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/*
* tw68 code to handle the i2c interface.
*
* Much of this code is derived from the bt87x driver. The original
* work was by Gerd Knorr; more recently the code was enhanced by Mauro
* Carvalho Chehab. Their work is gratefully acknowledged. Full credit
* goes to them - any problems within this code are mine.
*
* Copyright (C) 2009 William M. Brack <wbrack@mmm.com.hk>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include "tw68.h"
#include <media/v4l2-common.h>
#include <linux/i2c-algo-bit.h>
/*----------------------------------------------------------------*/
static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
#if 0
static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
#endif
#define d1printk if (1 == i2c_debug) printk
#define I2C_CLOCK 0xa6 /* 99.4 kHz */
/*----------------------------------------------------------------------*/
/* Although the TW68xx i2c controller has a "hardware" mode, where all of
* the low-level i2c/smbbus is handled by the chip, it appears that mode
* is not suitable for linux i2c handling routines because extended "bursts"
* of data (sequences of bytes without intervening START/STOP bits) are
* not possible. Instead, we put the chip into "software" mode, and handle
* the i2c bus at a low level. To accomplish this, we use the routines
* from the i2c modules.
*
* Because the particular boards which I had for testing did not have any
* devices attached to the i2c bus, I have been unable to test these
* routines.
*/
/*----------------------------------------------------------------------*/
/* I2C functions - "bit-banging" adapter (software i2c) */
/* tw68_bit_setcl
* Handles "toggling" the i2c clock bit
*/
static void tw68_bit_setscl(void *data, int state)
{
struct tw68_dev *dev = data;
tw_andorb(TW68_SBUSC, (state ? 1 : 0) << TW68_SSCLK, TW68_SSCLK_B);
}
/* tw68_bit_setsda
* Handles "toggling" the i2c data bit
*/
static void tw68_bit_setsda(void *data, int state)
{
struct tw68_dev *dev = data;
tw_andorb(TW68_SBUSC, (state ? 1 : 0) << TW68_SSDAT, TW68_SSDAT_B);
}
/* tw68_bit_getscl
*
* Returns the current state of the clock bit
*/
static int tw68_bit_getscl(void *data)
{
struct tw68_dev *dev = data;
return (tw_readb(TW68_SBUSC) & TW68_SSCLK_B) ? 1 : 0;
}
/* tw68_bit_getsda
*
* Returns the current state of the data bit
*/
static int tw68_bit_getsda(void *data)
{
struct tw68_dev *dev = data;
return (tw_readb(TW68_SBUSC) & TW68_SSDAT_B) ? 1 : 0;
}
static struct i2c_algo_bit_data __devinitdata tw68_i2c_algo_bit_template = {
.setsda = tw68_bit_setsda,
.setscl = tw68_bit_setscl,
.getsda = tw68_bit_getsda,
.getscl = tw68_bit_getscl,
.udelay = 16,
.timeout = 200,
};
static struct i2c_client tw68_client_template = {
.name = "tw68 internal",
};
/*----------------------------------------------------------------*/
static int attach_inform(struct i2c_client *client)
{
/* struct tw68_dev *dev = client->adapter->algo_data; */
d1printk("%s i2c attach [addr=0x%x,client=%s]\n",
client->driver->driver.name, client->addr, client->name);
switch (client->addr) {
/* No info yet on what addresses to expect */
}
return 0;
}
static struct i2c_adapter tw68_adap_sw_template = {
.owner = THIS_MODULE,
.name = "tw68_sw",
.client_register = attach_inform,
};
static int tw68_i2c_eeprom(struct tw68_dev *dev, unsigned char *eedata,
int len)
{
unsigned char buf;
int i, err;
dev->i2c_client.addr = 0xa0 >> 1;
buf = 256 - len;
err = i2c_master_send(&dev->i2c_client, &buf, 1);
if (1 != err) {
printk(KERN_INFO "%s: Huh, no eeprom present (err = %d)?\n",
dev->name, err);
return -1;
}
err = i2c_master_recv(&dev->i2c_client, eedata, len);
if (len != err) {
printk(KERN_WARNING "%s: i2c eeprom read error (err=%d)\n",
dev->name, err);
return -1;
}
for (i = 0; i < len; i++) {
if (0 == (i % 16))
printk(KERN_INFO "%s: i2c eeprom %02x:",
dev->name, i);
printk(KERN_INFO " %02x", eedata[i]);
if (15 == (i % 16))
printk("\n");
}
return 0;
}
#if 0
static char *i2c_devs[128] = {
[0xa0 >> 1] = "eeprom",
};
static void do_i2c_scan(char *name, struct i2c_client *c)
{
unsigned char buf;
int i, rc;
for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
c->addr = i;
rc = i2c_master_recv(c, &buf, 1);
if (rc < 0)
continue;
printk(KERN_INFO "%s: i2c scan: found device "
"@ 0x%x [%s]\n", name, i << 1,
i2c_devs[i] ? i2c_devs[i] : "???");
}
}
#endif
int __devinit tw68_i2c_register(struct tw68_dev *dev)
{
int rc;
printk(KERN_DEBUG "%s: Registering i2c module\n", __func__);
tw_writeb(TW68_I2C_RST, 1); /* reset the i2c module */
memcpy(&dev->i2c_client, &tw68_client_template,
sizeof(tw68_client_template));
memcpy(&dev->i2c_adap, &tw68_adap_sw_template,
sizeof(tw68_adap_sw_template));
dev->i2c_adap.algo_data = &dev->i2c_algo;
dev->i2c_adap.dev.parent = &dev->pci->dev;
memcpy(&dev->i2c_algo, &tw68_i2c_algo_bit_template,
sizeof(tw68_i2c_algo_bit_template));
dev->i2c_algo.data = dev;
/* TODO - may want to set better name (see bttv code) */
i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
dev->i2c_client.adapter = &dev->i2c_adap;
/* Assure chip is in "software" mode */
tw_writel(TW68_SBUSC, TW68_SSDAT | TW68_SSCLK);
tw68_bit_setscl(dev, 1);
tw68_bit_setsda(dev, 1);
rc = i2c_bit_add_bus(&dev->i2c_adap);
tw68_i2c_eeprom(dev, dev->eedata, sizeof(dev->eedata));
#if 0
if (i2c_scan)
do_i2c_scan(dev->name, &dev->i2c_client);
#endif
return rc;
}
int tw68_i2c_unregister(struct tw68_dev *dev)
{
i2c_del_adapter(&dev->i2c_adap);
return 0;
}
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