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>

diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index ce6f48c..8583c76 100644 (file)
--- 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 daf7440..05eab2f 100644 (file)
--- 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);