This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / drivers / i2c / algos / i2c-algo-sgi.c

diff --git a/drivers/i2c/algos/i2c-algo-sgi.c b/drivers/i2c/algos/i2c-algo-sgi.c
new file mode 100644 (file)
index 0000000..b4e0a06
--- /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");