From 9ae9742ac59b18cf989370f53d669daeb75bd7a3 Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Mon, 25 Nov 2013 17:43:26 +0900
Subject: Add ps2_busywait.c and recfactor PS/2 protocol

---
 protocol/ps2_busywait.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 protocol/ps2_busywait.c

(limited to 'protocol/ps2_busywait.c')

diff --git a/protocol/ps2_busywait.c b/protocol/ps2_busywait.c
new file mode 100644
index 000000000..1e2925889
--- /dev/null
+++ b/protocol/ps2_busywait.c
@@ -0,0 +1,179 @@
+/*
+Copyright 2010,2011,2012,2013 Jun WAKO <wakojun@gmail.com>
+
+This software is licensed with a Modified BSD License.
+All of this is supposed to be Free Software, Open Source, DFSG-free,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <stdbool.h>
+#include <util/delay.h>
+#include "ps2.h"
+#include "debug.h"
+
+
+/*
+ * PS/2 protocol busywait version
+ */
+
+#define WAIT(stat, us, err) do { \
+    if (!wait_##stat(us)) { \
+        ps2_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+uint8_t ps2_error = PS2_ERR_NONE;
+
+
+void ps2_host_init(void)
+{
+    // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
+    _delay_ms(2500);
+
+    inhibit();
+}
+
+uint8_t ps2_host_send(uint8_t data)
+{
+    uint8_t res = 0;
+    bool parity = true;
+    ps2_error = PS2_ERR_NONE;
+    /* terminate a transmission if we have */
+    inhibit();
+    _delay_us(200); // at least 100us
+
+    /* start bit [1] */
+    data_lo();
+    clock_hi();
+    WAIT(clock_lo, 20000, 10);   // may take 15ms at most until device starts clocking
+    /* data [2-9] */
+    for (uint8_t i = 0; i < 8; i++) {
+        _delay_us(15);
+        if (data&(1<<i)) {
+            parity = !parity;
+            data_hi();
+        } else {
+            data_lo();
+        }
+        WAIT(clock_hi, 50, 2);
+        WAIT(clock_lo, 50, 3);
+    }
+    /* parity [10] */
+    _delay_us(15);
+    if (parity) { data_hi(); } else { data_lo(); }
+    WAIT(clock_hi, 50, 4);
+    WAIT(clock_lo, 50, 5);
+    /* stop bit [11] */
+    _delay_us(15);
+    data_hi();
+    /* ack [12] */
+    WAIT(data_lo, 50, 6);
+    WAIT(clock_lo, 50, 7);
+
+    /* wait for idle state */
+    WAIT(clock_hi, 50, 8);
+    WAIT(data_hi, 50, 9);
+
+    res = ps2_host_recv_response();
+ERROR:
+    inhibit();
+    return res;
+}
+
+/* receive data when host want else inhibit communication */
+uint8_t ps2_host_recv_response(void)
+{
+    // TODO:
+    // Command might take 20ms to response([3]p.21)
+    // TrackPoint might take 25ms ([5]2.7)
+    uint8_t data = 0;
+    uint8_t try = 200;
+    while (try-- && (data = ps2_host_recv())) ;
+    return data;
+}
+
+/* send LED state to keyboard */
+void ps2_host_set_led(uint8_t led)
+{
+    ps2_host_send(0xED);
+    ps2_host_send(led);
+}
+
+
+/* called after start bit comes */
+uint8_t ps2_host_recv(void)
+{
+    uint8_t data = 0;
+    bool parity = true;
+    ps2_error = PS2_ERR_NONE;
+
+    /* release lines(idle state) */
+    idle();
+
+    /* start bit [1] */
+    WAIT(clock_lo, 100, 1); // TODO: this is enough?
+    WAIT(data_lo, 1, 2);
+    WAIT(clock_hi, 50, 3);
+
+    /* data [2-9] */
+    for (uint8_t i = 0; i < 8; i++) {
+        WAIT(clock_lo, 50, 4);
+        if (data_in()) {
+            parity = !parity;
+            data |= (1<<i);
+        }
+        WAIT(clock_hi, 50, 5);
+    }
+
+    /* parity [10] */
+    WAIT(clock_lo, 50, 6);
+    if (data_in() != parity) {
+        ps2_error = PS2_ERR_PARITY;
+        goto ERROR;
+    }
+    WAIT(clock_hi, 50, 7);
+
+    /* stop bit [11] */
+    WAIT(clock_lo, 50, 8);
+    WAIT(data_hi, 1, 9);
+    WAIT(clock_hi, 50, 10);
+
+    inhibit();
+    return data;
+ERROR:
+    if (ps2_error > PS2_ERR_STARTBIT3) {
+        printf("x%02X\n", ps2_error);
+    }
+    inhibit();
+    return 0;
+}
-- 
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