Messages in this thread Patch in this message | | | From | David Brownell <> | Subject | [RESEND patch 2.6.22-rc4] ads7846 pendown status check | Date | Fri, 13 Jul 2007 11:29:40 -0700 |
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From: Semih Hazar <semih.hazar@indefia.com>
Pendown status from the PENIRQ pin is currently read only at the beginning of a sample set. If the pen is lifted just after sampling has began then sampled values become wrong.
This patch adds an optional platform penirq_recheck_delay attribute. If non-zero, samples are only reported to the input subsystem if PENIRQ is still active that long after the samples taken.
Signed-off-by: Semih Hazar <semih.hazar@indefia.com> Cc: Imre Deak <imre.deak@solidboot.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> --- Still applies fine against 2.6.22-git ... this should be in 2.6.23
drivers/input/touchscreen/ads7846.c | 15 +++++++++++++++ include/linux/spi/ads7846.h | 6 ++++++ 2 files changed, 21 insertions(+)
--- g26.orig/include/linux/spi/ads7846.h 2007-06-16 04:33:43.000000000 -0700 +++ g26/include/linux/spi/ads7846.h 2007-06-16 09:46:32.000000000 -0700 @@ -24,6 +24,12 @@ struct ads7846_platform_data { */ u16 settle_delay_usecs; + /* If set to non-zero, after samples are taken this delay is applied + * and penirq is rechecked, to help avoid false events. This value + * is affected by the material used to build the touch layer. + */ + u16 penirq_recheck_delay_usecs; + u16 x_plate_ohms; u16 y_plate_ohms; --- g26.orig/drivers/input/touchscreen/ads7846.c 2007-06-16 09:46:22.000000000 -0700 +++ g26/drivers/input/touchscreen/ads7846.c 2007-06-16 09:46:32.000000000 -0700 @@ -107,6 +107,8 @@ struct ads7846 { u16 debounce_tol; u16 debounce_rep; + u16 penirq_recheck_delay_usecs; + spinlock_t lock; struct hrtimer timer; unsigned pendown:1; /* P: lock */ @@ -553,6 +555,15 @@ static void ads7846_rx(void *ads) return; } + /* Maybe check the pendown state before reporting. This discards + * false readings when the pen is lifted. + */ + if (ts->penirq_recheck_delay_usecs) { + udelay(ts->penirq_recheck_delay_usecs); + if (!ts->get_pendown_state()) + Rt = 0; + } + /* 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 @@ -896,6 +907,10 @@ static int __devinit ads7846_probe(struc ts->filter = ads7846_no_filter; ts->get_pendown_state = pdata->get_pendown_state; + if (pdata->penirq_recheck_delay_usecs) + ts->penirq_recheck_delay_usecs = + pdata->penirq_recheck_delay_usecs; + snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); input_dev->name = "ADS784x Touchscreen"; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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