svn commit: r352243 - head/sys/dev/ichiic

[Vladimir Kondratyev]

Author: wulf
Date: Thu Sep 12 12:33:09 2019
New Revision: 352243
URL: https://svnweb.freebsd.org/changeset/base/352243

Log:
  ig4(4): Fix SDA HOLD time set too low on Skylake controllers
  
  Execution of "Soft reset" command (IG4_REG_RESETS_SKL) at controller init
  stage sets SDA_HOLD register value to 0x0001 which is often too low for
  normal operation.
  
  Set SDA_HOLD back to 28 after reset to restore controller functionality.
  
  PR:		240339
  Reported by:	imp, GregV, et al.
  MFC after:	3 days

Modified:
  head/sys/dev/ichiic/ig4_iic.c

Modified: head/sys/dev/ichiic/ig4_iic.c
==============================================================================
--- head/sys/dev/ichiic/ig4_iic.c	Thu Sep 12 08:54:48 2019	(r352242)
+++ head/sys/dev/ichiic/ig4_iic.c	Thu Sep 12 12:33:09 2019	(r352243)
@@ -590,6 +590,8 @@ ig4iic_attach(ig4iic_softc_t *sc)
 	reg_write(sc, IG4_REG_SS_SCL_LCNT, 125);
 	reg_write(sc, IG4_REG_FS_SCL_HCNT, 100);
 	reg_write(sc, IG4_REG_FS_SCL_LCNT, 125);
+	if (sc->version == IG4_SKYLAKE)
+		reg_write(sc, IG4_REG_SDA_HOLD, 28);
 
 	/*
 	 * Use a threshold of 1 so we get interrupted on each character,