From c29c79bb548435a4de00ff67908b4a851c5bd4ff Mon Sep 17 00:00:00 2001
From: Hamad Kadmany <hkadmany@codeaurora.org>
Date: Thu, 31 Jan 2013 14:53:32 +0200
Subject: [PATCH] tsif: Add option to read TSIF clock reference counter

Reading the current value of TSIF clock reference counter
is required by some application.

Change-Id: I5ca2a280f864fbb9c4a69518ce9672538f9c8489
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>
---
 drivers/misc/tsif.c      | 18 +++++++++++++++++-
 include/linux/tsif_api.h | 13 ++++++++++++-
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/tsif.c b/drivers/misc/tsif.c
index b7b1203f781..05f6c86769f 100644
--- a/drivers/misc/tsif.c
+++ b/drivers/misc/tsif.c
@@ -1,7 +1,7 @@
 /*
  * TSIF Driver
  *
- * Copyright (c) 2009-2012, Code Aurora Forum. All rights reserved.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -1770,6 +1770,22 @@ void tsif_stop(void *cookie)
 }
 EXPORT_SYMBOL(tsif_stop);
 
+int tsif_get_ref_clk_counter(void *cookie, u32 *tcr_counter)
+{
+	struct msm_tsif_device *tsif_device = cookie;
+
+	if (!tsif_device || !tcr_counter)
+		return -EINVAL;
+
+	if (tsif_device->state == tsif_state_running)
+		*tcr_counter = ioread32(tsif_device->base + TSIF_CLK_REF_OFF);
+	else
+		*tcr_counter = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL(tsif_get_ref_clk_counter);
+
 void tsif_reclaim_packets(void *cookie, int read_index)
 {
 	struct msm_tsif_device *tsif_device = cookie;
diff --git a/include/linux/tsif_api.h b/include/linux/tsif_api.h
index 0c182282946..b69ddf595f3 100644
--- a/include/linux/tsif_api.h
+++ b/include/linux/tsif_api.h
@@ -3,7 +3,7 @@
  *
  * Kernel API
  *
- * Copyright (c) 2009-2010, 2012, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -255,6 +255,17 @@ int tsif_start(void *cookie);
  */
 void tsif_stop(void *cookie);
 
+/**
+ * tsif_get_ref_clk_counter - return the TSIF clock reference (TCR) counter.
+ * @cookie:      TSIF cookie previously obtained with tsif_attach()
+ * @tcr_counter: the value of TCR counter
+ *
+ * Return      error code
+ *
+ * TCR increments at a rate equal to 27 MHz/256 = 105.47 kHz.
+ */
+int tsif_get_ref_clk_counter(void *cookie, u32 *tcr_counter);
+
 /**
  * tsif_reclaim_packets - inform that buffer space may be reclaimed
  * @cookie:    TSIF cookie previously obtained with tsif_attach()