OMAP: hwmod: fix the i2c-reset timeout during bootup

The sequence of _ocp_softreset doesn't work for i2c. The i2c module has a
special sequence to reset the module. The sequence is
 - Disable the I2C.
 - Write to SOFTRESET bit.
 - Enable the I2C.
 - Poll on the RESETDONE bit.
The sequence is implemented as a function and the i2c_class is updated with
the correct 'reset' pointer.  omap_hwmod_softreset function is implemented
which triggers the softreset by writing into sysconfig register. On following
this sequence, i2c module resets properly and timeouts are not seen.

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>
[paul@pwsan.com: combined this patch with a patch to remove
 HWMOD_INIT_NO_RESET from the 44xx hwmod flags; change register
 offset conditional code to use the IP block revision; minor code
 cleanup]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 7d242c9e2a2c..02b6016393a8 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1656,6 +1656,33 @@ void omap_hwmod_write(u32 v, struct omap_hwmod *oh, u16 reg_offs)
 }
 
 /**
+ * omap_hwmod_softreset - reset a module via SYSCONFIG.SOFTRESET bit
+ * @oh: struct omap_hwmod *
+ *
+ * This is a public function exposed to drivers. Some drivers may need to do
+ * some settings before and after resetting the device.  Those drivers after
+ * doing the necessary settings could use this function to start a reset by
+ * setting the SYSCONFIG.SOFTRESET bit.
+ */
+int omap_hwmod_softreset(struct omap_hwmod *oh)
+{
+        u32 v;
+        int ret;
+
+        if (!oh || !(oh->_sysc_cache))
+                return -EINVAL;
+
+        v = oh->_sysc_cache;
+        ret = _set_softreset(oh, &v);
+        if (ret)
+                goto error;
+        _write_sysconfig(v, oh);
+
+error:
+        return ret;
+}
+
+/**
  * omap_hwmod_set_slave_idlemode - set the hwmod's OCP slave idlemode
  * @oh: struct omap_hwmod *
  * @idlemode: SIDLEMODE field bits (shifted to bit 0)