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>

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.

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
@@ -52,7 +57,7 @@ struct lm75_data {
 	struct i2c_client	client;
 	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;
@@ -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);
 
@@ -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);