ltr502als.c: Modify the way to change the config register

BZ: 26351

When change the device mode, we need to set the CONFIG REG to idle mode
first to disable interrupt. Otherwise, some interrupts may be triggered
abnormally during the mode switch.

Change-Id: I67792fce52fc1377aed9b5316b84a122451c7fde
Signed-off-by: Leo Yan <leo.yan@intel.com>
Reviewed-on: http://android.intel.com:8080/38779
Reviewed-by: Liu, Hong <hong.liu@intel.com>
Reviewed-by: Du, Alek <alek.du@intel.com>
Reviewed-by: Koskinen, Ilkka <ilkka.koskinen@intel.com>
Reviewed-by: Monroy, German <german.monroy@intel.com>
Tested-by: Wang, Zhifeng <zhifeng.wang@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/hwmon/ltr502als.c b/drivers/hwmon/ltr502als.c
index 5785a2f..5885343 100644 (file)
--- a/drivers/hwmon/ltr502als.c
+++ b/drivers/hwmon/ltr502als.c
@@ -11,7 +11,6 @@
  * GNU General Public License for more details.
  *
  */
-
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -107,7 +106,9 @@
 
 /* it takes about 650ms to generate the first interrupt when ALS is enabled*/
 #define ALS_FIRST_INT_DELAY    650
+#define PS_FIRST_INT_DELAY     400
 #define ALS_INIT_DATA          0xffff
+#define CONFIGREG_DELAY         50
 
 struct alsps_client {
        struct list_head list;
@@ -423,6 +424,7 @@ static int ltr502als_initchip(struct alsps_device *alsps)
 static void ltr502_switch(int mode)
 {
        u8 data;
+       u8 reg = 0;
 
        mode = mode & ENABLE_MASK;
        switch (mode) {
@@ -440,6 +442,19 @@ static void ltr502_switch(int mode)
                data = POWER_DOWN;
                break;
        }
+
+       if (alsps_read(alsps_dev, CONFIGREG, &reg) < 0) {
+               dev_err(&alsps_dev->client->dev, "fail to read CONFIGREG\n");
+               return;
+       }
+       if (reg == data)
+               return;
+
+       /* when change the device mode, we need to set the CONFIG REG to
+        * "idle" first to disable interrupt. Otherwise, some interrupts
+        * may be triggered abnormally during the mode switch */
+       alsps_write(alsps_dev, CONFIGREG, IDLE);
+       msleep(CONFIGREG_DELAY);
        alsps_write(alsps_dev, CONFIGREG, data);
 
        if (mode & AMBIENT_ENABLE) {
@@ -510,7 +525,7 @@ proximity_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        struct alsps_client *client = file->private_data;
 
        dev_dbg(&alsps_dev->client->dev,
-               "cmd = %d, arg = %d\n", (int)cmd, (int)arg);
+               "%s:cmd = %d, arg = %d\n", __func__, (int)cmd, (int)arg);
        /* 1 - enable; 0 - disable */
 
        mutex_lock(&alsps_dev->lock);
@@ -535,7 +550,7 @@ ambient_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        struct alsps_client *client = file->private_data;
 
        dev_dbg(&alsps_dev->client->dev,
-               "cmd = %d, arg = %d\n", (int)cmd, (int)arg);
+               "%s:cmd = %d, arg = %d\n", __func__, (int)cmd, (int)arg);
 
        mutex_lock(&alsps_dev->lock);
        /* 1 - enable; 0 - disable */
@@ -628,13 +643,14 @@ static void alsps_early_suspend(struct early_suspend *h)
        /* Only proximity is kept actice over the suspend period */
        ltr502_switch(alsps->alsps_switch & PROXIMITY_ENABLE);
 
-       /* If proximity status is changed during mode switch, there may be no
-        * interrupt occurred, so we need to check the data register after mode
-        * switching here */
-       /* Sleep 1 intergration cycle(100 ms) to ensure ADC sample */
-       msleep(100);
-       alsps_read(alsps, DATAREG, &data);
-       proximity_handle_irq(alsps, data);
+       /* If PS is enabled during early supend, some PS interrupt may be lost
+        * during the CONFIG REG switch, so we need to check the data register
+        * after mode switch after a specific delay time */
+       if (alsps->alsps_switch & PROXIMITY_ENABLE) {
+               msleep(PS_FIRST_INT_DELAY);
+               alsps_read(alsps, DATAREG, &data);
+               proximity_handle_irq(alsps, data);
+       }
        mutex_unlock(&alsps_dev->lock);
 }
 
@@ -699,7 +715,6 @@ static void als_avoid_slience(struct work_struct *work)
        mutex_unlock(&alsps->lock);
 }
 
-
 static struct alsps_device *ltr502als_alloc_dev(void)
 {
        struct alsps_device *alsps;