[PATCH v4 00/15] hw/i2c: Remove confusing i2c_send_recv() API

[PATCH v4 00/15] hw/i2c: Remove confusing i2c_send_recv() API

[Philippe Mathieu-Daudé]

This is a respin of Zoltan's patch:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg714711.html

Patches 1-13 reviewed (could be queued)
Missing review: 14-15 (but optionals)

Since v3:
- addressed minor review comments from Richard/Corey
- added R-b/A-b tags
- implemented Richard suggestion (last 2 patches, 14 & 15)

Since v2, tried to address Corey's review comments resulting
in a i2c_send_recv() removal and code easier to review (to my
taste at least).

BALATON Zoltan (1):
  hw/i2c: Make i2c_start_transfer() direction argument a boolean

Philippe Mathieu-Daudé (14):
  hw/input/lm832x: Move lm832x_key_event() declaration to "lm832x.h"
  hw/input/lm832x: Define TYPE_LM8323 in public header
  hw/display/sm501: Simplify sm501_i2c_write() logic
  hw/display/sm501: Replace i2c_send_recv() by i2c_recv() & i2c_send()
  hw/i2c/ppc4xx_i2c: Add reference to datasheet
  hw/i2c/ppc4xx_i2c: Replace i2c_send_recv() by i2c_recv() & i2c_send()
  hw/misc/auxbus: Fix MOT/classic I2C mode
  hw/misc/auxbus: Explode READ_I2C / WRITE_I2C_MOT cases
  hw/misc/auxbus: Replace 'is_write' boolean by its value
  hw/misc/auxbus: Replace i2c_send_recv() by i2c_recv() & i2c_send()
  hw/i2c: Remove confusing i2c_send_recv()
  hw/i2c: Rename i2c_set_slave_address() -> i2c_slave_set_address()
  hw/i2c: Extract i2c_do_start_transfer() from i2c_start_transfer()
  hw/i2c: Introduce i2c_start_recv() and i2c_start_send()

 include/hw/i2c/i2c.h      | 46 +++++++++++++++++++++---
 include/hw/input/lm832x.h | 28 +++++++++++++++
 hw/arm/nseries.c          |  3 +-
 hw/arm/pxa2xx.c           |  2 +-
 hw/arm/spitz.c            |  4 +--
 hw/display/ati.c          |  2 +-
 hw/display/sm501.c        | 16 +++++----
 hw/display/xlnx_dp.c      |  2 +-
 hw/i2c/core.c             | 76 ++++++++++++++++++++++-----------------
 hw/i2c/imx_i2c.c          |  2 +-
 hw/i2c/pm_smbus.c         |  4 +--
 hw/i2c/ppc4xx_i2c.c       | 15 +++++---
 hw/i2c/smbus_master.c     | 22 ++++++------
 hw/input/lm832x.c         |  2 +-
 hw/misc/auxbus.c          | 70 ++++++++++++++++++++++++++----------
 MAINTAINERS               |  1 +
 16 files changed, 207 insertions(+), 88 deletions(-)
 create mode 100644 include/hw/input/lm832x.h

-- 
2.31.1

[PATCH v4 01/15] hw/input/lm832x: Move lm832x_key_event() declaration to "lm832x.h"

[Philippe Mathieu-Daudé]

lm832x_key_event() is specific go LM832x devices, not to the
I2C bus API. Move it out of "i2c.h" to a new header.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/i2c/i2c.h      |  3 ---
 include/hw/input/lm832x.h | 26 ++++++++++++++++++++++++++
 hw/arm/nseries.c          |  1 +
 hw/input/lm832x.c         |  1 +
 MAINTAINERS               |  1 +
 5 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 include/hw/input/lm832x.h

diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index ff4129ea704..850815e707c 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -142,9 +142,6 @@ I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
  */
 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 
-/* lm832x.c */
-void lm832x_key_event(DeviceState *dev, int key, int state);
-
 extern const VMStateDescription vmstate_i2c_slave;
 
 #define VMSTATE_I2C_SLAVE(_field, _state) {                          \
diff --git a/include/hw/input/lm832x.h b/include/hw/input/lm832x.h
new file mode 100644
index 00000000000..f47e579ff90
--- /dev/null
+++ b/include/hw/input/lm832x.h
@@ -0,0 +1,26 @@
+/*
+ * National Semiconductor LM8322/8323 GPIO keyboard & PWM chips.
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Written by Andrzej Zaborowski <andrew@openedhand.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 or
+ * (at your option) version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_INPUT_LM832X
+#define HW_INPUT_LM832X
+
+void lm832x_key_event(DeviceState *dev, int key, int state);
+
+#endif
diff --git a/hw/arm/nseries.c b/hw/arm/nseries.c
index 0aefa5d0f3e..7b82b8682e8 100644
--- a/hw/arm/nseries.c
+++ b/hw/arm/nseries.c
@@ -34,6 +34,7 @@
 #include "hw/boards.h"
 #include "hw/i2c/i2c.h"
 #include "hw/display/blizzard.h"
+#include "hw/input/lm832x.h"
 #include "hw/input/tsc2xxx.h"
 #include "hw/misc/cbus.h"
 #include "hw/misc/tmp105.h"
diff --git a/hw/input/lm832x.c b/hw/input/lm832x.c
index 4cb1e9de01f..d2b92b457e3 100644
--- a/hw/input/lm832x.c
+++ b/hw/input/lm832x.c
@@ -19,6 +19,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "hw/input/lm832x.h"
 #include "hw/i2c/i2c.h"
 #include "hw/irq.h"
 #include "migration/vmstate.h"
diff --git a/MAINTAINERS b/MAINTAINERS
index 636bf2f5365..c56bc112ccf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -792,6 +792,7 @@ F: hw/input/tsc2005.c
 F: hw/misc/cbus.c
 F: hw/rtc/twl92230.c
 F: include/hw/display/blizzard.h
+F: include/hw/input/lm832x.h
 F: include/hw/input/tsc2xxx.h
 F: include/hw/misc/cbus.h
 F: tests/acceptance/machine_arm_n8x0.py
-- 
2.31.1

[PATCH v4 02/15] hw/input/lm832x: Define TYPE_LM8323 in public header

[Philippe Mathieu-Daudé]

Define TYPE_LM8323 in the public "hw/input/lm832x.h"
header and use it in hw/arm/nseries.c.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/input/lm832x.h | 2 ++
 hw/arm/nseries.c          | 2 +-
 hw/input/lm832x.c         | 1 -
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/hw/input/lm832x.h b/include/hw/input/lm832x.h
index f47e579ff90..2a58ccf8916 100644
--- a/include/hw/input/lm832x.h
+++ b/include/hw/input/lm832x.h
@@ -21,6 +21,8 @@
 #ifndef HW_INPUT_LM832X
 #define HW_INPUT_LM832X
 
+#define TYPE_LM8323 "lm8323"
+
 void lm832x_key_event(DeviceState *dev, int key, int state);
 
 #endif
diff --git a/hw/arm/nseries.c b/hw/arm/nseries.c
index 7b82b8682e8..3a51264e3cf 100644
--- a/hw/arm/nseries.c
+++ b/hw/arm/nseries.c
@@ -417,7 +417,7 @@ static void n810_kbd_setup(struct n800_s *s)
     /* Attach the LM8322 keyboard to the I2C bus,
      * should happen in n8x0_i2c_setup and s->kbd be initialised here.  */
     s->kbd = DEVICE(i2c_slave_create_simple(omap_i2c_bus(s->mpu->i2c[0]),
-                                            "lm8323", N810_LM8323_ADDR));
+                                            TYPE_LM8323, N810_LM8323_ADDR));
     qdev_connect_gpio_out(s->kbd, 0, kbd_irq);
 }
 
diff --git a/hw/input/lm832x.c b/hw/input/lm832x.c
index d2b92b457e3..19a646d9bb4 100644
--- a/hw/input/lm832x.c
+++ b/hw/input/lm832x.c
@@ -28,7 +28,6 @@
 #include "ui/console.h"
 #include "qom/object.h"
 
-#define TYPE_LM8323 "lm8323"
 OBJECT_DECLARE_SIMPLE_TYPE(LM823KbdState, LM8323)
 
 struct LM823KbdState {
-- 
2.31.1

[PATCH v4 03/15] hw/display/sm501: Simplify sm501_i2c_write() logic

[Philippe Mathieu-Daudé]

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/display/sm501.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index 8789722ef27..f276276f7f1 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -1036,8 +1036,9 @@ static void sm501_i2c_write(void *opaque, hwaddr addr, uint64_t value,
                 int res = i2c_start_transfer(s->i2c_bus,
                                              s->i2c_addr >> 1,
                                              s->i2c_addr & 1);
-                s->i2c_status |= (res ? SM501_I2C_STATUS_ERROR : 0);
-                if (!res) {
+                if (res) {
+                    s->i2c_status |= SM501_I2C_STATUS_ERROR;
+                } else {
                     int i;
                     for (i = 0; i <= s->i2c_byte_count; i++) {
                         res = i2c_send_recv(s->i2c_bus, &s->i2c_data[i],
-- 
2.31.1

[PATCH v4 04/15] hw/display/sm501: Replace i2c_send_recv() by i2c_recv() & i2c_send()

[Philippe Mathieu-Daudé]

Instead of using the confuse i2c_send_recv(), rewrite to directly
call i2c_recv() & i2c_send(), resulting in code easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/display/sm501.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index f276276f7f1..569661a0746 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -1033,17 +1033,18 @@ static void sm501_i2c_write(void *opaque, hwaddr addr, uint64_t value,
     case SM501_I2C_CONTROL:
         if (value & SM501_I2C_CONTROL_ENABLE) {
             if (value & SM501_I2C_CONTROL_START) {
+                bool is_recv = s->i2c_addr & 1;
                 int res = i2c_start_transfer(s->i2c_bus,
                                              s->i2c_addr >> 1,
-                                             s->i2c_addr & 1);
+                                             is_recv);
                 if (res) {
                     s->i2c_status |= SM501_I2C_STATUS_ERROR;
                 } else {
                     int i;
                     for (i = 0; i <= s->i2c_byte_count; i++) {
-                        res = i2c_send_recv(s->i2c_bus, &s->i2c_data[i],
-                                            !(s->i2c_addr & 1));
-                        if (res) {
+                        if (is_recv) {
+                            s->i2c_data[i] = i2c_recv(s->i2c_bus);
+                        } else if (i2c_send(s->i2c_bus, s->i2c_data[i]) < 0) {
                             s->i2c_status |= SM501_I2C_STATUS_ERROR;
                             return;
                         }
-- 
2.31.1

[PATCH v4 05/15] hw/i2c/ppc4xx_i2c: Add reference to datasheet

[Philippe Mathieu-Daudé]

It took me a while to find this model datasheet, since it is
an OCR scan. Add a reference to save other developers time.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/i2c/ppc4xx_i2c.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/i2c/ppc4xx_i2c.c b/hw/i2c/ppc4xx_i2c.c
index c0a8e045670..f4c5bc12d36 100644
--- a/hw/i2c/ppc4xx_i2c.c
+++ b/hw/i2c/ppc4xx_i2c.c
@@ -1,6 +1,8 @@
 /*
  * PPC4xx I2C controller emulation
  *
+ * Documentation: PPC405GP User's Manual, Chapter 22. IIC Bus Interface
+ *
  * Copyright (c) 2007 Jocelyn Mayer
  * Copyright (c) 2012 François Revol
  * Copyright (c) 2016-2018 BALATON Zoltan
-- 
2.31.1

[PATCH v4 06/15] hw/i2c/ppc4xx_i2c: Replace i2c_send_recv() by i2c_recv() & i2c_send()

[Philippe Mathieu-Daudé]

Instead of using the confuse i2c_send_recv(), rewrite to directly
call i2c_recv() & i2c_send(), resulting in code easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/i2c/ppc4xx_i2c.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/hw/i2c/ppc4xx_i2c.c b/hw/i2c/ppc4xx_i2c.c
index f4c5bc12d36..75d50f15158 100644
--- a/hw/i2c/ppc4xx_i2c.c
+++ b/hw/i2c/ppc4xx_i2c.c
@@ -240,11 +240,14 @@ static void ppc4xx_i2c_writeb(void *opaque, hwaddr addr, uint64_t value,
                         i2c->sts &= ~IIC_STS_ERR;
                     }
                 }
-                if (!(i2c->sts & IIC_STS_ERR) &&
-                    i2c_send_recv(i2c->bus, &i2c->mdata[i], !recv)) {
-                    i2c->sts |= IIC_STS_ERR;
-                    i2c->extsts |= IIC_EXTSTS_XFRA;
-                    break;
+                if (!(i2c->sts & IIC_STS_ERR)) {
+                    if (recv) {
+                        i2c->mdata[i] = i2c_recv(i2c->bus);
+                    } else if (i2c_send(i2c->bus, i2c->mdata[i]) < 0) {
+                        i2c->sts |= IIC_STS_ERR;
+                        i2c->extsts |= IIC_EXTSTS_XFRA;
+                        break;
+                    }
                 }
                 if (value & IIC_CNTL_RPST || !(value & IIC_CNTL_CHT)) {
                     i2c_end_transfer(i2c->bus);
-- 
2.31.1

[PATCH v4 07/15] hw/misc/auxbus: Fix MOT/classic I2C mode

[Philippe Mathieu-Daudé]

Since its introduction in commit 6fc7f77fd2 i2c_start_transfer()
uses incorrectly the direction of the transfer (the last argument
is called 'is_recv'). Fix by inverting the argument, we now have
is_recv = !is_write.

Fixes: 6fc7f77fd2 ("introduce aux-bus")
Reported-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/misc/auxbus.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/misc/auxbus.c b/hw/misc/auxbus.c
index 6c099ae2a2d..148b070ce4a 100644
--- a/hw/misc/auxbus.c
+++ b/hw/misc/auxbus.c
@@ -139,7 +139,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             i2c_end_transfer(i2c_bus);
         }
 
-        if (i2c_start_transfer(i2c_bus, address, is_write)) {
+        if (i2c_start_transfer(i2c_bus, address, !is_write)) {
             ret = AUX_I2C_NACK;
             break;
         }
@@ -170,7 +170,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             /*
              * No transactions started..
              */
-            if (i2c_start_transfer(i2c_bus, address, is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
                 break;
             }
         } else if ((address != bus->last_i2c_address) ||
@@ -179,7 +179,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
              * Transaction started but we need to restart..
              */
             i2c_end_transfer(i2c_bus);
-            if (i2c_start_transfer(i2c_bus, address, is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
                 break;
             }
         }
-- 
2.31.1

[PATCH v4 08/15] hw/misc/auxbus: Explode READ_I2C / WRITE_I2C_MOT cases

[Philippe Mathieu-Daudé]

To allow further simplifications in the following commits,
start copying WRITE_I2C code to the READ_I2C, and READ_I2C_MOT
to WRITE_I2C_MOT. No logical change.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/misc/auxbus.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/hw/misc/auxbus.c b/hw/misc/auxbus.c
index 148b070ce4a..9cc9cf3be32 100644
--- a/hw/misc/auxbus.c
+++ b/hw/misc/auxbus.c
@@ -133,6 +133,26 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
      * Classic I2C transactions..
      */
     case READ_I2C:
+        is_write = cmd == READ_I2C ? false : true;
+        if (i2c_bus_busy(i2c_bus)) {
+            i2c_end_transfer(i2c_bus);
+        }
+
+        if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+            ret = AUX_I2C_NACK;
+            break;
+        }
+
+        ret = AUX_I2C_ACK;
+        while (len > 0) {
+            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+                ret = AUX_I2C_NACK;
+                break;
+            }
+            len--;
+        }
+        i2c_end_transfer(i2c_bus);
+        break;
     case WRITE_I2C:
         is_write = cmd == READ_I2C ? false : true;
         if (i2c_bus_busy(i2c_bus)) {
@@ -163,6 +183,39 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
      *  - We changed the address.
      */
     case WRITE_I2C_MOT:
+        is_write = cmd == READ_I2C_MOT ? false : true;
+        ret = AUX_I2C_NACK;
+        if (!i2c_bus_busy(i2c_bus)) {
+            /*
+             * No transactions started..
+             */
+            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+                break;
+            }
+        } else if ((address != bus->last_i2c_address) ||
+                   (bus->last_transaction != cmd)) {
+            /*
+             * Transaction started but we need to restart..
+             */
+            i2c_end_transfer(i2c_bus);
+            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+                break;
+            }
+        }
+
+        bus->last_transaction = cmd;
+        bus->last_i2c_address = address;
+        while (len > 0) {
+            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+                i2c_end_transfer(i2c_bus);
+                break;
+            }
+            len--;
+        }
+        if (len == 0) {
+            ret = AUX_I2C_ACK;
+        }
+        break;
     case READ_I2C_MOT:
         is_write = cmd == READ_I2C_MOT ? false : true;
         ret = AUX_I2C_NACK;
-- 
2.31.1

[PATCH v4 09/15] hw/misc/auxbus: Replace 'is_write' boolean by its value

[Philippe Mathieu-Daudé]

Remove the 'is_write' boolean by directly using its value in place.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/misc/auxbus.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/hw/misc/auxbus.c b/hw/misc/auxbus.c
index 9cc9cf3be32..d96219aef88 100644
--- a/hw/misc/auxbus.c
+++ b/hw/misc/auxbus.c
@@ -106,7 +106,6 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
     AUXReply ret = AUX_NACK;
     I2CBus *i2c_bus = aux_get_i2c_bus(bus);
     size_t i;
-    bool is_write = false;
 
     DPRINTF("request at address 0x%" PRIX32 ", command %u, len %u\n", address,
             cmd, len);
@@ -117,11 +116,10 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
      */
     case WRITE_AUX:
     case READ_AUX:
-        is_write = cmd == READ_AUX ? false : true;
         for (i = 0; i < len; i++) {
             if (!address_space_rw(&bus->aux_addr_space, address++,
                                   MEMTXATTRS_UNSPECIFIED, data++, 1,
-                                  is_write)) {
+                                  cmd == WRITE_AUX)) {
                 ret = AUX_I2C_ACK;
             } else {
                 ret = AUX_NACK;
@@ -133,19 +131,18 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
      * Classic I2C transactions..
      */
     case READ_I2C:
-        is_write = cmd == READ_I2C ? false : true;
         if (i2c_bus_busy(i2c_bus)) {
             i2c_end_transfer(i2c_bus);
         }
 
-        if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+        if (i2c_start_transfer(i2c_bus, address, true)) {
             ret = AUX_I2C_NACK;
             break;
         }
 
         ret = AUX_I2C_ACK;
         while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+            if (i2c_send_recv(i2c_bus, data++, false) < 0) {
                 ret = AUX_I2C_NACK;
                 break;
             }
@@ -154,19 +151,18 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         i2c_end_transfer(i2c_bus);
         break;
     case WRITE_I2C:
-        is_write = cmd == READ_I2C ? false : true;
         if (i2c_bus_busy(i2c_bus)) {
             i2c_end_transfer(i2c_bus);
         }
 
-        if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+        if (i2c_start_transfer(i2c_bus, address, false)) {
             ret = AUX_I2C_NACK;
             break;
         }
 
         ret = AUX_I2C_ACK;
         while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+            if (i2c_send_recv(i2c_bus, data++, true) < 0) {
                 ret = AUX_I2C_NACK;
                 break;
             }
@@ -183,13 +179,12 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
      *  - We changed the address.
      */
     case WRITE_I2C_MOT:
-        is_write = cmd == READ_I2C_MOT ? false : true;
         ret = AUX_I2C_NACK;
         if (!i2c_bus_busy(i2c_bus)) {
             /*
              * No transactions started..
              */
-            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, false)) {
                 break;
             }
         } else if ((address != bus->last_i2c_address) ||
@@ -198,7 +193,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
              * Transaction started but we need to restart..
              */
             i2c_end_transfer(i2c_bus);
-            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, false)) {
                 break;
             }
         }
@@ -206,7 +201,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         bus->last_transaction = cmd;
         bus->last_i2c_address = address;
         while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+            if (i2c_send_recv(i2c_bus, data++, true) < 0) {
                 i2c_end_transfer(i2c_bus);
                 break;
             }
@@ -217,13 +212,12 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         }
         break;
     case READ_I2C_MOT:
-        is_write = cmd == READ_I2C_MOT ? false : true;
         ret = AUX_I2C_NACK;
         if (!i2c_bus_busy(i2c_bus)) {
             /*
              * No transactions started..
              */
-            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, true)) {
                 break;
             }
         } else if ((address != bus->last_i2c_address) ||
@@ -232,7 +226,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
              * Transaction started but we need to restart..
              */
             i2c_end_transfer(i2c_bus);
-            if (i2c_start_transfer(i2c_bus, address, !is_write)) {
+            if (i2c_start_transfer(i2c_bus, address, true)) {
                 break;
             }
         }
@@ -240,7 +234,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         bus->last_transaction = cmd;
         bus->last_i2c_address = address;
         while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, is_write) < 0) {
+            if (i2c_send_recv(i2c_bus, data++, false) < 0) {
                 i2c_end_transfer(i2c_bus);
                 break;
             }
-- 
2.31.1

[PATCH v4 10/15] hw/misc/auxbus: Replace i2c_send_recv() by i2c_recv() & i2c_send()

[Philippe Mathieu-Daudé]

Instead of using the confuse i2c_send_recv(), replace
  i2c_send_recv(send = true) by i2c_send() and
  i2c_send_recv(send = false) by i2c_recv().
During the replacement we also change a while() statement by for().
The resulting code is easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/misc/auxbus.c | 35 +++++++++++------------------------
 1 file changed, 11 insertions(+), 24 deletions(-)

diff --git a/hw/misc/auxbus.c b/hw/misc/auxbus.c
index d96219aef88..44aa9730bc9 100644
--- a/hw/misc/auxbus.c
+++ b/hw/misc/auxbus.c
@@ -141,12 +141,8 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         }
 
         ret = AUX_I2C_ACK;
-        while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, false) < 0) {
-                ret = AUX_I2C_NACK;
-                break;
-            }
-            len--;
+        for (i = 0; i < len; i++) {
+            data[i] = i2c_recv(i2c_bus);
         }
         i2c_end_transfer(i2c_bus);
         break;
@@ -161,12 +157,11 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
         }
 
         ret = AUX_I2C_ACK;
-        while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, true) < 0) {
+        for (i = 0; i < len; i++) {
+            if (i2c_send(i2c_bus, data[i]) < 0) {
                 ret = AUX_I2C_NACK;
                 break;
             }
-            len--;
         }
         i2c_end_transfer(i2c_bus);
         break;
@@ -200,15 +195,13 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
 
         bus->last_transaction = cmd;
         bus->last_i2c_address = address;
-        while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, true) < 0) {
+        ret = AUX_I2C_ACK;
+        for (i = 0; i < len; i++) {
+            if (i2c_send(i2c_bus, data[i]) < 0) {
                 i2c_end_transfer(i2c_bus);
+                ret = AUX_I2C_NACK;
                 break;
             }
-            len--;
-        }
-        if (len == 0) {
-            ret = AUX_I2C_ACK;
         }
         break;
     case READ_I2C_MOT:
@@ -233,16 +226,10 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
 
         bus->last_transaction = cmd;
         bus->last_i2c_address = address;
-        while (len > 0) {
-            if (i2c_send_recv(i2c_bus, data++, false) < 0) {
-                i2c_end_transfer(i2c_bus);
-                break;
-            }
-            len--;
-        }
-        if (len == 0) {
-            ret = AUX_I2C_ACK;
+        for (i = 0; i < len; i++) {
+            data[i] = i2c_recv(i2c_bus);
         }
+        ret = AUX_I2C_ACK;
         break;
     default:
         qemu_log_mask(LOG_UNIMP, "AUX cmd=%u not implemented\n", cmd);
-- 
2.31.1

[PATCH v4 11/15] hw/i2c: Remove confusing i2c_send_recv()

[Philippe Mathieu-Daudé]

We replaced all the i2c_send_recv() calls by the clearer i2c_recv()
and i2c_send(), so we can remove this confusing API.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/i2c/i2c.h |  1 -
 hw/i2c/core.c        | 50 +++++++++++++++++++-------------------------
 2 files changed, 21 insertions(+), 30 deletions(-)

diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 850815e707c..99635b837a5 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -84,7 +84,6 @@ int i2c_bus_busy(I2CBus *bus);
 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
 void i2c_end_transfer(I2CBus *bus);
 void i2c_nack(I2CBus *bus);
-int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
 int i2c_send(I2CBus *bus, uint8_t data);
 uint8_t i2c_recv(I2CBus *bus);
 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 3a7bae311df..27a66df7f34 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -188,50 +188,42 @@ void i2c_end_transfer(I2CBus *bus)
     bus->broadcast = false;
 }
 
-int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
+int i2c_send(I2CBus *bus, uint8_t data)
 {
     I2CSlaveClass *sc;
     I2CSlave *s;
     I2CNode *node;
     int ret = 0;
 
-    if (send) {
-        QLIST_FOREACH(node, &bus->current_devs, next) {
-            s = node->elt;
-            sc = I2C_SLAVE_GET_CLASS(s);
-            if (sc->send) {
-                trace_i2c_send(s->address, *data);
-                ret = ret || sc->send(s, *data);
-            } else {
-                ret = -1;
-            }
+    QLIST_FOREACH(node, &bus->current_devs, next) {
+        s = node->elt;
+        sc = I2C_SLAVE_GET_CLASS(s);
+        if (sc->send) {
+            trace_i2c_send(s->address, data);
+            ret = ret || sc->send(s, data);
+        } else {
+            ret = -1;
         }
-        return ret ? -1 : 0;
-    } else {
-        ret = 0xff;
-        if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) {
-            sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
-            if (sc->recv) {
-                s = QLIST_FIRST(&bus->current_devs)->elt;
-                ret = sc->recv(s);
-                trace_i2c_recv(s->address, ret);
-            }
-        }
-        *data = ret;
-        return 0;
     }
-}
 
-int i2c_send(I2CBus *bus, uint8_t data)
-{
-    return i2c_send_recv(bus, &data, true);
+    return ret ? -1 : 0;
 }
 
 uint8_t i2c_recv(I2CBus *bus)
 {
     uint8_t data = 0xff;
+    I2CSlaveClass *sc;
+    I2CSlave *s;
+
+    if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) {
+        sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
+        if (sc->recv) {
+            s = QLIST_FIRST(&bus->current_devs)->elt;
+            data = sc->recv(s);
+            trace_i2c_recv(s->address, data);
+        }
+    }
 
-    i2c_send_recv(bus, &data, false);
     return data;
 }
 
-- 
2.31.1

[PATCH v4 12/15] hw/i2c: Rename i2c_set_slave_address() -> i2c_slave_set_address()

[Philippe Mathieu-Daudé]

Other functions from I2C slave API are named "i2c_slave_XXX()".
Follow that pattern with set_address(). Add docstring along.
No logical change.

Patch created mechanically using:

  $ sed -i s/i2c_set_slave_address/i2c_slave_set_address/ \
    $(git grep -l i2c_set_slave_address)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/i2c/i2c.h | 8 +++++++-
 hw/arm/pxa2xx.c      | 2 +-
 hw/arm/spitz.c       | 4 ++--
 hw/display/ati.c     | 2 +-
 hw/display/sm501.c   | 2 +-
 hw/display/xlnx_dp.c | 2 +-
 hw/i2c/core.c        | 2 +-
 hw/i2c/imx_i2c.c     | 2 +-
 8 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 99635b837a5..2adf521b271 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -79,7 +79,6 @@ struct I2CBus {
 };
 
 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
-void i2c_set_slave_address(I2CSlave *dev, uint8_t address);
 int i2c_bus_busy(I2CBus *bus);
 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
 void i2c_end_transfer(I2CBus *bus);
@@ -141,6 +140,13 @@ I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr);
  */
 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp);
 
+/**
+ * Set the I2C bus address of a slave device
+ * @dev: I2C slave device
+ * @address: I2C address of the slave when put on a bus
+ */
+void i2c_slave_set_address(I2CSlave *dev, uint8_t address);
+
 extern const VMStateDescription vmstate_i2c_slave;
 
 #define VMSTATE_I2C_SLAVE(_field, _state) {                          \
diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
index fdc4955e95b..15a247efae2 100644
--- a/hw/arm/pxa2xx.c
+++ b/hw/arm/pxa2xx.c
@@ -1437,7 +1437,7 @@ static void pxa2xx_i2c_write(void *opaque, hwaddr addr,
         break;
 
     case ISAR:
-        i2c_set_slave_address(I2C_SLAVE(s->slave), value & 0x7f);
+        i2c_slave_set_address(I2C_SLAVE(s->slave), value & 0x7f);
         break;
 
     case IDBR:
diff --git a/hw/arm/spitz.c b/hw/arm/spitz.c
index b45a929cbd9..c0f0f8193f4 100644
--- a/hw/arm/spitz.c
+++ b/hw/arm/spitz.c
@@ -769,9 +769,9 @@ static void spitz_wm8750_addr(void *opaque, int line, int level)
 {
     I2CSlave *wm = (I2CSlave *) opaque;
     if (level)
-        i2c_set_slave_address(wm, SPITZ_WM_ADDRH);
+        i2c_slave_set_address(wm, SPITZ_WM_ADDRH);
     else
-        i2c_set_slave_address(wm, SPITZ_WM_ADDRL);
+        i2c_slave_set_address(wm, SPITZ_WM_ADDRL);
 }
 
 static void spitz_i2c_setup(PXA2xxState *cpu)
diff --git a/hw/display/ati.c b/hw/display/ati.c
index 4c3ad8f47b0..31f22754dce 100644
--- a/hw/display/ati.c
+++ b/hw/display/ati.c
@@ -968,7 +968,7 @@ static void ati_vga_realize(PCIDevice *dev, Error **errp)
     I2CBus *i2cbus = i2c_init_bus(DEVICE(s), "ati-vga.ddc");
     bitbang_i2c_init(&s->bbi2c, i2cbus);
     I2CSlave *i2cddc = I2C_SLAVE(qdev_new(TYPE_I2CDDC));
-    i2c_set_slave_address(i2cddc, 0x50);
+    i2c_slave_set_address(i2cddc, 0x50);
     qdev_realize_and_unref(DEVICE(i2cddc), BUS(i2cbus), &error_abort);
 
     /* mmio register space */
diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index 569661a0746..663c37e7f28 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -1828,7 +1828,7 @@ static void sm501_init(SM501State *s, DeviceState *dev,
     s->i2c_bus = i2c_init_bus(dev, "sm501.i2c");
     /* ddc */
     I2CDDCState *ddc = I2CDDC(qdev_new(TYPE_I2CDDC));
-    i2c_set_slave_address(I2C_SLAVE(ddc), 0x50);
+    i2c_slave_set_address(I2C_SLAVE(ddc), 0x50);
     qdev_realize_and_unref(DEVICE(ddc), BUS(s->i2c_bus), &error_abort);
 
     /* mmio */
diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
index 4fd6aeb18b5..2bb7a5441ad 100644
--- a/hw/display/xlnx_dp.c
+++ b/hw/display/xlnx_dp.c
@@ -1253,7 +1253,7 @@ static void xlnx_dp_init(Object *obj)
     object_property_add_child(OBJECT(s), "dpcd", OBJECT(s->dpcd));
 
     s->edid = I2CDDC(qdev_new("i2c-ddc"));
-    i2c_set_slave_address(I2C_SLAVE(s->edid), 0x50);
+    i2c_slave_set_address(I2C_SLAVE(s->edid), 0x50);
     object_property_add_child(OBJECT(s), "edid", OBJECT(s->edid));
 
     fifo8_create(&s->rx_fifo, 16);
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 27a66df7f34..6af24c9e797 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -66,7 +66,7 @@ I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
     return bus;
 }
 
-void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
+void i2c_slave_set_address(I2CSlave *dev, uint8_t address)
 {
     dev->address = address;
 }
diff --git a/hw/i2c/imx_i2c.c b/hw/i2c/imx_i2c.c
index 2e02e1c4faa..9792583fea7 100644
--- a/hw/i2c/imx_i2c.c
+++ b/hw/i2c/imx_i2c.c
@@ -171,7 +171,7 @@ static void imx_i2c_write(void *opaque, hwaddr offset,
     switch (offset) {
     case IADR_ADDR:
         s->iadr = value & IADR_MASK;
-        /* i2c_set_slave_address(s->bus, (uint8_t)s->iadr); */
+        /* i2c_slave_set_address(s->bus, (uint8_t)s->iadr); */
         break;
     case IFDR_ADDR:
         s->ifdr = value & IFDR_MASK;
-- 
2.31.1

[PATCH v4 13/15] hw/i2c: Make i2c_start_transfer() direction argument a boolean

[Philippe Mathieu-Daudé]

From: BALATON Zoltan <balaton@eik.bme.hu>

Make the argument representing the direction of the transfer a
boolean type.
Rename the boolean argument as 'is_recv' to match i2c_recv_send().
Document the function prototype.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-Id: <20200621145235.9E241745712@zero.eik.bme.hu>
[PMD: Split patch, added docstring]
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/i2c/i2c.h | 12 +++++++++++-
 hw/i2c/core.c        |  4 ++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 2adf521b271..21f2dba1bf7 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -80,7 +80,17 @@ struct I2CBus {
 
 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
 int i2c_bus_busy(I2CBus *bus);
-int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv);
+
+/**
+ * i2c_start_transfer: start a transfer on an I2C bus.
+ *
+ * @bus: #I2CBus to be used
+ * @address: address of the slave
+ * @is_recv: indicates the transfer direction
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv);
 void i2c_end_transfer(I2CBus *bus);
 void i2c_nack(I2CBus *bus);
 int i2c_send(I2CBus *bus, uint8_t data);
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 6af24c9e797..6639ca8c2e0 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -115,7 +115,7 @@ bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
  * without releasing the bus.  If that fails, the bus is still
  * in a transaction.
  */
-int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
+int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
 {
     I2CSlaveClass *sc;
     I2CNode *node;
@@ -157,7 +157,7 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
 
         if (sc->event) {
             trace_i2c_event("start", s->address);
-            rv = sc->event(s, recv ? I2C_START_RECV : I2C_START_SEND);
+            rv = sc->event(s, is_recv ? I2C_START_RECV : I2C_START_SEND);
             if (rv && !bus->broadcast) {
                 if (bus_scanned) {
                     /* First call, terminate the transfer. */
-- 
2.31.1

[PATCH v4 14/15] hw/i2c: Extract i2c_do_start_transfer() from i2c_start_transfer()

[Philippe Mathieu-Daudé]

To allow further simplications, extract i2c_do_start_transfer()
from i2c_start_transfer(). This is mostly the same function,
but the former is static and takes an enum argument.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/i2c/core.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 6639ca8c2e0..69df4c0df6b 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -115,12 +115,15 @@ bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
  * without releasing the bus.  If that fails, the bus is still
  * in a transaction.
  */
-int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
+static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
+                                 enum i2c_event event)
 {
     I2CSlaveClass *sc;
     I2CNode *node;
     bool bus_scanned = false;
 
+    assert(event == I2C_START_RECV || event == I2C_START_SEND);
+
     if (address == I2C_BROADCAST) {
         /*
          * This is a broadcast, the current_devs will be all the devices of the
@@ -157,7 +160,7 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
 
         if (sc->event) {
             trace_i2c_event("start", s->address);
-            rv = sc->event(s, is_recv ? I2C_START_RECV : I2C_START_SEND);
+            rv = sc->event(s, event);
             if (rv && !bus->broadcast) {
                 if (bus_scanned) {
                     /* First call, terminate the transfer. */
@@ -170,6 +173,13 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
     return 0;
 }
 
+int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
+{
+    return i2c_do_start_transfer(bus, address, is_recv
+                                               ? I2C_START_RECV
+                                               : I2C_START_SEND);
+}
+
 void i2c_end_transfer(I2CBus *bus)
 {
     I2CSlaveClass *sc;
-- 
2.31.1

[PATCH v4 15/15] hw/i2c: Introduce i2c_start_recv() and i2c_start_send()

[Philippe Mathieu-Daudé]

To ease reviewing code using the I2C bus API, introduce the
i2c_start_recv() and i2c_start_send() helpers which don't
take the confusing 'is_recv' boolean argument.

Use these new helpers in the SMBus / AUX bus models.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/i2c/i2c.h  | 24 ++++++++++++++++++++++++
 hw/i2c/core.c         | 10 ++++++++++
 hw/i2c/pm_smbus.c     |  4 ++--
 hw/i2c/smbus_master.c | 22 +++++++++++-----------
 hw/misc/auxbus.c      | 12 ++++++------
 5 files changed, 53 insertions(+), 19 deletions(-)

diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 21f2dba1bf7..5ca3b708c0b 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -88,9 +88,33 @@ int i2c_bus_busy(I2CBus *bus);
  * @address: address of the slave
  * @is_recv: indicates the transfer direction
  *
+ * When @is_recv is a known boolean constant, use the
+ * i2c_start_recv() or i2c_start_send() helper instead.
+ *
  * Returns: 0 on success, -1 on error
  */
 int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv);
+
+/**
+ * i2c_start_recv: start a 'receive' transfer on an I2C bus.
+ *
+ * @bus: #I2CBus to be used
+ * @address: address of the slave
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int i2c_start_recv(I2CBus *bus, uint8_t address);
+
+/**
+ * i2c_start_send: start a 'send' transfer on an I2C bus.
+ *
+ * @bus: #I2CBus to be used
+ * @address: address of the slave
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int i2c_start_send(I2CBus *bus, uint8_t address);
+
 void i2c_end_transfer(I2CBus *bus);
 void i2c_nack(I2CBus *bus);
 int i2c_send(I2CBus *bus, uint8_t data);
diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 69df4c0df6b..7156f55ded7 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -180,6 +180,16 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
                                                : I2C_START_SEND);
 }
 
+int i2c_start_recv(I2CBus *bus, uint8_t address)
+{
+    return i2c_do_start_transfer(bus, address, I2C_START_RECV);
+}
+
+int i2c_start_send(I2CBus *bus, uint8_t address)
+{
+    return i2c_do_start_transfer(bus, address, I2C_START_SEND);
+}
+
 void i2c_end_transfer(I2CBus *bus)
 {
     I2CSlaveClass *sc;
diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c
index 06e1e5321b9..d7eae548cbc 100644
--- a/hw/i2c/pm_smbus.c
+++ b/hw/i2c/pm_smbus.c
@@ -128,14 +128,14 @@ static void smb_transaction(PMSMBus *s)
          * So at least Linux may or may not set the read bit here.
          * So just ignore the read bit for this command.
          */
-        if (i2c_start_transfer(bus, addr, 0)) {
+        if (i2c_start_send(bus, addr)) {
             goto error;
         }
         ret = i2c_send(bus, s->smb_data1);
         if (ret) {
             goto error;
         }
-        if (i2c_start_transfer(bus, addr, 1)) {
+        if (i2c_start_recv(bus, addr)) {
             goto error;
         }
         s->in_i2c_block_read = true;
diff --git a/hw/i2c/smbus_master.c b/hw/i2c/smbus_master.c
index dc43b8637d1..6a53c34e70b 100644
--- a/hw/i2c/smbus_master.c
+++ b/hw/i2c/smbus_master.c
@@ -29,7 +29,7 @@ int smbus_receive_byte(I2CBus *bus, uint8_t addr)
 {
     uint8_t data;
 
-    if (i2c_start_transfer(bus, addr, 1)) {
+    if (i2c_start_recv(bus, addr)) {
         return -1;
     }
     data = i2c_recv(bus);
@@ -40,7 +40,7 @@ int smbus_receive_byte(I2CBus *bus, uint8_t addr)
 
 int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
 {
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, data);
@@ -51,11 +51,11 @@ int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
 int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
 {
     uint8_t data;
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, command);
-    if (i2c_start_transfer(bus, addr, 1)) {
+    if (i2c_start_recv(bus, addr)) {
         i2c_end_transfer(bus);
         return -1;
     }
@@ -67,7 +67,7 @@ int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
 
 int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
 {
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, command);
@@ -79,11 +79,11 @@ int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
 int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
 {
     uint16_t data;
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, command);
-    if (i2c_start_transfer(bus, addr, 1)) {
+    if (i2c_start_recv(bus, addr)) {
         i2c_end_transfer(bus);
         return -1;
     }
@@ -96,7 +96,7 @@ int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
 
 int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
 {
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, command);
@@ -113,12 +113,12 @@ int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
     int i;
 
     if (send_cmd) {
-        if (i2c_start_transfer(bus, addr, 0)) {
+        if (i2c_start_send(bus, addr)) {
             return -1;
         }
         i2c_send(bus, command);
     }
-    if (i2c_start_transfer(bus, addr, 1)) {
+    if (i2c_start_recv(bus, addr)) {
         if (send_cmd) {
             i2c_end_transfer(bus);
         }
@@ -149,7 +149,7 @@ int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
         len = 32;
     }
 
-    if (i2c_start_transfer(bus, addr, 0)) {
+    if (i2c_start_send(bus, addr)) {
         return -1;
     }
     i2c_send(bus, command);
diff --git a/hw/misc/auxbus.c b/hw/misc/auxbus.c
index 44aa9730bc9..434ff8d910d 100644
--- a/hw/misc/auxbus.c
+++ b/hw/misc/auxbus.c
@@ -135,7 +135,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             i2c_end_transfer(i2c_bus);
         }
 
-        if (i2c_start_transfer(i2c_bus, address, true)) {
+        if (i2c_start_recv(i2c_bus, address)) {
             ret = AUX_I2C_NACK;
             break;
         }
@@ -151,7 +151,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             i2c_end_transfer(i2c_bus);
         }
 
-        if (i2c_start_transfer(i2c_bus, address, false)) {
+        if (i2c_start_send(i2c_bus, address)) {
             ret = AUX_I2C_NACK;
             break;
         }
@@ -179,7 +179,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             /*
              * No transactions started..
              */
-            if (i2c_start_transfer(i2c_bus, address, false)) {
+            if (i2c_start_send(i2c_bus, address)) {
                 break;
             }
         } else if ((address != bus->last_i2c_address) ||
@@ -188,7 +188,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
              * Transaction started but we need to restart..
              */
             i2c_end_transfer(i2c_bus);
-            if (i2c_start_transfer(i2c_bus, address, false)) {
+            if (i2c_start_send(i2c_bus, address)) {
                 break;
             }
         }
@@ -210,7 +210,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
             /*
              * No transactions started..
              */
-            if (i2c_start_transfer(i2c_bus, address, true)) {
+            if (i2c_start_recv(i2c_bus, address)) {
                 break;
             }
         } else if ((address != bus->last_i2c_address) ||
@@ -219,7 +219,7 @@ AUXReply aux_request(AUXBus *bus, AUXCommand cmd, uint32_t address,
              * Transaction started but we need to restart..
              */
             i2c_end_transfer(i2c_bus);
-            if (i2c_start_transfer(i2c_bus, address, true)) {
+            if (i2c_start_recv(i2c_bus, address)) {
                 break;
             }
         }
-- 
2.31.1

Re: [PATCH v4 03/15] hw/display/sm501: Simplify sm501_i2c_write() logic

[BALATON Zoltan]

[-- Attachment #1: Type: text/plain, Size: 1191 bytes --]

On Wed, 16 Jun 2021, Philippe Mathieu-Daudé wrote:
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Acked-by: Corey Minyard <cminyard@mvista.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>

> ---
> hw/display/sm501.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/hw/display/sm501.c b/hw/display/sm501.c
> index 8789722ef27..f276276f7f1 100644
> --- a/hw/display/sm501.c
> +++ b/hw/display/sm501.c
> @@ -1036,8 +1036,9 @@ static void sm501_i2c_write(void *opaque, hwaddr addr, uint64_t value,
>                 int res = i2c_start_transfer(s->i2c_bus,
>                                              s->i2c_addr >> 1,
>                                              s->i2c_addr & 1);
> -                s->i2c_status |= (res ? SM501_I2C_STATUS_ERROR : 0);
> -                if (!res) {
> +                if (res) {
> +                    s->i2c_status |= SM501_I2C_STATUS_ERROR;
> +                } else {
>                     int i;
>                     for (i = 0; i <= s->i2c_byte_count; i++) {
>                         res = i2c_send_recv(s->i2c_bus, &s->i2c_data[i],
>

Re: [PATCH v4 14/15] hw/i2c: Extract i2c_do_start_transfer() from i2c_start_transfer()

[Richard Henderson]

On 6/16/21 2:42 PM, Philippe Mathieu-Daudé wrote:
> +static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
> +                                 enum i2c_event event)
>   {
>       I2CSlaveClass *sc;
>       I2CNode *node;
>       bool bus_scanned = false;
>   
> +    assert(event == I2C_START_RECV || event == I2C_START_SEND);

I don't think you need the assert, given that its scope is limited, and there will be 
exactly 3 users that immediately follow.  Document it if you like.

Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH v4 15/15] hw/i2c: Introduce i2c_start_recv() and i2c_start_send()

[Richard Henderson]

On 6/16/21 2:42 PM, Philippe Mathieu-Daudé wrote:
> To ease reviewing code using the I2C bus API, introduce the
> i2c_start_recv() and i2c_start_send() helpers which don't
> take the confusing 'is_recv' boolean argument.
> 
> Use these new helpers in the SMBus / AUX bus models.
> 
> Suggested-by: Richard Henderson<richard.henderson@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé<f4bug@amsat.org>
> ---
>   include/hw/i2c/i2c.h  | 24 ++++++++++++++++++++++++
>   hw/i2c/core.c         | 10 ++++++++++
>   hw/i2c/pm_smbus.c     |  4 ++--
>   hw/i2c/smbus_master.c | 22 +++++++++++-----------
>   hw/misc/auxbus.c      | 12 ++++++------
>   5 files changed, 53 insertions(+), 19 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~