mfd: Add power off functionality to TWL

TWL family of PMICs, used in master mode, have a power off
functionality. The resulting power off sequence shuts down all the SoC
supplies, LDOs, etc. The sequence is described in the datasheets
chapter "Power-Off Sequence".
Note, that board must be wired correctly for the power off to work as
expected.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 42 insertions, 2 deletions

diff --git a/drivers/mfd/twl4030-power.c b/drivers/mfd/twl4030-power.c
index a764676f0922..d905f5171153 100644
--- a/drivers/mfd/twl4030-power.c
+++ b/drivers/mfd/twl4030-power.c
@@ -34,7 +34,8 @@
 static u8 twl4030_start_script_address = 0x2b;
 
 #define PWR_P1_SW_EVENTS        0x10
-#define PWR_DEVOFF      (1<<0)
+#define PWR_DEVOFF              (1 << 0)
+#define SEQ_OFFSYNC             (1 << 0)
 
 #define PHY_TO_OFF_PM_MASTER(p)         (p - 0x36)
 #define PHY_TO_OFF_PM_RECEIVER(p)       (p - 0x5b)
@@ -511,12 +512,27 @@ int twl4030_remove_script(u8 flags)
         return err;
 }
 
+/*
+ * In master mode, start the power off sequence.
+ * After a successful execution, TWL shuts down the power to the SoC
+ * and all peripherals connected to it.
+ */
+void twl4030_power_off(void)
+{
+        int err;
+
+        err = twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, PWR_DEVOFF,
+                               TWL4030_PM_MASTER_P1_SW_EVENTS);
+        if (err)
+                pr_err("TWL4030 Unable to power off\n");
+}
+
 void __init twl4030_power_init(struct twl4030_power_data *twl4030_scripts)
 {
         int err = 0;
         int i;
         struct twl4030_resconfig *resconfig;
-        u8 address = twl4030_start_script_address;
+        u8 val, address = twl4030_start_script_address;
 
         err = twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER,
                         TWL4030_PM_MASTER_KEY_CFG1,
@@ -548,6 +564,28 @@ void __init twl4030_power_init(struct twl4030_power_data *twl4030_scripts)
                 }
         }
 
+        /* Board has to be wired properly to use this feature */
+        if (twl4030_scripts->use_poweroff && !pm_power_off) {
+                /* Default for SEQ_OFFSYNC is set, lets ensure this */
+                err = twl_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &val,
+                                      TWL4030_PM_MASTER_CFG_P123_TRANSITION);
+                if (err) {
+                        pr_warning("TWL4030 Unable to read registers\n");
+
+                } else if (!(val & SEQ_OFFSYNC)) {
+                        val |= SEQ_OFFSYNC;
+                        err = twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, val,
+                                        TWL4030_PM_MASTER_CFG_P123_TRANSITION);
+                        if (err) {
+                                pr_err("TWL4030 Unable to setup SEQ_OFFSYNC\n");
+                                goto relock;
+                        }
+                }
+
+                pm_power_off = twl4030_power_off;
+        }
+
+relock:
         err = twl_i2c_write_u8(TWL4030_MODULE_PM_MASTER, 0,
                         TWL4030_PM_MASTER_PROTECT_KEY);
         if (err)
diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h
index 114c0f6fc63d..78d3465251d6 100644
--- a/include/linux/i2c/twl.h
+++ b/include/linux/i2c/twl.h
@@ -652,10 +652,12 @@ struct twl4030_power_data {
         unsigned num;
         struct twl4030_resconfig *resource_config;
 #define TWL4030_RESCONFIG_UNDEF ((u8)-1)
+        bool use_poweroff;      /* Board is wired for TWL poweroff */
 };
 
 extern void twl4030_power_init(struct twl4030_power_data *triton2_scripts);
 extern int twl4030_remove_script(u8 flags);
+extern void twl4030_power_off(void);
 
 struct twl4030_codec_data {
         unsigned int digimic_delay; /* in ms */