MFD: twl6040: Cache the vibra control registers

The vibra control register will be used from the ASoC codec driver as well.
In order to avoid latency issues caused by I2C read access, cache the two
control register within the core driver, so we do not need to reach out
to the chip to read it back.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 16 insertions, 4 deletions

diff --git a/drivers/mfd/twl6040-core.c b/drivers/mfd/twl6040-core.c
index 7dc8c4715001..75987c8ca049 100644
--- a/drivers/mfd/twl6040-core.c
+++ b/drivers/mfd/twl6040-core.c
@@ -34,16 +34,24 @@
 #include <linux/mfd/core.h>
 #include <linux/mfd/twl6040.h>
 
+#define VIBRACTRL_MEMBER(reg) ((reg == TWL6040_REG_VIBCTLL) ? 0 : 1)
+
 int twl6040_reg_read(struct twl6040 *twl6040, unsigned int reg)
 {
         int ret;
         u8 val = 0;
 
         mutex_lock(&twl6040->io_mutex);
-        ret = twl_i2c_read_u8(TWL_MODULE_AUDIO_VOICE, &val, reg);
-        if (ret < 0) {
-                mutex_unlock(&twl6040->io_mutex);
-                return ret;
+        /* Vibra control registers from cache */
+        if (unlikely(reg == TWL6040_REG_VIBCTLL ||
+                     reg == TWL6040_REG_VIBCTLR)) {
+                val = twl6040->vibra_ctrl_cache[VIBRACTRL_MEMBER(reg)];
+        } else {
+                ret = twl_i2c_read_u8(TWL_MODULE_AUDIO_VOICE, &val, reg);
+                if (ret < 0) {
+                        mutex_unlock(&twl6040->io_mutex);
+                        return ret;
+                }
         }
         mutex_unlock(&twl6040->io_mutex);
 
@@ -57,6 +65,9 @@ int twl6040_reg_write(struct twl6040 *twl6040, unsigned int reg, u8 val)
 
         mutex_lock(&twl6040->io_mutex);
         ret = twl_i2c_write_u8(TWL_MODULE_AUDIO_VOICE, val, reg);
+        /* Cache the vibra control registers */
+        if (reg == TWL6040_REG_VIBCTLL || reg == TWL6040_REG_VIBCTLR)
+                twl6040->vibra_ctrl_cache[VIBRACTRL_MEMBER(reg)] = val;
         mutex_unlock(&twl6040->io_mutex);
 
         return ret;
diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index e6c755db4560..2f8585a4c74b 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -184,6 +184,7 @@ struct twl6040 {
         int audpwron;
         int power_count;
         int rev;
+        u8 vibra_ctrl_cache[2];
 
         int pll;
         unsigned int sysclk;