* [Qemu-devel] [PATCH] Maxim MAX7310 GPIO expander. I2C bus support.
@ 2007-03-16 20:46 andrzej zaborowski
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From: andrzej zaborowski @ 2007-03-16 20:46 UTC (permalink / raw)
To: qemu-devel
[-- Attachment #1: Type: text/plain, Size: 100 bytes --]
Adds an 8-port GPIO expansion chip that connects over I2C and a simple
I2C bus api.
Cheers,
Andrew
[-- Attachment #2: 0002-Maxim-MAX7310-GPIO-expander.-I2C-bus-support.txt --]
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From 0babece5fd378a12a71c43791c76308751c6dc96 Mon Sep 17 00:00:00 2001
From: Andrzej Zaborowski <balrog@zabor.org>
Date: Fri, 16 Mar 2007 15:11:23 +0100
Subject: [PATCH] Maxim MAX7310 GPIO expander. I2C bus support.
---
hw/i2c.h | 160 ++++++++++++++++++++++++++++++++++++++++++++++++++++
hw/max7310.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
vl.h | 4 +
3 files changed, 340 insertions(+), 0 deletions(-)
diff --git a/hw/i2c.h b/hw/i2c.h
new file mode 100644
index 0000000..d866f28
--- /dev/null
+++ b/hw/i2c.h
@@ -0,0 +1,160 @@
+/*
+ * Simplified I2C(tm) bus / SMBus(tm).
+ *
+ * Copyright (c) 2006 Openedhand Ltd.
+ * Written by Andrzej Zaborowski <balrog@zabor.org>
+ *
+ * This file is licensed under GNU GPL v2.
+ */
+
+#define I2C_MAX_MSG 4096
+
+struct i2c_slave_s {
+ uint8_t address;
+ int (*tx)(void *opaque, uint8_t *data, int len);
+ void (*start)(void *opaque, int dir);
+ void (*stop)(void *opaque);
+ void *opaque;
+};
+
+struct i2c_bus_s {
+ struct i2c_slave_s *slave[0x80];
+ uint8_t current;
+ int dir;
+};
+
+/* I2C master - drives the clock signal on a bus. There can be multiple
+ * masters on one bus. */
+struct i2c_master_s {
+ struct i2c_bus_s *bus;
+ uint8_t message[I2C_MAX_MSG];
+ int message_len;
+ int ack;
+
+ uint8_t data;
+};
+
+static inline int i2c_bus_start(struct i2c_bus_s *bus, uint8_t byte)
+{
+ struct i2c_slave_s *slave;
+
+ bus->current = byte >> 1;
+ bus->dir = byte & 1;
+ slave = bus->slave[bus->current];
+
+ return !slave;
+}
+
+static inline int i2c_start_submit(struct i2c_bus_s *bus)
+{
+ struct i2c_slave_s *slave = bus->slave[bus->current];
+ if (!slave)
+ return 1;
+
+ if (slave->start)
+ slave->start(slave->opaque, bus->dir);
+ return 0;
+}
+
+static inline int i2c_stop_submit(struct i2c_bus_s *bus)
+{
+ struct i2c_slave_s *slave = bus->slave[bus->current];
+ if (!slave)
+ return 1;
+
+ if (slave->stop)
+ slave->stop(slave->opaque);
+ return 0;
+}
+
+static inline int i2c_msg_submit(struct i2c_bus_s *bus,
+ uint8_t message[], int len)
+{
+ struct i2c_slave_s *slave = bus->slave[bus->current];
+ if (!slave)
+ return 1;
+
+ return slave->tx ? slave->tx(slave->opaque, message, len) : 1;
+}
+
+static inline void i2c_master_submit(struct i2c_master_s *master,
+ int start, int stop)
+{
+ int ret = 0;
+
+ if (!master->bus) {
+ master->ack = 0;
+ return;
+ }
+
+ if (start) {
+ if (master->message_len)
+ if (!master->bus->dir) { /* Master --> Slave */
+ i2c_start_submit(master->bus);
+ ret = i2c_msg_submit(master->bus,
+ master->message, master->message_len);
+ master->message_len = 0;
+ }
+
+ ret = i2c_bus_start(master->bus, master->data);
+ master->message_len = 0;
+
+ if (master->bus->dir) { /* Master <-- Slave */
+ i2c_start_submit(master->bus);
+ master->message_len = 1;
+ if (stop)
+ i2c_msg_submit(master->bus, master->message, 0);
+ }
+ } else if (stop < 2) {
+ if (!master->bus->dir) { /* Master --> Slave */
+ if (master->message_len < I2C_MAX_MSG)
+ master->message[master->message_len ++] = master->data;
+ } else { /* Master <-- Slave */
+ ret = i2c_msg_submit(master->bus,
+ master->message, master->message_len);
+ master->data = master->message[0];
+ }
+ }
+
+ if (stop) {
+ if (!master->bus->dir) { /* Master --> Slave */
+ i2c_start_submit(master->bus);
+ ret = i2c_msg_submit(master->bus,
+ master->message, master->message_len);
+ master->message_len = 0;
+ }
+
+ i2c_stop_submit(master->bus);
+ }
+
+ master->ack = !ret;
+}
+
+/* Call with zero `addr' to detach. */
+static inline void i2c_slave_attach(struct i2c_bus_s *bus, uint8_t addr,
+ struct i2c_slave_s *dev)
+{
+ if (addr >= 0x80)
+ cpu_abort(cpu_single_env, "bad I2C address");
+
+ if (dev->address)
+ bus->slave[dev->address] = 0;
+
+ dev->address = addr;
+
+ if (dev->address)
+ bus->slave[dev->address] = dev;
+}
+
+static inline void i2c_master_attach(struct i2c_bus_s *bus,
+ struct i2c_master_s *dev)
+{
+ dev->bus = bus;
+}
+
+/* max7310.c */
+struct i2c_slave_s *max7310_init(void);
+void max7310_reset(struct i2c_slave_s *i2c);
+void max7310_gpio_set(struct i2c_slave_s *i2c, int line, int level);
+void max7310_gpio_handler_set(struct i2c_slave_s *i2c, int line,
+ gpio_handler_t handler, void *opaque);
diff --git a/hw/max7310.c b/hw/max7310.c
new file mode 100644
index 0000000..7e8813d
--- /dev/null
+++ b/hw/max7310.c
@@ -0,0 +1,176 @@
+/*
+ * MAX7310 8-port GPIO expansion chip.
+ *
+ * Copyright (c) 2006 Openedhand Ltd.
+ * Written by Andrzej Zaborowski <balrog@zabor.org>
+ *
+ * This file is licensed under GNU GPL v2.
+ */
+
+#include "vl.h"
+
+struct max7310_s {
+ uint8_t level;
+ uint8_t direction;
+ uint8_t polarity;
+ uint8_t status;
+ uint8_t command;
+ int i2c_dir;
+ struct i2c_slave_s i2c;
+ struct {
+ gpio_handler_t fn;
+ void *opaque;
+ } handler[8];
+};
+
+void max7310_reset(struct i2c_slave_s *i2c)
+{
+ struct max7310_s *s = (struct max7310_s *) i2c->opaque;
+ s->level &= s->direction;
+ s->direction = 0xff;
+ s->polarity = 0xf0;
+ s->status = 0x01;
+ s->command = 0x00;
+}
+
+static void max7310_start(void *opaque, int dir)
+{
+ struct max7310_s *s = (struct max7310_s *) opaque;
+ s->i2c_dir = dir;
+}
+
+static int max7310_read(void *opaque, uint8_t *data, int len)
+{
+ struct max7310_s *s = (struct max7310_s *) opaque;
+
+ switch (s->command) {
+ case 0x00: /* Input port */
+ memset(data, s->level ^ s->polarity, len);
+ break;
+
+ case 0x01: /* Output port */
+ memset(data, s->level & ~s->direction, len);
+ break;
+
+ case 0x02: /* Polarity inversion */
+ memset(data, s->polarity, len);
+ break;
+
+ case 0x03: /* Configuration */
+ memset(data, s->direction, len);
+ break;
+
+ case 0x04: /* Timeout */
+ memset(data, s->status, len);
+ break;
+
+ case 0xff: /* Reserved */
+ memset(data, 0xff, len);
+ break;
+
+ default:
+#ifdef VERBOSE
+ printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
+#endif
+ return 1;
+ }
+ return 0;
+}
+
+static int max7310_write(void *opaque, uint8_t *data, int len)
+{
+ struct max7310_s *s = (struct max7310_s *) opaque;
+ uint8_t diff;
+ int line;
+
+ if (len >= 1)
+ s->command = data[0];
+
+ if (len < 2) {
+#ifdef VERBOSE
+ printf("%s: message too short (%i bytes)\n", __FUNCTION__, len);
+#endif
+ return 0;
+ }
+
+ switch (s->command) {
+ case 0x01: /* Output port */
+ for (diff = (data[1] ^ s->level) & ~s->direction; diff;
+ diff &= ~(1 << line)) {
+ line = ffs(diff) - 1;
+ if (s->handler[line].fn)
+ s->handler[line].fn(line, (data[1] >> line) & 1,
+ s->handler[line].opaque);
+ }
+ s->level = (s->level & s->direction) | (data[1] & ~s->direction);
+ break;
+
+ case 0x02: /* Polarity inversion */
+ s->polarity = data[1];
+ break;
+
+ case 0x03: /* Configuration */
+ s->level &= ~(s->direction ^ data[1]);
+ s->direction = data[1];
+ break;
+
+ case 0x04: /* Timeout */
+ s->status = data[1];
+ break;
+
+ default:
+#ifdef VERBOSE
+ printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
+#endif
+ return 1;
+ }
+
+ return 0;
+}
+
+static int max7310_tx(void *opaque, uint8_t *data, int len)
+{
+ struct max7310_s *s = (struct max7310_s *) opaque;
+ if (len) {
+ if (s->i2c_dir)
+ return max7310_write(opaque, data, len);
+ else
+ return max7310_read(opaque, data, len);
+ }
+
+ return 0;
+}
+
+struct i2c_slave_s *max7310_init(void)
+{
+ struct max7310_s *s = qemu_mallocz(sizeof(struct max7310_s));
+ s->i2c.opaque = s;
+ s->i2c.tx = max7310_tx;
+ s->i2c.start = max7310_start;
+
+ max7310_reset(&s->i2c);
+ return &s->i2c;
+}
+
+void max7310_gpio_set(struct i2c_slave_s *i2c, int line, int level)
+{
+ struct max7310_s *s = (struct max7310_s *) i2c->opaque;
+ if (line >= sizeof(s->handler) / sizeof(*s->handler) || line < 0)
+ cpu_abort(cpu_single_env, "bad GPIO line");
+
+ if (level)
+ s->level |= s->direction & (1 << line);
+ else
+ s->level &= ~(s->direction & (1 << line));
+}
+
+void max7310_gpio_handler_set(struct i2c_slave_s *i2c, int line,
+ gpio_handler_t handler, void *opaque)
+{
+ struct max7310_s *s = (struct max7310_s *) i2c->opaque;
+ if (line >= sizeof(s->handler) / sizeof(*s->handler) || line < 0)
+ cpu_abort(cpu_single_env, "bad GPIO line");
+
+ s->handler[line].fn = handler;
+ s->handler[line].opaque = opaque;
+}
diff --git a/vl.h b/vl.h
index 95f3139..b30fb87 100644
--- a/vl.h
+++ b/vl.h
@@ -1438,6 +1438,10 @@ struct pcmcia_card_s {
/* dscm1xxxx.c */
struct pcmcia_card_s *dscm1xxxx_init(BlockDriverState *bdrv);
+typedef void (*gpio_handler_t)(int line, int level, void *opaque);
+
+#include "hw/i2c.h"
+
#include "gdbstub.h"
#endif /* defined(QEMU_TOOL) */
--
1.4.4.3
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