UM0851 datasheet(109/245 Pages) STMICROELECTRONICS

109 / 245 page

UM0851

Communication device drivers

Doc ID 16604 Rev 2

109/245

void (*write_reg)(struct net_device *dev,

enum c_regs reg, u16 val);

#ifdef CCAN_DEBUG

unsigned int bufstat[MAX_OBJECT + 1];

#endif

};

To write and read the CAN IP registers the APIs spr_can_write_reg() and

spr_can_read_reg() are used respectively:

static u16 spr_can_read_reg(struct net_device *dev, enum c_regs reg);

static void spr_can_write_reg(struct net_device *dev, enum c_regs reg,

u16 val);

4.9.5

User-land applications over the CAN driver

This section describes how to design a simple application that accesses the services

provided by the CAN driver. For designing a typical user-land application that uses the CAN

driver, the following steps should be followed:

To open a socket for communicating over a CAN network:

Pass PF_CAN as the first argument to the socket() system call. Currently, there are two

CAN protocols to choose from, the raw socket protocol (RAW) and the broadcast

manager (BCM):

/* Open a RAW socket */

s = socket(PF_CAN, SOCK_RAW, CAN_RAW);

/* Open a BCM socket */

s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM);

Now, bind the socket to a CAN interface using the bind() system call. An example of

binding a raw socket to the CAN interface can0 is given below:

int s;

struct sockaddr_can addr;

struct ifreq ifr;

s = socket(PF_CAN, SOCK_RAW, CAN_RAW);

strcpy(ifr.ifr_name, "can0" );

ioctl(s, SIOCGIFINDEX, &ifr);

addr.can_family = AF_CAN;

addr.can_ifindex = ifr.ifr_ifindex;

bind(s, (struct sockaddr *)&addr, sizeof(addr));

After binding (CAN_RAW) or connecting (CAN_BCM) the socket, you can read and

write from/to the socket using read() and write() APIs respectively:

/* Read nbytes from a CAN socket */

nbytes = read(s, &frame, sizeof(struct can_frame));

/* Write nbytes to a CAN socket */

nbytes = write(s, &frame, sizeof(struct can_frame));

You can also use other standard APIs like send(), sendto(), sendmsg() and recv() to perform

the desired operations on the socket.

UM0851 Datasheet(PDF) 109 Page - STMicroelectronics

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