i2c: Shrink struct i2c_client

This shrinks the size of "struct i2c_client" by 40 bytes:

 - Substantially shrinks the string used to identify the chip type
 - The "flags" don't need to be so big
 - Removes some internal padding

It also adds kerneldoc for that struct, explaining how "name" is really a
chip type identifier; it's otherwise potentially confusing.

Because the I2C_NAME_SIZE symbol was abused for both i2c_client.name
and for i2c_adapter.name, this needed to affect i2c_adapter too.  The
adapters which used that symbol now use the more-obviously-correct
idiom of taking the size of that field.

JD: Shorten i2c_adapter.name from 50 to 48 bytes while we're here, to
avoid wasting space in padding.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

19 files changed, 35 insertions, 28 deletions

diff --git a/drivers/i2c/busses/i2c-ali1535.c b/drivers/i2c/busses/i2c-ali1535.c
index 1e277ba5a9f3..f14372ac2fc5 100644
--- a/drivers/i2c/busses/i2c-ali1535.c
+++ b/drivers/i2c/busses/i2c-ali1535.c
@@ -497,7 +497,7 @@ static int __devinit ali1535_probe(struct pci_dev *dev, const struct pci_device_
         /* set up the sysfs linkage to our parent device */
         ali1535_adapter.dev.parent = &dev->dev;
 
-        snprintf(ali1535_adapter.name, I2C_NAME_SIZE, 
+        snprintf(ali1535_adapter.name, sizeof(ali1535_adapter.name),
                 "SMBus ALI1535 adapter at %04x", ali1535_smba);
         return i2c_add_adapter(&ali1535_adapter);
 }
diff --git a/drivers/i2c/busses/i2c-ali15x3.c b/drivers/i2c/busses/i2c-ali15x3.c
index e47fe01bf42a..93bf87d70961 100644
--- a/drivers/i2c/busses/i2c-ali15x3.c
+++ b/drivers/i2c/busses/i2c-ali15x3.c
@@ -492,7 +492,7 @@ static int __devinit ali15x3_probe(struct pci_dev *dev, const struct pci_device_
         /* set up the sysfs linkage to our parent device */
         ali15x3_adapter.dev.parent = &dev->dev;
 
-        snprintf(ali15x3_adapter.name, I2C_NAME_SIZE,
+        snprintf(ali15x3_adapter.name, sizeof(ali15x3_adapter.name),
                 "SMBus ALI15X3 adapter at %04x", ali15x3_smba);
         return i2c_add_adapter(&ali15x3_adapter);
 }
diff --git a/drivers/i2c/busses/i2c-amd8111.c b/drivers/i2c/busses/i2c-amd8111.c
index 0c70f8293341..c9fca7b49267 100644
--- a/drivers/i2c/busses/i2c-amd8111.c
+++ b/drivers/i2c/busses/i2c-amd8111.c
@@ -365,7 +365,7 @@ static int __devinit amd8111_probe(struct pci_dev *dev,
         }
 
         smbus->adapter.owner = THIS_MODULE;
-        snprintf(smbus->adapter.name, I2C_NAME_SIZE,
+        snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
                 "SMBus2 AMD8111 adapter at %04x", smbus->base);
         smbus->adapter.id = I2C_HW_SMBUS_AMD8111;
         smbus->adapter.class = I2C_CLASS_HWMON;
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index a320e7d82c1f..611b57192c96 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -527,7 +527,7 @@ static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id
         /* set up the sysfs linkage to our parent device */
         i801_adapter.dev.parent = &dev->dev;
 
-        snprintf(i801_adapter.name, I2C_NAME_SIZE,
+        snprintf(i801_adapter.name, sizeof(i801_adapter.name),
                 "SMBus I801 adapter at %04lx", i801_smba);
         err = i2c_add_adapter(&i801_adapter);
         if (err) {
diff --git a/drivers/i2c/busses/i2c-ixp2000.c b/drivers/i2c/busses/i2c-ixp2000.c
index efa3ecc5522a..6352121a2827 100644
--- a/drivers/i2c/busses/i2c-ixp2000.c
+++ b/drivers/i2c/busses/i2c-ixp2000.c
@@ -118,7 +118,7 @@ static int ixp2000_i2c_probe(struct platform_device *plat_dev)
 
         drv_data->adapter.id = I2C_HW_B_IXP2000,
         strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
-                I2C_NAME_SIZE);
+                sizeof(drv_data->adapter.name));
         drv_data->adapter.algo_data = &drv_data->algo_data,
 
         drv_data->adapter.dev.parent = &plat_dev->dev;
diff --git a/drivers/i2c/busses/i2c-ixp4xx.c b/drivers/i2c/busses/i2c-ixp4xx.c
index 08e89b83984a..069ed7f3b395 100644
--- a/drivers/i2c/busses/i2c-ixp4xx.c
+++ b/drivers/i2c/busses/i2c-ixp4xx.c
@@ -127,7 +127,7 @@ static int ixp4xx_i2c_probe(struct platform_device *plat_dev)
         drv_data->adapter.id = I2C_HW_B_IXP4XX;
         drv_data->adapter.class = I2C_CLASS_HWMON;
         strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
-                I2C_NAME_SIZE);
+                sizeof(drv_data->adapter.name));
         drv_data->adapter.algo_data = &drv_data->algo_data;
 
         drv_data->adapter.dev.parent = &plat_dev->dev;
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index a3283b907eb8..a55b3335d1be 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -508,7 +508,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
         }
 
         strlcpy(drv_data->adapter.name, MV64XXX_I2C_CTLR_NAME " adapter",
-                I2C_NAME_SIZE);
+                sizeof(drv_data->adapter.name));
 
         init_waitqueue_head(&drv_data->waitq);
         spin_lock_init(&drv_data->lock);
diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c
index 1514ec5b77f8..cdc67dc914c3 100644
--- a/drivers/i2c/busses/i2c-nforce2.c
+++ b/drivers/i2c/busses/i2c-nforce2.c
@@ -240,7 +240,7 @@ static int __devinit nforce2_probe_smb (struct pci_dev *dev, int bar,
         smbus->adapter.algo = &smbus_algorithm;
         smbus->adapter.algo_data = smbus;
         smbus->adapter.dev.parent = &dev->dev;
-        snprintf(smbus->adapter.name, I2C_NAME_SIZE,
+        snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
                 "SMBus nForce2 adapter at %04x", smbus->base);
 
         error = i2c_add_adapter(&smbus->adapter);
diff --git a/drivers/i2c/busses/i2c-pasemi.c b/drivers/i2c/busses/i2c-pasemi.c
index bf89eeef74e9..58e32714afb5 100644
--- a/drivers/i2c/busses/i2c-pasemi.c
+++ b/drivers/i2c/busses/i2c-pasemi.c
@@ -358,7 +358,7 @@ static int __devinit pasemi_smb_probe(struct pci_dev *dev,
         }
 
         smbus->adapter.owner = THIS_MODULE;
-        snprintf(smbus->adapter.name, I2C_NAME_SIZE,
+        snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
                  "PA Semi SMBus adapter at 0x%lx", smbus->base);
         smbus->adapter.class = I2C_CLASS_HWMON;
         smbus->adapter.algo = &smbus_algorithm;
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 21b180904085..5a52bf5e3fb0 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -428,7 +428,7 @@ static int __devinit piix4_probe(struct pci_dev *dev,
         /* set up the sysfs linkage to our parent device */
         piix4_adapter.dev.parent = &dev->dev;
 
-        snprintf(piix4_adapter.name, I2C_NAME_SIZE,
+        snprintf(piix4_adapter.name, sizeof(piix4_adapter.name),
                 "SMBus PIIX4 adapter at %04x", piix4_smba);
 
         if ((retval = i2c_add_adapter(&piix4_adapter))) {
diff --git a/drivers/i2c/busses/i2c-sis96x.c b/drivers/i2c/busses/i2c-sis96x.c
index 4157b0cd604c..dc235bb8e24d 100644
--- a/drivers/i2c/busses/i2c-sis96x.c
+++ b/drivers/i2c/busses/i2c-sis96x.c
@@ -300,7 +300,7 @@ static int __devinit sis96x_probe(struct pci_dev *dev,
         /* set up the sysfs linkage to our parent device */
         sis96x_adapter.dev.parent = &dev->dev;
 
-        snprintf(sis96x_adapter.name, I2C_NAME_SIZE,
+        snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name),
                 "SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
 
         if ((retval = i2c_add_adapter(&sis96x_adapter))) {
diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index 03c5fc868548..7a2bc06304fc 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -404,7 +404,7 @@ found:
         }
 
         vt596_adapter.dev.parent = &pdev->dev;
-        snprintf(vt596_adapter.name, I2C_NAME_SIZE,
+        snprintf(vt596_adapter.name, sizeof(vt596_adapter.name),
                  "SMBus Via Pro adapter at %04x", vt596_smba);
 
         vt596_pdev = pci_dev_get(pdev);
diff --git a/drivers/i2c/busses/scx200_acb.c b/drivers/i2c/busses/scx200_acb.c
index 0b082c5a0195..d816ab089fe2 100644
--- a/drivers/i2c/busses/scx200_acb.c
+++ b/drivers/i2c/busses/scx200_acb.c
@@ -441,7 +441,7 @@ static __init struct scx200_acb_iface *scx200_create_iface(const char *text,
 
         adapter = &iface->adapter;
         i2c_set_adapdata(adapter, iface);
-        snprintf(adapter->name, I2C_NAME_SIZE, "%s ACB%d", text, index);
+        snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
         adapter->owner = THIS_MODULE;
         adapter->id = I2C_HW_SMBUS_SCX200;
         adapter->algo = &scx200_acb_algorithm;
diff --git a/drivers/media/dvb/b2c2/flexcop-i2c.c b/drivers/media/dvb/b2c2/flexcop-i2c.c
index 5347a406fff7..02a0ea6e1c17 100644
--- a/drivers/media/dvb/b2c2/flexcop-i2c.c
+++ b/drivers/media/dvb/b2c2/flexcop-i2c.c
@@ -183,7 +183,8 @@ int flexcop_i2c_init(struct flexcop_device *fc)
         mutex_init(&fc->i2c_mutex);
 
         memset(&fc->i2c_adap, 0, sizeof(struct i2c_adapter));
-        strncpy(fc->i2c_adap.name, "B2C2 FlexCop device",I2C_NAME_SIZE);
+        strncpy(fc->i2c_adap.name, "B2C2 FlexCop device",
+                sizeof(fc->i2c_adap.name));
 
         i2c_set_adapdata(&fc->i2c_adap,fc);
 
diff --git a/drivers/media/dvb/dvb-usb/dvb-usb-i2c.c b/drivers/media/dvb/dvb-usb/dvb-usb-i2c.c
index 70df31b0a8a9..088b6dee3a7f 100644
--- a/drivers/media/dvb/dvb-usb/dvb-usb-i2c.c
+++ b/drivers/media/dvb/dvb-usb/dvb-usb-i2c.c
@@ -19,7 +19,7 @@ int dvb_usb_i2c_init(struct dvb_usb_device *d)
                 return -EINVAL;
         }
 
-        strncpy(d->i2c_adap.name,d->desc->name,I2C_NAME_SIZE);
+        strncpy(d->i2c_adap.name, d->desc->name, sizeof(d->i2c_adap.name));
 #ifdef I2C_ADAP_CLASS_TV_DIGITAL
         d->i2c_adap.class = I2C_ADAP_CLASS_TV_DIGITAL,
 #else
diff --git a/drivers/media/dvb/frontends/dibx000_common.c b/drivers/media/dvb/frontends/dibx000_common.c
index a18c8f45a2ee..315e09e95b0c 100644
--- a/drivers/media/dvb/frontends/dibx000_common.c
+++ b/drivers/media/dvb/frontends/dibx000_common.c
@@ -105,9 +105,9 @@ struct i2c_adapter * dibx000_get_i2c_adapter(struct dibx000_i2c_master *mst, enu
 }
 EXPORT_SYMBOL(dibx000_get_i2c_adapter);
 
-static int i2c_adapter_init(struct i2c_adapter *i2c_adap, struct i2c_algorithm *algo, const char name[I2C_NAME_SIZE], struct dibx000_i2c_master *mst)
+static int i2c_adapter_init(struct i2c_adapter *i2c_adap, struct i2c_algorithm *algo, const char *name, struct dibx000_i2c_master *mst)
 {
-        strncpy(i2c_adap->name, name, I2C_NAME_SIZE);
+        strncpy(i2c_adap->name, name, sizeof(i2c_adap->name));
         i2c_adap->class     = I2C_CLASS_TV_DIGITAL,
         i2c_adap->algo      = algo;
         i2c_adap->algo_data = NULL;
diff --git a/drivers/video/intelfb/intelfb_i2c.c b/drivers/video/intelfb/intelfb_i2c.c
index f4ede5f6b588..61e4c8759b23 100644
--- a/drivers/video/intelfb/intelfb_i2c.c
+++ b/drivers/video/intelfb/intelfb_i2c.c
@@ -104,7 +104,8 @@ static int intelfb_setup_i2c_bus(struct intelfb_info *dinfo,
 
         chan->dinfo                                     = dinfo;
         chan->reg                                       = reg;
-        snprintf(chan->adapter.name, I2C_NAME_SIZE, "intelfb %s", name);
+        snprintf(chan->adapter.name, sizeof(chan->adapter.name),
+                 "intelfb %s", name);
         chan->adapter.owner                     = THIS_MODULE;
         chan->adapter.id                        = I2C_HW_B_INTELFB;
         chan->adapter.algo_data         = &chan->algo;
diff --git a/drivers/video/matrox/i2c-matroxfb.c b/drivers/video/matrox/i2c-matroxfb.c
index 5ec718a5fe22..4baab7be58de 100644
--- a/drivers/video/matrox/i2c-matroxfb.c
+++ b/drivers/video/matrox/i2c-matroxfb.c
@@ -111,7 +111,7 @@ static int i2c_bus_reg(struct i2c_bit_adapter* b, struct matrox_fb_info* minfo,
         b->mask.data = data;
         b->mask.clock = clock;
         b->adapter = matrox_i2c_adapter_template;
-        snprintf(b->adapter.name, I2C_NAME_SIZE, name,
+        snprintf(b->adapter.name, sizeof(b->adapter.name), name,
                 minfo->fbcon.node);
         i2c_set_adapdata(&b->adapter, b);
         b->adapter.algo_data = &b->bac;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 47c2a1907372..953e71fb07b4 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -140,25 +140,30 @@ struct i2c_driver {
 };
 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 
-#define I2C_NAME_SIZE   50
-
-/*
- * i2c_client identifies a single device (i.e. chip) that is connected to an
- * i2c bus. The behaviour is defined by the routines of the driver. This
- * function is mainly used for lookup & other admin. functions.
+#define I2C_NAME_SIZE   20
+
+/**
+ * struct i2c_client - represent an I2C slave device
+ * @addr: Address used on the I2C bus connected to the parent adapter.
+ * @name: Indicates the type of the device, usually a chip name that's
+ *      generic enough to hide second-sourcing and compatible revisions.
+ * @dev: Driver model device node for the slave.
+ *
+ * An i2c_client identifies a single device (i.e. chip) connected to an
+ * i2c bus. The behaviour is defined by the routines of the driver.
  */
 struct i2c_client {
-        unsigned int flags;             /* div., see below              */
+        unsigned short flags;           /* div., see below              */
         unsigned short addr;            /* chip address - NOTE: 7bit    */
                                         /* addresses are stored in the  */
                                         /* _LOWER_ 7 bits               */
+        char name[I2C_NAME_SIZE];
         struct i2c_adapter *adapter;    /* the adapter we sit on        */
         struct i2c_driver *driver;      /* and our access routines      */
         int usage_count;                /* How many accesses currently  */
                                         /* to the client                */
         struct device dev;              /* the device structure         */
         struct list_head list;
-        char name[I2C_NAME_SIZE];
         struct completion released;
 };
 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
@@ -231,7 +236,7 @@ struct i2c_adapter {
         int nr;
         struct list_head clients;
         struct list_head list;
-        char name[I2C_NAME_SIZE];
+        char name[48];
         struct completion dev_released;
 };
 #define dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)