From 029dfff30cc468b3e21c2004a135d3380a8c20e6 Mon Sep 17 00:00:00 2001
From: Nico Huber <nico.huber@secunet.com>
Date: Wed, 12 Jul 2017 17:59:16 +0200
Subject: i2c: Move to Linux like `struct i2c_msg`
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Our current struct for I2C segments `i2c_seg` was close to being compa-
tible to the Linux version `i2c_msg`, close to being compatible to SMBus
and close to being readable (e.g. what was `chip` supposed to mean?) but
turned out to be hard to fix.

Instead of extending it in a backwards compatible way (and not touching
current controller drivers), replace it with a Linux source compatible
`struct i2c_msg` and patch all the drivers and users with Coccinelle.

The new `struct i2c_msg` should ease porting drivers from Linux and help
to write SMBus compatible controller drivers.

Beside integer type changes, the field `read` is replaced with a generic
field `flags` and `chip` is renamed to `slave`.

Patched with Coccinelle using the clumsy spatch below and some manual
changes:

* Nested struct initializers and one field access skipped by Coccinelle.
* Removed assumption in the code that I2C_M_RD is 1.
* In `i2c.h`, changed all occurences of `chip` to `slave`.

    @@ @@
    -struct i2c_seg
    +struct i2c_msg

    @@ identifier msg; expression e; @@
    (
     struct i2c_msg msg = {
    -    .read = 0,
    +    .flags = 0,
     };
    |
     struct i2c_msg msg = {
    -    .read = 1,
    +    .flags = I2C_M_RD,
     };
    |
     struct i2c_msg msg = {
    -    .chip = e,
    +    .slave = e,
     };
    )

    @@ struct i2c_msg msg; statement S1, S2; @@
    (
    -if (msg.read)
    +if (msg.flags & I2C_M_RD)
     S1 else S2
    |
    -if (msg.read)
    +if (msg.flags & I2C_M_RD)
     S1
    )

    @@ struct i2c_msg *msg; statement S1, S2; @@
    (
    -if (msg->read)
    +if (msg->flags & I2C_M_RD)
     S1 else S2
    |
    -if (msg->read)
    +if (msg->flags & I2C_M_RD)
     S1
    )

    @@ struct i2c_msg msg; expression e; @@
    (
    -msg.read = 0;
    +msg.flags = 0;
    |
    -msg.read = 1;
    +msg.flags = I2C_M_RD;
    |
    -msg.read = e;
    +msg.flags = e ? I2C_M_RD : 0;
    |
    -!!(msg.read)
    +(msg.flags & I2C_M_RD)
    |
    -(msg.read)
    +(msg.flags & I2C_M_RD)
    )

    @@ struct i2c_msg *msg; expression e; @@
    (
    -msg->read = 0;
    +msg->flags = 0;
    |
    -msg->read = 1;
    +msg->flags = I2C_M_RD;
    |
    -msg->read = e;
    +msg->flags = e ? I2C_M_RD : 0;
    |
    -!!(msg->read)
    +(msg->flags & I2C_M_RD)
    |
    -(msg->read)
    +(msg->flags & I2C_M_RD)
    )

    @@ struct i2c_msg msg; @@
    -msg.chip
    +msg.slave

    @@ struct i2c_msg *msg; expression e; @@
    -msg[e].chip
    +msg[e].slave

    @ slave disable ptr_to_array @ struct i2c_msg *msg; @@
    -msg->chip
    +msg->slave

Change-Id: Ifd7cabf0a18ffd7a1def25d1d7059b713d0b7ea9
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20542
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
---
 src/cpu/allwinner/a10/twi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'src/cpu')

diff --git a/src/cpu/allwinner/a10/twi.c b/src/cpu/allwinner/a10/twi.c
index 3ef5606d27..123d34ec05 100644
--- a/src/cpu/allwinner/a10/twi.c
+++ b/src/cpu/allwinner/a10/twi.c
@@ -185,10 +185,10 @@ static int i2c_write(struct a1x_twi *twi, uint8_t chip,
 	return len;
 }
 
-int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned bus, struct i2c_msg *segments, int count)
 {
 	int i, ret = CB_SUCCESS;
-	struct i2c_seg *seg = segments;
+	struct i2c_msg *seg = segments;
 	struct a1x_twi *twi = (void *)TWI_BASE(bus);
 
 
@@ -198,12 +198,12 @@ int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
 	for (i = 0; i < count; i++) {
 		seg = segments + i;
 
-		if (seg->read) {
-			ret = i2c_read(twi, seg->chip, seg->buf, seg->len);
+		if (seg->flags & I2C_M_RD) {
+			ret = i2c_read(twi, seg->slave, seg->buf, seg->len);
 			if (ret < 0)
 				break;
 		} else {
-			ret = i2c_write(twi, seg->chip, seg->buf, seg->len);
+			ret = i2c_write(twi, seg->slave, seg->buf, seg->len);
 			if (ret < 0)
 				break;
 		}
-- 
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