linux-kernel - [RFC] i2c: omap: TEST: do IP reset during probe.

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Date:	Wed, 26 Nov 2014 23:05:22 +0400
From:	Alexander Kochetkov <al.kochet@...il.com>
To:	Kevin Hilman <khilman@...nel.org>, linux-omap@...r.kernel.org,
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Felipe Balbi <balbi@...com>, Wolfram Sang <wsa@...-dreams.de>,
	Tony Lindgren <tony@...mide.com>,
	Alexander Kochetkov <al.kochet@...il.com>
Subject: [RFC] i2c: omap: TEST: do IP reset during probe.

NOT FOR UPSTREAM

The patch checks if IP reset during probe could bring I2C bus
to a free state on omap2430 - omap3530 boards.

I guess, IP hold one of I2C lines in a low state.
I guess, u-boot haven't sent a stop condition.

The patch is rebased on branch 'i2c/for-next' of
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
(6e79807443cba7397cd855ed29d6faba51d4c893)

Signed-off-by: Alexander Kochetkov <al.kochet@...il.com>
Reported-by: Kevin Hilman <khilman@...nel.org>
Tested-by: Kevin Hilman <khilman@...nel.org>
---
 drivers/i2c/busses/i2c-omap.c |   41 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 4563200..865c9a1 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -282,6 +282,26 @@ static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
 				(i2c_dev->regs[reg] << i2c_dev->reg_shift));
 }
 
+static int omap_i2c_wait_for_bb_valid(struct omap_i2c_dev *dev);
+
+static inline void
+omap_i2c_dump_state(const char *func, int line, struct omap_i2c_dev *dev, const char *msg)
+{
+	u16 systest = omap_i2c_read_reg(dev, OMAP_I2C_SYSTEST_REG);
+	dev_info(dev->dev, "%s: STAT=0x%04x; IE=0x%04x; CON=0x%04x; SYSTEST=0x%04x; SDA=%d%d [OI]; SCL=%d%d [OI] (%s:%d)\n",
+		msg,
+		omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG),
+		omap_i2c_read_reg(dev, OMAP_I2C_IE_REG),
+		omap_i2c_read_reg(dev, OMAP_I2C_CON_REG),
+		systest,
+		(systest & OMAP_I2C_SYSTEST_SDA_O_FUNC) ? 1 : 0,
+		(systest & OMAP_I2C_SYSTEST_SDA_I_FUNC) ? 1 : 0,
+		(systest & OMAP_I2C_SYSTEST_SCL_O_FUNC) ? 1 : 0,
+		(systest & OMAP_I2C_SYSTEST_SCL_I_FUNC) ? 1 : 0,
+		func, line);
+}
+#define OMAP_I2C_DUMP_STATE(dev, msg) omap_i2c_dump_state(__func__, __LINE__, (dev), (msg))
+
 static void __omap_i2c_init(struct omap_i2c_dev *dev)
 {
 
@@ -469,6 +489,23 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
 
 	__omap_i2c_init(dev);
 
+	msleep(1);
+	OMAP_I2C_DUMP_STATE(dev, "init0");
+
+	dev->bb_valid = 0;
+	omap_i2c_wait_for_bb_valid(dev);
+	OMAP_I2C_DUMP_STATE(dev, "init1");
+	dev_info(dev->dev, "init1: bb_valid=%d\n", dev->bb_valid);
+
+	omap_i2c_reset(dev);
+	__omap_i2c_init(dev);
+	dev->bb_valid = 0;
+	omap_i2c_wait_for_bb_valid(dev);
+	OMAP_I2C_DUMP_STATE(dev, "init2");
+	dev_info(dev->dev, "init2: bb_valid=%d\n", dev->bb_valid);
+
+	dev->bb_valid = 1;
+
 	return 0;
 }
 
@@ -1367,8 +1404,8 @@ omap_i2c_probe(struct platform_device *pdev)
 		goto err_unuse_clocks;
 	}
 
-	dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n", adap->nr,
-		 major, minor, dev->speed);
+	dev_info(dev->dev, "bus %d rev%d.%d at %d kHz (rev %08x)\n", adap->nr,
+		 major, minor, dev->speed, dev->rev);
 
 	pm_runtime_mark_last_busy(dev->dev);
 	pm_runtime_put_autosuspend(dev->dev);
-- 
1.7.9.5

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