From d570e9ef84e559b09e729f27f5381b6868f6cc5f Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Tue, 4 Aug 2009 22:07:26 -0700 Subject: Input: tsc2007 - make get_pendown_state platform callback optional In cases when get_pendown_state callback is not available have the driver to fallback on pressure calculation to determine if the pen is up. Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/tsc2007.c | 172 +++++++++++++++++++----------------- 1 file changed, 93 insertions(+), 79 deletions(-) (limited to 'drivers/input/touchscreen') diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c index f710af4d0ff..3714d19f102 100644 --- a/drivers/input/touchscreen/tsc2007.c +++ b/drivers/input/touchscreen/tsc2007.c @@ -70,7 +70,6 @@ struct tsc2007 { struct input_dev *input; char phys[32]; struct delayed_work work; - struct ts_event tc; struct i2c_client *client; @@ -106,51 +105,96 @@ static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) return val; } -static void tsc2007_send_event(void *tsc) +static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) { - struct tsc2007 *ts = tsc; - u32 rt; - u16 x, y, z1, z2; + /* y- still on; turn on only y+ (and ADC) */ + tc->y = tsc2007_xfer(tsc, READ_Y); + + /* turn y- off, x+ on, then leave in lowpower */ + tc->x = tsc2007_xfer(tsc, READ_X); + + /* turn y+ off, x- on; we'll use formula #1 */ + tc->z1 = tsc2007_xfer(tsc, READ_Z1); + tc->z2 = tsc2007_xfer(tsc, READ_Z2); - x = ts->tc.x; - y = ts->tc.y; - z1 = ts->tc.z1; - z2 = ts->tc.z2; + /* Prepare for next touch reading - power down ADC, enable PENIRQ */ + tsc2007_xfer(tsc, PWRDOWN); +} + +static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc) +{ + u32 rt = 0; /* range filtering */ - if (x == MAX_12BIT) - x = 0; + if (tc->x == MAX_12BIT) + tc->x = 0; - if (likely(x && z1)) { + if (likely(tc->x && tc->z1)) { /* compute touch pressure resistance using equation #1 */ - rt = z2; - rt -= z1; - rt *= x; - rt *= ts->x_plate_ohms; - rt /= z1; + rt = tc->z2 - tc->z1; + rt *= tc->x; + rt *= tsc->x_plate_ohms; + rt /= tc->z1; rt = (rt + 2047) >> 12; - } else - rt = 0; - - /* - * Sample found inconsistent by debouncing or pressure is beyond - * the maximum. Don't report it to user space, repeat at least - * once more the measurement - */ - if (rt > MAX_12BIT) { - dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); - return; } + return rt; +} + +static void tsc2007_send_up_event(struct tsc2007 *tsc) +{ + struct input_dev *input = tsc->input; + + dev_dbg(&tsc->client->dev, "UP\n"); + + input_report_key(input, BTN_TOUCH, 0); + input_report_abs(input, ABS_PRESSURE, 0); + input_sync(input); +} + +static void tsc2007_work(struct work_struct *work) +{ + struct tsc2007 *ts = + container_of(to_delayed_work(work), struct tsc2007, work); + struct ts_event tc; + u32 rt; + /* * NOTE: We can't rely on the pressure to determine the pen down - * state, even this controller has a pressure sensor. The pressure - * value can fluctuate for quite a while after lifting the pen and - * in some cases may not even settle at the expected value. + * state, even though this controller has a pressure sensor. + * The pressure value can fluctuate for quite a while after + * lifting the pen and in some cases may not even settle at the + * expected value. * * The only safe way to check for the pen up condition is in the - * work function by reading the pen signal state (it's a GPIO and IRQ). + * work function by reading the pen signal state (it's a GPIO + * and IRQ). Unfortunately such callback is not always available, + * in that case we have rely on the pressure anyway. */ + if (ts->get_pendown_state) { + if (unlikely(!ts->get_pendown_state())) { + tsc2007_send_up_event(ts); + ts->pendown = false; + goto out; + } + + dev_dbg(&ts->client->dev, "pen is still down\n"); + } + + tsc2007_read_values(ts, &tc); + + rt = tsc2007_calculate_pressure(ts, &tc); + if (rt > MAX_12BIT) { + /* + * Sample found inconsistent by debouncing or pressure is + * beyond the maximum. Don't report it to user space, + * repeat at least once more the measurement. + */ + dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); + goto out; + + } + if (rt) { struct input_dev *input = ts->input; @@ -161,68 +205,38 @@ static void tsc2007_send_event(void *tsc) ts->pendown = true; } - input_report_abs(input, ABS_X, x); - input_report_abs(input, ABS_Y, y); + input_report_abs(input, ABS_X, tc.x); + input_report_abs(input, ABS_Y, tc.y); input_report_abs(input, ABS_PRESSURE, rt); input_sync(input); dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n", - x, y, rt); - } -} - -static int tsc2007_read_values(struct tsc2007 *tsc) -{ - /* y- still on; turn on only y+ (and ADC) */ - tsc->tc.y = tsc2007_xfer(tsc, READ_Y); - - /* turn y- off, x+ on, then leave in lowpower */ - tsc->tc.x = tsc2007_xfer(tsc, READ_X); - - /* turn y+ off, x- on; we'll use formula #1 */ - tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1); - tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2); - - /* Prepare for next touch reading - power down ADC, enable PENIRQ */ - tsc2007_xfer(tsc, PWRDOWN); - - return 0; -} - -static void tsc2007_work(struct work_struct *work) -{ - struct tsc2007 *ts = - container_of(to_delayed_work(work), struct tsc2007, work); - - if (unlikely(!ts->get_pendown_state() && ts->pendown)) { - struct input_dev *input = ts->input; - - dev_dbg(&ts->client->dev, "UP\n"); - - input_report_key(input, BTN_TOUCH, 0); - input_report_abs(input, ABS_PRESSURE, 0); - input_sync(input); + tc.x, tc.y, rt); + } else if (!ts->get_pendown_state && ts->pendown) { + /* + * We don't have callback to check pendown state, so we + * have to assume that since pressure reported is 0 the + * pen was lifted up. + */ + tsc2007_send_up_event(ts); ts->pendown = false; - enable_irq(ts->irq); - } else { - /* pen is still down, continue with the measurement */ - dev_dbg(&ts->client->dev, "pen is still down\n"); - - tsc2007_read_values(ts); - tsc2007_send_event(ts); + } + out: + if (ts->pendown) schedule_delayed_work(&ts->work, msecs_to_jiffies(TS_POLL_PERIOD)); - } + else + enable_irq(ts->irq); } static irqreturn_t tsc2007_irq(int irq, void *handle) { struct tsc2007 *ts = handle; - if (likely(ts->get_pendown_state())) { + if (!ts->get_pendown_state || likely(ts->get_pendown_state())) { disable_irq_nosync(ts->irq); schedule_delayed_work(&ts->work, msecs_to_jiffies(TS_POLL_DELAY)); @@ -255,7 +269,7 @@ static int __devinit tsc2007_probe(struct i2c_client *client, struct input_dev *input_dev; int err; - if (!pdata || !pdata->get_pendown_state) { + if (!pdata) { dev_err(&client->dev, "platform data is required!\n"); return -EINVAL; } -- cgit v1.2.3-70-g09d2