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/*
* drivers/media/video/smiapp/smiapp-regs.c
*
* Generic driver for SMIA/SMIA++ compliant camera modules
*
* Copyright (C) 2011--2012 Nokia Corporation
* Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* 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 St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include "smiapp.h"
#include "smiapp-regs.h"
static uint32_t float_to_u32_mul_1000000(struct i2c_client *client,
uint32_t phloat)
{
int32_t exp;
uint64_t man;
if (phloat >= 0x80000000) {
dev_err(&client->dev, "this is a negative number\n");
return 0;
}
if (phloat == 0x7f800000)
return ~0; /* Inf. */
if ((phloat & 0x7f800000) == 0x7f800000) {
dev_err(&client->dev, "NaN or other special number\n");
return 0;
}
/* Valid cases begin here */
if (phloat == 0)
return 0; /* Valid zero */
if (phloat > 0x4f800000)
return ~0; /* larger than 4294967295 */
/*
* Unbias exponent (note how phloat is now guaranteed to
* have 0 in the high bit)
*/
exp = ((int32_t)phloat >> 23) - 127;
/* Extract mantissa, add missing '1' bit and it's in MHz */
man = ((phloat & 0x7fffff) | 0x800000) * 1000000ULL;
if (exp < 0)
man >>= -exp;
else
man <<= exp;
man >>= 23; /* Remove mantissa bias */
return man & 0xffffffff;
}
/*
* Read a 8/16/32-bit i2c register. The value is returned in 'val'.
* Returns zero if successful, or non-zero otherwise.
*/
int smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val)
{
struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
struct i2c_msg msg;
unsigned char data[4];
unsigned int len = (u8)(reg >> 16);
u16 offset = reg;
int r;
if (len != SMIA_REG_8BIT && len != SMIA_REG_16BIT
&& len != SMIA_REG_32BIT)
return -EINVAL;
msg.addr = client->addr;
msg.flags = 0;
msg.len = 2;
msg.buf = data;
/* high byte goes out first */
data[0] = (u8) (offset >> 8);
data[1] = (u8) offset;
r = i2c_transfer(client->adapter, &msg, 1);
if (r != 1) {
if (r >= 0)
r = -EBUSY;
goto err;
}
msg.len = len;
msg.flags = I2C_M_RD;
r = i2c_transfer(client->adapter, &msg, 1);
if (r != 1) {
if (r >= 0)
r = -EBUSY;
goto err;
}
*val = 0;
/* high byte comes first */
switch (len) {
case SMIA_REG_32BIT:
*val = (data[0] << 24) + (data[1] << 16) + (data[2] << 8) +
data[3];
break;
case SMIA_REG_16BIT:
*val = (data[0] << 8) + data[1];
break;
case SMIA_REG_8BIT:
*val = data[0];
break;
default:
BUG();
}
if (reg & SMIA_REG_FLAG_FLOAT)
*val = float_to_u32_mul_1000000(client, *val);
return 0;
err:
dev_err(&client->dev, "read from offset 0x%x error %d\n", offset, r);
return r;
}
/*
* Write to a 8/16-bit register.
* Returns zero if successful, or non-zero otherwise.
*/
int smiapp_write(struct smiapp_sensor *sensor, u32 reg, u32 val)
{
struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
struct i2c_msg msg;
unsigned char data[6];
unsigned int retries;
unsigned int flags = reg >> 24;
unsigned int len = (u8)(reg >> 16);
u16 offset = reg;
int r;
if ((len != SMIA_REG_8BIT && len != SMIA_REG_16BIT &&
len != SMIA_REG_32BIT) || flags)
return -EINVAL;
msg.addr = client->addr;
msg.flags = 0; /* Write */
msg.len = 2 + len;
msg.buf = data;
/* high byte goes out first */
data[0] = (u8) (reg >> 8);
data[1] = (u8) (reg & 0xff);
switch (len) {
case SMIA_REG_8BIT:
data[2] = val;
break;
case SMIA_REG_16BIT:
data[2] = val >> 8;
data[3] = val;
break;
case SMIA_REG_32BIT:
data[2] = val >> 24;
data[3] = val >> 16;
data[4] = val >> 8;
data[5] = val;
break;
default:
BUG();
}
for (retries = 0; retries < 5; retries++) {
/*
* Due to unknown reason sensor stops responding. This
* loop is a temporaty solution until the root cause
* is found.
*/
r = i2c_transfer(client->adapter, &msg, 1);
if (r == 1) {
if (retries)
dev_err(&client->dev,
"sensor i2c stall encountered. "
"retries: %d\n", retries);
return 0;
}
usleep_range(2000, 2000);
}
dev_err(&client->dev,
"wrote 0x%x to offset 0x%x error %d\n", val, offset, r);
return r;
}
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