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Input: ads7846 - add support for AD7843 parts

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The AD7873 is almost identical to the ADS7846; the only difference is
related to the Power Management bits PD0 and PD1.  This results in a
slightly different PENIRQ enable behavior.  For the AD7873, VREF should
be turned off during differential measurements.

So, add the AD7873/43 to the list of driver supported devices, and prevent
VREF usage during differential/ratiometric conversion modes.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Michael Hennerich 2010-03-09 20:38:45 -08:00 committed by Dmitry Torokhov
parent 9e49f6c133
commit 06a09124b5
3 changed files with 16 additions and 5 deletions
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9
drivers/input/touchscreen/Kconfig
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@ -24,17 +24,18 @@ config TOUCHSCREEN_88PM860X
module will be called 88pm860x-ts. module will be called 88pm860x-ts.
config TOUCHSCREEN_ADS7846 config TOUCHSCREEN_ADS7846
tristate "ADS7846/TSC2046 and ADS7843 based touchscreens" tristate "ADS7846/TSC2046/AD7873 and AD(S)7843 based touchscreens"
depends on SPI_MASTER depends on SPI_MASTER
depends on HWMON = n || HWMON depends on HWMON = n || HWMON
help help
Say Y here if you have a touchscreen interface using the Say Y here if you have a touchscreen interface using the
ADS7846/TSC2046 or ADS7843 controller, and your board-specific ADS7846/TSC2046/AD7873 or ADS7843/AD7843 controller,
setup code includes that in its table of SPI devices. and your board-specific setup code includes that in its
table of SPI devices.
If HWMON is selected, and the driver is told the reference voltage If HWMON is selected, and the driver is told the reference voltage
on your board, you will also get hwmon interfaces for the voltage on your board, you will also get hwmon interfaces for the voltage
(and on ads7846/tsc2046, temperature) sensors of this chip. (and on ads7846/tsc2046/ad7873, temperature) sensors of this chip.
If unsure, say N (but it's safe to say "Y"). If unsure, say N (but it's safe to say "Y").

10
drivers/input/touchscreen/ads7846.c
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@ -36,6 +36,7 @@
* TSC2046 is just newer ads7846 silicon. * TSC2046 is just newer ads7846 silicon.
* Support for ads7843 tested on Atmel at91sam926x-EK. * Support for ads7843 tested on Atmel at91sam926x-EK.
* Support for ads7845 has only been stubbed in. * Support for ads7845 has only been stubbed in.
* Support for Analog Devices AD7873 and AD7843 tested.
* *
* IRQ handling needs a workaround because of a shortcoming in handling * IRQ handling needs a workaround because of a shortcoming in handling
* edge triggered IRQs on some platforms like the OMAP1/2. These * edge triggered IRQs on some platforms like the OMAP1/2. These
@ -984,6 +985,15 @@ static int __devinit ads7846_probe(struct spi_device *spi)
vref = pdata->keep_vref_on; vref = pdata->keep_vref_on;
if (ts->model == 7873) {
/* The AD7873 is almost identical to the ADS7846
* keep VREF off during differential/ratiometric
* conversion modes
*/
ts->model = 7846;
vref = 0;
}
/* set up the transfers to read touchscreen state; this assumes we /* set up the transfers to read touchscreen state; this assumes we
* use formula #2 for pressure, not #3. * use formula #2 for pressure, not #3.
*/ */

2
include/linux/spi/ads7846.h
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@ -12,7 +12,7 @@ enum ads7846_filter {
}; };
struct ads7846_platform_data { struct ads7846_platform_data {
u16 model; /* 7843, 7845, 7846. */ u16 model; /* 7843, 7845, 7846, 7873. */
u16 vref_delay_usecs; /* 0 for external vref; etc */ u16 vref_delay_usecs; /* 0 for external vref; etc */
u16 vref_mv; /* external vref value, milliVolts */ u16 vref_mv; /* external vref value, milliVolts */
bool keep_vref_on; /* set to keep vref on for differential bool keep_vref_on; /* set to keep vref on for differential