[PATCH 2/2] i2c: constify i2c_adapter_quirks structures

From: Julia Lawall
Date: Sat Oct 15 2016 - 13:52:47 EST


Check for i2c_adapter_quirks structures that are only stored in the
quirks field of an i2c_adapter structure. This field is declared
const, so i2c_adapter_quirks structures that have this property can be
declared as const also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct i2c_adapter_quirks i@p = { ... };

@ok@
identifier r.i;
struct i2c_adapter e;
position p;
@@
e.quirks = &i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct i2c_adapter_quirks e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct i2c_adapter_quirks i = { ... };
// </smpl>

The effect on the layout of the .o files is shown by the following
output of the size command, first before then after the
transformation:

text data bss dec hex filename
3651 472 8 4131 1023 drivers/i2c/busses/i2c-axxia.o
3683 440 8 4131 1023 drivers/i2c/busses/i2c-axxia.o

text data bss dec hex filename
1069 216 0 1285 505 drivers/i2c/busses/i2c-dln2.o
1101 192 0 1293 50d drivers/i2c/busses/i2c-dln2.o

text data bss dec hex filename
3211 484 1 3696 e70 drivers/i2c/busses/i2c-viperboard.o
3243 460 1 3704 e78 drivers/i2c/busses/i2c-viperboard.o

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
drivers/i2c/busses/i2c-axxia.c | 2 +-
drivers/i2c/busses/i2c-dln2.c | 2 +-
drivers/i2c/busses/i2c-viperboard.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
index 4351a93..13f0748 100644
--- a/drivers/i2c/busses/i2c-axxia.c
+++ b/drivers/i2c/busses/i2c-axxia.c
@@ -489,7 +489,7 @@ static u32 axxia_i2c_func(struct i2c_adapter *adap)
.functionality = axxia_i2c_func,
};

-static struct i2c_adapter_quirks axxia_i2c_quirks = {
+static const struct i2c_adapter_quirks axxia_i2c_quirks = {
.max_read_len = 255,
.max_write_len = 255,
};
diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
index 8acda2a..69075a3 100644
--- a/drivers/i2c/busses/i2c-dln2.c
+++ b/drivers/i2c/busses/i2c-dln2.c
@@ -182,7 +182,7 @@ static u32 dln2_i2c_func(struct i2c_adapter *a)
.functionality = dln2_i2c_func,
};

-static struct i2c_adapter_quirks dln2_i2c_quirks = {
+static const struct i2c_adapter_quirks dln2_i2c_quirks = {
.max_read_len = DLN2_I2C_MAX_XFER_SIZE,
.max_write_len = DLN2_I2C_MAX_XFER_SIZE,
};
diff --git a/drivers/i2c/busses/i2c-viperboard.c b/drivers/i2c/busses/i2c-viperboard.c
index 543456a..e4be86b 100644
--- a/drivers/i2c/busses/i2c-viperboard.c
+++ b/drivers/i2c/busses/i2c-viperboard.c
@@ -354,7 +354,7 @@ static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
.functionality = vprbrd_i2c_func,
};

-static struct i2c_adapter_quirks vprbrd_quirks = {
+static const struct i2c_adapter_quirks vprbrd_quirks = {
.max_read_len = 2048,
.max_write_len = 2048,
};