ARM: OMAP2+ hwmod: Allow modules to disable HW_AUTO

Introduce HWMOD_CLKDM_NOAUTO flag that allows the hwmod's
clockdomain to be prevented from HW_AUTO while the hwmod is active.

This is needed to workaround some modules which don't function
correctly with HW_AUTO. e.g. DCAN on DRA7.

Signed-off-by: Roger Quadros <rogerq@ti.com>
[nsekhar@ti.com: rebased to v4.9 kernel]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

2 files changed, 12 insertions, 2 deletions

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 8a4039325845..8bcea0d83fa0 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -2027,7 +2027,7 @@ static int _enable(struct omap_hwmod *oh)
 
         r = (soc_ops.wait_target_ready) ? soc_ops.wait_target_ready(oh) :
                 -EINVAL;
-        if (oh->clkdm)
+        if (oh->clkdm && !(oh->flags & HWMOD_CLKDM_NOAUTO))
                 clkdm_allow_idle(oh->clkdm);
 
         if (!r) {
@@ -2084,7 +2084,12 @@ static int _idle(struct omap_hwmod *oh)
                 _idle_sysc(oh);
         _del_initiator_dep(oh, mpu_oh);
 
-        if (oh->clkdm)
+        /*
+         * If HWMOD_CLKDM_NOAUTO is set then we don't
+         * deny idle the clkdm again since idle was already denied
+         * in _enable()
+         */
+        if (oh->clkdm && !(oh->flags & HWMOD_CLKDM_NOAUTO))
                 clkdm_deny_idle(oh->clkdm);
 
         if (oh->flags & HWMOD_BLOCK_WFI)
diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h
index 7ba9f53145dd..a8f779381fd8 100644
--- a/arch/arm/mach-omap2/omap_hwmod.h
+++ b/arch/arm/mach-omap2/omap_hwmod.h
@@ -531,6 +531,10 @@ struct omap_hwmod_omap4_prcm {
  *     operate and they need to be handled at the same time as the main_clk.
  * HWMOD_NO_IDLE: Do not idle the hwmod at all. Useful to handle certain
  *     IPs like CPSW on DRA7, where clocks to this module cannot be disabled.
+ * HWMOD_CLKDM_NOAUTO: Allows the hwmod's clockdomain to be prevented from
+ *     entering HW_AUTO while hwmod is active. This is needed to workaround
+ *     some modules which don't function correctly with HW_AUTO. For example,
+ *     DCAN on DRA7x SoC needs this to workaround errata i893.
  */
 #define HWMOD_SWSUP_SIDLE                       (1 << 0)
 #define HWMOD_SWSUP_MSTANDBY                    (1 << 1)
@@ -548,6 +552,7 @@ struct omap_hwmod_omap4_prcm {
 #define HWMOD_RECONFIG_IO_CHAIN                 (1 << 13)
 #define HWMOD_OPT_CLKS_NEEDED                   (1 << 14)
 #define HWMOD_NO_IDLE                           (1 << 15)
+#define HWMOD_CLKDM_NOAUTO                      (1 << 16)
 
 /*
  * omap_hwmod._int_flags definitions