[media] em28xx: extend the support for device buttons

The current code supports only a single snapshot button assigned to
register 0x0c bit 5. But devices may be equipped with multiple buttons
with different functionalities and they can also be assigned to the
various GPI-ports.
Extend the em28xx-input code to handle multiple buttons assigned to different
GPI-ports / register addresses and bits.
Also make easier to extend the code with further button types.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

3 files changed, 154 insertions, 43 deletions

diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index a5196697627f..ebb112c17109 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -413,6 +413,20 @@ static struct em28xx_reg_seq pctv_520e[] = {
 };
 
 /*
+ *  Button definitions
+ */
+static struct em28xx_button std_snapshot_button[] = {
+        {
+                .role         = EM28XX_BUTTON_SNAPSHOT,
+                .reg_r        = EM28XX_R0C_USBSUSP,
+                .reg_clearing = EM28XX_R0C_USBSUSP,
+                .mask         = EM28XX_R0C_USBSUSP_SNAPSHOT,
+                .inverted     = 0,
+        },
+        {-1, 0, 0, 0, 0},
+};
+
+/*
  *  Board definitions
  */
 struct em28xx_board em28xx_boards[] = {
@@ -1391,7 +1405,7 @@ struct em28xx_board em28xx_boards[] = {
         },
         [EM2820_BOARD_PROLINK_PLAYTV_USB2] = {
                 .name         = "SIIG AVTuner-PVR / Pixelview Prolink PlayTV USB 2.0",
-                .has_snapshot_button = 1,
+                .buttons = std_snapshot_button,
                 .tda9887_conf = TDA9887_PRESENT,
                 .tuner_type   = TUNER_YMEC_TVF_5533MF,
                 .decoder      = EM28XX_SAA711X,
@@ -1413,7 +1427,7 @@ struct em28xx_board em28xx_boards[] = {
         },
         [EM2860_BOARD_SAA711X_REFERENCE_DESIGN] = {
                 .name                = "EM2860/SAA711X Reference Design",
-                .has_snapshot_button = 1,
+                .buttons = std_snapshot_button,
                 .tuner_type          = TUNER_ABSENT,
                 .decoder             = EM28XX_SAA711X,
                 .input               = { {
@@ -2841,7 +2855,7 @@ static void request_module_async(struct work_struct *work)
 
         if (dev->board.has_dvb)
                 request_module("em28xx-dvb");
-        if (dev->board.has_snapshot_button ||
+        if (dev->board.buttons ||
             ((dev->board.ir_codes || dev->board.has_ir_i2c) && !disable_ir))
                 request_module("em28xx-rc");
 #endif /* CONFIG_MODULES */
diff --git a/drivers/media/usb/em28xx/em28xx-input.c b/drivers/media/usb/em28xx/em28xx-input.c
index ea181e4b68c5..20c6a8ae1462 100644
--- a/drivers/media/usb/em28xx/em28xx-input.c
+++ b/drivers/media/usb/em28xx/em28xx-input.c
@@ -31,7 +31,7 @@
 #include "em28xx.h"
 
 #define EM28XX_SNAPSHOT_KEY KEY_CAMERA
-#define EM28XX_SBUTTON_QUERY_INTERVAL 500
+#define EM28XX_BUTTONS_QUERY_INTERVAL 500
 
 static unsigned int ir_debug;
 module_param(ir_debug, int, 0644);
@@ -470,38 +470,69 @@ static int em28xx_probe_i2c_ir(struct em28xx *dev)
 }
 
 /**********************************************************
- Handle Webcam snapshot button
+ Handle buttons
  **********************************************************/
 
-static void em28xx_query_sbutton(struct work_struct *work)
+static void em28xx_query_buttons(struct work_struct *work)
 {
-        /* Poll the register and see if the button is depressed */
         struct em28xx *dev =
-                container_of(work, struct em28xx, sbutton_query_work.work);
-        int ret;
-
-        ret = em28xx_read_reg(dev, EM28XX_R0C_USBSUSP);
-
-        if (ret & EM28XX_R0C_USBSUSP_SNAPSHOT) {
-                u8 cleared;
-                /* Button is depressed, clear the register */
-                cleared = ((u8) ret) & ~EM28XX_R0C_USBSUSP_SNAPSHOT;
-                em28xx_write_regs(dev, EM28XX_R0C_USBSUSP, &cleared, 1);
-
-                /* Not emulate the keypress */
-                input_report_key(dev->sbutton_input_dev, EM28XX_SNAPSHOT_KEY,
-                                 1);
-                /* Now unpress the key */
-                input_report_key(dev->sbutton_input_dev, EM28XX_SNAPSHOT_KEY,
-                                 0);
+                container_of(work, struct em28xx, buttons_query_work.work);
+        u8 i, j;
+        int regval;
+        bool pressed;
+
+        /* Poll and evaluate all addresses */
+        for (i = 0; i < dev->num_button_polling_addresses; i++) {
+                /* Read value from register */
+                regval = em28xx_read_reg(dev, dev->button_polling_addresses[i]);
+                if (regval < 0)
+                        continue;
+                /* Check states of the buttons and act */
+                j = 0;
+                while (dev->board.buttons[j].role >= 0 &&
+                         dev->board.buttons[j].role < EM28XX_NUM_BUTTON_ROLES) {
+                        struct em28xx_button *button = &dev->board.buttons[j];
+                        /* Check if button uses the current address */
+                        if (button->reg_r != dev->button_polling_addresses[i]) {
+                                j++;
+                                continue;
+                        }
+                        /* Determine if button is pressed */
+                        pressed = regval & button->mask;
+                        if (button->inverted)
+                                pressed = !pressed;
+                        /* Handle button state */
+                        if (!pressed) {
+                                j++;
+                                continue;
+                        }
+                        switch (button->role) {
+                        case EM28XX_BUTTON_SNAPSHOT:
+                                /* Emulate the keypress */
+                                input_report_key(dev->sbutton_input_dev,
+                                                 EM28XX_SNAPSHOT_KEY, 1);
+                                /* Unpress the key */
+                                input_report_key(dev->sbutton_input_dev,
+                                                 EM28XX_SNAPSHOT_KEY, 0);
+                                break;
+                        default:
+                                WARN_ONCE(1, "BUG: unhandled button role.");
+                        }
+                        /* Clear button state (if needed) */
+                        if (button->reg_clearing)
+                                em28xx_write_reg(dev, button->reg_clearing,
+                                                 (~regval & button->mask)
+                                                    | (regval & ~button->mask));
+                        /* Next button */
+                        j++;
+                }
         }
-
         /* Schedule next poll */
-        schedule_delayed_work(&dev->sbutton_query_work,
-                              msecs_to_jiffies(EM28XX_SBUTTON_QUERY_INTERVAL));
+        schedule_delayed_work(&dev->buttons_query_work,
+                              msecs_to_jiffies(EM28XX_BUTTONS_QUERY_INTERVAL));
 }
 
-static void em28xx_register_snapshot_button(struct em28xx *dev)
+static int em28xx_register_snapshot_button(struct em28xx *dev)
 {
         struct input_dev *input_dev;
         int err;
@@ -510,14 +541,13 @@ static void em28xx_register_snapshot_button(struct em28xx *dev)
         input_dev = input_allocate_device();
         if (!input_dev) {
                 em28xx_errdev("input_allocate_device failed\n");
-                return;
+                return -ENOMEM;
         }
 
         usb_make_path(dev->udev, dev->snapshot_button_path,
                       sizeof(dev->snapshot_button_path));
         strlcat(dev->snapshot_button_path, "/sbutton",
                 sizeof(dev->snapshot_button_path));
-        INIT_DELAYED_WORK(&dev->sbutton_query_work, em28xx_query_sbutton);
 
         input_dev->name = "em28xx snapshot button";
         input_dev->phys = dev->snapshot_button_path;
@@ -535,25 +565,71 @@ static void em28xx_register_snapshot_button(struct em28xx *dev)
         if (err) {
                 em28xx_errdev("input_register_device failed\n");
                 input_free_device(input_dev);
-                return;
+                return err;
         }
 
         dev->sbutton_input_dev = input_dev;
-        schedule_delayed_work(&dev->sbutton_query_work,
-                              msecs_to_jiffies(EM28XX_SBUTTON_QUERY_INTERVAL));
-        return;
+        return 0;
+}
 
+static void em28xx_init_buttons(struct em28xx *dev)
+{
+        u8  i = 0, j = 0;
+        bool addr_new = 0;
+
+        while (dev->board.buttons[i].role >= 0 &&
+                         dev->board.buttons[i].role < EM28XX_NUM_BUTTON_ROLES) {
+                struct em28xx_button *button = &dev->board.buttons[i];
+                /* Check if polling address is already on the list */
+                addr_new = 1;
+                for (j = 0; j < dev->num_button_polling_addresses; j++) {
+                        if (button->reg_r == dev->button_polling_addresses[j]) {
+                                addr_new = 0;
+                                break;
+                        }
+                }
+                /* Check if max. number of polling addresses is exceeded */
+                if (addr_new && dev->num_button_polling_addresses
+                                           >= EM28XX_NUM_BUTTON_ADDRESSES_MAX) {
+                        WARN_ONCE(1, "BUG: maximum number of button polling addresses exceeded.");
+                        addr_new = 0;
+                }
+                /* Register input device (if needed) */
+                if (button->role == EM28XX_BUTTON_SNAPSHOT) {
+                        if (em28xx_register_snapshot_button(dev) < 0)
+                                addr_new = 0;
+                }
+                /* Add read address to list of polling addresses */
+                if (addr_new) {
+                        unsigned int index = dev->num_button_polling_addresses;
+                        dev->button_polling_addresses[index] = button->reg_r;
+                        dev->num_button_polling_addresses++;
+                }
+                /* Next button */
+                i++;
+        }
+
+        /* Start polling */
+        if (dev->num_button_polling_addresses) {
+                INIT_DELAYED_WORK(&dev->buttons_query_work,
+                                                          em28xx_query_buttons);
+                schedule_delayed_work(&dev->buttons_query_work,
+                               msecs_to_jiffies(EM28XX_BUTTONS_QUERY_INTERVAL));
+        }
 }
 
-static void em28xx_deregister_snapshot_button(struct em28xx *dev)
+static void em28xx_shutdown_buttons(struct em28xx *dev)
 {
+        /* Cancel polling */
+        cancel_delayed_work_sync(&dev->buttons_query_work);
+        /* Clear polling addresses list */
+        dev->num_button_polling_addresses = 0;
+        /* Deregister input devices */
         if (dev->sbutton_input_dev != NULL) {
                 em28xx_info("Deregistering snapshot button\n");
-                cancel_delayed_work_sync(&dev->sbutton_query_work);
                 input_unregister_device(dev->sbutton_input_dev);
                 dev->sbutton_input_dev = NULL;
         }
-        return;
 }
 
 static int em28xx_ir_init(struct em28xx *dev)
@@ -564,8 +640,8 @@ static int em28xx_ir_init(struct em28xx *dev)
         u64 rc_type;
         u16 i2c_rc_dev_addr = 0;
 
-        if (dev->board.has_snapshot_button)
-                em28xx_register_snapshot_button(dev);
+        if (dev->board.buttons)
+                em28xx_init_buttons(dev);
 
         if (dev->board.has_ir_i2c) {
                 i2c_rc_dev_addr = em28xx_probe_i2c_ir(dev);
@@ -688,7 +764,7 @@ static int em28xx_ir_fini(struct em28xx *dev)
 {
         struct em28xx_IR *ir = dev->ir;
 
-        em28xx_deregister_snapshot_button(dev);
+        em28xx_shutdown_buttons(dev);
 
         /* skip detach on non attached boards */
         if (!ir)
diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h
index 8003c2f7bb96..e185d00e9044 100644
--- a/drivers/media/usb/em28xx/em28xx.h
+++ b/drivers/media/usb/em28xx/em28xx.h
@@ -181,6 +181,9 @@
 /* time in msecs to wait for i2c writes to finish */
 #define EM2800_I2C_XFER_TIMEOUT         20
 
+/* max. number of button state polling addresses */
+#define EM28XX_NUM_BUTTON_ADDRESSES_MAX         5
+
 enum em28xx_mode {
         EM28XX_SUSPEND,
         EM28XX_ANALOG_MODE,
@@ -380,6 +383,19 @@ struct em28xx_led {
         bool inverted;
 };
 
+enum em28xx_button_role {
+        EM28XX_BUTTON_SNAPSHOT = 0,
+        EM28XX_NUM_BUTTON_ROLES, /* must be the last */
+};
+
+struct em28xx_button {
+        enum em28xx_button_role role;
+        u8 reg_r;
+        u8 reg_clearing;
+        u8 mask;
+        bool inverted;
+};
+
 struct em28xx_board {
         char *name;
         int vchannels;
@@ -401,7 +417,6 @@ struct em28xx_board {
         unsigned int mts_firmware:1;
         unsigned int max_range_640_480:1;
         unsigned int has_dvb:1;
-        unsigned int has_snapshot_button:1;
         unsigned int is_webcam:1;
         unsigned int valid:1;
         unsigned int has_ir_i2c:1;
@@ -419,6 +434,9 @@ struct em28xx_board {
 
         /* LEDs that need to be controlled explicitly */
         struct em28xx_led         *analog_capturing_led;
+
+        /* Buttons */
+        struct em28xx_button      *buttons;
 };
 
 struct em28xx_eeprom {
@@ -648,10 +666,13 @@ struct em28xx {
 
         enum em28xx_mode mode;
 
-        /* Snapshot button */
+        /* Button state polling */
+        struct delayed_work buttons_query_work;
+        u8 button_polling_addresses[EM28XX_NUM_BUTTON_ADDRESSES_MAX];
+        u8 num_button_polling_addresses;
+        /* Snapshot button input device */
         char snapshot_button_path[30];  /* path of the input dev */
         struct input_dev *sbutton_input_dev;
-        struct delayed_work sbutton_query_work;
 
         struct em28xx_dvb *dvb;
 };