OMAP3: PM: Enable IO-CHAIN wakeup

OMAP 3430 ES3.1 chips have a separate bit for IO daisy-chain
wake up enabling. It needs to be enabled when entering
retention or off state, otherwise waking up might not work
in all situations.

Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 35 insertions, 3 deletions

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 7623edabc419..511a57dc7015 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -94,6 +94,35 @@ static inline void omap3_per_restore_context(void)
         omap_gpio_restore_context();
 }
 
+static void omap3_enable_io_chain(void)
+{
+        int timeout = 0;
+
+        if (omap_rev() >= OMAP3430_REV_ES3_1) {
+                prm_set_mod_reg_bits(OMAP3430_EN_IO_CHAIN, WKUP_MOD, PM_WKEN);
+                /* Do a readback to assure write has been done */
+                prm_read_mod_reg(WKUP_MOD, PM_WKEN);
+
+                while (!(prm_read_mod_reg(WKUP_MOD, PM_WKST) &
+                         OMAP3430_ST_IO_CHAIN)) {
+                        timeout++;
+                        if (timeout > 1000) {
+                                printk(KERN_ERR "Wake up daisy chain "
+                                       "activation failed.\n");
+                                return;
+                        }
+                        prm_set_mod_reg_bits(OMAP3430_ST_IO_CHAIN,
+                                             WKUP_MOD, PM_WKST);
+                }
+        }
+}
+
+static void omap3_disable_io_chain(void)
+{
+        if (omap_rev() >= OMAP3430_REV_ES3_1)
+                prm_clear_mod_reg_bits(OMAP3430_EN_IO_CHAIN, WKUP_MOD, PM_WKEN);
+}
+
 static void omap3_core_save_context(void)
 {
         u32 control_padconf_off;
@@ -367,8 +396,9 @@ static void omap_sram_idle(void)
                         omap3_core_save_context();
                         omap3_prcm_save_context();
                 }
-                /* Enable IO-PAD wakeup */
+                /* Enable IO-PAD and IO-CHAIN wakeups */
                 prm_set_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
+                omap3_enable_io_chain();
         }
 
         /*
@@ -432,9 +462,11 @@ static void omap_sram_idle(void)
                         pwrdm_set_next_pwrst(per_pwrdm, PWRDM_POWER_OFF);
         }
 
-        /* Disable IO-PAD wakeup */
-        if (core_next_state < PWRDM_POWER_ON)
+        /* Disable IO-PAD and IO-CHAIN wakeup */
+        if (core_next_state < PWRDM_POWER_ON) {
                 prm_clear_mod_reg_bits(OMAP3430_EN_IO, WKUP_MOD, PM_WKEN);
+                omap3_disable_io_chain();
+        }
 
         pwrdm_post_transition();