[PATCH] touchscreen: tps6507x-ts: only poll while touch event is occurring

[Jon Ringle]

We only need to poll for touch events after an interrupt occurs due to the
user touching the screen. We continue to poll until the user stops touching
the screen

Signed-off-by: Jon Ringle <jringle@xxxxxxxxxxxxx>
---
 drivers/input/touchscreen/tps6507x-ts.c | 191 +++++++++++++++++++++++++-------
 include/linux/mfd/tps6507x.h            |   1 +
 2 files changed, 153 insertions(+), 39 deletions(-)

diff --git a/drivers/input/touchscreen/tps6507x-ts.c b/drivers/input/touchscreen/tps6507x-ts.c
index 94cde2c..fa1fb24 100644
--- a/drivers/input/touchscreen/tps6507x-ts.c
+++ b/drivers/input/touchscreen/tps6507x-ts.c
@@ -17,11 +17,14 @@
 #include <linux/workqueue.h>
 #include <linux/slab.h>
 #include <linux/input.h>
-#include <linux/input-polldev.h>
 #include <linux/platform_device.h>
 #include <linux/mfd/tps6507x.h>
 #include <linux/input/tps6507x-ts.h>
 #include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>

 #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
 #define TPS_DEFAULT_MIN_PRESSURE 0x30
@@ -39,13 +42,17 @@ struct ts_event {
 };

 struct tps6507x_ts {
+       struct input_dev        *input_dev;
        struct device           *dev;
-       struct input_polled_dev *poll_dev;
        struct tps6507x_dev     *mfd;
        char                    phys[32];
+       struct delayed_work     work;
        struct ts_event         tc;
+       int                     irq;
+       unsigned long           poll_period;    /* ms */
        u16                     min_pressure;
        bool                    pendown;
+       int                     open_count;
 };

 static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
@@ -155,13 +162,20 @@ static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
        return ret;
 }

-static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
+static void tps6507x_ts_handler(struct work_struct *work)
 {
-       struct tps6507x_ts *tsc = poll_dev->private;
-       struct input_dev *input_dev = poll_dev->input;
+       struct tps6507x_ts *tsc =  container_of(work, struct tps6507x_ts, work.work);
+       struct input_dev *input_dev = tsc->input_dev;
        bool pendown;
+       int schd;
+       int poll = 0;
        s32 ret;

+       if (tsc->irq) {
+               // Disable the touch interrupt
+               tps6507x_write_u8(tsc, TPS6507X_REG_INT, 0);
+       }
+
        ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
                                      &tsc->tc.pressure);
        if (ret)
@@ -178,9 +192,11 @@ static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
        }

        if (pendown) {
+               int report_pendown = 0;

                if (!tsc->pendown) {
                        dev_dbg(tsc->dev, "DOWN\n");
+                       report_pendown = 1;
                        input_report_key(input_dev, BTN_TOUCH, 1);
                } else
                        dev_dbg(tsc->dev, "still down\n");
@@ -195,15 +211,89 @@ static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
                if (ret)
                        goto done;

-               input_report_abs(input_dev, ABS_X, tsc->tc.x);
-               input_report_abs(input_dev, ABS_Y, tsc->tc.y);
-               input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
-               input_sync(input_dev);
-               tsc->pendown = true;
+               if (tsc->tc.x && tsc->tc.y) {
+                       if (report_pendown)
+                               input_report_key(input_dev, BTN_TOUCH, 1);
+
+                       input_report_abs(input_dev, ABS_X, tsc->tc.x);
+                       input_report_abs(input_dev, ABS_Y, tsc->tc.y);
+                       input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
+                       input_sync(input_dev);
+                       tsc->pendown = true;
+               } else {
+                       dev_dbg(tsc->dev, "discarding bogus read x=%d, y=%d, pressure=%d\n", tsc->tc.x, tsc->tc.y, tsc->tc.pressure);
+               }
+               poll = 1;
        }

 done:
        tps6507x_adc_standby(tsc);
+       if (tsc->irq && !poll) {
+               // Re-enable the interrupt
+               tps6507x_write_u8(tsc, TPS6507X_REG_INT, TPS6507X_REG_MASK_TSC);
+       } else {
+               /* always poll if not using interrupts */
+               schd = schedule_delayed_work(&tsc->work,
+                                            msecs_to_jiffies(tsc->poll_period));
+       }
+}
+
+static irqreturn_t tps6507x_ts_irq(int irq, void * dev_id)
+{
+       struct tps6507x_ts * tsc = (struct tps6507x_ts *)dev_id;
+
+       schedule_delayed_work(&tsc->work, 0);
+
+       return IRQ_HANDLED;
+}
+
+static int tps6507x_ts_open(struct input_dev *input_dev)
+{
+       int ret;
+       struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
+
+       tsc->open_count++;
+
+//     printk("%s: %s\n", __func__, comm);
+       dump_stack();
+
+       if (tsc->irq) {
+
+               tps6507x_write_u8(tsc, TPS6507X_REG_INT, 0);
+               tps6507x_adc_standby(tsc);
+
+               ret = request_irq(tsc->irq,tps6507x_ts_irq, 0, "TPS6507x",tsc);
+
+               if(ret < 0) {
+                       tsc->open_count--;
+                       dev_err(tsc->dev, "cannot register irq");
+                       return ret;
+               }
+               // Enable the touch event interrupt
+               tps6507x_write_u8(tsc, TPS6507X_REG_INT, TPS6507X_REG_MASK_TSC);
+       } else {
+               ret = schedule_delayed_work(&tsc->work,
+                                           msecs_to_jiffies(tsc->poll_period));
+
+               if (!ret) {
+                       tsc->open_count--;
+                       dev_err(tsc->dev, "schedule failed");
+                       return -ENOMEM;
+               }
+       }
+
+       return 0;
+}
+
+static void tps6507x_ts_close(struct input_dev *input_dev)
+{
+       struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
+
+       tsc->open_count--;
+
+       if(tsc->irq) {
+               free_irq(tsc->irq,tsc);
+       }
 }

 static int tps6507x_ts_probe(struct platform_device *pdev)
@@ -212,8 +302,8 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
        const struct tps6507x_board *tps_board;
        const struct touchscreen_init_data *init_data;
        struct tps6507x_ts *tsc;
-       struct input_polled_dev *poll_dev;
        struct input_dev *input_dev;
+       int schd;
        int error;

        /*
@@ -239,29 +329,18 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
                return -ENOMEM;
        }

+       tps6507x_dev->ts = tsc;
        tsc->mfd = tps6507x_dev;
        tsc->dev = tps6507x_dev->dev;
-       tsc->min_pressure = init_data ?
-                       init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
-
-       snprintf(tsc->phys, sizeof(tsc->phys),
-                "%s/input0", dev_name(tsc->dev));
-
-       poll_dev = input_allocate_polled_device();
-       if (!poll_dev) {
-               dev_err(tsc->dev, "Failed to allocate polled input device.\n");
+       input_dev = input_allocate_device();
+       if (!input_dev) {
+               dev_err(tsc->dev, "Failed to allocate input device.\n");
                error = -ENOMEM;
                goto err_free_mem;
        }

-       tsc->poll_dev = poll_dev;
-
-       poll_dev->private = tsc;
-       poll_dev->poll = tps6507x_ts_poll;
-       poll_dev->poll_interval = init_data ?
-                       init_data->poll_period : TSC_DEFAULT_POLL_PERIOD;
-
-       input_dev = poll_dev->input;
+       input_dev->open = tps6507x_ts_open;
+       input_dev->close = tps6507x_ts_close;
        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

@@ -270,42 +349,76 @@ static int tps6507x_ts_probe(struct platform_device *pdev)
        input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);

        input_dev->name = "TPS6507x Touchscreen";
-       input_dev->phys = tsc->phys;
-       input_dev->dev.parent = tsc->dev;
        input_dev->id.bustype = BUS_I2C;
+       input_dev->dev.parent = tsc->dev;
+
+       snprintf(tsc->phys, sizeof(tsc->phys),
+                "%s/input0", dev_name(tsc->dev));
+       input_dev->phys = tsc->phys;
+
+       dev_dbg(tsc->dev, "device: %s\n", input_dev->phys);
+
+       input_set_drvdata(input_dev, tsc);
+
+       tsc->input_dev = input_dev;
+
+       INIT_DELAYED_WORK(&tsc->work, tps6507x_ts_handler);
        if (init_data) {
+               tsc->poll_period = init_data->poll_period;
+               tsc->irq = gpio_to_irq(init_data->irq_pin);
+               tsc->min_pressure = init_data->min_pressure;
                input_dev->id.vendor = init_data->vendor;
                input_dev->id.product = init_data->product;
                input_dev->id.version = init_data->version;
+       } else {
+               tsc->poll_period = TSC_DEFAULT_POLL_PERIOD;
+               tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
        }

        error = tps6507x_adc_standby(tsc);
        if (error)
-               goto err_free_polled_dev;
+               goto err_free_dev;

-       error = input_register_polled_device(poll_dev);
+       error = input_register_device(input_dev);
        if (error)
-               goto err_free_polled_dev;
+               goto err_free_dev;
+
+       if (!tsc->irq) {
+               schd = schedule_delayed_work(&tsc->work,
+                                            msecs_to_jiffies(tsc->poll_period));
+
+               if (!schd) {
+                       dev_err(tsc->dev, "schedule failed");
+                       goto err_cancel_work;
+               }
+       }

        platform_set_drvdata(pdev, tsc);

        return 0;

-err_free_polled_dev:
-       input_free_polled_device(poll_dev);
+err_cancel_work:
+       cancel_delayed_work_sync(&tsc->work);
+err_free_dev:
+       input_free_device(input_dev);
 err_free_mem:
        kfree(tsc);
+       tps6507x_dev->ts = NULL;
+
        return error;
 }

 static int tps6507x_ts_remove(struct platform_device *pdev)
 {
-       struct tps6507x_ts *tsc = platform_get_drvdata(pdev);
-       struct input_polled_dev *poll_dev = tsc->poll_dev;
+       struct tps6507x_dev *tps6507x_dev = platform_get_drvdata(pdev);
+       struct tps6507x_ts *tsc = tps6507x_dev->ts;
+       struct input_dev *input_dev = tsc->input_dev;
+
+       cancel_delayed_work_sync(&tsc->work);

-       input_unregister_polled_device(poll_dev);
-       input_free_polled_device(poll_dev);
+       input_unregister_device(input_dev);

+       tps6507x_dev->ts = NULL;
        kfree(tsc);

        return 0;
diff --git a/include/linux/mfd/tps6507x.h b/include/linux/mfd/tps6507x.h
index c2ae569..c923e486 100644
--- a/include/linux/mfd/tps6507x.h
+++ b/include/linux/mfd/tps6507x.h
@@ -163,6 +163,7 @@ struct tps6507x_dev {

        /* Client devices */
        struct tps6507x_pmic *pmic;
+       struct tps6507x_ts *ts;
 };

 #endif /*  __LINUX_MFD_TPS6507X_H */
--
1.8.5.4


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