i2c: Move to Linux like `struct i2c_msg`

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>

2 files changed, 14 insertions, 12 deletions

diff --git a/src/soc/samsung/exynos5250/i2c.c b/src/soc/samsung/exynos5250/i2c.c
index 2f3f28fb2b..6319a10b34 100644
--- a/src/soc/samsung/exynos5250/i2c.c
+++ b/src/soc/samsung/exynos5250/i2c.c
@@ -234,7 +234,8 @@ static int i2c_recv_buf(struct i2c_regs *regs, uint8_t *data, int len)
 	return 0;
 }
 
-int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int seg_count)
+int platform_i2c_transfer(unsigned bus, struct i2c_msg *segments,
+			  int seg_count)
 {
 	struct s3c24x0_i2c_bus *i2c = &i2c_busses[bus];
 	struct i2c_regs *regs = i2c->regs;
@@ -247,12 +248,12 @@ int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int seg_count)
 
 	int i;
 	for (i = 0; i < seg_count; i++) {
-		struct i2c_seg *seg = &segments[i];
+		struct i2c_msg *seg = &segments[i];
 
-		res = i2c_send_start(regs, seg->read, seg->chip);
+		res = i2c_send_start(regs, seg->flags & I2C_M_RD, seg->slave);
 		if (res)
 			break;
-		if (seg->read)
+		if (seg->flags & I2C_M_RD)
 			res = i2c_recv_buf(regs, seg->buf, seg->len);
 		else
 			res = i2c_xmit_buf(regs, seg->buf, seg->len);
diff --git a/src/soc/samsung/exynos5420/i2c.c b/src/soc/samsung/exynos5420/i2c.c
index 9a9b197cc5..ae9560ffdd 100644
--- a/src/soc/samsung/exynos5420/i2c.c
+++ b/src/soc/samsung/exynos5420/i2c.c
@@ -445,11 +445,12 @@ static int hsi2c_recvdata(struct hsi2c_regs *regs, uint8_t *data, int len)
 	return len ? -1 : 0;
 }
 
-static int hsi2c_segment(struct i2c_seg *seg, struct hsi2c_regs *regs, int stop)
+static int hsi2c_segment(struct i2c_msg *seg, struct hsi2c_regs *regs,
+			 int stop)
 {
 	const uint32_t usi_ctl = Hsi2cFuncModeI2c | Hsi2cMaster;
 
-	write32(&regs->i2c_addr, HSI2C_SLV_ADDR_MAS(seg->chip));
+	write32(&regs->i2c_addr, HSI2C_SLV_ADDR_MAS(seg->slave));
 
 	/*
 	 * We really only want to stop after this transaction (I think) if the
@@ -461,7 +462,7 @@ static int hsi2c_segment(struct i2c_seg *seg, struct hsi2c_regs *regs, int stop)
 	uint32_t autoconf =
 		seg->len | Hsi2cMasterRun | Hsi2cStopAfterTrans;
 
-	if (seg->read) {
+	if (seg->flags & I2C_M_RD) {
 		write32(&regs->usi_ctl, usi_ctl | Hsi2cRxchon);
 		write32(&regs->i2c_auto_conf, autoconf | Hsi2cReadWrite);
 
@@ -482,7 +483,7 @@ static int hsi2c_segment(struct i2c_seg *seg, struct hsi2c_regs *regs, int stop)
 	return 0;
 }
 
-static int hsi2c_transfer(struct i2c_bus *i2c, struct i2c_seg *segments,
+static int hsi2c_transfer(struct i2c_bus *i2c, struct i2c_msg *segments,
 			  int count)
 {
 	struct hsi2c_regs *regs = i2c->hsregs;
@@ -627,7 +628,7 @@ static int i2c_recv_buf(struct i2c_regs *regs, uint8_t *data, int len)
 	return 0;
 }
 
-int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned bus, struct i2c_msg *segments, int count)
 {
 	struct i2c_bus *i2c = &i2c_busses[bus];
 	if (i2c->is_highspeed)
@@ -643,12 +644,12 @@ int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
 
 	int i;
 	for (i = 0; i < count; i++) {
-		struct i2c_seg *seg = &segments[i];
+		struct i2c_msg *seg = &segments[i];
 
-		res = i2c_send_start(regs, seg->read, seg->chip);
+		res = i2c_send_start(regs, seg->flags & I2C_M_RD, seg->slave);
 		if (res)
 			break;
-		if (seg->read)
+		if (seg->flags & I2C_M_RD)
 			res = i2c_recv_buf(regs, seg->buf, seg->len);
 		else
 			res = i2c_xmit_buf(regs, seg->buf, seg->len);