[Qemu-devel] [PATCH] Texas Instruments ADS7846 ADC chip.

[Qemu-devel] [PATCH] Texas Instruments ADS7846 ADC chip.

[andrzej zaborowski]

[-- Attachment #1: Type: text/plain, Size: 240 bytes --]

This is an ADC chip with eight inputs usually used for power
management (battery current measurements) on small systems and a
touchscreen controller. This chip or similar ones (7845 etc) are seen
a lot in all kinds of PDAs.

Cheers,
Andrew

[-- Attachment #2: 0011-Texas-Instruments-ADS7846-ADC-chip.txt --]
[-- Type: text/plain, Size: 4343 bytes --]

From f6be7abd757e49e67b81847634c1075e222be0bc Mon Sep 17 00:00:00 2001
From: Andrzej Zaborowski <balrog@zabor.org>
Date: Fri, 16 Mar 2007 16:53:08 +0100
Subject: [PATCH] Texas Instruments ADS7846 ADC chip.

---
 hw/ads7846.c |  134 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 vl.h         |    8 ++++
 2 files changed, 142 insertions(+), 0 deletions(-)

diff --git a/hw/ads7846.c b/hw/ads7846.c
new file mode 100644
index 0000000..3297b7b
--- /dev/null
+++ b/hw/ads7846.c
@@ -0,0 +1,134 @@
+/*
+ * TI ADS7846 chip emulation.
+ *
+ * Copyright (c) 2006 Openedhand Ltd.
+ * Written by Andrzej Zaborowski <balrog@zabor.org>
+ *
+ * This code is licensed under the GNU GPL v2.
+ */
+
+#include <vl.h>
+
+struct ads7846_state_s {
+    void (*interrupt)(void *opaque, int level);
+    void *opaque;
+
+    int input[8];
+    int pressure;
+    int noise;
+
+    int cycle;
+    int output;
+};
+
+/* Control-byte bitfields */
+#define CB_PD0		(1 << 0)
+#define CB_PD1		(1 << 1)
+#define CB_SER		(1 << 2)
+#define CB_MODE		(1 << 3)
+#define CB_A0		(1 << 4)
+#define CB_A1		(1 << 5)
+#define CB_A2		(1 << 6)
+#define CB_START	(1 << 7)
+
+#define X_AXIS_DMAX	3680
+#define X_AXIS_MIN	150
+#define Y_AXIS_DMAX	3640
+#define Y_AXIS_MIN	190
+
+#define ADS_VBAT	2000
+#define ADS_VAUX	2000
+#define ADS_TEMP0	2000
+#define ADS_TEMP1	3000
+#define ADS_XPOS(x, y)	(X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))
+#define ADS_YPOS(x, y)	(Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))
+#define ADS_Z1POS(x, y)	600
+#define ADS_Z2POS(x, y)	(600 + 6000 / ADS_XPOS(x, y))
+
+static void ads7846_int_update(struct ads7846_state_s *s)
+{
+    if (s->interrupt)
+        s->interrupt(s->opaque, s->pressure == 0);
+}
+
+uint32_t ads7846_read(void *opaque)
+{
+    struct ads7846_state_s *s = (struct ads7846_state_s *) opaque;
+
+    return s->output;
+}
+
+void ads7846_write(void *opaque, uint32_t value)
+{
+    struct ads7846_state_s *s = (struct ads7846_state_s *) opaque;
+
+    switch (s->cycle ++) {
+    case 0:
+        if (!(value & CB_START)) {
+            s->cycle = 0;
+            break;
+        }
+
+        s->output = s->input[(value >> 4) & 7];
+
+        /* Imitate the ADC noise, some drivers expect this.  */
+        s->noise = (s->noise + 3) & 7;
+        switch ((value >> 4) & 7) {
+        case 1: s->output += s->noise ^ 2; break;
+        case 3: s->output += s->noise ^ 0; break;
+        case 4: s->output += s->noise ^ 7; break;
+        case 5: s->output += s->noise ^ 5; break;
+        }
+
+        if (value & CB_MODE)
+            s->output >>= 4;	/* 8 bits instead of 12 */
+
+        break;
+    case 1:
+        s->cycle = 0;
+        break;
+    }
+}
+
+static void ads7846_ts_event(void *opaque,
+                int x, int y, int z, int buttons_state)
+{
+    struct ads7846_state_s *s = opaque;
+
+    if (buttons_state) {
+        s->input[1] = ADS_YPOS(x, y);
+        s->input[3] = ADS_Z1POS(x, y);
+        s->input[4] = ADS_Z2POS(x, y);
+        s->input[5] = ADS_XPOS(x, y);
+    }
+
+    if (s->pressure == !buttons_state) {
+        s->pressure = !!buttons_state;
+
+         ads7846_int_update(s);
+    }
+}
+
+struct ads7846_state_s *ads7846_init(
+                void (*penirq)(void *opaque, int level), void *opaque)
+{
+    struct ads7846_state_s *s;
+    s = (struct ads7846_state_s *)
+            qemu_mallocz(sizeof(struct ads7846_state_s));
+    memset(s, 0, sizeof(struct ads7846_state_s));
+
+    s->interrupt = penirq;
+    s->opaque = opaque;
+
+    s->input[0] = ADS_TEMP0;	/* TEMP0 */
+    s->input[2] = ADS_VBAT;	/* VBAT */
+    s->input[6] = ADS_VAUX;	/* VAUX */
+    s->input[7] = ADS_TEMP1;	/* TEMP1 */
+
+    /* We want absolute coordinates */
+    qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
+                    "QEMU ADS7846-driven Touchscreen");
+
+    ads7846_int_update(s);
+    return s;
+}
diff --git a/vl.h b/vl.h
index 7c88c72..2f2e340 100644
--- a/vl.h
+++ b/vl.h
@@ -1414,6 +1414,14 @@ uint8_t nand_getio(struct nand_flash_s *s);
 
 #include "ecc.h"
 
+
+/* ads7846.c */
+struct ads7846_state_s;
+uint32_t ads7846_read(void *opaque);
+void ads7846_write(void *opaque, uint32_t value);
+struct ads7846_state_s *ads7846_init(
+                void (*penirq)(void *opaque, int level), void *opaque);
+
 /* PCMCIA/Cardbus */
 
 struct pcmcia_socket_s {
-- 
1.4.4.3