From b4be468cc1e65110d9144751bf7079dad6f142b7 Mon Sep 17 00:00:00 2001
From: Michael Hennerich <michael.hennerich@analog.com>
Date: Mon, 9 Mar 2009 20:12:52 -0700
Subject: Input: add AD7879 Touchscreen driver
[randy.dunlap@oracle.com: don't use bus_id]
[dtor@mail.ru: locking and other fixups]
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
include/linux/spi/ad7879.h | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
create mode 100644 include/linux/spi/ad7879.h
(limited to 'include/linux/spi')
diff --git a/include/linux/spi/ad7879.h b/include/linux/spi/ad7879.h
new file mode 100644
index 00000000000..4231104c9af
--- /dev/null
+++ b/include/linux/spi/ad7879.h
@@ -0,0 +1,35 @@
+/* linux/spi/ad7879.h */
+
+/* Touchscreen characteristics vary between boards and models. The
+ * platform_data for the device's "struct device" holds this information.
+ *
+ * It's OK if the min/max values are zero.
+ */
+struct ad7879_platform_data {
+ u16 model; /* 7879 */
+ u16 x_plate_ohms;
+ u16 x_min, x_max;
+ u16 y_min, y_max;
+ u16 pressure_min, pressure_max;
+
+ /* [0..255] 0=OFF Starts at 1=550us and goes
+ * all the way to 9.440ms in steps of 35us.
+ */
+ u8 pen_down_acc_interval;
+ /* [0..15] Starts at 0=128us and goes all the
+ * way to 4.096ms in steps of 128us.
+ */
+ u8 first_conversion_delay;
+ /* [0..3] 0 = 2us, 1 = 4us, 2 = 8us, 3 = 16us */
+ u8 acquisition_time;
+ /* [0..3] Average X middle samples 0 = 2, 1 = 4, 2 = 8, 3 = 16 */
+ u8 averaging;
+ /* [0..3] Perform X measurements 0 = OFF,
+ * 1 = 4, 2 = 8, 3 = 16 (median > averaging)
+ */
+ u8 median;
+ /* 1 = AUX/VBAT/GPIO set to GPIO Output */
+ u8 gpio_output;
+ /* Initial GPIO pin state (valid if gpio_output = 1) */
+ u8 gpio_default;
+};
--
cgit v1.2.3-70-g09d2
From fd746d540abf8c686f5f868ae62112692e684088 Mon Sep 17 00:00:00 2001
From: Eric Miao <eric.miao@marvell.com>
Date: Sat, 11 Apr 2009 16:54:59 -0700
Subject: Input: ads7846 - introduce platform specific way to synchronize
sampling
Noises can be introduced when LCD signals are being driven, some platforms
provide a signal to assist the synchronization of this sampling procedure.
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
drivers/input/touchscreen/ads7846.c | 10 ++++++++++
include/linux/spi/ads7846.h | 1 +
2 files changed, 11 insertions(+)
(limited to 'include/linux/spi')
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 7c27c8b9b6d..cf7e69766b2 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -127,6 +127,8 @@ struct ads7846 {
void (*filter_cleanup)(void *data);
int (*get_pendown_state)(void);
int gpio_pendown;
+
+ void (*wait_for_sync)(void);
};
/* leave chip selected when we're done, for quicker re-select? */
@@ -511,6 +513,10 @@ static int get_pendown_state(struct ads7846 *ts)
return !gpio_get_value(ts->gpio_pendown);
}
+static void null_wait_for_sync(void)
+{
+}
+
/*
* PENIRQ only kicks the timer. The timer only reissues the SPI transfer,
* to retrieve touchscreen status.
@@ -686,6 +692,7 @@ static void ads7846_rx_val(void *ads)
default:
BUG();
}
+ ts->wait_for_sync();
status = spi_async(ts->spi, m);
if (status)
dev_err(&ts->spi->dev, "spi_async --> %d\n",
@@ -723,6 +730,7 @@ static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
} else {
/* pen is still down, continue with the measurement */
ts->msg_idx = 0;
+ ts->wait_for_sync();
status = spi_async(ts->spi, &ts->msg[0]);
if (status)
dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
@@ -947,6 +955,8 @@ static int __devinit ads7846_probe(struct spi_device *spi)
ts->penirq_recheck_delay_usecs =
pdata->penirq_recheck_delay_usecs;
+ ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
+
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
input_dev->name = "ADS784x Touchscreen";
diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index 05eab2f11e6..2ea20320c09 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -51,5 +51,6 @@ struct ads7846_platform_data {
void **filter_data);
int (*filter) (void *filter_data, int data_idx, int *val);
void (*filter_cleanup)(void *filter_data);
+ void (*wait_for_sync)(void);
};
--
cgit v1.2.3-70-g09d2
From 6e538aaf50ae782a890cbc02c27950448d8193e1 Mon Sep 17 00:00:00 2001
From: David Brownell <dbrownell@users.sourceforge.net>
Date: Tue, 21 Apr 2009 12:24:49 -0700
Subject: spi: documentation: emphasise spi_master.setup() semantics
This is a doc-only patch which I hope will reduce the number of
spi_master controller driver patches starting out with a common
implementation bug.
(As in: almost every spi_master driver I see starts out with its
version of this bug. Sigh.)
It just re-emphasizes that the setup() method may be called for one
device while a transfer is active on another ... which means that most
driver implementations shouldn't touch any registers.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/spi/spi-summary | 6 ++++++
include/linux/spi/spi.h | 7 ++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
(limited to 'include/linux/spi')
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index 0f5122eb282..4a02d2508bc 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -511,10 +511,16 @@ SPI MASTER METHODS
This sets up the device clock rate, SPI mode, and word sizes.
Drivers may change the defaults provided by board_info, and then
call spi_setup(spi) to invoke this routine. It may sleep.
+
Unless each SPI slave has its own configuration registers, don't
change them right away ... otherwise drivers could corrupt I/O
that's in progress for other SPI devices.
+ ** BUG ALERT: for some reason the first version of
+ ** many spi_master drivers seems to get this wrong.
+ ** When you code setup(), ASSUME that the controller
+ ** is actively processing transfers for another device.
+
master->transfer(struct spi_device *spi, struct spi_message *message)
This must not sleep. Its responsibility is arrange that the
transfer happens and its complete() callback is issued. The two
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 2cc43fa380c..a0faa18f7b1 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -245,7 +245,12 @@ struct spi_master {
*/
u16 dma_alignment;
- /* setup mode and clock, etc (spi driver may call many times) */
+ /* Setup mode and clock, etc (spi driver may call many times).
+ *
+ * IMPORTANT: this may be called when transfers to another
+ * device are active. DO NOT UPDATE SHARED REGISTERS in ways
+ * which could break those transfers.
+ */
int (*setup)(struct spi_device *spi);
/* bidirectional bulk transfers
--
cgit v1.2.3-70-g09d2