Re: [PATCH 13/13] drivers/media/tuners/e4000.c: use macros for i2c_msg initialization

[Julia Lawall]

On Sun, 7 Oct 2012, walter harms wrote:



Am 07.10.2012 17:38, schrieb Julia Lawall:
From: Julia Lawall <julia.law...@lip6.fr>

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

In the second i2c_msg structure, a length expressed as an explicit constant
is also re-expressed as the size of the buffer, reg.

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.law...@lip6.fr>

---
 drivers/media/tuners/e4000.c |   20 +++-----------------
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/media/tuners/e4000.c b/drivers/media/tuners/e4000.c
index 1b33ed3..8f182fc 100644
--- a/drivers/media/tuners/e4000.c
+++ b/drivers/media/tuners/e4000.c
@@ -26,12 +26,7 @@ static int e4000_wr_regs(struct e4000_priv *priv, u8 reg, u8 
*val, int len)
        int ret;
        u8 buf[1 + len];
        struct i2c_msg msg[1] = {
-               {
-                       .addr = priv->cfg->i2c_addr,
-                       .flags = 0,
-                       .len = sizeof(buf),
-                       .buf = buf,
-               }
+               I2C_MSG_WRITE(priv->cfg->i2c_addr, buf, sizeof(buf))
        };


Any reason why struct i2c_msg is an array ?

I assumed that it looked more harmonious with the other uses of 
i2c_transfer, which takes as arguments an array and the number of 
elements.

But there are some files that instead use i2c_transfer(priv->i2c, &msg, 1).
I can change them all to do that if that is preferred.  But maybe I 
will wait a little bit to see if there are other issues to address at 
the same time.

thanks,
julia


re,
wh

        buf[0] = reg;
@@ -54,17 +49,8 @@ static int e4000_rd_regs(struct e4000_priv *priv, u8 reg, u8 
*val, int len)
        int ret;
        u8 buf[len];
        struct i2c_msg msg[2] = {
-               {
-                       .addr = priv->cfg->i2c_addr,
-                       .flags = 0,
-                       .len = 1,
-                       .buf = &reg,
-               }, {
-                       .addr = priv->cfg->i2c_addr,
-                       .flags = I2C_M_RD,
-                       .len = sizeof(buf),
-                       .buf = buf,
-               }
+               I2C_MSG_WRITE(priv->cfg->i2c_addr, &reg, sizeof(reg)),
+               I2C_MSG_READ(priv->cfg->i2c_addr, buf, sizeof(buf))
        };

        ret = i2c_transfer(priv->i2c, msg, 2);

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