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* Driver for the Conexant CX25821 PCIe bridge
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* Copyright (C) 2009 Conexant Systems Inc.
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* Authors <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
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* Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/i2c.h>
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static unsigned int i2c_debug;
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module_param(i2c_debug, int, 0644);
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MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
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static unsigned int i2c_scan;
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module_param(i2c_scan, int, 0444);
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MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
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#define dprintk(level, fmt, arg...) \
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if (i2c_debug >= level) \
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printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg); \
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#define I2C_WAIT_DELAY 32
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#define I2C_WAIT_RETRY 64
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#define I2C_EXTEND (1 << 3)
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#define I2C_NOSTOP (1 << 4)
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static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
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struct cx25821_i2c *bus = i2c_adap->algo_data;
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struct cx25821_dev *dev = bus->dev;
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return cx_read(bus->reg_stat) & 0x01;
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static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
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struct cx25821_i2c *bus = i2c_adap->algo_data;
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struct cx25821_dev *dev = bus->dev;
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return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
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static int i2c_wait_done(struct i2c_adapter *i2c_adap)
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for (count = 0; count < I2C_WAIT_RETRY; count++) {
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if (!i2c_is_busy(i2c_adap))
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udelay(I2C_WAIT_DELAY);
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if (I2C_WAIT_RETRY == count)
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static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
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const struct i2c_msg *msg, int joined_rlen)
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struct cx25821_i2c *bus = i2c_adap->algo_data;
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struct cx25821_dev *dev = bus->dev;
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u32 wdata, addr, ctrl;
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dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
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msg->len, joined_rlen);
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dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
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/* Deal with i2c probe functions with zero payload */
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cx_write(bus->reg_addr, msg->addr << 25);
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cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
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if (!i2c_wait_done(i2c_adap))
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if (!i2c_slave_did_ack(i2c_adap))
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dprintk(1, "%s(): returns 0\n", __func__);
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/* dev, reg + first byte */
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addr = (msg->addr << 25) | msg->buf[0];
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ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
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ctrl |= I2C_NOSTOP | I2C_EXTEND;
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else if (joined_rlen)
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cx_write(bus->reg_addr, addr);
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cx_write(bus->reg_wdata, wdata);
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cx_write(bus->reg_ctrl, ctrl);
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retval = i2c_wait_done(i2c_adap);
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if (!(ctrl & I2C_NOSTOP))
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for (cnt = 1; cnt < msg->len; cnt++) {
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/* following bytes */
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wdata = msg->buf[cnt];
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ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
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if (cnt < msg->len - 1)
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ctrl |= I2C_NOSTOP | I2C_EXTEND;
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else if (joined_rlen)
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cx_write(bus->reg_addr, addr);
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cx_write(bus->reg_wdata, wdata);
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cx_write(bus->reg_ctrl, ctrl);
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retval = i2c_wait_done(i2c_adap);
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dprintk(1, " %02x", msg->buf[cnt]);
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if (!(ctrl & I2C_NOSTOP))
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pr_err(" ERR: %d\n", retval);
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static int i2c_readbytes(struct i2c_adapter *i2c_adap,
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const struct i2c_msg *msg, int joined)
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struct cx25821_i2c *bus = i2c_adap->algo_data;
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struct cx25821_dev *dev = bus->dev;
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if (i2c_debug && !joined)
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dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
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/* Deal with i2c probe functions with zero payload */
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cx_write(bus->reg_addr, msg->addr << 25);
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cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
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if (!i2c_wait_done(i2c_adap))
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if (!i2c_slave_did_ack(i2c_adap))
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dprintk(1, "%s(): returns 0\n", __func__);
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dprintk(1, " <R %02x", (msg->addr << 1) + 1);
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for (cnt = 0; cnt < msg->len; cnt++) {
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ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
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if (cnt < msg->len - 1)
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ctrl |= I2C_NOSTOP | I2C_EXTEND;
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cx_write(bus->reg_addr, msg->addr << 25);
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cx_write(bus->reg_ctrl, ctrl);
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retval = i2c_wait_done(i2c_adap);
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msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
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dprintk(1, " %02x", msg->buf[cnt]);
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if (!(ctrl & I2C_NOSTOP))
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pr_err(" ERR: %d\n", retval);
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static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
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struct cx25821_i2c *bus = i2c_adap->algo_data;
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struct cx25821_dev *dev = bus->dev;
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dprintk(1, "%s(num = %d)\n", __func__, num);
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for (i = 0; i < num; i++) {
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dprintk(1, "%s(num = %d) addr = 0x%02x len = 0x%x\n",
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__func__, num, msgs[i].addr, msgs[i].len);
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if (msgs[i].flags & I2C_M_RD) {
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retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
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} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
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msgs[i].addr == msgs[i + 1].addr) {
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/* write then read from same address */
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i2c_sendbytes(i2c_adap, &msgs[i], msgs[i + 1].len);
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retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
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retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
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static u32 cx25821_functionality(struct i2c_adapter *adap)
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return I2C_FUNC_SMBUS_EMUL |
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I2C_FUNC_SMBUS_WORD_DATA |
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I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
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static struct i2c_algorithm cx25821_i2c_algo_template = {
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.master_xfer = i2c_xfer,
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.functionality = cx25821_functionality,
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#ifdef NEED_ALGO_CONTROL
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.algo_control = dummy_algo_control,
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static struct i2c_adapter cx25821_i2c_adap_template = {
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.owner = THIS_MODULE,
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.algo = &cx25821_i2c_algo_template,
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static struct i2c_client cx25821_i2c_client_template = {
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.name = "cx25821 internal",
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/* init + register i2c algo-bit adapter */
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int cx25821_i2c_register(struct cx25821_i2c *bus)
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struct cx25821_dev *dev = bus->dev;
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dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
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memcpy(&bus->i2c_adap, &cx25821_i2c_adap_template,
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sizeof(bus->i2c_adap));
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memcpy(&bus->i2c_algo, &cx25821_i2c_algo_template,
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sizeof(bus->i2c_algo));
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memcpy(&bus->i2c_client, &cx25821_i2c_client_template,
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sizeof(bus->i2c_client));
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bus->i2c_adap.dev.parent = &dev->pci->dev;
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strlcpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
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bus->i2c_algo.data = bus;
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bus->i2c_adap.algo_data = bus;
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i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
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i2c_add_adapter(&bus->i2c_adap);
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bus->i2c_client.adapter = &bus->i2c_adap;
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bus->i2c_client.addr = (0x88 >> 1);
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int cx25821_i2c_unregister(struct cx25821_i2c *bus)
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i2c_del_adapter(&bus->i2c_adap);
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void cx25821_av_clk(struct cx25821_dev *dev, int enable)
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/* write 0 to bus 2 addr 0x144 via i2x_xfer() */
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dprintk(1, "%s(enabled = %d)\n", __func__, enable);
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msg.flags = I2C_M_TEN;
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i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
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int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
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struct i2c_client *client = &bus->i2c_client;
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u8 addr[2] = { 0, 0 };
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u8 buf[4] = { 0, 0, 0, 0 };
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struct i2c_msg msgs[2] = {
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.addr = client->addr,
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.addr = client->addr,
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addr[0] = (reg_addr >> 8);
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addr[1] = (reg_addr & 0xff);
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retval = i2c_xfer(client->adapter, msgs, 2);
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v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
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int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
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struct i2c_client *client = &bus->i2c_client;
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u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
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struct i2c_msg msgs[1] = {
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.addr = client->addr,
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buf[0] = reg_addr >> 8;
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buf[1] = reg_addr & 0xff;
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buf[5] = (value >> 24) & 0xff;
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buf[4] = (value >> 16) & 0xff;
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buf[3] = (value >> 8) & 0xff;
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buf[2] = value & 0xff;
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retval = i2c_xfer(client->adapter, msgs, 1);