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Date:      Wed, 29 May 2019 09:08:21 +0000 (UTC)
From:      Andriy Gapon <avg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r348355 - head/sys/dev/iicbus
Message-ID:  <201905290908.x4T98L89066643@repo.freebsd.org>
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Author: avg
Date: Wed May 29 09:08:20 2019
New Revision: 348355
URL: https://svnweb.freebsd.org/changeset/base/348355

Log:
  revert r273728 and parts of r306589, iicbus no-stop by default feature
  
  Since drm2 removal, there has not been any consumer of the feature in the
  tree.  I am also unaware of any out-of-tree consumer.
  More importantly, the feature has been broken from the very start, both
  before and after r306589, because the ivar was set on a device that does
  not support it and it was read from another device that also does not
  support it.
  
  A bus-wide no-stop flag cannot be implemented as an ivar as iicbus
  attaches as a child of various drivers.  Implementing the ivar in each
  and every I2C driver is just impractical.
  
  If we ever want to implement this feature properly, then probably the
  easiest way to do it would be via a flag in the softc of iicbus.
  In fact, we might have to do that in the stable branches if we want to
  fix the code for them.
  
  Reported by:	ian (long time ago)
  MFC after:	1 month (maybe)
  X-MFC-note:	cannot just merge the change, must keep drm2 happy

Modified:
  head/sys/dev/iicbus/iicbus.c
  head/sys/dev/iicbus/iicbus.h
  head/sys/dev/iicbus/iiconf.c

Modified: head/sys/dev/iicbus/iicbus.c
==============================================================================
--- head/sys/dev/iicbus/iicbus.c	Wed May 29 07:33:51 2019	(r348354)
+++ head/sys/dev/iicbus/iicbus.c	Wed May 29 09:08:20 2019	(r348355)
@@ -194,9 +194,6 @@ iicbus_read_ivar(device_t bus, device_t child, int whi
 	case IICBUS_IVAR_ADDR:
 		*result = devi->addr;
 		break;
-	case IICBUS_IVAR_NOSTOP:
-		*result = devi->nostop;
-		break;
 	}
 	return (0);
 }
@@ -213,9 +210,6 @@ iicbus_write_ivar(device_t bus, device_t child, int wh
 		if (devi->addr != 0)
 			return (EINVAL);
 		devi->addr = value;
-	case IICBUS_IVAR_NOSTOP:
-		devi->nostop = value;
-		break;
 	}
 	return (0);
 }

Modified: head/sys/dev/iicbus/iicbus.h
==============================================================================
--- head/sys/dev/iicbus/iicbus.h	Wed May 29 07:33:51 2019	(r348354)
+++ head/sys/dev/iicbus/iicbus.h	Wed May 29 09:08:20 2019	(r348355)
@@ -54,19 +54,16 @@ struct iicbus_ivar
 {
 	uint32_t	addr;
 	struct resource_list	rl;
-	bool		nostop;
 };
 
 enum {
-	IICBUS_IVAR_ADDR,		/* Address or base address */
-	IICBUS_IVAR_NOSTOP,		/* nostop defaults */
+	IICBUS_IVAR_ADDR		/* Address or base address */
 };
 
 #define IICBUS_ACCESSOR(A, B, T)					\
 	__BUS_ACCESSOR(iicbus, A, IICBUS, B, T)
 	
 IICBUS_ACCESSOR(addr,		ADDR,		uint32_t)
-IICBUS_ACCESSOR(nostop,		NOSTOP,		bool)
 
 #define	IICBUS_LOCK(sc)			mtx_lock(&(sc)->lock)
 #define	IICBUS_UNLOCK(sc)      		mtx_unlock(&(sc)->lock)

Modified: head/sys/dev/iicbus/iiconf.c
==============================================================================
--- head/sys/dev/iicbus/iiconf.c	Wed May 29 07:33:51 2019	(r348354)
+++ head/sys/dev/iicbus/iiconf.c	Wed May 29 09:08:20 2019	(r348355)
@@ -427,7 +427,7 @@ iicbus_transfer_gen(device_t dev, struct iic_msg *msgs
 {
 	int i, error, lenread, lenwrote, nkid, rpstart, addr;
 	device_t *children, bus;
-	bool nostop, started;
+	bool started;
 
 	if ((error = device_get_children(dev, &children, &nkid)) != 0)
 		return (IIC_ERESOURCE);
@@ -438,7 +438,6 @@ iicbus_transfer_gen(device_t dev, struct iic_msg *msgs
 	bus = children[0];
 	rpstart = 0;
 	free(children, M_TEMP);
-	nostop = iicbus_get_nostop(dev);
 	started = false;
 	for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
 		addr = msgs[i].slave;
@@ -466,12 +465,11 @@ iicbus_transfer_gen(device_t dev, struct iic_msg *msgs
 		if (error != 0)
 			break;
 
-		if ((msgs[i].flags & IIC_M_NOSTOP) != 0 ||
-		    (nostop && i + 1 < nmsgs)) {
-			rpstart = 1;	/* Next message gets repeated start */
-		} else {
+		if (!(msgs[i].flags & IIC_M_NOSTOP)) {
 			rpstart = 0;
 			iicbus_stop(bus);
+		} else {
+			rpstart = 1;	/* Next message gets repeated start */
 		}
 	}
 	if (error != 0 && started)

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