[PATCH 1/2] OMAP2/3: hwmod: fix the i2c-reset timeout during bootup

["Avinash.H.M" <avinashhm@ti.com>]

The i2c module has a special reset sequence. The sequence is
- Disable the I2C.
- Write to SOFTRESET bit.
- Enable the I2C.
- Poll on the RESETDONE bit.
This sequence must be followed for i2c reset in omap2, omap3. The sequence is
implemented as a function and the i2c_class is updated with the correct
'reset' pointer.

Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Avinash.H.M <avinashhm@ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c             |   59 ++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_2420_data.c   |    1 +
 arch/arm/mach-omap2/omap_hwmod_2430_data.c   |    1 +
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c   |    1 +
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    2 +
 5 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index e034294..f61c9c8 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -156,6 +156,10 @@
 /* Name of the OMAP hwmod for the MPU */
 #define MPU_INITIATOR_NAME		"mpu"
 
+/* In register I2C_CON, Bit 15 is the I2C enable bit */
+#define I2C_EN				BIT(15)
+#define I2C_CON_OFFSET			0x24
+
 /* omap_hwmod_list contains all registered struct omap_hwmods */
 static LIST_HEAD(omap_hwmod_list);
 
@@ -2369,3 +2373,58 @@ int omap_hwmod_no_setup_reset(struct omap_hwmod *oh)
 
 	return 0;
 }
+
+/**
+ * omap_i2c_reset- reset the omap i2c module.
+ * @oh: struct omap_hwmod *
+ *
+ * The i2c moudle in omap2, omap3 had a special sequence to reset. The
+ * sequence is:
+ * - Disable the I2C.
+ * - Write to SOFTRESET bit.
+ * - Enable the I2C.
+ * - Poll on the RESETDONE bit.
+ * The sequence is implemented in below function. This is called for 2420,
+ * 2430 and omap3.
+ */
+int omap_i2c_reset(struct omap_hwmod *oh)
+{
+	u32 v = 0;
+	int ret = 0, c = 0;
+
+	/* Disable I2C */
+	v = omap_hwmod_read(oh, I2C_CON_OFFSET);
+	v = v & ~I2C_EN;
+	omap_hwmod_write(v, oh, I2C_CON_OFFSET);
+
+	/* Write to the SOFTRESET bit */
+	v = oh->_sysc_cache;
+	ret = _set_softreset(oh, &v);
+	if (ret)
+		goto err1;
+	_write_sysconfig(v, oh);
+
+	/* Enable I2C */
+	v = omap_hwmod_read(oh, I2C_CON_OFFSET);
+	v |= I2C_EN;
+	omap_hwmod_write(v, oh, I2C_CON_OFFSET);
+
+	/* Poll on RESETDONE bit */
+	omap_test_timeout((omap_hwmod_read(oh,
+				oh->class->sysc->syss_offs)
+				& SYSS_RESETDONE_MASK),
+				MAX_MODULE_SOFTRESET_WAIT, c);
+
+	if (c == MAX_MODULE_SOFTRESET_WAIT)
+		pr_warning("%s: %s: softreset failed (waited %d usec)\n",
+			__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
+	else
+		pr_debug("%s: %s: softreset in %d usec\n", __func__,
+			oh->name, c);
+
+	return 0;
+
+err1:
+	pr_warning("%s: returned error from _set_softreset\n", __func__);
+	return ret;
+}
diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index 8eb3ce1..82ff5f7 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -1447,6 +1447,7 @@ static struct omap_hwmod_class_sysconfig i2c_sysc = {
 static struct omap_hwmod_class i2c_class = {
 	.name		= "i2c",
 	.sysc		= &i2c_sysc,
+	.reset		= &omap_i2c_reset,
 };
 
 static struct omap_i2c_dev_attr i2c_dev_attr;
diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
index a860fb5..ce292f0 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2430_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
@@ -1524,6 +1524,7 @@ static struct omap_hwmod_class_sysconfig i2c_sysc = {
 static struct omap_hwmod_class i2c_class = {
 	.name		= "i2c",
 	.sysc		= &i2c_sysc,
+	.reset		= &omap_i2c_reset,
 };
 
 static struct omap_i2c_dev_attr i2c_dev_attr = {
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index b98e2df..c74f972 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -1460,6 +1460,7 @@ static struct omap_hwmod omap3xxx_uart4_hwmod = {
 static struct omap_hwmod_class i2c_class = {
 	.name = "i2c",
 	.sysc = &i2c_sysc,
+	.reset = &omap_i2c_reset,
 };
 
 /*
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 1adea9c..26b7ad3 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -545,6 +545,8 @@ struct omap_hwmod {
 };
 
 int omap_hwmod_register(struct omap_hwmod **ohs);
+int omap_i2c_reset(struct omap_hwmod *oh);
+
 struct omap_hwmod *omap_hwmod_lookup(const char *name);
 int omap_hwmod_for_each(int (*fn)(struct omap_hwmod *oh, void *data),
 			void *data);
-- 
1.7.1