[RMI Driver] Implement power saving support

Implement standard values and functions to operate on power control
register. This allow to modify both reporting rate and sleep mode
in order to save power.

Change-Id: I2bdffd4160e10eec488eb5e19de8a2a258ddbb04
Reviewed-on: http://gerrit.rockbox.org/529
Reviewed-by: Amaury Pouly <amaury.pouly@gmail.com>

2 files changed, 42 insertions, 0 deletions

diff --git a/firmware/drivers/synaptics-rmi.c b/firmware/drivers/synaptics-rmi.c
index c979927fee..1b7cf2f8ef 100644
--- a/firmware/drivers/synaptics-rmi.c
+++ b/firmware/drivers/synaptics-rmi.c
@@ -25,6 +25,8 @@
 static int rmi_cur_page;
 static int rmi_i2c_addr;
 
+static unsigned char dev_ctl_reg;
+
 /* NOTE:
  * RMI over i2c supports some special aliases on page 0x2 but this driver don't
  * use them */
@@ -33,6 +35,7 @@ int rmi_init(int i2c_dev_addr)
 {
     rmi_i2c_addr = i2c_dev_addr;
     rmi_cur_page = 0x4;
+    dev_ctl_reg = rmi_read_single(RMI_DEVICE_CONTROL);
     return 0;
 }
 
@@ -75,3 +78,27 @@ int rmi_write_single(int address, unsigned char byte)
 {
     return rmi_write(address, 1, &byte);
 }
+
+/* set the device to the given sleep mode */
+void rmi_set_sleep_mode(unsigned char sleep_mode)
+{
+    /* valid value different from the actual one*/
+    if((dev_ctl_reg & RMI_SLEEP_MODE_BM) != sleep_mode)
+    {
+        dev_ctl_reg &= ~RMI_SLEEP_MODE_BM;
+        dev_ctl_reg |= sleep_mode;
+        rmi_write_single(RMI_DEVICE_CONTROL, dev_ctl_reg);
+    }
+}
+
+/* set the device's report rate to the given value */
+void rmi_set_report_rate(unsigned char report_rate)
+{
+    /* valid value different from the actual one*/
+    if((dev_ctl_reg & RMI_REPORT_RATE_BM) != report_rate)
+    {
+        dev_ctl_reg &= ~RMI_REPORT_RATE_BM;
+        dev_ctl_reg |= report_rate;
+        rmi_write_single(RMI_DEVICE_CONTROL, dev_ctl_reg);
+    }
+}
diff --git a/firmware/export/synaptics-rmi.h b/firmware/export/synaptics-rmi.h
index 38a9955dcc..564f1fd7e7 100644
--- a/firmware/export/synaptics-rmi.h
+++ b/firmware/export/synaptics-rmi.h
@@ -97,6 +97,17 @@ struct rmi_2d_absolute_data_t
 #define RMI_2D_GEST_FLICK_X_BM          0x0f
 #define RMI_2D_GEST_FLICK_Y_BM          0xf0
 #define RMI_2D_GEST_FLICK_Y_BP          4
+/* RMI Device Control register */
+#define RMI_REPORT_RATE_BM               0xc0
+#define RMI_SLEEP_MODE_BM                0x07
+#define RMI_REPORT_RATE_NORMAL           0x80
+#define RMI_REPORT_RATE_LOW              0x40
+#define RMI_SLEEP_MODE_FORCE_FULLY_AWAKE 0x00
+#define RMI_SLEEP_MODE_NORMAL            0x01
+#define RMI_SLEEP_MODE_LOW_POWER         0x02
+#define RMI_SLEEP_MODE_VERY_LOW_POWER    0x03
+#define RMI_SLEEP_MODE_SENSOR_SLEEP      0x04
+
 
 struct rmi_2d_relative_data_t
 {
@@ -127,5 +138,9 @@ int rmi_write(int address, int byte_count, const unsigned char *buffer);
 /* Write one register
  * WARNING: don't cross a page boundary ! */
 int rmi_write_single(int address, unsigned char byte);
+/* set the device to the given sleep mode */
+void rmi_set_sleep_mode(unsigned char sleep_mode);
+/* set the device's report rate to the given value */
+void rmi_set_report_rate(unsigned char report_rate);
 
 #endif