OMAP: hwmod: Fix softreset for modules with optional clocks

Some modules (like GPIO, DSS...) require optionals clock to be enabled
in order to complete the sofreset properly.
Add a HWMOD_CONTROL_OPT_CLKS_IN_RESET flag to force all optional clocks
to be enabled before reset. Disabled them once the reset is done.

TODO:
For the moment it is very hard to understand from the HW spec, which
optional clock is needed and which one is not. So the current approach
will enable all the optional clocks.
Paul proposed a much finer approach that will allow to tag only the needed
clock in the optional clock table. This might be doable as soon as we have
a clear understanding of these dependencies.

Reported-by: Partha Basak <p-basak2@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 46 insertions, 5 deletions

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 5027879b062..f320cfb911d 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -546,6 +546,36 @@ static int _disable_clocks(struct omap_hwmod *oh)
 	return 0;
 }
 
+static void _enable_optional_clocks(struct omap_hwmod *oh)
+{
+	struct omap_hwmod_opt_clk *oc;
+	int i;
+
+	pr_debug("omap_hwmod: %s: enabling optional clocks\n", oh->name);
+
+	for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
+		if (oc->_clk) {
+			pr_debug("omap_hwmod: enable %s:%s\n", oc->role,
+				 oc->_clk->name);
+			clk_enable(oc->_clk);
+		}
+}
+
+static void _disable_optional_clocks(struct omap_hwmod *oh)
+{
+	struct omap_hwmod_opt_clk *oc;
+	int i;
+
+	pr_debug("omap_hwmod: %s: disabling optional clocks\n", oh->name);
+
+	for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
+		if (oc->_clk) {
+			pr_debug("omap_hwmod: disable %s:%s\n", oc->role,
+				 oc->_clk->name);
+			clk_disable(oc->_clk);
+		}
+}
+
 /**
  * _find_mpu_port_index - find hwmod OCP slave port ID intended for MPU use
  * @oh: struct omap_hwmod *
@@ -976,8 +1006,9 @@ static int _read_hardreset(struct omap_hwmod *oh, const char *name)
  */
 static int _reset(struct omap_hwmod *oh)
 {
-	u32 r, v;
+	u32 v;
 	int c = 0;
+	int ret = 0;
 
 	if (!oh->class->sysc ||
 	    !(oh->class->sysc->sysc_flags & SYSC_HAS_SOFTRESET))
@@ -990,12 +1021,16 @@ static int _reset(struct omap_hwmod *oh)
 		return -EINVAL;
 	}
 
+	/* For some modules, all optionnal clocks need to be enabled as well */
+	if (oh->flags & HWMOD_CONTROL_OPT_CLKS_IN_RESET)
+		_enable_optional_clocks(oh);
+
 	pr_debug("omap_hwmod: %s: resetting\n", oh->name);
 
 	v = oh->_sysc_cache;
-	r = _set_softreset(oh, &v);
-	if (r)
-		return r;
+	ret = _set_softreset(oh, &v);
+	if (ret)
+		goto dis_opt_clks;
 	_write_sysconfig(v, oh);
 
 	if (oh->class->sysc->sysc_flags & SYSS_HAS_RESET_STATUS)
@@ -1020,7 +1055,13 @@ static int _reset(struct omap_hwmod *oh)
 	 * _wait_target_ready() or _reset()
 	 */
 
-	return (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 0;
+	ret = (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 0;
+
+dis_opt_clks:
+	if (oh->flags & HWMOD_CONTROL_OPT_CLKS_IN_RESET)
+		_disable_optional_clocks(oh);
+
+	return ret;
 }
 
 /**