From: Naveen Chakka <naveen.cha...@in.bosch.com>

To know the current communication status of the touch controller during
runtime, sysfs interface is added

sysfs interface: /sys/class/i2c-dev/i2c-*/device/*/touch_dev_stat
Executing the above sysfs interface provides two output values

1)Status of the touch device
        value 0 represents device is inactive
        value 1 represents device is active
2)Error counter
        value represents the number of times device in inactive since last read

Signed-off-by: Naveen Chakka <naveen.cha...@in.bosch.com>
Signed-off-by: Sanjeev Chugh <sanjeev_ch...@mentor.com>
Signed-off-by: George G. Davis <george_da...@mentor.com>
Signed-off-by: Jiada Wang <jiada_w...@mentor.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 109 +++++++++++++++++++++--
 1 file changed, 102 insertions(+), 7 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c 
b/drivers/input/touchscreen/atmel_mxt_ts.c
index 8444f7292e29..e67c29f0e0ca 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -25,6 +25,7 @@
 #include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/gpio/consumer.h>
+#include <linux/timer.h>
 #include <asm/unaligned.h>
 #include <linux/regulator/consumer.h>
 #include <linux/workqueue.h>
@@ -222,6 +223,7 @@ enum t100_type {
 #define MXT_CHG_DELAY          100     /* msec */
 #define MXT_POWERON_DELAY      150     /* msec */
 #define MXT_BOOTLOADER_WAIT    36E5    /* 1 minute */
+#define MXT_WATCHDOG_TIMEOUT   1000    /* msec */
 
 /* Command to unlock bootloader */
 #define MXT_UNLOCK_CMD_MSB     0xaa
@@ -317,6 +319,12 @@ struct mxt_flash {
        struct delayed_work work;
 };
 
+struct mxt_statusinfo {
+       bool dev_status;
+       bool intp_triggered;
+       u32 error_count;
+};
+
 /* Each client has this additional data */
 struct mxt_data {
        struct i2c_client *client;
@@ -372,6 +380,9 @@ struct mxt_data {
        const char *pcfg_name;
        const char *input_name;
        struct mxt_flash *flash;
+       struct work_struct watchdog_work;
+       struct timer_list watchdog_timer;
+       struct mxt_statusinfo mxt_status;
 
        /* Cached parameters from object table */
        u16 T5_address;
@@ -1624,11 +1635,30 @@ static int mxt_process_messages(struct mxt_data *data)
        return total_handled;
 }
 
+static void mxt_start_wd_timer(struct mxt_data *data)
+{
+       mod_timer(&data->watchdog_timer, jiffies +
+                       msecs_to_jiffies(MXT_WATCHDOG_TIMEOUT));
+}
+
+static void mxt_stop_wd_timer(struct mxt_data *data)
+{
+       /*
+        * Ensure we wait until the watchdog timer
+        * running on a different CPU finishes
+        */
+       del_timer_sync(&data->watchdog_timer);
+       cancel_work_sync(&data->watchdog_work);
+       del_timer_sync(&data->watchdog_timer);
+}
+
 static irqreturn_t mxt_interrupt(int irq, void *dev_id)
 {
        struct mxt_data *data = dev_id;
        int ret;
 
+       data->mxt_status.intp_triggered = true;
+
        if (data->in_bootloader) {
                complete(&data->chg_completion);
 
@@ -1636,21 +1666,25 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
                        cancel_delayed_work_sync(&data->flash->work);
 
                ret = mxt_check_bootloader(data);
-               return IRQ_RETVAL(ret);
+               ret = IRQ_RETVAL(ret);
+               goto exit;
        }
 
-       if (!data->object_table)
-               return IRQ_HANDLED;
+       if (!data->object_table) {
+               ret = IRQ_HANDLED;
+               goto exit;
+       }
 
        if (data->T44_address)
                ret = mxt_process_messages_t44(data);
        else
                ret = mxt_process_messages(data);
 
-       if (ret <= 0)
-               return IRQ_NONE;
-       else
-               return IRQ_HANDLED;
+       ret = (ret <= 0) ? IRQ_NONE : IRQ_HANDLED;
+
+exit:
+       data->mxt_status.intp_triggered = false;
+       return ret;
 }
 
 static int mxt_t6_command(struct mxt_data *data, u16 cmd_offset,
@@ -2970,6 +3004,36 @@ static int mxt_bootloader_status(struct mxt_data *data)
        return 0;
 }
 
+static void mxt_watchdog_timer(struct timer_list *t)
+{
+       struct mxt_data *data = from_timer(data, t, watchdog_timer);
+
+       if (!work_pending(&data->watchdog_work)) {
+               if (!data->mxt_status.intp_triggered)
+                       schedule_work(&data->watchdog_work);
+       }
+
+       mxt_start_wd_timer(data);
+}
+
+static void mxt_watchdog_work(struct work_struct *work)
+{
+       struct mxt_data *data =
+               container_of(work, struct mxt_data, watchdog_work);
+       u16 info_buf;
+       int ret = 0;
+       u8 size = 2;
+
+       ret = __mxt_read_reg(data->client, 0, size, &info_buf);
+
+       if (ret) {
+               data->mxt_status.error_count++;
+               data->mxt_status.dev_status = false;
+       } else {
+               data->mxt_status.dev_status = true;
+       }
+}
+
 static int mxt_initialize(struct mxt_data *data)
 {
        struct i2c_client *client = data->client;
@@ -3947,6 +4011,22 @@ static const struct attribute_group mxt_fw_attr_group = {
        .attrs = mxt_fw_attrs,
 };
 
+static ssize_t mxt_touch_device_status(struct device *dev, struct
+                                      device_attribute *attr, char *buf)
+{
+       struct mxt_data *data = dev_get_drvdata(dev);
+       int ret = 0;
+
+       if (data->mxt_status.dev_status)
+               data->mxt_status.error_count = 0;
+
+       ret =  snprintf(buf, PAGE_SIZE, "%d %d\n", data->mxt_status.dev_status,
+                       data->mxt_status.error_count);
+       /* clear the error counter once it is read */
+       data->mxt_status.error_count = 0;
+       return ret;
+}
+
 static DEVICE_ATTR(fw_version, S_IRUGO, mxt_fw_version_show, NULL);
 static DEVICE_ATTR(hw_version, S_IRUGO, mxt_hw_version_show, NULL);
 static DEVICE_ATTR(object, S_IRUGO, mxt_object_show, NULL);
@@ -3958,6 +4038,7 @@ static DEVICE_ATTR(debug_v2_enable, S_IWUSR | S_IRUSR, 
NULL,
                   mxt_debug_v2_enable_store);
 static DEVICE_ATTR(debug_notify, S_IRUGO, mxt_debug_notify_show, NULL);
 static DEVICE_ATTR(t25, 0600, mxt_t25_selftest_show, mxt_t25_selftest_store);
+static DEVICE_ATTR(touch_dev_stat, 0444, mxt_touch_device_status, NULL);
 
 static struct attribute *mxt_attrs[] = {
        &dev_attr_fw_version.attr,
@@ -3969,6 +4050,7 @@ static struct attribute *mxt_attrs[] = {
        &dev_attr_debug_v2_enable.attr,
        &dev_attr_debug_notify.attr,
        &dev_attr_t25.attr,
+       &dev_attr_touch_dev_stat.attr,
        NULL
 };
 
@@ -4322,6 +4404,13 @@ static int mxt_probe(struct i2c_client *client, const 
struct i2c_device_id *id)
                msleep(MXT_RESET_TIME);
        }
 
+       INIT_WORK(&data->watchdog_work, mxt_watchdog_work);
+
+       /* setup watchdog timer */
+       timer_setup(&data->watchdog_timer, mxt_watchdog_timer, 0);
+
+       mxt_start_wd_timer(data);
+
        error = mxt_initialize(data);
        if (error)
                goto err_free_object;
@@ -4336,8 +4425,11 @@ static int mxt_probe(struct i2c_client *client, const 
struct i2c_device_id *id)
        return 0;
 
 err_free_object:
+       cancel_work_sync(&data->watchdog_work);
+       mxt_stop_wd_timer(data);
        mxt_free_input_device(data);
        mxt_free_object_table(data);
+       del_timer(&data->watchdog_timer);
        if (data->reset_gpio) {
                sysfs_remove_link(&client->dev.kobj, "reset");
                gpiod_unexport(data->reset_gpio);
@@ -4360,6 +4452,9 @@ static int mxt_remove(struct i2c_client *client)
        mxt_free_input_device(data);
        mxt_free_object_table(data);
 
+       cancel_work_sync(&data->watchdog_work);
+       mxt_stop_wd_timer(data);
+
        return 0;
 }
 
-- 
2.19.2

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