334 lines
7.0 KiB
C
334 lines
7.0 KiB
C
/*
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* drivers/sbus/char/vfc_i2c.c
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*
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* Driver for the Videopix Frame Grabber.
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*
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* Functions that support the Phillips i2c(I squared C) bus on the vfc
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* Documentation for the Phillips I2C bus can be found on the
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* phillips home page
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*
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* Copyright (C) 1996 Manish Vachharajani (mvachhar@noc.rutgers.edu)
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*
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*/
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/* NOTE: It seems to me that the documentation regarding the
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pcd8584t/pcf8584 does not show the correct way to address the i2c bus.
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Based on the information on the I2C bus itself and the remainder of
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the Phillips docs the following algorithms appear to be correct. I am
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fairly certain that the flowcharts in the phillips docs are wrong. */
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/delay.h>
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#include <asm/openprom.h>
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#include <asm/oplib.h>
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#include <asm/io.h>
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#include <asm/system.h>
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#include <asm/sbus.h>
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#if 0
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#define VFC_I2C_DEBUG
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#endif
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#include "vfc.h"
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#include "vfc_i2c.h"
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#define WRITE_S1(__val) \
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sbus_writel(__val, &dev->regs->i2c_s1)
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#define WRITE_REG(__val) \
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sbus_writel(__val, &dev->regs->i2c_reg)
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#define VFC_I2C_READ (0x1)
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#define VFC_I2C_WRITE (0x0)
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/******
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The i2c bus controller chip on the VFC is a pcd8584t, but
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phillips claims it doesn't exist. As far as I can tell it is
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identical to the PCF8584 so I treat it like it is the pcf8584.
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NOTE: The pcf8584 only cares
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about the msb of the word you feed it
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*****/
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int vfc_pcf8584_init(struct vfc_dev *dev)
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{
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/* This will also choose register S0_OWN so we can set it. */
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WRITE_S1(RESET);
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/* The pcf8584 shifts this value left one bit and uses
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* it as its i2c bus address.
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*/
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WRITE_REG(0x55000000);
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/* This will set the i2c bus at the same speed sun uses,
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* and set another magic bit.
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*/
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WRITE_S1(SELECT(S2));
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WRITE_REG(0x14000000);
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/* Enable the serial port, idle the i2c bus and set
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* the data reg to s0.
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*/
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WRITE_S1(CLEAR_I2C_BUS);
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udelay(100);
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return 0;
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}
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void vfc_i2c_delay_no_busy(struct vfc_dev *dev, unsigned long usecs)
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{
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schedule_timeout_uninterruptible(usecs_to_jiffies(usecs));
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}
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void inline vfc_i2c_delay(struct vfc_dev *dev)
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{
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vfc_i2c_delay_no_busy(dev, 100);
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}
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int vfc_init_i2c_bus(struct vfc_dev *dev)
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{
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WRITE_S1(ENABLE_SERIAL | SELECT(S0) | ACK);
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vfc_i2c_reset_bus(dev);
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return 0;
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}
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int vfc_i2c_reset_bus(struct vfc_dev *dev)
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{
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VFC_I2C_DEBUG_PRINTK((KERN_DEBUG "vfc%d: Resetting the i2c bus\n",
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dev->instance));
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if(dev == NULL)
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return -EINVAL;
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if(dev->regs == NULL)
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return -EINVAL;
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WRITE_S1(SEND_I2C_STOP);
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WRITE_S1(SEND_I2C_STOP | ACK);
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vfc_i2c_delay(dev);
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WRITE_S1(CLEAR_I2C_BUS);
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VFC_I2C_DEBUG_PRINTK((KERN_DEBUG "vfc%d: I2C status %x\n",
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dev->instance,
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sbus_readl(&dev->regs->i2c_s1)));
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return 0;
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}
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int vfc_i2c_wait_for_bus(struct vfc_dev *dev)
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{
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int timeout = 1000;
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while(!(sbus_readl(&dev->regs->i2c_s1) & BB)) {
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if(!(timeout--))
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return -ETIMEDOUT;
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vfc_i2c_delay(dev);
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}
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return 0;
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}
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int vfc_i2c_wait_for_pin(struct vfc_dev *dev, int ack)
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{
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int timeout = 1000;
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int s1;
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while ((s1 = sbus_readl(&dev->regs->i2c_s1)) & PIN) {
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if (!(timeout--))
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return -ETIMEDOUT;
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vfc_i2c_delay(dev);
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}
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if (ack == VFC_I2C_ACK_CHECK) {
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if(s1 & LRB)
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return -EIO;
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}
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return 0;
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}
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#define SHIFT(a) ((a) << 24)
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int vfc_i2c_xmit_addr(struct vfc_dev *dev, unsigned char addr, char mode)
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{
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int ret, raddr;
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#if 1
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WRITE_S1(SEND_I2C_STOP | ACK);
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WRITE_S1(SELECT(S0) | ENABLE_SERIAL);
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vfc_i2c_delay(dev);
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#endif
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switch(mode) {
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case VFC_I2C_READ:
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raddr = SHIFT(((unsigned int)addr | 0x1));
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WRITE_REG(raddr);
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VFC_I2C_DEBUG_PRINTK(("vfc%d: receiving from i2c addr 0x%x\n",
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dev->instance, addr | 0x1));
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break;
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case VFC_I2C_WRITE:
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raddr = SHIFT((unsigned int)addr & ~0x1);
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WRITE_REG(raddr);
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VFC_I2C_DEBUG_PRINTK(("vfc%d: sending to i2c addr 0x%x\n",
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dev->instance, addr & ~0x1));
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break;
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default:
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return -EINVAL;
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};
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WRITE_S1(SEND_I2C_START);
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vfc_i2c_delay(dev);
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ret = vfc_i2c_wait_for_pin(dev,VFC_I2C_ACK_CHECK); /* We wait
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for the
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i2c send
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to finish
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here but
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Sun
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doesn't,
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hmm */
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if (ret) {
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printk(KERN_ERR "vfc%d: VFC xmit addr timed out or no ack\n",
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dev->instance);
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return ret;
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} else if (mode == VFC_I2C_READ) {
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if ((ret = sbus_readl(&dev->regs->i2c_reg) & 0xff000000) != raddr) {
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printk(KERN_WARNING
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"vfc%d: returned slave address "
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"mismatch(%x,%x)\n",
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dev->instance, raddr, ret);
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}
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}
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return 0;
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}
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int vfc_i2c_xmit_byte(struct vfc_dev *dev,unsigned char *byte)
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{
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int ret;
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u32 val = SHIFT((unsigned int)*byte);
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WRITE_REG(val);
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ret = vfc_i2c_wait_for_pin(dev, VFC_I2C_ACK_CHECK);
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switch(ret) {
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case -ETIMEDOUT:
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printk(KERN_ERR "vfc%d: VFC xmit byte timed out or no ack\n",
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dev->instance);
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break;
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case -EIO:
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ret = XMIT_LAST_BYTE;
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break;
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default:
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break;
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};
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return ret;
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}
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int vfc_i2c_recv_byte(struct vfc_dev *dev, unsigned char *byte, int last)
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{
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int ret;
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if (last) {
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WRITE_REG(NEGATIVE_ACK);
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VFC_I2C_DEBUG_PRINTK(("vfc%d: sending negative ack\n",
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dev->instance));
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} else {
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WRITE_S1(ACK);
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}
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ret = vfc_i2c_wait_for_pin(dev, VFC_I2C_NO_ACK_CHECK);
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if(ret) {
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printk(KERN_ERR "vfc%d: "
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"VFC recv byte timed out\n",
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dev->instance);
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}
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*byte = (sbus_readl(&dev->regs->i2c_reg)) >> 24;
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return ret;
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}
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int vfc_i2c_recvbuf(struct vfc_dev *dev, unsigned char addr,
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char *buf, int count)
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{
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int ret, last;
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if(!(count && buf && dev && dev->regs) )
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return -EINVAL;
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if ((ret = vfc_i2c_wait_for_bus(dev))) {
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printk(KERN_ERR "vfc%d: VFC I2C bus busy\n", dev->instance);
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return ret;
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}
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if ((ret = vfc_i2c_xmit_addr(dev, addr, VFC_I2C_READ))) {
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WRITE_S1(SEND_I2C_STOP);
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vfc_i2c_delay(dev);
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return ret;
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}
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last = 0;
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while (count--) {
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if (!count)
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last = 1;
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if ((ret = vfc_i2c_recv_byte(dev, buf, last))) {
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printk(KERN_ERR "vfc%d: "
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"VFC error while receiving byte\n",
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dev->instance);
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WRITE_S1(SEND_I2C_STOP);
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ret = -EINVAL;
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}
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buf++;
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}
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WRITE_S1(SEND_I2C_STOP | ACK);
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vfc_i2c_delay(dev);
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return ret;
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}
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int vfc_i2c_sendbuf(struct vfc_dev *dev, unsigned char addr,
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char *buf, int count)
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{
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int ret;
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if (!(buf && dev && dev->regs))
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return -EINVAL;
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if ((ret = vfc_i2c_wait_for_bus(dev))) {
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printk(KERN_ERR "vfc%d: VFC I2C bus busy\n", dev->instance);
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return ret;
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}
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if ((ret = vfc_i2c_xmit_addr(dev, addr, VFC_I2C_WRITE))) {
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WRITE_S1(SEND_I2C_STOP);
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vfc_i2c_delay(dev);
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return ret;
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}
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while(count--) {
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ret = vfc_i2c_xmit_byte(dev, buf);
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switch(ret) {
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case XMIT_LAST_BYTE:
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VFC_I2C_DEBUG_PRINTK(("vfc%d: "
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"Receiver ended transmission with "
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" %d bytes remaining\n",
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dev->instance, count));
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ret = 0;
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goto done;
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break;
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case 0:
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break;
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default:
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printk(KERN_ERR "vfc%d: "
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"VFC error while sending byte\n", dev->instance);
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break;
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};
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buf++;
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}
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done:
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WRITE_S1(SEND_I2C_STOP | ACK);
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vfc_i2c_delay(dev);
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return ret;
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}
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