OMAP4 powerdomain: Support LOWPOWERSTATECHANGE for powerdomains

Some powerdomains in OMAP4 support a direct transition from one sleep
state to another deeper sleep state without having to wakeup the
powerdomain. This patch adds an api in the powerdomain framework to
set the LOWPOWERSTATECHANGE bit in PWRSTCTRL register.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 4a91d38d7b1a..f9f0bca1926a 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -980,6 +980,34 @@ bool pwrdm_has_hdwr_sar(struct powerdomain *pwrdm)
 }
 
 /**
+ * pwrdm_set_lowpwrstchange - Request a low power state change
+ * @pwrdm: struct powerdomain *
+ *
+ * Allows a powerdomain to transtion to a lower power sleep state
+ * from an existing sleep state without waking up the powerdomain.
+ * Returns -EINVAL if the powerdomain pointer is null or if the
+ * powerdomain does not support LOWPOWERSTATECHANGE, or returns 0
+ * upon success.
+ */
+int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm)
+{
+        if (!pwrdm)
+                return -EINVAL;
+
+        if (!(pwrdm->flags & PWRDM_HAS_LOWPOWERSTATECHANGE))
+                return -EINVAL;
+
+        pr_debug("powerdomain: %s: setting LOWPOWERSTATECHANGE bit\n",
+                 pwrdm->name);
+
+        prm_rmw_mod_reg_bits(OMAP4430_LOWPOWERSTATECHANGE_MASK,
+                             (1 << OMAP4430_LOWPOWERSTATECHANGE_SHIFT),
+                             pwrdm->prcm_offs, pwrstctrl_reg_offs);
+
+        return 0;
+}
+
+/**
  * pwrdm_wait_transition - wait for powerdomain power transition to finish
  * @pwrdm: struct powerdomain * to wait for
  *