From: Liu Ying <Ying.liu@freescale.com>
Date: Fri, 18 Jan 2013 08:20:22 +0000 (+0800)
Subject: ENGR00240740-1 IPUv3:Workaround bootup ipu error
X-Git-Tag: v3.0.35-fsl~147
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4917a040618030d48574210635438270bea6d907;p=karo-tx-linux.git

ENGR00240740-1 IPUv3:Workaround bootup ipu error

Enabling IPU hsp clock in mxcfb_probe() context by calling
ipu_init_channel() can avoid the IPU display channel(setup
in bootloader) from being damaged by some IPU common driver
APIS which enable/disable IPU hsp clock when doing driver
probe. However, somehow, after LDO bypass patch set is pushed
to kernel, this clock enablement can trigger IPU errors
(IPU_INT_STAT_5 - 0x00800000/IPU_INT_STAT_10 - 0x00100000) and
a display flash. A workaround is to enable IPU hsp clock when
we are at ipu_probe() context, which is earlier than mxcfb_probe()
context, and then to disable(cleanup) the clock once more when
fb_set_par() is triggered by the user for the first time. This
patch exports an interface to disable ipu hsp clock so that
fb_set_par() may call it, and enables ipu hsp clock in ipu_probe()
context.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit 06e5772151c3b8e060110fbb2b1ce83ef6be70dd)
---

diff --git a/drivers/mxc/ipu3/ipu_common.c b/drivers/mxc/ipu3/ipu_common.c
index 762aebc20654..5afb60142b3f 100644
--- a/drivers/mxc/ipu3/ipu_common.c
+++ b/drivers/mxc/ipu3/ipu_common.c
@@ -163,8 +163,18 @@ static int __devinit ipu_clk_setup_enable(struct ipu_soc *ipu,
 	clk_debug_register(&ipu->pixel_clk[0]);
 	clk_debug_register(&ipu->pixel_clk[1]);
 
-	if (!plat_data->bypass_reset)
-		clk_enable(ipu->ipu_clk);
+	/*
+	 * Enable ipu hsp clock anyway, so that we
+	 * may keep the clock on until user space
+	 * triggers frame buffer set_par(), i.e., any
+	 * ipu interface which enables/disables ipu
+	 * hsp clock with pair(called in IPUv3 fb
+	 * driver or mxc v4l2 driver<probed after fb
+	 * driver>) cannot eventually disables the
+	 * clock to damage the channel setup by
+	 * bootloader.
+	 */
+	clk_enable(ipu->ipu_clk);
 
 	ipu->pixel_clk[0].parent = ipu->ipu_clk;
 	ipu->pixel_clk[1].parent = ipu->ipu_clk;
@@ -203,6 +213,12 @@ void _ipu_put(struct ipu_soc *ipu)
 	clk_disable(ipu->ipu_clk);
 }
 
+void ipu_disable_hsp_clk(struct ipu_soc *ipu)
+{
+	_ipu_put(ipu);
+}
+EXPORT_SYMBOL(ipu_disable_hsp_clk);
+
 /*!
  * This function is called by the driver framework to initialize the IPU
  * hardware.