Re: [PATCH 9/13] drivers/media/tuners/fc0011.c: use macros fori2c_msg initialization

From: Julia Lawall
Date: Sun Oct 07 2012 - 12:50:55 EST


On Sun, 7 Oct 2012, walter harms wrote:



Am 07.10.2012 17:38, schrieb Julia Lawall:
From: Julia Lawall <Julia.Lawall@xxxxxxx>

Introduce use of I2c_MSG_READ/WRITE/OP, for readability.

A length expressed as an explicit constant is also re-expressed as the size
of the buffer in each case.

A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression a,b,c;
identifier x;
@@

struct i2c_msg x =
- {.addr = a, .buf = b, .len = c, .flags = I2C_M_RD}
+ I2C_MSG_READ(a,b,c)
;

@@
expression a,b,c;
identifier x;
@@

struct i2c_msg x =
- {.addr = a, .buf = b, .len = c, .flags = 0}
+ I2C_MSG_WRITE(a,b,c)
;

@@
expression a,b,c,d;
identifier x;
@@

struct i2c_msg x =
- {.addr = a, .buf = b, .len = c, .flags = d}
+ I2C_MSG_OP(a,b,c,d)
;
// </smpl>

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

---
drivers/media/tuners/fc0011.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/media/tuners/fc0011.c b/drivers/media/tuners/fc0011.c
index e488254..5dbba98 100644
--- a/drivers/media/tuners/fc0011.c
+++ b/drivers/media/tuners/fc0011.c
@@ -80,8 +80,7 @@ struct fc0011_priv {
static int fc0011_writereg(struct fc0011_priv *priv, u8 reg, u8 val)
{
u8 buf[2] = { reg, val };
- struct i2c_msg msg = { .addr = priv->addr,
- .flags = 0, .buf = buf, .len = 2 };
+ struct i2c_msg msg = I2C_MSG_WRITE(priv->addr, buf, sizeof(buf));

if (i2c_transfer(priv->i2c, &msg, 1) != 1) {
dev_err(&priv->i2c->dev,
@@ -97,10 +96,8 @@ static int fc0011_readreg(struct fc0011_priv *priv, u8 reg, u8 *val)
{
u8 dummy;
struct i2c_msg msg[2] = {
- { .addr = priv->addr,
- .flags = 0, .buf = &reg, .len = 1 },
- { .addr = priv->addr,
- .flags = I2C_M_RD, .buf = val ? : &dummy, .len = 1 },
+ I2C_MSG_WRITE(priv->addr, &reg, sizeof(reg)),
+ I2C_MSG_READ(priv->addr, val ? : &dummy, sizeof(dummy)),
};


This dummy looks strange, can it be that this is used uninitialised ?

I'm not sure to understand the question. The read, when it happens in i2c_transfer will initialize dummy. On the other hand, I don't know what i2c_transfer does when the buffer is NULL and the size is 1. It does not look very elegant at least.

julia
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