us to access lm75_{read,write}_value. */
+        /* OK. For now, we presume we have a valid address. We create the
+           client structure, even though there may be no sensor present.
+           But it allows us to use i2c_smbus_read_*_data() calls. */
         if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
                 err = -ENOMEM;
                 goto exit;
@@ -174,17 +169,17 @@ static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
                  || i2c_smbus_read_word_data(new_client, 5) != hyst
                  || i2c_smbus_read_word_data(new_client, 6) != hyst
                  || i2c_smbus_read_word_data(new_client, 7) != hyst)
-                        goto exit_free;
+                        goto exit_free;
                 os = i2c_smbus_read_word_data(new_client, 3);
                 if (i2c_smbus_read_word_data(new_client, 4) != os
                  || i2c_smbus_read_word_data(new_client, 5) != os
                  || i2c_smbus_read_word_data(new_client, 6) != os
                  || i2c_smbus_read_word_data(new_client, 7) != os)
-                        goto exit_free;
+                        goto exit_free;
 
                 /* Unused bits */
                 if (conf & 0xe0)
-                        goto exit_free;
+                        goto exit_free;
 
                 /* Addresses cycling */
                 for (i = 8; i < 0xff; i += 8)
@@ -194,16 +189,10 @@ static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
                                 goto exit_free;
         }
 
-        /* Determine the chip type - only one kind supported! */
-        if (kind <= 0)
-                kind = lm75;
-
-        if (kind == lm75) {
-                name = "lm75";
-        }
+        /* NOTE: we treat "force=..." and "force_lm75=..." the same. */
+        strlcpy(new_client->name, "lm75", I2C_NAME_SIZE);
 
         /* Fill in the remaining client fields and put it into the global list */
-        strlcpy(new_client->name, name, I2C_NAME_SIZE);
         data->valid = 0;
         mutex_init(&data->update_lock);
 
@@ -213,7 +202,7 @@ static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
 
         /* Initialize the LM75 chip */
         lm75_init_client(new_client);
-        
+
         /* Register sysfs hooks */
         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group)))
                 goto exit_detach;
@@ -236,6 +225,13 @@ exit:
         return err;
 }
 
+static int lm75_attach_adapter(struct i2c_adapter *adapter)
+{
+        if (!(adapter->class & I2C_CLASS_HWMON))
+                return 0;
+        return i2c_probe(adapter, &addr_data, lm75_detect);
+}
+
 static int lm75_detach_client(struct i2c_client *client)
 {
         struct lm75_data *data = i2c_get_clientdata(client);
@@ -246,6 +242,18 @@ static int lm75_detach_client(struct i2c_client *client)
         return 0;
 }
 
+static struct i2c_driver lm75_driver = {
+        .driver = {
+                .name   = "lm75",
+        },
+        .attach_adapter = lm75_attach_adapter,
+        .detach_client  = lm75_detach_client,
+};
+
+/*-----------------------------------------------------------------------*/
+
+/* register access */
+
 /* All registers are word-sized, except for the configuration register.
    LM75 uses a high-byte first convention, which is exactly opposite to
    the SMBus standard. */
@@ -309,6 +317,10 @@ static struct lm75_data *lm75_update_device(struct device *dev)
         return data;
 }
 
+/*-----------------------------------------------------------------------*/
+
+/* module glue */
+
 static int __init sensors_lm75_init(void)
 {
         return i2c_add_driver(&lm75_driver);