imx233: introduce new generic button driver

This driver will subsume the old button-lradc driver and support far more
options. It can sense LRADC channels, PSWITCH, GPIOs and it handles special
"buttons" like headphone insertion and hold detection. It also provides a
more natural description of the buttons using a target-defined table with some
macros to make it easy to read and write. It uniformely handles debouncing on
LRADC channels and PSWITCH.

Change-Id: Ie61d1f593fdcf3bd456ba1d53a1fd784286834ce

1 files changed, 174 insertions, 0 deletions

diff --git a/firmware/target/arm/imx233/button-imx233.h b/firmware/target/arm/imx233/button-imx233.h
new file mode 100644
index 0000000000..61adff8436
--- /dev/null
+++ b/firmware/target/arm/imx233/button-imx233.h
@@ -0,0 +1,174 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2014 by Amaury Pouly
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#ifndef __button_imx233__
+#define __button_imx233__
+
+#include "button.h"
+#include "button-target.h"
+#include "lradc-imx233.h"
+#include "pinctrl-imx233.h"
+#include "power-imx233.h"
+
+/* special values for .btn field */
+#define IMX233_BUTTON_END   -1 /* end of the list */
+#define IMX233_BUTTON_HOLD  -2 /* HOLD button */
+#define IMX233_BUTTON_JACK  -3 /* JACK detect */
+#define IMX233_BUTTON_VDDIO -4 /* VDDIO value */
+
+/* values for .periph field */
+#define IMX233_BUTTON_GPIO      0 /* GPIO pin */
+#define IMX233_BUTTON_LRADC     1 /* LRADC channel */
+#define IMX233_BUTTON_PSWITCH   2 /* PSWITCH */
+
+/* values for the .flags field */
+#define IMX233_BUTTON_INVERTED  (1 << 0) /* invert button detection */
+#define IMX233_BUTTON_PULLUP    (1 << 1) /* pin needs a pullup (GPIO) */
+
+/** target-defined
+ * NOTE for proper operation:
+ * - the table must end which a dummy entry of type IMX233_BUTTON_END
+ * - default is active: high for GPIO, around value for LRADC, exact value for PSWITCH
+ * - inverted flags reverses the above behaviour
+ * - if lradc channel is relative, the .relative field specify a entry in the
+ *   button table to which it is relative. This entry must have <0 .btn value
+ *   and be of type LRADC. For example, if a channel is VDDIO relative, set
+ *   .relative to IMX233_BUTTON_VDDIO and create an entry which .btn set to
+ *   IMX233_BUTTON_VDDIO, channel set to VDDIO source and value set to the ideal values
+ *   for which no correction is necessary. Note that the IMX233_BUTTON_VDDIO value is 
+ *   defined for convenience */
+struct imx233_button_map_t
+{
+    int btn; /* target button or magic value (END, HOLD, JACK) */
+    int periph; /* GPIO, LRADC, or PSWITCH, ... */
+    union
+    {
+        struct
+        {
+            int bank;
+            int pin;
+        }gpio;
+        struct
+        {
+            int src; /* source channel */
+            int value; /* expected value */
+            int relative; /* button to which it is relative or -1 if none */
+        }lradc;
+        struct
+        {
+            int level; /* value of the PSWITCH field: low, mid, high */
+        }pswitch;
+    }u;
+    int flags; /* flags */
+    const char *name; /* name of the button */
+    /** private fields */
+    bool last_val; /* last interpreted value */
+    int rounds; /* how many rounds it survived (debouncing) */
+    int threshold; /* round threshold for acceptance */
+};
+
+/* macros for the common cases */
+#define IMX233_BUTTON_PATH_GPIO(bank_, pin_) .periph = IMX233_BUTTON_GPIO, \
+    .u = {.gpio = {.bank = bank_, .pin = pin_}}
+#define IMX233_BUTTON_PATH_LRADC_REL(src_, val_, rel_) .periph = IMX233_BUTTON_LRADC, \
+    .u = {.lradc = {.src = src_, .value = val_, .relative = rel_}}
+#define IMX233_BUTTON_PATH_LRADC(src_, val_) IMX233_BUTTON_PATH_LRADC_REL(src_, val_, -1)
+#define IMX233_BUTTON_PATH_PSWITCH(lvl_) .periph = IMX233_BUTTON_PSWITCH, \
+    .u = {.pswitch = {.level = lvl_}}
+#define IMX233_BUTTON_PATH_END() .periph = -1
+/* special macro for VDDIO, for convenience */
+#define IMX233_BUTTON_PATH_VDDIO(val_) IMX233_BUTTON_PATH_LRADC(LRADC_SRC_VDDIO, val_)
+
+#define IMX233_BUTTON_NAMEFLAGS1(_,name_) .name = name_
+#define IMX233_BUTTON_NAMEFLAGS2(_,name_,f1)  .name = name_, .flags = IMX233_BUTTON_##f1
+#define IMX233_BUTTON_NAMEFLAGS3(_,name_,f1,f2)   .name = name_, \
+    .flags = IMX233_BUTTON_##f1 | IMX233_BUTTON_##f2
+#define IMX233_BUTTON_NAMEFLAGS4(_,name_,f1,f2,f3)    .name = name_, \
+    .flags =IMX233_BUTTON_##f1 | IMX233_BUTTON_##f2 | IMX233_BUTTON_##f3
+
+#define IMX233_BUTTON__(btn_, path_, ...) \
+    {.btn = btn_, IMX233_BUTTON_PATH_##path_, \
+     REG_VARIADIC(IMX233_BUTTON_NAMEFLAGS, dummy, __VA_ARGS__)}
+#define IMX233_BUTTON_(btn_, path_, ...) \
+    IMX233_BUTTON__(IMX233_BUTTON_##btn_, path_, __VA_ARGS__)
+#define IMX233_BUTTON(btn_, path_, ...) \
+    IMX233_BUTTON__(BUTTON_##btn_, path_, __VA_ARGS__)
+
+#define IMX233_BUTTON_END_() \
+    {.btn = IMX233_BUTTON_END}
+
+/**
+ * This header provides macro to ease definition of buttons. There three types of
+ * buttons:
+ * - normal buttons: BUTTON_X -> defined using IMX233_BUTTON(X, ...)
+ * - special buttons IMX233_BUTTON_X -> defined using IMX233_BUTTON_(X, ...)
+ * - others: X -> defined using IMX233_BUTTON__(X, ...)
+ * A definition contains three mandatory parts and a fourth optional:
+ * IMX233_BUTTON(btn, path_spec, name [, flags])
+ * The path_spec can be of the form:
+ * - GPIO(bank, pin)
+ * - LRADC(src, value)
+ * - LRADC_REL(src, value, rel_idx)
+ * - PSWITCH(level)
+ * - END()
+ * The optional flags are specified as a list, without the IMX233_BUTTON_ prefix.
+ * Examples:
+ * - BUTTON_POWER named "power", mapped to PSWITCH mid level, no flags:
+ *   IMX233_BUTTON(POWER, PSWICTH(1), "power")
+ * - IMX233_BUTTON_JACK named "jack", mapped to GPIO B2P17 inverted and pullup:
+ *   IMX233_BUTTON_(JACK, GPIO(2, 17), "jack", INVERTED, PULLUP)
+ * - BIZARRE named "bizarre", mapped to LRADC channel 0, expected value 42:
+ *   IMX233_BUTTON__(BIZARRE, LRADC(0, 42), "bizarre")
+ * - BUTTON_PLAY named "play", mapped to LRADc channel 2, expected value 300 related
+ *   to button entry IDX
+ *   IMX233_BUTTON(PLAY, LRADC_REL(2, 300, IDX), "play")
+ * - VDDIO entry, expected value 4000 (for relative entries):
+ *   IMX233_BUTTON_(VDDIO, VDDIO(4000), "vddio")
+ * - last entry:
+ *   IMX233_BUTTON_(END, END(), "")
+ * 
+ * The driver also provides default implementations for headphones_inserted()
+ * and button_hold() which can be overriden since they have weak linkage.
+ */
+
+extern struct imx233_button_map_t imx233_button_map[];
+
+/* initialise button driver */
+void imx233_button_init(void);
+/* others gives the bitmask of other buttons: the function will OR the result
+ * with them except if hold is detected in which case 0 is always returned */
+int imx233_button_read(int others);
+#ifdef HAS_BUTTON_HOLD
+bool imx233_button_read_hold(void);
+bool button_hold(void);
+#endif
+#ifdef HAVE_HEADPHONE_DETECTION
+bool imx233_button_read_jack(void);
+bool headphones_inserted(void);
+#endif
+/* return interpreted button value, after processing.
+ * Argument is an index into the imx233_button_map table */
+bool imx233_button_read_btn(int idx);
+/* return raw value for a button, before any processing: GPIO state, LRADC
+ * channel value, PSWITCH value. Return -1 if there is no match.
+ * Argument is an index into the imx233_button_map table */
+int imx233_button_read_raw(int idx);
+
+#endif /* __button_imx233__ */
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