patch-2.3.43 linux/drivers/acorn/char/i2c.c

• Lines: 204
• Date: Sun Feb 6 17:45:25 2000
• Orig file: v2.3.42/linux/drivers/acorn/char/i2c.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/drivers/acorn/char/i2c.c linux/drivers/acorn/char/i2c.c
@@ -0,0 +1,203 @@
+/*
+ * linux/drivers/acorn/char/i2c.c
+ *
+ * Copyright (C) 2000 Russell King
+ *
+ * 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/sched.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/ioc.h>
+#include <asm/system.h>
+
+#include "pcf8583.h"
+
+extern unsigned long
+mktime(unsigned int year, unsigned int mon, unsigned int day,
+       unsigned int hour, unsigned int min, unsigned int sec);
+extern int (*set_rtc)(void);
+
+static struct i2c_client *rtc_client;
+
+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;
+}
+
+/*
+ * Read the current RTC time and date, and update xtime.
+ */
+static void get_rtc_time(void)
+{
+	unsigned char ctrl;
+	unsigned char year;
+	struct rtc_tm rtctm;
+	struct mem rtcmem = { 0xc0, 1, &year };
+
+	/*
+	 * Ensure that the RTC is running.
+	 */
+	rtc_command(RTC_GETCTRL, &ctrl);
+	if (ctrl & 0xc0) {
+		unsigned char new_ctrl;
+
+		new_ctrl = ctrl & ~0xc0;
+
+		printk("RTC: resetting control %02X -> %02X\n",
+		       ctrl, new_ctrl);
+
+		rtc_command(RTC_SETCTRL, &new_ctrl);
+	}
+
+	/*
+	 * Acorn machines store the year in
+	 * the static RAM at location 192.
+	 */
+	if (rtc_command(MEM_READ, &rtcmem))
+		return;
+
+	if (rtc_command(RTC_GETDATETIME, &rtctm))
+		return;
+
+	if (year < 70)
+		year += 100;
+
+	xtime.tv_usec = rtctm.cs * 10000;
+	xtime.tv_sec  = mktime(1900 + year, rtctm.mon, rtctm.mday,
+			       rtctm.hours, rtctm.mins, rtctm.secs);
+}
+
+/*
+ * Set the RTC time only.  Note that
+ * we do not touch the date.
+ */
+static int 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_usec / 10000;
+	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);
+}
+
+
+#define FORCE_ONES	0xdc
+#define SCL		0x02
+#define SDA		0x01
+
+static int ioc_control;
+
+static void ioc_setscl(void *data, int state)
+{
+	if (state)
+		ioc_control |= SCL;
+	else
+		ioc_control &= ~SCL;
+ 	outb(ioc_control, IOC_CONTROL);
+}
+
+static void ioc_setsda(void *data, int state)
+{
+	if (state)
+		ioc_control |= SDA;
+	else
+		ioc_control &= ~SDA;
+ 	outb(ioc_control, IOC_CONTROL);
+}
+
+static int ioc_getscl(void *data)
+{
+	return (inb(IOC_CONTROL) & SCL) != 0;
+}
+
+static int ioc_getsda(void *data)
+{
+	return (inb(IOC_CONTROL) & SDA) != 0;
+}
+
+static struct i2c_algo_bit_data ioc_data = {
+	NULL,
+	ioc_setsda,
+	ioc_setscl,
+	ioc_getsda,
+	ioc_getscl,
+	80, 80, 100
+};
+
+static int ioc_client_reg(struct i2c_client *client)
+{
+	if (client->id == I2C_DRIVERID_PCF8583 &&
+	    client->addr == 0x50) {
+		rtc_client = client;
+		get_rtc_time();
+		set_rtc = 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 = {
+	"IOC/IOMD",
+	I2C_HW_B_IOC,
+	NULL,
+	&ioc_data,
+	NULL,
+	NULL,
+	ioc_client_reg,
+	ioc_client_unreg
+};
+
+static int __init i2c_ioc_init(void)
+{
+	ioc_control = inb(IOC_CONTROL) | FORCE_ONES;
+
+	ioc_setscl(NULL, 1);
+	ioc_setsda(NULL, 1);
+
+	return i2c_bit_add_bus(&ioc_ops);
+}
+
+__initcall(i2c_ioc_init);