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`
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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/ec/google/chromeec/ec_i2c.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'src/ec')

diff --git a/src/ec/google/chromeec/ec_i2c.c b/src/ec/google/chromeec/ec_i2c.c
index eca1eb9b4d..40bd0bb219 100644
--- a/src/ec/google/chromeec/ec_i2c.c
+++ b/src/ec/google/chromeec/ec_i2c.c
@@ -45,20 +45,20 @@ enum {
 
 struct i2c_ec {
 	int bus;
-	struct i2c_seg segs[SEGS_PER_CMD];
+	struct i2c_msg segs[SEGS_PER_CMD];
 };
 
 static struct i2c_ec ec_dev = {
 	.bus = CONFIG_EC_GOOGLE_CHROMEEC_I2C_BUS,
 	.segs[CMD_INDEX] = {
-		.read = 0,
-		.chip = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
+		.flags = 0,
+		.slave = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
 		/* Framing byte to be transferred prior to request. */
 		.buf = &req_buf.framing_bytes[3],
 	},
 	.segs[RESP_INDEX] = {
-		.read = 1,
-		.chip = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
+		.flags = I2C_M_RD,
+		.slave = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
 		/* return code and total length before full response. */
 		.buf = &resp_buf.framing_bytes[2],
 	},
@@ -100,7 +100,7 @@ static int crosec_i2c_io(size_t req_size, size_t resp_size, void *context)
 
 	if (i2c_transfer(ec->bus, ec->segs, ARRAY_SIZE(ec->segs)) != 0) {
 		printk(BIOS_ERR, "%s: Cannot complete read from i2c-%d:%#x\n",
-		       __func__, ec->bus, ec->segs[0].chip);
+		       __func__, ec->bus, ec->segs[0].slave);
 		return -1;
 	}
 
-- 
cgit v1.2.3