Input: ad7879 - support auxiliary GPIOs via gpiolib

Drop the simple fancy sysfs hooks for the aux GPIOs and expose these via
the gpiolib interface so that other drivers can use them.

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>

2 files changed, 149 insertions, 60 deletions

diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
index c21e6d3a8844..794d070c6900 100644
--- a/drivers/input/touchscreen/ad7879.c
+++ b/drivers/input/touchscreen/ad7879.c
@@ -47,6 +47,7 @@
 #include <linux/workqueue.h>
 #include <linux/spi/spi.h>
 #include <linux/i2c.h>
+#include <linux/gpio.h>
 
 #include <linux/spi/ad7879.h>
 
@@ -132,7 +133,9 @@ struct ad7879 {
         struct input_dev        *input;
         struct work_struct      work;
         struct timer_list       timer;
-
+#ifdef CONFIG_GPIOLIB
+        struct gpio_chip        gc;
+#endif
         struct mutex            mutex;
         unsigned                disabled:1;     /* P: mutex */
 
@@ -150,11 +153,9 @@ struct ad7879 {
         u8                      median;
         u16                     x_plate_ohms;
         u16                     pressure_max;
-        u16                     gpio_init;
         u16                     cmd_crtl1;
         u16                     cmd_crtl2;
         u16                     cmd_crtl3;
-        unsigned                gpio:1;
 };
 
 static int ad7879_read(bus_device *, u8);
@@ -237,24 +238,6 @@ static irqreturn_t ad7879_irq(int irq, void *handle)
 
 static void ad7879_setup(struct ad7879 *ts)
 {
-        ts->cmd_crtl3 = AD7879_YPLUS_BIT |
-                        AD7879_XPLUS_BIT |
-                        AD7879_Z2_BIT |
-                        AD7879_Z1_BIT |
-                        AD7879_TEMPMASK_BIT |
-                        AD7879_AUXVBATMASK_BIT |
-                        AD7879_GPIOALERTMASK_BIT;
-
-        ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
-                        AD7879_AVG(ts->averaging) |
-                        AD7879_MFS(ts->median) |
-                        AD7879_FCD(ts->first_conversion_delay) |
-                        ts->gpio_init;
-
-        ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
-                        AD7879_ACQ(ts->acquisition_time) |
-                        AD7879_TMR(ts->pen_down_acc_interval);
-
         ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
         ad7879_write(ts->bus, AD7879_REG_CTRL3, ts->cmd_crtl3);
         ad7879_write(ts->bus, AD7879_REG_CTRL1, ts->cmd_crtl1);
@@ -324,48 +307,132 @@ static ssize_t ad7879_disable_store(struct device *dev,
 
 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
 
-static ssize_t ad7879_gpio_show(struct device *dev,
-                                     struct device_attribute *attr, char *buf)
+static struct attribute *ad7879_attributes[] = {
+        &dev_attr_disable.attr,
+        NULL
+};
+
+static const struct attribute_group ad7879_attr_group = {
+        .attrs = ad7879_attributes,
+};
+
+#ifdef CONFIG_GPIOLIB
+static int ad7879_gpio_direction_input(struct gpio_chip *chip,
+                                        unsigned gpio)
 {
-        struct ad7879 *ts = dev_get_drvdata(dev);
+        struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+        int err;
 
-        return sprintf(buf, "%u\n", ts->gpio);
+        mutex_lock(&ts->mutex);
+        ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
+        err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        mutex_unlock(&ts->mutex);
+
+        return err;
 }
 
-static ssize_t ad7879_gpio_store(struct device *dev,
-                                     struct device_attribute *attr,
-                                     const char *buf, size_t count)
+static int ad7879_gpio_direction_output(struct gpio_chip *chip,
+                                        unsigned gpio, int level)
 {
-        struct ad7879 *ts = dev_get_drvdata(dev);
-        unsigned long val;
-        int error;
+        struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+        int err;
 
-        error = strict_strtoul(buf, 10, &val);
-        if (error)
-                return error;
+        mutex_lock(&ts->mutex);
+        ts->cmd_crtl2 &= ~AD7879_GPIODIR;
+        ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
+        if (level)
+                ts->cmd_crtl2 |= AD7879_GPIO_DATA;
+        else
+                ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
+
+        err = ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        mutex_unlock(&ts->mutex);
+
+        return err;
+}
+
+static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+        struct ad7879 *ts = container_of(chip, struct ad7879, gc);
+        u16 val;
 
         mutex_lock(&ts->mutex);
-        ts->gpio = !!val;
-        error = ad7879_write(ts->bus, AD7879_REG_CTRL2,
-                           ts->gpio ?
-                                ts->cmd_crtl2 & ~AD7879_GPIO_DATA :
-                                ts->cmd_crtl2 | AD7879_GPIO_DATA);
+        val = ad7879_read(ts->bus, AD7879_REG_CTRL2);
         mutex_unlock(&ts->mutex);
 
-        return error ? : count;
+        return !!(val & AD7879_GPIO_DATA);
 }
 
-static DEVICE_ATTR(gpio, 0664, ad7879_gpio_show, ad7879_gpio_store);
+static void ad7879_gpio_set_value(struct gpio_chip *chip,
+                                  unsigned gpio, int value)
+{
+        struct ad7879 *ts = container_of(chip, struct ad7879, gc);
 
-static struct attribute *ad7879_attributes[] = {
-        &dev_attr_disable.attr,
-        &dev_attr_gpio.attr,
-        NULL
-};
+        mutex_lock(&ts->mutex);
+        if (value)
+                ts->cmd_crtl2 |= AD7879_GPIO_DATA;
+        else
+                ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
 
-static const struct attribute_group ad7879_attr_group = {
-        .attrs = ad7879_attributes,
-};
+        ad7879_write(ts->bus, AD7879_REG_CTRL2, ts->cmd_crtl2);
+        mutex_unlock(&ts->mutex);
+}
+
+static int __devinit ad7879_gpio_add(struct device *dev)
+{
+        struct ad7879 *ts = dev_get_drvdata(dev);
+        struct ad7879_platform_data *pdata = dev->platform_data;
+        int ret = 0;
+
+        if (pdata->gpio_export) {
+                ts->gc.direction_input = ad7879_gpio_direction_input;
+                ts->gc.direction_output = ad7879_gpio_direction_output;
+                ts->gc.get = ad7879_gpio_get_value;
+                ts->gc.set = ad7879_gpio_set_value;
+                ts->gc.can_sleep = 1;
+                ts->gc.base = pdata->gpio_base;
+                ts->gc.ngpio = 1;
+                ts->gc.label = "AD7879-GPIO";
+                ts->gc.owner = THIS_MODULE;
+                ts->gc.dev = dev;
+
+                ret = gpiochip_add(&ts->gc);
+                if (ret)
+                        dev_err(dev, "failed to register gpio %d\n",
+                                ts->gc.base);
+        }
+
+        return ret;
+}
+
+/*
+ * We mark ad7879_gpio_remove inline so there is a chance the code
+ * gets discarded when not needed. We can't do __devinit/__devexit
+ * markup since it is used in both probe and remove methods.
+ */
+static inline void ad7879_gpio_remove(struct device *dev)
+{
+        struct ad7879 *ts = dev_get_drvdata(dev);
+        struct ad7879_platform_data *pdata = dev->platform_data;
+        int ret;
+
+        if (pdata->gpio_export) {
+                ret = gpiochip_remove(&ts->gc);
+                if (ret)
+                        dev_err(dev, "failed to remove gpio %d\n",
+                                ts->gc.base);
+        }
+}
+#else
+static inline int ad7879_gpio_add(struct device *dev)
+{
+        return 0;
+}
+
+static inline void ad7879_gpio_remove(struct device *dev)
+{
+}
+#endif
 
 static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
 {
@@ -403,12 +470,6 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
         ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
         ts->median = pdata->median;
 
-        if (pdata->gpio_output)
-                ts->gpio_init = AD7879_GPIO_EN |
-                                (pdata->gpio_default ? 0 : AD7879_GPIO_DATA);
-        else
-                ts->gpio_init = AD7879_GPIO_EN | AD7879_GPIODIR;
-
         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&bus->dev));
 
         input_dev->name = "AD7879 Touchscreen";
@@ -446,6 +507,23 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
                 goto err_free_mem;
         }
 
+        ts->cmd_crtl3 = AD7879_YPLUS_BIT |
+                        AD7879_XPLUS_BIT |
+                        AD7879_Z2_BIT |
+                        AD7879_Z1_BIT |
+                        AD7879_TEMPMASK_BIT |
+                        AD7879_AUXVBATMASK_BIT |
+                        AD7879_GPIOALERTMASK_BIT;
+
+        ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
+                        AD7879_AVG(ts->averaging) |
+                        AD7879_MFS(ts->median) |
+                        AD7879_FCD(ts->first_conversion_delay);
+
+        ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
+                        AD7879_ACQ(ts->acquisition_time) |
+                        AD7879_TMR(ts->pen_down_acc_interval);
+
         ad7879_setup(ts);
 
         err = request_irq(bus->irq, ad7879_irq,
@@ -460,15 +538,21 @@ static int __devinit ad7879_construct(bus_device *bus, struct ad7879 *ts)
         if (err)
                 goto err_free_irq;
 
-        err = input_register_device(input_dev);
+        err = ad7879_gpio_add(&bus->dev);
         if (err)
                 goto err_remove_attr;
 
+        err = input_register_device(input_dev);
+        if (err)
+                goto err_remove_gpio;
+
         dev_info(&bus->dev, "Rev.%d touchscreen, irq %d\n",
                  revid >> 8, bus->irq);
 
         return 0;
 
+err_remove_gpio:
+        ad7879_gpio_remove(&bus->dev);
 err_remove_attr:
         sysfs_remove_group(&bus->dev.kobj, &ad7879_attr_group);
 err_free_irq:
@@ -481,6 +565,7 @@ err_free_mem:
 
 static int __devexit ad7879_destroy(bus_device *bus, struct ad7879 *ts)
 {
+        ad7879_gpio_remove(&bus->dev);
         ad7879_disable(ts);
         sysfs_remove_group(&ts->bus->dev.kobj, &ad7879_attr_group);
         free_irq(ts->bus->irq, ts);
diff --git a/include/linux/spi/ad7879.h b/include/linux/spi/ad7879.h
index 4231104c9afa..6334cee1a3be 100644
--- a/include/linux/spi/ad7879.h
+++ b/include/linux/spi/ad7879.h
@@ -28,8 +28,12 @@ struct ad7879_platform_data {
          * 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;
+        /* 1 = AUX/VBAT/GPIO export GPIO to gpiolib
+         * requires CONFIG_GPIOLIB
+         */
+        bool    gpio_export;
+        /* identifies the first GPIO number handled by this chip;
+         * or, if negative, requests dynamic ID allocation.
+         */
+        s32     gpio_base;
 };