1 #ifndef I2C_H 2 #define I2C_H 3 4 /* 5 * linux i2c interface. Works a little bit like the scsi subsystem. 6 * There are: 7 * 8 * i2c the basic control module (like scsi_mod) 9 * bus driver a driver with a i2c bus (hostadapter driver) 10 * chip driver a driver for a chip connected 11 * to a i2c bus (cdrom/hd driver) 12 * 13 * A device will be attached to one bus and one chip driver. Every chip 14 * driver gets a unique ID. 15 * 16 * A chip driver can provide a ioctl-like callback for the 17 * communication with other parts of the kernel (not every i2c chip is 18 * useful without other devices, a TV card tuner for example). 19 * 20 * "i2c internal" parts of the structs: only the i2c module is allowed to 21 * write to them, for others they are read-only. 22 * 23 */ 24 25 #include <linux/version.h> 26 27 #define I2C_BUS_MAX 4 /* max # of bus drivers */ 28 #define I2C_DRIVER_MAX 8 /* max # of chip drivers */ 29 #define I2C_DEVICE_MAX 8 /* max # if devices per bus/driver */ 30 31 struct i2c_bus; 32 struct i2c_driver; 33 struct i2c_device; 34 35 #define I2C_DRIVERID_MSP3400 1 36 #define I2C_DRIVERID_TUNER 2 37 #define I2C_DRIVERID_VIDEOTEXT 3 38 #define I2C_DRIVERID_VIDEODECODER 4 39 #define I2C_DRIVERID_VIDEOENCODER 5 40 41 #define I2C_BUSID_BT848 1 /* I2C bus on a BT848 */ 42 #define I2C_BUSID_PARPORT 2 /* Bit banging on a parallel port */ 43 #define I2C_BUSID_BUZ 3 44 #define I2C_BUSID_ZORAN 4 45 #define I2C_BUSID_CYBER2000 5 46 47 /* 48 * struct for a driver for a i2c chip (tuner, soundprocessor, 49 * videotext, ... ). 50 * 51 * a driver will register within the i2c module. The i2c module will 52 * callback the driver (i2c_attach) for every device it finds on a i2c 53 * bus at the specified address. If the driver decides to "accept" 54 * the, device, it must return a struct i2c_device, and NULL 55 * otherwise. 56 * 57 * i2c_detach = i2c_attach ** -1 58 * 59 * i2c_command will be used to pass commands to the driver in a 60 * ioctl-line manner. 61 * 62 */ 63 64 struct i2c_driver 65 { 66 char name[32]; /* some useful label */ 67 int id; /* device type ID */ 68 unsigned char addr_l, addr_h; /* address range of the chip */ 69 70 int (*attach)(struct i2c_device *device); 71 int (*detach)(struct i2c_device *device); 72 int (*command)(struct i2c_device *device,unsigned int cmd, void *arg); 73 74 /* i2c internal */ 75 struct i2c_device *devices[I2C_DEVICE_MAX]; 76 int devcount; 77 }; 78 79 80 /* 81 * this holds the informations about a i2c bus available in the system. 82 * 83 * a chip with a i2c bus interface (like bt848) registers the bus within 84 * the i2c module. This struct provides functions to access the i2c bus. 85 * 86 * One must hold the spinlock to access the i2c bus (XXX: is the irqsave 87 * required? Maybe better use a semaphore?). 88 * [-AC-] having a spinlock_irqsave is only needed if we have drivers wishing 89 * to bang their i2c bus from an interrupt. 90 * 91 * attach/detach_inform is a callback to inform the bus driver about 92 * attached chip drivers. 93 * 94 */ 95 96 /* needed: unsigned long flags */ 97 98 #if LINUX_VERSION_CODE >= 0x020100 99 # if 0 100 # define LOCK_FLAGS unsigned long flags; 101 # define LOCK_I2C_BUS(bus) spin_lock_irqsave(&(bus->bus_lock),flags); 102 # define UNLOCK_I2C_BUS(bus) spin_unlock_irqrestore(&(bus->bus_lock),flags); 103 # else 104 # define LOCK_FLAGS 105 # define LOCK_I2C_BUS(bus) spin_lock(&(bus->bus_lock)); 106 # define UNLOCK_I2C_BUS(bus) spin_unlock(&(bus->bus_lock)); 107 # endif 108 #else 109 # define LOCK_FLAGS unsigned long flags; 110 # define LOCK_I2C_BUS(bus) { save_flags(flags); cli(); } 111 # define UNLOCK_I2C_BUS(bus) { restore_flags(flags); } 112 #endif 113 114 struct i2c_bus 115 { 116 char name[32]; /* some useful label */ 117 int id; 118 void *data; /* free for use by the bus driver */ 119 120 #if LINUX_VERSION_CODE >= 0x020100 121 spinlock_t bus_lock; 122 #endif 123 124 /* attach/detach inform callbacks */ 125 void (*attach_inform)(struct i2c_bus *bus, int id); 126 void (*detach_inform)(struct i2c_bus *bus, int id); 127 128 /* Software I2C */ 129 void (*i2c_setlines)(struct i2c_bus *bus, int ctrl, int data); 130 int (*i2c_getdataline)(struct i2c_bus *bus); 131 132 /* Hardware I2C */ 133 int (*i2c_read)(struct i2c_bus *bus, unsigned char addr); 134 int (*i2c_write)(struct i2c_bus *bus, unsigned char addr, 135 unsigned char b1, unsigned char b2, int both); 136 137 /* internal data for i2c module */ 138 struct i2c_device *devices[I2C_DEVICE_MAX]; 139 int devcount; 140 }; 141 142 143 /* 144 * This holds per-device data for a i2c device 145 */ 146 147 struct i2c_device 148 { 149 char name[32]; /* some useful label */ 150 void *data; /* free for use by the chip driver */ 151 unsigned char addr; /* chip addr */ 152 153 /* i2c internal */ 154 struct i2c_bus *bus; 155 struct i2c_driver *driver; 156 }; 157 158 159 /* ------------------------------------------------------------------- */ 160 /* i2c module functions */ 161 162 /* register/unregister a i2c bus */ 163 int i2c_register_bus(struct i2c_bus *bus); 164 int i2c_unregister_bus(struct i2c_bus *bus); 165 166 /* register/unregister a chip driver */ 167 int i2c_register_driver(struct i2c_driver *driver); 168 int i2c_unregister_driver(struct i2c_driver *driver); 169 170 /* send a command to a chip using the ioctl-like callback interface */ 171 int i2c_control_device(struct i2c_bus *bus, int id, 172 unsigned int cmd, void *arg); 173 174 /* i2c bus access functions */ 175 void i2c_start(struct i2c_bus *bus); 176 void i2c_stop(struct i2c_bus *bus); 177 void i2c_one(struct i2c_bus *bus); 178 void i2c_zero(struct i2c_bus *bus); 179 int i2c_ack(struct i2c_bus *bus); 180 181 int i2c_sendbyte(struct i2c_bus *bus,unsigned char data,int wait_for_ack); 182 unsigned char i2c_readbyte(struct i2c_bus *bus,int last); 183 184 /* i2c (maybe) hardware functions */ 185 int i2c_read(struct i2c_bus *bus, unsigned char addr); 186 int i2c_write(struct i2c_bus *bus, unsigned char addr, 187 unsigned char b1, unsigned char b2, int both); 188 189 int i2c_init(void); 190 #endif /* I2C_H */ 191