Input: ads7846 - introduce .gpio_pendown to get pendown state

The GPIO connected to ADS7846 nPENIRQ signal is usually used to get
the pendown state as well. Introduce a .gpio_pendown, and use this
to decide the pendown state if .get_pendown_state is NULL.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

2 files changed, 57 insertions, 14 deletions

diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index ce6f48c695f5..8583c766d565 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -24,6 +24,7 @@
 #include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/gpio.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/ads7846.h>
 #include <asm/irq.h>
@@ -116,6 +117,7 @@ struct ads7846 {
         void                    *filter_data;
         void                    (*filter_cleanup)(void *data);
         int                     (*get_pendown_state)(void);
+        int                     gpio_pendown;
 };
 
 /* leave chip selected when we're done, for quicker re-select? */
@@ -491,6 +493,14 @@ static struct attribute_group ads784x_attr_group = {
 
 /*--------------------------------------------------------------------------*/
 
+static int get_pendown_state(struct ads7846 *ts)
+{
+        if (ts->get_pendown_state)
+                return ts->get_pendown_state();
+
+        return !gpio_get_value(ts->gpio_pendown);
+}
+
 /*
  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
  * to retrieve touchscreen status.
@@ -550,7 +560,7 @@ static void ads7846_rx(void *ads)
          */
         if (ts->penirq_recheck_delay_usecs) {
                 udelay(ts->penirq_recheck_delay_usecs);
-                if (!ts->get_pendown_state())
+                if (!get_pendown_state(ts))
                         Rt = 0;
         }
 
@@ -677,7 +687,7 @@ static enum hrtimer_restart ads7846_timer(struct hrtimer *handle)
 
         spin_lock_irq(&ts->lock);
 
-        if (unlikely(!ts->get_pendown_state() ||
+        if (unlikely(!get_pendown_state(ts) ||
                      device_suspended(&ts->spi->dev))) {
                 if (ts->pendown) {
                         struct input_dev *input = ts->input;
@@ -716,7 +726,7 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
         unsigned long flags;
 
         spin_lock_irqsave(&ts->lock, flags);
-        if (likely(ts->get_pendown_state())) {
+        if (likely(get_pendown_state(ts))) {
                 if (!ts->irq_disabled) {
                         /* The ARM do_simple_IRQ() dispatcher doesn't act
                          * like the other dispatchers:  it will report IRQs
@@ -806,6 +816,36 @@ static int ads7846_resume(struct spi_device *spi)
         return 0;
 }
 
+static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts)
+{
+        struct ads7846_platform_data *pdata = spi->dev.platform_data;
+        int err;
+
+        /* REVISIT when the irq can be triggered active-low, or if for some
+         * reason the touchscreen isn't hooked up, we don't need to access
+         * the pendown state.
+         */
+        if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) {
+                dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
+                return -EINVAL;
+        }
+
+        if (pdata->get_pendown_state) {
+                ts->get_pendown_state = pdata->get_pendown_state;
+                return 0;
+        }
+
+        err = gpio_request(pdata->gpio_pendown, "ads7846_pendown");
+        if (err) {
+                dev_err(&spi->dev, "failed to request pendown GPIO%d\n",
+                                pdata->gpio_pendown);
+                return err;
+        }
+
+        ts->gpio_pendown = pdata->gpio_pendown;
+        return 0;
+}
+
 static int __devinit ads7846_probe(struct spi_device *spi)
 {
         struct ads7846                  *ts;
@@ -833,15 +873,6 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                 return -EINVAL;
         }
 
-        /* REVISIT when the irq can be triggered active-low, or if for some
-         * reason the touchscreen isn't hooked up, we don't need to access
-         * the pendown state.
-         */
-        if (pdata->get_pendown_state == NULL) {
-                dev_dbg(&spi->dev, "no get_pendown_state function?\n");
-                return -EINVAL;
-        }
-
         /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
          * that even if the hardware can do that, the SPI controller driver
          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
@@ -893,7 +924,10 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                 ts->filter_data = ts;
         } else
                 ts->filter = ads7846_no_filter;
-        ts->get_pendown_state = pdata->get_pendown_state;
+
+        err = setup_pendown(spi, ts);
+        if (err)
+                goto err_cleanup_filter;
 
         if (pdata->penirq_recheck_delay_usecs)
                 ts->penirq_recheck_delay_usecs =
@@ -1085,7 +1119,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                         spi->dev.driver->name, ts)) {
                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
                 err = -EBUSY;
-                goto err_cleanup_filter;
+                goto err_free_gpio;
         }
 
         err = ads784x_hwmon_register(spi, ts);
@@ -1116,6 +1150,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
         ads784x_hwmon_unregister(spi, ts);
  err_free_irq:
         free_irq(spi->irq, ts);
+ err_free_gpio:
+        if (ts->gpio_pendown != -1)
+                gpio_free(ts->gpio_pendown);
  err_cleanup_filter:
         if (ts->filter_cleanup)
                 ts->filter_cleanup(ts->filter_data);
@@ -1140,6 +1177,9 @@ static int __devexit ads7846_remove(struct spi_device *spi)
         /* suspend left the IRQ disabled */
         enable_irq(ts->spi->irq);
 
+        if (ts->gpio_pendown != -1)
+                gpio_free(ts->gpio_pendown);
+
         if (ts->filter_cleanup)
                 ts->filter_cleanup(ts->filter_data);
 
diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index daf744017a31..05eab2f11e63 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -43,6 +43,9 @@ struct ads7846_platform_data {
         u16     debounce_tol;           /* tolerance used for filtering */
         u16     debounce_rep;           /* additional consecutive good readings
                                          * required after the first two */
+        int     gpio_pendown;           /* the GPIO used to decide the pendown
+                                         * state if get_pendown_state == NULL
+                                         */
         int     (*get_pendown_state)(void);
         int     (*filter_init)  (struct ads7846_platform_data *pdata,
                                  void **filter_data);