[ARM] Acorn: move the i2c bus driver into drivers/i2c
authorRussell King <rmk@dyn-67.arm.linux.org.uk>
Sun, 4 Mar 2007 20:40:50 +0000 (20:40 +0000)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Sun, 4 Mar 2007 20:40:50 +0000 (20:40 +0000)
Move the Acorn IOC/IOMD I2C bus driver from drivers/i2c, strip
out the reminants of the platform specific parts of the old
PCF8583 RTC code, and remove the old obsolete PCF8583 driver.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
drivers/acorn/char/Makefile
drivers/acorn/char/i2c.c [deleted file]
drivers/acorn/char/pcf8583.c [deleted file]
drivers/acorn/char/pcf8583.h [deleted file]
drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-acorn.c [new file with mode: 0644]

index 2fa9a8b..d006c9f 100644 (file)
@@ -2,5 +2,4 @@
 # Makefile for the acorn character device drivers.
 #
 
-obj-$(CONFIG_ARCH_ACORN)       += i2c.o pcf8583.o
 obj-$(CONFIG_L7200_KEYB)       += defkeymap-l7200.o keyb_l7200.o
diff --git a/drivers/acorn/char/i2c.c b/drivers/acorn/char/i2c.c
deleted file mode 100644 (file)
index d276fd1..0000000
+++ /dev/null
@@ -1,368 +0,0 @@
-/*
- *  linux/drivers/acorn/char/i2c.c
- *
- *  Copyright (C) 2000 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- *  ARM IOC/IOMD i2c driver.
- *
- *  On Acorn machines, the following i2c devices are on the bus:
- *     - PCF8583 real time clock & static RAM
- */
-#include <linux/capability.h>
-#include <linux/init.h>
-#include <linux/time.h>
-#include <linux/miscdevice.h>
-#include <linux/rtc.h>
-#include <linux/i2c.h>
-#include <linux/i2c-algo-bit.h>
-#include <linux/fs.h>
-
-#include <asm/hardware.h>
-#include <asm/io.h>
-#include <asm/hardware/ioc.h>
-#include <asm/system.h>
-#include <asm/uaccess.h>
-
-#include "pcf8583.h"
-
-extern int (*set_rtc)(void);
-
-static struct i2c_client *rtc_client;
-static const unsigned char days_in_mon[] = 
-       { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
-
-#define CMOS_CHECKSUM  (63)
-
-/*
- * Acorn machines store the year in the static RAM at
- * location 128.
- */
-#define CMOS_YEAR      (64 + 128)
-
-static inline int rtc_command(int cmd, void *data)
-{
-       int ret = -EIO;
-
-       if (rtc_client)
-               ret = rtc_client->driver->command(rtc_client, cmd, data);
-
-       return ret;
-}
-
-/*
- * Update the century + year bytes in the CMOS RAM, ensuring
- * that the check byte is correctly adjusted for the change.
- */
-static int rtc_update_year(unsigned int new_year)
-{
-       unsigned char yr[2], chk;
-       struct mem cmos_year  = { CMOS_YEAR, sizeof(yr), yr };
-       struct mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
-       int ret;
-
-       ret = rtc_command(MEM_READ, &cmos_check);
-       if (ret)
-               goto out;
-       ret = rtc_command(MEM_READ, &cmos_year);
-       if (ret)
-               goto out;
-
-       chk -= yr[1] + yr[0];
-
-       yr[1] = new_year / 100;
-       yr[0] = new_year % 100;
-
-       chk += yr[1] + yr[0];
-
-       ret = rtc_command(MEM_WRITE, &cmos_year);
-       if (ret == 0)
-               ret = rtc_command(MEM_WRITE, &cmos_check);
- out:
-       return ret;
-}
-
-/*
- * Read the current RTC time and date, and update xtime.
- */
-static void get_rtc_time(struct rtc_tm *rtctm, unsigned int *year)
-{
-       unsigned char ctrl, yr[2];
-       struct mem rtcmem = { CMOS_YEAR, sizeof(yr), yr };
-       int real_year, year_offset;
-
-       /*
-        * Ensure that the RTC is running.
-        */
-       rtc_command(RTC_GETCTRL, &ctrl);
-       if (ctrl & 0xc0) {
-               unsigned char new_ctrl = ctrl & ~0xc0;
-
-               printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",
-                      ctrl, new_ctrl);
-
-               rtc_command(RTC_SETCTRL, &new_ctrl);
-       }
-
-       if (rtc_command(RTC_GETDATETIME, rtctm) ||
-           rtc_command(MEM_READ, &rtcmem))
-               return;
-
-       real_year = yr[0];
-
-       /*
-        * The RTC year holds the LSB two bits of the current
-        * year, which should reflect the LSB two bits of the
-        * CMOS copy of the year.  Any difference indicates
-        * that we have to correct the CMOS version.
-        */
-       year_offset = rtctm->year_off - (real_year & 3);
-       if (year_offset < 0)
-               /*
-                * RTC year wrapped.  Adjust it appropriately.
-                */
-               year_offset += 4;
-
-       *year = real_year + year_offset + yr[1] * 100;
-}
-
-static int set_rtc_time(struct rtc_tm *rtctm, unsigned int year)
-{
-       unsigned char leap;
-       int ret;
-
-       leap = (!(year % 4) && (year % 100)) || !(year % 400);
-
-       if (rtctm->mon > 12 || rtctm->mon == 0 || rtctm->mday == 0)
-               return -EINVAL;
-
-       if (rtctm->mday > (days_in_mon[rtctm->mon] + (rtctm->mon == 2 && leap)))
-               return -EINVAL;
-
-       if (rtctm->hours >= 24 || rtctm->mins >= 60 || rtctm->secs >= 60)
-               return -EINVAL;
-
-       /*
-        * The RTC's own 2-bit year must reflect the least
-        * significant two bits of the CMOS year.
-        */
-       rtctm->year_off = (year % 100) & 3;
-
-       ret = rtc_command(RTC_SETDATETIME, rtctm);
-       if (ret == 0)
-               ret = rtc_update_year(year);
-
-       return ret;
-}
-
-/*
- * Set the RTC time only.  Note that
- * we do not touch the date.
- */
-static int k_set_rtc_time(void)
-{
-       struct rtc_tm new_rtctm, old_rtctm;
-       unsigned long nowtime = xtime.tv_sec;
-
-       if (rtc_command(RTC_GETDATETIME, &old_rtctm))
-               return 0;
-
-       new_rtctm.cs    = xtime.tv_nsec / 10000000;
-       new_rtctm.secs  = nowtime % 60; nowtime /= 60;
-       new_rtctm.mins  = nowtime % 60; nowtime /= 60;
-       new_rtctm.hours = nowtime % 24;
-
-       /*
-        * avoid writing when we're going to change the day
-        * of the month.  We will retry in the next minute.
-        * This basically means that if the RTC must not drift
-        * by more than 1 minute in 11 minutes.
-        *
-        * [ rtc: 1/1/2000 23:58:00, real 2/1/2000 00:01:00,
-        *   rtc gets set to 1/1/2000 00:01:00 ]
-        */
-       if ((old_rtctm.hours == 23 && old_rtctm.mins == 59) ||
-           (new_rtctm.hours == 23 && new_rtctm.mins == 59))
-               return 1;
-
-       return rtc_command(RTC_SETTIME, &new_rtctm);
-}
-
-static int rtc_ioctl(struct inode *inode, struct file *file,
-                    unsigned int cmd, unsigned long arg)
-{
-       unsigned int year;
-       struct rtc_time rtctm;
-       struct rtc_tm rtc_raw;
-
-       switch (cmd) {
-       case RTC_ALM_READ:
-       case RTC_ALM_SET:
-               break;
-
-       case RTC_RD_TIME:
-               memset(&rtctm, 0, sizeof(struct rtc_time));
-               get_rtc_time(&rtc_raw, &year);
-               rtctm.tm_sec  = rtc_raw.secs;
-               rtctm.tm_min  = rtc_raw.mins;
-               rtctm.tm_hour = rtc_raw.hours;
-               rtctm.tm_mday = rtc_raw.mday;
-               rtctm.tm_mon  = rtc_raw.mon - 1; /* month starts at 0 */
-               rtctm.tm_year = year - 1900; /* starts at 1900 */
-               return copy_to_user((void *)arg, &rtctm, sizeof(rtctm))
-                                ? -EFAULT : 0;
-
-       case RTC_SET_TIME:
-               if (!capable(CAP_SYS_TIME))
-                       return -EACCES;
-
-               if (copy_from_user(&rtctm, (void *)arg, sizeof(rtctm)))
-                       return -EFAULT;
-               rtc_raw.secs     = rtctm.tm_sec;
-               rtc_raw.mins     = rtctm.tm_min;
-               rtc_raw.hours    = rtctm.tm_hour;
-               rtc_raw.mday     = rtctm.tm_mday;
-               rtc_raw.mon      = rtctm.tm_mon + 1;
-               year             = rtctm.tm_year + 1900;
-               return set_rtc_time(&rtc_raw, year);
-               break;
-
-       case RTC_EPOCH_READ:
-               return put_user(1900, (unsigned long *)arg);
-
-       }
-       return -EINVAL;
-}
-
-static const struct file_operations rtc_fops = {
-       .ioctl  = rtc_ioctl,
-};
-
-static struct miscdevice rtc_dev = {
-       .minor  = RTC_MINOR,
-       .name   = "rtc",
-       .fops   = &rtc_fops,
-};
-
-/* IOC / IOMD i2c driver */
-
-#define FORCE_ONES     0xdc
-#define SCL            0x02
-#define SDA            0x01
-
-/*
- * We must preserve all non-i2c output bits in IOC_CONTROL.
- * Note also that we need to preserve the value of SCL and
- * SDA outputs as well (which may be different from the
- * values read back from IOC_CONTROL).
- */
-static u_int force_ones;
-
-static void ioc_setscl(void *data, int state)
-{
-       u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
-       u_int ones = force_ones;
-
-       if (state)
-               ones |= SCL;
-       else
-               ones &= ~SCL;
-
-       force_ones = ones;
-
-       ioc_writeb(ioc_control | ones, IOC_CONTROL);
-}
-
-static void ioc_setsda(void *data, int state)
-{
-       u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
-       u_int ones = force_ones;
-
-       if (state)
-               ones |= SDA;
-       else
-               ones &= ~SDA;
-
-       force_ones = ones;
-
-       ioc_writeb(ioc_control | ones, IOC_CONTROL);
-}
-
-static int ioc_getscl(void *data)
-{
-       return (ioc_readb(IOC_CONTROL) & SCL) != 0;
-}
-
-static int ioc_getsda(void *data)
-{
-       return (ioc_readb(IOC_CONTROL) & SDA) != 0;
-}
-
-static struct i2c_algo_bit_data ioc_data = {
-       .setsda         = ioc_setsda,
-       .setscl         = ioc_setscl,
-       .getsda         = ioc_getsda,
-       .getscl         = ioc_getscl,
-       .udelay         = 80,
-       .timeout        = 100
-};
-
-static int ioc_client_reg(struct i2c_client *client)
-{
-       if (client->driver->id == I2C_DRIVERID_PCF8583 &&
-           client->addr == 0x50) {
-               struct rtc_tm rtctm;
-               unsigned int year;
-               struct timespec tv;
-
-               rtc_client = client;
-               get_rtc_time(&rtctm, &year);
-
-               tv.tv_nsec = rtctm.cs * 10000000;
-               tv.tv_sec  = mktime(year, rtctm.mon, rtctm.mday,
-                                   rtctm.hours, rtctm.mins, rtctm.secs);
-               do_settimeofday(&tv);
-               set_rtc = k_set_rtc_time;
-       }
-
-       return 0;
-}
-
-static int ioc_client_unreg(struct i2c_client *client)
-{
-       if (client == rtc_client) {
-               set_rtc = NULL;
-               rtc_client = NULL;
-       }
-
-       return 0;
-}
-
-static struct i2c_adapter ioc_ops = {
-       .id                     = I2C_HW_B_IOC,
-       .algo_data              = &ioc_data,
-       .client_register        = ioc_client_reg,
-       .client_unregister      = ioc_client_unreg,
-};
-
-static int __init i2c_ioc_init(void)
-{
-       int ret;
-
-       force_ones = FORCE_ONES | SCL | SDA;
-
-       ret = i2c_bit_add_bus(&ioc_ops);
-
-       if (ret >= 0){
-               ret = misc_register(&rtc_dev);
-               if(ret < 0)
-                       i2c_del_adapter(&ioc_ops);
-       }
-
-       return ret;
-}
-
-__initcall(i2c_ioc_init);
diff --git a/drivers/acorn/char/pcf8583.c b/drivers/acorn/char/pcf8583.c
deleted file mode 100644 (file)
index 9b49f31..0000000
+++ /dev/null
@@ -1,284 +0,0 @@
-/*
- *  linux/drivers/acorn/char/pcf8583.c
- *
- *  Copyright (C) 2000 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- *  Driver for PCF8583 RTC & RAM chip
- */
-#include <linux/module.h>
-#include <linux/i2c.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-#include <linux/mc146818rtc.h>
-#include <linux/init.h>
-#include <linux/errno.h>
-#include <linux/bcd.h>
-
-#include "pcf8583.h"
-
-static struct i2c_driver pcf8583_driver;
-
-static unsigned short ignore[] = { I2C_CLIENT_END };
-static unsigned short normal_addr[] = { 0x50, I2C_CLIENT_END };
-static unsigned short *forces[] = { NULL };
-
-static struct i2c_client_address_data addr_data = {
-       .normal_i2c             = normal_addr,
-       .probe                  = ignore,
-       .ignore                 = ignore,
-       .forces                 = forces,
-};
-
-#define set_ctrl(x, v) i2c_set_clientdata(x, (void *)(unsigned int)(v))
-#define get_ctrl(x)    ((unsigned int)i2c_get_clientdata(x))
-
-static int
-pcf8583_attach(struct i2c_adapter *adap, int addr, int kind)
-{
-       struct i2c_client *c;
-       unsigned char buf[1], ad[1] = { 0 };
-       struct i2c_msg msgs[2] = {
-               {
-                       .addr = addr,
-                       .flags = 0,
-                       .len = 1,
-                       .buf = ad,
-               }, {
-                       .addr = addr,
-                       .flags = I2C_M_RD,
-                       .len = 1,
-                       .buf = buf,
-               }
-       };
-
-       c = kmalloc(sizeof(*c), GFP_KERNEL);
-       if (!c)
-               return -ENOMEM;
-
-       memset(c, 0, sizeof(*c));
-       c->addr         = addr;
-       c->adapter      = adap;
-       c->driver       = &pcf8583_driver;
-
-       if (i2c_transfer(c->adapter, msgs, 2) == 2)
-               set_ctrl(c, buf[0]);
-
-       return i2c_attach_client(c);
-}
-
-static int
-pcf8583_probe(struct i2c_adapter *adap)
-{
-       return i2c_probe(adap, &addr_data, pcf8583_attach);
-}
-
-static int
-pcf8583_detach(struct i2c_client *client)
-{
-       i2c_detach_client(client);
-       kfree(client);
-       return 0;
-}
-
-static int
-pcf8583_get_datetime(struct i2c_client *client, struct rtc_tm *dt)
-{
-       unsigned char buf[8], addr[1] = { 1 };
-       struct i2c_msg msgs[2] = {
-               {
-                       .addr = client->addr,
-                       .flags = 0,
-                       .len = 1,
-                       .buf = addr,
-               }, {
-                       .addr = client->addr,
-                       .flags = I2C_M_RD,
-                       .len = 6,
-                       .buf = buf,
-               }
-       };
-       int ret = -EIO;
-
-       memset(buf, 0, sizeof(buf));
-
-       ret = i2c_transfer(client->adapter, msgs, 2);
-       if (ret == 2) {
-               dt->year_off = buf[4] >> 6;
-               dt->wday     = buf[5] >> 5;
-
-               buf[4] &= 0x3f;
-               buf[5] &= 0x1f;
-
-               dt->cs       = BCD_TO_BIN(buf[0]);
-               dt->secs     = BCD_TO_BIN(buf[1]);
-               dt->mins     = BCD_TO_BIN(buf[2]);
-               dt->hours    = BCD_TO_BIN(buf[3]);
-               dt->mday     = BCD_TO_BIN(buf[4]);
-               dt->mon      = BCD_TO_BIN(buf[5]);
-
-               ret = 0;
-       }
-
-       return ret;
-}
-
-static int
-pcf8583_set_datetime(struct i2c_client *client, struct rtc_tm *dt, int datetoo)
-{
-       unsigned char buf[8];
-       int ret, len = 6;
-
-       buf[0] = 0;
-       buf[1] = get_ctrl(client) | 0x80;
-       buf[2] = BIN_TO_BCD(dt->cs);
-       buf[3] = BIN_TO_BCD(dt->secs);
-       buf[4] = BIN_TO_BCD(dt->mins);
-       buf[5] = BIN_TO_BCD(dt->hours);
-
-       if (datetoo) {
-               len = 8;
-               buf[6] = BIN_TO_BCD(dt->mday) | (dt->year_off << 6);
-               buf[7] = BIN_TO_BCD(dt->mon)  | (dt->wday << 5);
-       }
-
-       ret = i2c_master_send(client, (char *)buf, len);
-       if (ret == len)
-               ret = 0;
-
-       buf[1] = get_ctrl(client);
-       i2c_master_send(client, (char *)buf, 2);
-
-       return ret;
-}
-
-static int
-pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
-{
-       *ctrl = get_ctrl(client);
-       return 0;
-}
-
-static int
-pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
-{
-       unsigned char buf[2];
-
-       buf[0] = 0;
-       buf[1] = *ctrl;
-       set_ctrl(client, *ctrl);
-
-       return i2c_master_send(client, (char *)buf, 2);
-}
-
-static int
-pcf8583_read_mem(struct i2c_client *client, struct mem *mem)
-{
-       unsigned char addr[1];
-       struct i2c_msg msgs[2] = {
-               {
-                       .addr = client->addr,
-                       .flags = 0,
-                       .len = 1,
-                       .buf = addr,
-               }, {
-                       .addr = client->addr,
-                       .flags = I2C_M_RD,
-                       .len = mem->nr,
-                       .buf = mem->data,
-               }
-       };
-
-       if (mem->loc < 8)
-               return -EINVAL;
-
-       addr[0] = mem->loc;
-
-       return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
-}
-
-static int
-pcf8583_write_mem(struct i2c_client *client, struct mem *mem)
-{
-       unsigned char addr[1];
-       struct i2c_msg msgs[2] = {
-               {
-                       .addr = client->addr,
-                       .flags = 0,
-                       .len = 1,
-                       .buf = addr,
-               }, {
-                       .addr = client->addr,
-                       .flags = I2C_M_NOSTART,
-                       .len = mem->nr,
-                       .buf = mem->data,
-               }
-       };
-
-       if (mem->loc < 8)
-               return -EINVAL;
-
-       addr[0] = mem->loc;
-
-       return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
-}
-
-static int
-pcf8583_command(struct i2c_client *client, unsigned int cmd, void *arg)
-{
-       switch (cmd) {
-       case RTC_GETDATETIME:
-               return pcf8583_get_datetime(client, arg);
-               
-       case RTC_SETTIME:
-               return pcf8583_set_datetime(client, arg, 0);
-
-       case RTC_SETDATETIME:
-               return pcf8583_set_datetime(client, arg, 1);
-
-       case RTC_GETCTRL:
-               return pcf8583_get_ctrl(client, arg);
-
-       case RTC_SETCTRL:
-               return pcf8583_set_ctrl(client, arg);
-
-       case MEM_READ:
-               return pcf8583_read_mem(client, arg);
-
-       case MEM_WRITE:
-               return pcf8583_write_mem(client, arg);
-
-       default:
-               return -EINVAL;
-       }
-}
-
-static struct i2c_driver pcf8583_driver = {
-       .driver = {
-               .name   = "PCF8583",
-       },
-       .id             = I2C_DRIVERID_PCF8583,
-       .attach_adapter = pcf8583_probe,
-       .detach_client  = pcf8583_detach,
-       .command        = pcf8583_command
-};
-
-static __init int pcf8583_init(void)
-{
-       return i2c_add_driver(&pcf8583_driver);
-}
-
-static __exit void pcf8583_exit(void)
-{
-       i2c_del_driver(&pcf8583_driver);
-}
-
-module_init(pcf8583_init);
-module_exit(pcf8583_exit);
-
-MODULE_AUTHOR("Russell King");
-MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
-MODULE_LICENSE("GPL");
diff --git a/drivers/acorn/char/pcf8583.h b/drivers/acorn/char/pcf8583.h
deleted file mode 100644 (file)
index 847f7fd..0000000
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- *  linux/drivers/acorn/char/pcf8583.h
- *
- *  Copyright (C) 2000 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-struct rtc_tm {
-       unsigned char   cs;
-       unsigned char   secs;
-       unsigned char   mins;
-       unsigned char   hours;
-       unsigned char   mday;
-       unsigned char   mon;
-       unsigned char   year_off;
-       unsigned char   wday;
-};
-
-struct mem {
-       unsigned int    loc;
-       unsigned int    nr;
-       unsigned char   *data;
-};
-
-#define RTC_GETDATETIME        0
-#define RTC_SETTIME    1
-#define RTC_SETDATETIME        2
-#define RTC_GETCTRL    3
-#define RTC_SETCTRL    4
-#define MEM_READ       5
-#define MEM_WRITE      6
-
-#define CTRL_STOP      0x80
-#define CTRL_HOLD      0x40
-#define CTRL_32KHZ     0x00
-#define CTRL_MASK      0x08
-#define CTRL_ALARMEN   0x04
-#define CTRL_ALARM     0x02
-#define CTRL_TIMER     0x01
index 4d44a2d..fb19dbb 100644 (file)
@@ -495,6 +495,16 @@ config I2C_VERSATILE
          This driver can also be built as a module.  If so, the module
          will be called i2c-versatile.
 
+config I2C_ACORN
+       bool "Acorn IOC/IOMD I2C bus support"
+       depends on I2C && ARCH_ACORN
+       default y
+       select I2C_ALGOBIT
+       help
+         Say yes if you want to support the I2C bus on Acorn platforms.
+
+         If you don't know, say Y.
+
 config I2C_VIA
        tristate "VIA 82C586B"
        depends on I2C && PCI && EXPERIMENTAL
index 03505aa..290b540 100644 (file)
@@ -42,6 +42,7 @@ obj-$(CONFIG_I2C_SIS630)      += i2c-sis630.o
 obj-$(CONFIG_I2C_SIS96X)       += i2c-sis96x.o
 obj-$(CONFIG_I2C_STUB)         += i2c-stub.o
 obj-$(CONFIG_I2C_VERSATILE)    += i2c-versatile.o
+obj-$(CONFIG_I2C_ACORN)                += i2c-acorn.o
 obj-$(CONFIG_I2C_VIA)          += i2c-via.o
 obj-$(CONFIG_I2C_VIAPRO)       += i2c-viapro.o
 obj-$(CONFIG_I2C_VOODOO3)      += i2c-voodoo3.o
diff --git a/drivers/i2c/busses/i2c-acorn.c b/drivers/i2c/busses/i2c-acorn.c
new file mode 100644 (file)
index 0000000..09bd7f4
--- /dev/null
@@ -0,0 +1,97 @@
+/*
+ *  linux/drivers/acorn/char/i2c.c
+ *
+ *  Copyright (C) 2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  ARM IOC/IOMD i2c driver.
+ *
+ *  On Acorn machines, the following i2c devices are on the bus:
+ *     - PCF8583 real time clock & static RAM
+ */
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/hardware/ioc.h>
+#include <asm/system.h>
+
+#define FORCE_ONES     0xdc
+#define SCL            0x02
+#define SDA            0x01
+
+/*
+ * We must preserve all non-i2c output bits in IOC_CONTROL.
+ * Note also that we need to preserve the value of SCL and
+ * SDA outputs as well (which may be different from the
+ * values read back from IOC_CONTROL).
+ */
+static u_int force_ones;
+
+static void ioc_setscl(void *data, int state)
+{
+       u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
+       u_int ones = force_ones;
+
+       if (state)
+               ones |= SCL;
+       else
+               ones &= ~SCL;
+
+       force_ones = ones;
+
+       ioc_writeb(ioc_control | ones, IOC_CONTROL);
+}
+
+static void ioc_setsda(void *data, int state)
+{
+       u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA);
+       u_int ones = force_ones;
+
+       if (state)
+               ones |= SDA;
+       else
+               ones &= ~SDA;
+
+       force_ones = ones;
+
+       ioc_writeb(ioc_control | ones, IOC_CONTROL);
+}
+
+static int ioc_getscl(void *data)
+{
+       return (ioc_readb(IOC_CONTROL) & SCL) != 0;
+}
+
+static int ioc_getsda(void *data)
+{
+       return (ioc_readb(IOC_CONTROL) & SDA) != 0;
+}
+
+static struct i2c_algo_bit_data ioc_data = {
+       .setsda         = ioc_setsda,
+       .setscl         = ioc_setscl,
+       .getsda         = ioc_getsda,
+       .getscl         = ioc_getscl,
+       .udelay         = 80,
+       .timeout        = 100
+};
+
+static struct i2c_adapter ioc_ops = {
+       .id                     = I2C_HW_B_IOC,
+       .algo_data              = &ioc_data,
+};
+
+static int __init i2c_ioc_init(void)
+{
+       force_ones = FORCE_ONES | SCL | SDA;
+
+       return i2c_bit_add_bus(&ioc_ops);
+}
+
+__initcall(i2c_ioc_init);