mfd: Add stmpe auto sleep feature

Some STMPE devices support entering sleep mode automatically on a
specified timeout of inactivity on the I2C bus with the host system.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Sundar R Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 77 insertions, 0 deletions

diff --git a/drivers/mfd/stmpe.c b/drivers/mfd/stmpe.c
index a7f3099fdcfd..0754c5e91995 100644
--- a/drivers/mfd/stmpe.c
+++ b/drivers/mfd/stmpe.c
@@ -455,6 +455,67 @@ static struct stmpe_variant_block stmpe1601_blocks[] = {
         },
 };
 
+/* supported autosleep timeout delay (in msecs) */
+static const int stmpe_autosleep_delay[] = {
+        4, 16, 32, 64, 128, 256, 512, 1024,
+};
+
+static int stmpe_round_timeout(int timeout)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(stmpe_autosleep_delay); i++) {
+                if (stmpe_autosleep_delay[i] >= timeout)
+                        return i;
+        }
+
+        /*
+         * requests for delays longer than supported should not return the
+         * longest supported delay
+         */
+        return -EINVAL;
+}
+
+static int stmpe_autosleep(struct stmpe *stmpe, int autosleep_timeout)
+{
+        int ret;
+
+        if (!stmpe->variant->enable_autosleep)
+                return -ENOSYS;
+
+        mutex_lock(&stmpe->lock);
+        ret = stmpe->variant->enable_autosleep(stmpe, autosleep_timeout);
+        mutex_unlock(&stmpe->lock);
+
+        return ret;
+}
+
+/*
+ * Both stmpe 1601/2403 support same layout for autosleep
+ */
+static int stmpe1601_autosleep(struct stmpe *stmpe,
+                int autosleep_timeout)
+{
+        int ret, timeout;
+
+        /* choose the best available timeout */
+        timeout = stmpe_round_timeout(autosleep_timeout);
+        if (timeout < 0) {
+                dev_err(stmpe->dev, "invalid timeout\n");
+                return timeout;
+        }
+
+        ret = __stmpe_set_bits(stmpe, STMPE1601_REG_SYS_CTRL2,
+                        STMPE1601_AUTOSLEEP_TIMEOUT_MASK,
+                        timeout);
+        if (ret < 0)
+                return ret;
+
+        return __stmpe_set_bits(stmpe, STMPE1601_REG_SYS_CTRL2,
+                        STPME1601_AUTOSLEEP_ENABLE,
+                        STPME1601_AUTOSLEEP_ENABLE);
+}
+
 static int stmpe1601_enable(struct stmpe *stmpe, unsigned int blocks,
                             bool enable)
 {
@@ -497,6 +558,7 @@ static struct stmpe_variant_info stmpe1601 = {
         .num_irqs       = STMPE1601_NR_INTERNAL_IRQS,
         .enable         = stmpe1601_enable,
         .get_altfunc    = stmpe1601_get_altfunc,
+        .enable_autosleep       = stmpe1601_autosleep,
 };
 
 /*
@@ -589,6 +651,7 @@ static struct stmpe_variant_info stmpe2403 = {
         .num_irqs       = STMPE24XX_NR_INTERNAL_IRQS,
         .enable         = stmpe24xx_enable,
         .get_altfunc    = stmpe24xx_get_altfunc,
+        .enable_autosleep       = stmpe1601_autosleep, /* same as stmpe1601 */
 };
 
 static struct stmpe_variant_info *stmpe_variant_info[] = {
@@ -731,6 +794,7 @@ static void stmpe_irq_remove(struct stmpe *stmpe)
 static int __devinit stmpe_chip_init(struct stmpe *stmpe)
 {
         unsigned int irq_trigger = stmpe->pdata->irq_trigger;
+        int autosleep_timeout = stmpe->pdata->autosleep_timeout;
         struct stmpe_variant_info *variant = stmpe->variant;
         u8 icr = STMPE_ICR_LSB_GIM;
         unsigned int id;
@@ -766,6 +830,12 @@ static int __devinit stmpe_chip_init(struct stmpe *stmpe)
         if (stmpe->pdata->irq_invert_polarity)
                 icr ^= STMPE_ICR_LSB_HIGH;
 
+        if (stmpe->pdata->autosleep) {
+                ret = stmpe_autosleep(stmpe, autosleep_timeout);
+                if (ret)
+                        return ret;
+        }
+
         return stmpe_reg_write(stmpe, stmpe->regs[STMPE_IDX_ICR_LSB], icr);
 }
 
diff --git a/drivers/mfd/stmpe.h b/drivers/mfd/stmpe.h
index 991f0ecbeb34..0dbdc4e8cd77 100644
--- a/drivers/mfd/stmpe.h
+++ b/drivers/mfd/stmpe.h
@@ -49,6 +49,7 @@ struct stmpe_variant_block {
  *              Called with the I/O lock held.
  * @get_altfunc: callback to get the alternate function number for the
  *               specific block
+ * @enable_autosleep: callback to configure autosleep with specified timeout
  */
 struct stmpe_variant_info {
         const char *name;
@@ -62,6 +63,7 @@ struct stmpe_variant_info {
         int num_irqs;
         int (*enable)(struct stmpe *stmpe, unsigned int blocks, bool enable);
         int (*get_altfunc)(struct stmpe *stmpe, enum stmpe_block block);
+        int (*enable_autosleep)(struct stmpe *stmpe, int autosleep_timeout);
 };
 
 #define STMPE_ICR_LSB_HIGH      (1 << 2)
@@ -118,6 +120,7 @@ struct stmpe_variant_info {
 #define STMPE1601_NR_INTERNAL_IRQS      9
 
 #define STMPE1601_REG_SYS_CTRL                  0x02
+#define STMPE1601_REG_SYS_CTRL2                 0x03
 #define STMPE1601_REG_ICR_LSB                   0x11
 #define STMPE1601_REG_IER_LSB                   0x13
 #define STMPE1601_REG_ISR_MSB                   0x14
@@ -137,6 +140,10 @@ struct stmpe_variant_info {
 #define STMPE1601_SYS_CTRL_ENABLE_KPC           (1 << 1)
 #define STMPE1601_SYSCON_ENABLE_SPWM            (1 << 0)
 
+/* The 1601/2403 share the same masks */
+#define STMPE1601_AUTOSLEEP_TIMEOUT_MASK        (0x7)
+#define STPME1601_AUTOSLEEP_ENABLE              (1 << 3)
+
 /*
  * STMPE24xx
  */