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<p><font size="2">Hi Scott,<br>
<br>
When I call if i2c_master_send(&ds75->i2c_client,buffer,2) it crashes. In module initialization I don't see any errors. Below are kernel messages. Could you please let me know what may be the reason for this crash.<br>
<br>
-----------Logs---------<br>
Loading Temperature Sensor Interface module (temp_if.ko)<br>
<font color="#ff0000"><font color="#0000ff">ds75_init<br>
DS75_DRIVER : Open<br>
DS75_DRIVER : Device Open Successful!<br>
DS75_DRIVER : ioctl TEMP_READ cmd 1<br>
ds75_temp_read calling i2c_master_send<br>
In i2c_master_send enter-------<br>
</font>Unable to handle kernel paging request for data at address 0x00000010<br>
</font>Faulting instruction address: 0xc01b06a4<br>
Oops: Kernel access of bad area, sig: 11 [#1]<br>
<br>
Modules linked in: temp_if gpio_if<br>
NIP: C01B06A4 LR: C01B06A0 CTR: C019BC90<br>
REGS: c309bdc0 TRAP: 0300 Not tainted (2.6.21.7-hrt1-cfs-v22-grsec-WR2.0bl_cgl)<br>
MSR: 00009032 <EE,ME,IR,DR> CR: 44004822 XER: 00000000<br>
DAR: 00000010, DSISR: 20000000<br>
TASK = c306f810[145] 'epn412' THREAD: c309a000<br>
GPR00: 00007D00 C309BE70 C306F810 C02A0000 00000001 00000001 00000000 FDFBD0A0<br>
GPR08: 003DE8A0 A827A936 00003F78 C02EAE88 00000001 1011C7C0 03EFD000 FFFFFFFF<br>
GPR16: 00000001 00000000 007FFC00 37942FA8 1012EAC0 1001E530 37942FB4 00000003<br>
GPR24: 37942FB4 00000000 003D0F00 C309BEA8 FFFFFFF7 00000008 C309BEA8 00000002<br>
Call Trace:<br>
[C309BE70] [C01B0698] (unreliable)<br>
[C309BEA0] [C50B71DC]<br>
[C309BED0] [C007A0D0]<br>
[C309BEE0] [C007A158]<br>
[C309BF10] [C007A4EC]<br>
[C309BF40] [C000E780]<br>
--- Exception: c01Instruction dump:<br>
7c0802a6 bf61001c 7c7d1b78 3c60c02a 386313b4 7cbf2b78 90010034 7c9b2378<br>
4be6bc79 386007d0 4be5ac6d 3c60c02a <839d0008> 386313d8 4be6bc61 a01d0004<br>
<br>
<br>
<br>
<br>
<strong>Below is the driver code.<br>
-------------------------<br>
</strong><br>
#include "temp_if.h"<br>
#include <asm-powerpc/uaccess.h><br>
#include <linux/i2c.h><br>
//#include <asm/arch/platform.h><br>
<br>
<br>
#define I2C_DEBUG<br>
<br>
#ifdef I2C_DEBUG<br>
#define I2C_DBG1(x) printk(KERN_WARNING x)<br>
#define I2C_DBG2(x,y) printk(KERN_WARNING x,y)<br>
#define I2C_DBG3(x,y,z) printk(KERN_WARNING x,y,z)<br>
#define I2C_DBG4(w,x,y,z) printk(KERN_WARNING w,x,y,z)<br>
#else<br>
#define I2C_DBG1(x) <br>
#define I2C_DBG2(x,y)<br>
#define I2C_DBG3(x,y,z)<br>
#define I2C_DBG4(w,x,y,z)<br>
#endif<br>
<br>
/* Function Prototype */<br>
static int ds75_open(struct inode *inode, struct file *filp);<br>
static int ds75_iotcl(struct inode *inode, struct file *flip, unsigned int cmd, unsigned long arg);<br>
static int ds75_release(struct inode *inode, struct file *flip);<br>
int ds75_attach_client(struct ds75_data * ds75, struct i2c_adapter *adapter);<br>
<br>
int ds75_attach_adapter(struct i2c_adapter *adapter);<br>
int ds75_detach_client(struct i2c_client *client);<br>
<br>
<br>
<br>
<br>
/* Structure */<br>
static struct file_operations tmpsensor_fops =<br>
{<br>
ioctl: ds75_iotcl,<br>
open: ds75_open,<br>
release: ds75_release, <br>
<br>
};<br>
<br>
static struct i2c_driver ds75_driver = {<br>
.driver = {<br>
.name = "DS75",<br>
},<br>
.attach_adapter = ds75_attach_adapter,<br>
.detach_client = ds75_detach_client,<br>
};<br>
<br>
/* Global Variable */<br>
static int s_nI2CMajor = 0;<br>
static int s_bI2CDevOpen = 0;<br>
static int s_nUseCnt = 0;<br>
struct ds75_data *ds75;<br>
<br>
<br>
static int ds75_open(struct inode *inode, struct file *flip)<br>
{<br>
I2C_DBG1( "DS75_DRIVER : Open\n");<br>
if(s_bI2CDevOpen == 0)<br>
{<br>
I2C_DBG1("DS75_DRIVER : Device Open Successful!\n");<br>
s_bI2CDevOpen = 1;<br>
s_nUseCnt++;<br>
<br>
}<br>
else<br>
{<br>
I2C_DBG1("DS75_DRIVER : Device Already Opened Successfully!\n");<br>
s_bI2CDevOpen = 1;<br>
s_nUseCnt++;<br>
}<br>
return 0;<br>
}<br>
<br>
<br>
static int ds75_release(struct inode *inode, struct file *flip)<br>
{<br>
I2C_DBG1 (KERN_INFO "Entering ds75_release\n" );<br>
if(s_bI2CDevOpen)<br>
{<br>
if( s_nUseCnt <= 0 )<br>
{<br>
I2C_DBG1("DS75_DRIVER : i2c driver can't be released!\n");<br>
return -EIO;<br>
}<br>
else<br>
{<br>
I2C_DBG1("DS75_DRIVER : Release Successful!\n");<br>
s_nUseCnt--;<br>
if( s_nUseCnt == 0 )<br>
{<br>
s_bI2CDevOpen = 0;<br>
I2C_DBG1("DS75_DRIVER : I2C Driver is Closed!\n");<br>
}<br>
}<br>
return 0;<br>
}<br>
else<br>
{<br>
I2C_DBG1("DS75_DRIVER : Release Fail! (Device is Not Open)\n");<br>
return -EIO;<br>
}<br>
}<br>
<br>
/*<br>
This function will read the Temperature from the device and copies to user space<br>
*/<br>
static int ds75_temp_read(struct ds75_msg_t *pData)<br>
{<br>
//unsigned char buffer[4];<br>
signed char buffer[4];<br>
int ret;<br>
buffer[0]=0; /* Writing 0 in to Pointer register. --> Temprature read register */<br>
if ((ret = i2c_master_send(&ds75->i2c_client,buffer,2)) !=2)<br>
{<br>
I2C_DBG2("DS75_DRIVER : Error writing to I2C ret = %d\n",ret);<br>
return -1;<br>
}<br>
<br>
/* reading from the temperature read register */<br>
if (i2c_master_recv(&ds75->i2c_client,buffer,2)!= 2)<br>
{<br>
I2C_DBG1("DS75_DRIVER : Error reading from I2C\n");<br>
return -1;<br>
}<br>
<br>
//I2C_DBG3("DS75_DRIVER: data[0] = %d, data[1] = %d \n",buffer[0],buffer[1]);<br>
//I2C_DBG3("DS75_DRIVER: data[0] = %d, data[1] = %d \n",buffer[0],buffer[1]);<br>
<br>
/* Copy User Memory Area */<br>
if(copy_to_user(pData->ReadData,buffer, 2 ) != 0)<br>
{<br>
I2C_DBG1("DS75_DRIVER : error in copying to user space");<br>
return -1;<br>
}<br>
<br>
return 0; /* Success */<br>
<br>
}<br>
<br>
<br>
static int ds75_iotcl(struct inode *inode, struct file *flip, unsigned int cmd, unsigned long arg)<br>
{<br>
int nRetVal = 0;<br>
<br>
if( ((struct ds75_msg_t *)arg) == NULL ){<br>
I2C_DBG1("DS75_DRIVER : ioctl Message Buff must not be NULL\n");<br>
return -EFAULT;<br>
}<br>
<br>
switch(cmd){<br>
case TEMP_READ:<br>
I2C_DBG2("DS75_DRIVER : ioctl TEMP_READ cmd %d\n",cmd);<br>
nRetVal = ds75_temp_read((struct ds75_msg_t *) arg);<br>
break;<br>
<br>
default:<br>
/* Error! */<br>
I2C_DBG1("DS75_DRIVER : Command not implemented\n");<br>
nRetVal = -EIO;<br>
break;<br>
}<br>
return nRetVal;<br>
}<br>
<br>
<br>
/*<br>
* i2c_attach_client - tries to detect and initialize slics<br>
*/<br>
int ds75_attach_client(struct ds75_data * ds75, struct i2c_adapter *adapter)<br>
{<br>
struct i2c_client * client;<br>
<br>
/* register i2c client */<br>
client = &ds75->i2c_client;<br>
client->adapter = adapter;<br>
client->driver = &ds75_driver;<br>
// client->flags = I2C_CLIENT_ALLOW_USE;<br>
client->addr = DS75_ADDR; <br>
strlcpy(client->name, "DS75", I2C_NAME_SIZE);<br>
i2c_set_clientdata(client, ds75);<br>
<br>
if (i2c_attach_client(client))<br>
return -1;<br>
<br>
printk (KERN_INFO DS75_DRIVER_NAME ": I2C client attached\n");<br>
return 0;<br>
}<br>
<br>
/*<br>
* i2c_attach_adapter - initializes the maxim driver<br>
*/<br>
int ds75_attach_adapter(struct i2c_adapter *adapter)<br>
{<br>
/* allocate maxim_data structure */<br>
ds75 = kmalloc(sizeof (struct ds75_data), GFP_KERNEL);<br>
if (ds75 == NULL)<br>
{<br>
printk (KERN_ERR "Unable to allocate memory for ds75 temp sensor driver\n");<br>
goto err0;<br>
}<br>
memset(ds75, 0, sizeof(struct ds75_data));<br>
<br>
/* Attach Spi Client */<br>
if (ds75_attach_client(ds75, adapter) != 0)<br>
{<br>
printk (KERN_ERR "No ds75 device detected\n");<br>
goto err1;<br>
}<br>
<br>
return 0;<br>
<br>
err1:<br>
kfree(ds75);<br>
err0:<br>
return -1;<br>
}<br>
<br>
/*<br>
* i2c_detach_client - cleans up the maxim driver<br>
*/<br>
int ds75_detach_client(struct i2c_client *client)<br>
{<br>
struct ds75_data *ds75 = i2c_get_clientdata(client);<br>
<br>
if (ds75->owned_irq)<br>
{<br>
free_irq(ds75->irq, ds75);<br>
ds75->owned_irq = 0;<br>
<br>
}<br>
<br>
i2c_detach_client(&ds75->i2c_client);<br>
<br>
kfree (ds75); // Free the kernel memory */<br>
<br>
return 0;<br>
}<br>
<br>
<br>
<br>
<br>
/*<br>
* Temperature sensor DS75 init -<br>
*<br>
*/<br>
int __init ds75_init(void)<br>
{<br>
int rc;<br>
rc = i2c_add_driver(&ds75_driver);<br>
if (rc)<br>
{<br>
printk (KERN_ERR DS75_DRIVER_NAME ": unable to add driver\n");<br>
return rc;<br>
}<br>
<br>
rc = register_chrdev (DS75_DEVICE_MAJOR_NUM, DS75_DRIVER_NAME, &tmpsensor_fops);<br>
if (rc)<br>
{<br>
printk (KERN_ERR DS75_DRIVER_NAME ": unable to register char device\n");<br>
return rc;<br>
}<br>
<br>
return 0;<br>
}<br>
<br>
/**<br>
* maxim _exit -<br>
*<br>
*<br>
*/<br>
void __exit ds75_exit(void)<br>
{<br>
unregister_chrdev (DS75_DEVICE_MAJOR_NUM, DS75_DRIVER_NAME);<br>
<br>
i2c_del_driver(&ds75_driver);<br>
}<br>
<br>
MODULE_AUTHOR("xxxx");<br>
MODULE_DESCRIPTION("DS75 I2C driver");<br>
MODULE_LICENSE("GPL");<br>
<br>
module_init(ds75_init);<br>
module_exit(ds75_exit);<br>
<br>
<br>
Regards,<br>
Smitha</font> </p>
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