patch-2.1.34 linux/drivers/sbus/char/vfc_i2c.c

• Lines: 320
• Date: Fri Apr 11 10:47:37 1997
• Orig file: v2.1.33/linux/drivers/sbus/char/vfc_i2c.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.33/linux/drivers/sbus/char/vfc_i2c.c linux/drivers/sbus/char/vfc_i2c.c
@@ -0,0 +1,319 @@
+/*
+ * drivers/sbus/char/vfc_i2c.c
+ *
+ * Driver for the Videopix Frame Grabber.
+ * 
+ * Functions that support the Phillips i2c(I squared C) bus on the vfc
+ *  Documentation for the Phillips I2C bus can be found on the 
+ *  phillips home page
+ *
+ * Copyright (C) 1996 Manish Vachharajani (mvachhar@noc.rutgers.edu)
+ *
+ */
+
+/* NOTE: It seems to me that the documentation regarding the
+pcd8584t/pcf8584 does not show the correct way to address the i2c bus.
+Based on the information on the I2C bus itself and the remainder of
+the Phillips docs the following algorithims apper to be correct.  I am
+fairly certain that the flowcharts in the phillips docs are wrong. */
+
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/malloc.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/sbus.h>
+
+#if 0
+#define VFC_DEBUG
+#endif
+
+#include "vfc.h"
+#include "vfc_i2c.h"
+
+#define VFC_I2C_READ (0x1)
+#define VFC_I2C_WRITE (0x0)
+     
+/****** 
+  The i2c bus controller chip on the VFC is a pcd8584t, but
+  phillips claims it doesn't exist.  As far as I can tell it is
+  identical to the PCF8584 so I treat it like it is the pcf8584.
+  
+  NOTE: The pcf8584 only cares
+  about the msb of the word you feed it 
+*****/
+
+int vfc_pcf8584_init(struct vfc_dev *dev) 
+{
+	dev->regs->i2c_s1=RESET;        /* This will also choose
+					   register S0_OWN so we can set it*/
+
+	dev->regs->i2c_reg=0x55000000;  /* the pcf8584 shifts this
+					   value left one bit and uses
+					   it as its i2c bus address */
+	dev->regs->i2c_s1=SELECT(S2);
+	dev->regs->i2c_reg=0x14000000;  /* this will set the i2c bus at
+					   the same speed sun uses,
+					   and set another magic bit */
+	
+	dev->regs->i2c_s1=CLEAR_I2C_BUS;   /* enable the serial port,
+					   idle the i2c bus and set
+					   the data reg to s0 */
+	udelay(100);
+	return 0;
+}
+
+void vfc_i2c_delay_wakeup(struct vfc_dev *dev) 
+{
+	wake_up(&dev->poll_wait);
+}
+
+void vfc_i2c_delay_no_busy(struct vfc_dev *dev,unsigned long usecs) 
+{
+	dev->poll_timer.next = NULL;
+	dev->poll_timer.prev = NULL;
+	dev->poll_timer.expires = jiffies + 
+		((unsigned long)usecs*(HZ))/1000000;
+	dev->poll_timer.data=(unsigned long)dev;
+	dev->poll_timer.function=(void *)(unsigned long)vfc_i2c_delay_wakeup;
+	add_timer(&dev->poll_timer);
+	sleep_on(&dev->poll_wait);
+	del_timer(&dev->poll_timer);
+}
+
+void inline vfc_i2c_delay(struct vfc_dev *dev) 
+{ 
+	vfc_i2c_delay_no_busy(dev,100);
+}
+
+int vfc_init_i2c_bus(struct vfc_dev *dev)
+{
+	dev->regs->i2c_s1= ENABLE_SERIAL | ACK;
+	vfc_i2c_reset_bus(dev);
+	return 0;
+}
+
+int vfc_i2c_reset_bus(struct vfc_dev *dev) 
+{
+	VFC_DEBUG_PRINTK((KERN_DEBUG "vfc%d: Resetting the i2c bus\n",
+			  dev->instance));
+	if(!dev) return -EINVAL;
+	if(!dev->regs) return -EINVAL;
+	dev->regs->i2c_s1=SEND_I2C_STOP;
+	dev->regs->i2c_s1=SEND_I2C_STOP | ACK;
+	vfc_i2c_delay(dev);
+	dev->regs->i2c_s1=CLEAR_I2C_BUS;
+	VFC_DEBUG_PRINTK((KERN_DEBUG "vfc%d: I2C status %x\n",
+			  dev->instance, dev->regs->i2c_s1));
+	return 0;
+}
+
+int vfc_i2c_wait_for_bus(struct vfc_dev *dev) 
+{
+	int timeout=1000; 
+
+	while(!(dev->regs->i2c_s1 & BB)) {
+		if(!(timeout--)) return -ETIMEDOUT;
+		vfc_i2c_delay(dev);
+	}
+	return 0;
+}
+
+int vfc_i2c_wait_for_pin(struct vfc_dev *dev, int ack)
+{
+	int timeout=1000; 
+	int s1;
+
+	while((s1=dev->regs->i2c_s1) & PIN) {
+		if(!(timeout--)) return -ETIMEDOUT;
+		vfc_i2c_delay(dev);
+	}
+	if(ack==VFC_I2C_ACK_CHECK) {
+		if(s1 & LRB) return -EIO; 
+	}
+	return 0;
+}
+
+#define SHIFT(a) ((a) << 24)
+int vfc_i2c_xmit_addr(struct vfc_dev *dev, unsigned char addr, char mode) 
+{ 
+	int ret,raddr;
+#if 1
+	dev->regs->i2c_s1=SEND_I2C_STOP;
+	dev->regs->i2c_s1=SELECT(S0) | ENABLE_SERIAL;
+	vfc_i2c_delay(dev);
+#endif
+
+	switch(mode) {
+	case VFC_I2C_READ:
+		dev->regs->i2c_reg=raddr=SHIFT((unsigned int)addr | 0x1);
+		VFC_DEBUG_PRINTK(("vfc%d: recieving from i2c addr 0x%x\n",
+				  dev->instance,addr | 0x1));
+		break;
+	case VFC_I2C_WRITE:
+		dev->regs->i2c_reg=raddr=SHIFT((unsigned int)addr & ~0x1);
+		VFC_DEBUG_PRINTK(("vfc%d: sending to i2c addr 0x%x\n",
+				  dev->instance,addr & ~0x1));
+		break;
+	default:
+		return -EINVAL;
+	}
+	dev->regs->i2c_s1 = SEND_I2C_START;
+	vfc_i2c_delay(dev);
+	ret=vfc_i2c_wait_for_pin(dev,VFC_I2C_ACK_CHECK); /* We wait
+							    for the
+							    i2c send
+							    to finish
+							    here but
+							    Sun
+							    doesn't,
+							    hmm */
+	if(ret) {
+		printk(KERN_ERR "vfc%d: VFC xmit addr timed out or no ack\n",
+		       dev->instance);
+		return ret;
+	} else if(mode == VFC_I2C_READ) {
+		if((ret=dev->regs->i2c_reg & 0xff000000) != raddr) {
+			printk(KERN_WARNING 
+			       "vfc%d: returned slave address "
+			       "mismatch(%x,%x)\n",
+			       dev->instance,raddr,ret);
+		}
+	}	
+	return 0;
+}
+
+int vfc_i2c_xmit_byte(struct vfc_dev *dev,unsigned char *byte) 
+{
+	int ret;
+	dev->regs->i2c_reg=SHIFT((unsigned int)*byte);
+
+	ret=vfc_i2c_wait_for_pin(dev,VFC_I2C_ACK_CHECK); 
+	switch(ret) {
+	case -ETIMEDOUT: 
+		printk(KERN_ERR "vfc%d: VFC xmit byte timed out or no ack\n",
+		       dev->instance);
+		break;
+	case -EIO:
+		ret=XMIT_LAST_BYTE;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+int vfc_i2c_recv_byte(struct vfc_dev *dev, unsigned char *byte, int last) 
+{
+	int ret;
+	if(last) {
+		dev->regs->i2c_reg=NEGATIVE_ACK;
+		VFC_DEBUG_PRINTK((KERN_DEBUG "vfc%d: sending negative ack\n",
+				  dev->instance));
+	} else {
+		dev->regs->i2c_s1=ACK;
+	}
+
+	ret=vfc_i2c_wait_for_pin(dev,VFC_I2C_NO_ACK_CHECK);
+	if(ret) {
+		printk(KERN_ERR "vfc%d: "
+		       "VFC recv byte timed out\n",dev->instance);
+	}
+	*byte=(dev->regs->i2c_reg) >> 24;
+	return ret;
+}
+
+int vfc_i2c_recvbuf(struct vfc_dev *dev, unsigned char addr,
+		    char *buf, int count)
+{
+	int ret,last;
+
+	if(!(count && buf && dev && dev->regs) ) return -EINVAL;
+
+	if((ret=vfc_i2c_wait_for_bus(dev))) {
+		printk(KERN_ERR "vfc%d: VFC I2C bus busy\n",dev->instance);
+		return ret;
+	}
+
+	if((ret=vfc_i2c_xmit_addr(dev,addr,VFC_I2C_READ))) {
+		dev->regs->i2c_s1=SEND_I2C_STOP;
+		vfc_i2c_delay(dev);
+		return ret;
+	}
+	
+	last=0;
+	while(count--) {
+		if(!count) last=1;
+		if((ret=vfc_i2c_recv_byte(dev,buf,last))) {
+			printk(KERN_ERR "vfc%d: "
+			       "VFC error while recieving byte\n",
+			       dev->instance);
+		}
+		buf++;
+	}
+	
+	dev->regs->i2c_s1=SEND_I2C_STOP | ACK;
+	vfc_i2c_delay(dev);
+	return ret;
+}
+
+int vfc_i2c_sendbuf(struct vfc_dev *dev, unsigned char addr, 
+		    char *buf, int count) 
+{
+	int ret;
+	
+	if(!(buf && dev && dev->regs) ) return -EINVAL;
+	
+	if((ret=vfc_i2c_wait_for_bus(dev))) {
+		printk(KERN_ERR "vfc%d: VFC I2C bus busy\n",dev->instance);
+		return ret;
+	}
+	
+	if((ret=vfc_i2c_xmit_addr(dev,addr,VFC_I2C_WRITE))) {
+		dev->regs->i2c_s1=SEND_I2C_STOP;
+		vfc_i2c_delay(dev);
+		return ret;
+	}
+	
+	while(count--) {
+		ret=vfc_i2c_xmit_byte(dev,buf);
+		switch(ret) {
+		case XMIT_LAST_BYTE:
+			VFC_DEBUG_PRINTK(("vfc%d: "
+					  "Reciever ended transmission with "
+					  " %d bytes remaining\n",
+					  dev->instance,count));
+			ret=0;
+			goto done;
+			break;
+		case 0:
+			break;
+		default:
+			printk(KERN_ERR "vfc%d: "
+			       "VFC error while sending byte\n",dev->instance);
+			break;
+		}
+		buf++;
+	}
+done:
+	dev->regs->i2c_s1=SEND_I2C_STOP | ACK;
+	
+	vfc_i2c_delay(dev);
+	return ret;
+}
+
+
+
+
+
+
+
+
+