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-rw-r--r--drivers/i2c/algos/i2c-algo-sgi.c189
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/i2c/algos/i2c-algo-sgi.c b/drivers/i2c/algos/i2c-algo-sgi.c
new file mode 100644
index 000000000000..422721b241e5
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-sgi.c
@@ -0,0 +1,189 @@
+/*
+ * i2c-algo-sgi.c: i2c driver algorithms for SGI adapters.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * Copyright (C) 2003 Ladislav Michl <ladis@linux-mips.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+
+#include <linux/i2c.h>
+#include <linux/i2c-algo-sgi.h>
+
+
+#define SGI_I2C_FORCE_IDLE (0 << 0)
+#define SGI_I2C_NOT_IDLE (1 << 0)
+#define SGI_I2C_WRITE (0 << 1)
+#define SGI_I2C_READ (1 << 1)
+#define SGI_I2C_RELEASE_BUS (0 << 2)
+#define SGI_I2C_HOLD_BUS (1 << 2)
+#define SGI_I2C_XFER_DONE (0 << 4)
+#define SGI_I2C_XFER_BUSY (1 << 4)
+#define SGI_I2C_ACK (0 << 5)
+#define SGI_I2C_NACK (1 << 5)
+#define SGI_I2C_BUS_OK (0 << 7)
+#define SGI_I2C_BUS_ERR (1 << 7)
+
+#define get_control() adap->getctrl(adap->data)
+#define set_control(val) adap->setctrl(adap->data, val)
+#define read_data() adap->rdata(adap->data)
+#define write_data(val) adap->wdata(adap->data, val)
+
+
+static int wait_xfer_done(struct i2c_algo_sgi_data *adap)
+{
+ int i;
+
+ for (i = 0; i < adap->xfer_timeout; i++) {
+ if ((get_control() & SGI_I2C_XFER_BUSY) == 0)
+ return 0;
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int wait_ack(struct i2c_algo_sgi_data *adap)
+{
+ int i;
+
+ if (wait_xfer_done(adap))
+ return -ETIMEDOUT;
+ for (i = 0; i < adap->ack_timeout; i++) {
+ if ((get_control() & SGI_I2C_NACK) == 0)
+ return 0;
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int force_idle(struct i2c_algo_sgi_data *adap)
+{
+ int i;
+
+ set_control(SGI_I2C_FORCE_IDLE);
+ for (i = 0; i < adap->xfer_timeout; i++) {
+ if ((get_control() & SGI_I2C_NOT_IDLE) == 0)
+ goto out;
+ udelay(1);
+ }
+ return -ETIMEDOUT;
+out:
+ if (get_control() & SGI_I2C_BUS_ERR)
+ return -EIO;
+ return 0;
+}
+
+static int do_address(struct i2c_algo_sgi_data *adap, unsigned int addr,
+ int rd)
+{
+ if (rd)
+ set_control(SGI_I2C_NOT_IDLE);
+ /* Check if bus is idle, eventually force it to do so */
+ if (get_control() & SGI_I2C_NOT_IDLE)
+ if (force_idle(adap))
+ return -EIO;
+ /* Write out the i2c chip address and specify operation */
+ set_control(SGI_I2C_HOLD_BUS | SGI_I2C_WRITE | SGI_I2C_NOT_IDLE);
+ if (rd)
+ addr |= 1;
+ write_data(addr);
+ if (wait_ack(adap))
+ return -EIO;
+ return 0;
+}
+
+static int i2c_read(struct i2c_algo_sgi_data *adap, unsigned char *buf,
+ unsigned int len)
+{
+ int i;
+
+ set_control(SGI_I2C_HOLD_BUS | SGI_I2C_READ | SGI_I2C_NOT_IDLE);
+ for (i = 0; i < len; i++) {
+ if (wait_xfer_done(adap))
+ return -EIO;
+ buf[i] = read_data();
+ }
+ set_control(SGI_I2C_RELEASE_BUS | SGI_I2C_FORCE_IDLE);
+
+ return 0;
+
+}
+
+static int i2c_write(struct i2c_algo_sgi_data *adap, unsigned char *buf,
+ unsigned int len)
+{
+ int i;
+
+ /* We are already in write state */
+ for (i = 0; i < len; i++) {
+ write_data(buf[i]);
+ if (wait_ack(adap))
+ return -EIO;
+ }
+ return 0;
+}
+
+static int sgi_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct i2c_algo_sgi_data *adap = i2c_adap->algo_data;
+ struct i2c_msg *p;
+ int i, err = 0;
+
+ for (i = 0; !err && i < num; i++) {
+ p = &msgs[i];
+ err = do_address(adap, p->addr, p->flags & I2C_M_RD);
+ if (err || !p->len)
+ continue;
+ if (p->flags & I2C_M_RD)
+ err = i2c_read(adap, p->buf, p->len);
+ else
+ err = i2c_write(adap, p->buf, p->len);
+ }
+
+ return err;
+}
+
+static u32 sgi_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm sgi_algo = {
+ .name = "SGI algorithm",
+ .id = I2C_ALGO_SGI,
+ .master_xfer = sgi_xfer,
+ .functionality = sgi_func,
+};
+
+/*
+ * registering functions to load algorithms at runtime
+ */
+int i2c_sgi_add_bus(struct i2c_adapter *adap)
+{
+ adap->id |= sgi_algo.id;
+ adap->algo = &sgi_algo;
+
+ return i2c_add_adapter(adap);
+}
+
+
+int i2c_sgi_del_bus(struct i2c_adapter *adap)
+{
+ return i2c_del_adapter(adap);
+}
+
+EXPORT_SYMBOL(i2c_sgi_add_bus);
+EXPORT_SYMBOL(i2c_sgi_del_bus);
+
+MODULE_AUTHOR("Ladislav Michl <ladis@linux-mips.org>");
+MODULE_DESCRIPTION("I2C-Bus SGI algorithm");
+MODULE_LICENSE("GPL");