linux/drivers/media/dvb/frontends/dibx000_common.c
David Brownell 2096b956d2 i2c: Shrink struct i2c_client
This shrinks the size of "struct i2c_client" by 40 bytes:

 - Substantially shrinks the string used to identify the chip type
 - The "flags" don't need to be so big
 - Removes some internal padding

It also adds kerneldoc for that struct, explaining how "name" is really a
chip type identifier; it's otherwise potentially confusing.

Because the I2C_NAME_SIZE symbol was abused for both i2c_client.name
and for i2c_adapter.name, this needed to affect i2c_adapter too.  The
adapters which used that symbol now use the more-obviously-correct
idiom of taking the size of that field.

JD: Shorten i2c_adapter.name from 50 to 48 bytes while we're here, to
avoid wasting space in padding.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00

153 lines
4.1 KiB
C

#include <linux/i2c.h>
#include "dibx000_common.h"
static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "turn on debugging (default: 0)");
#define dprintk(args...) do { if (debug) { printk(KERN_DEBUG "DiBX000: "); printk(args); } } while (0)
static int dibx000_write_word(struct dibx000_i2c_master *mst, u16 reg, u16 val)
{
u8 b[4] = {
(reg >> 8) & 0xff, reg & 0xff,
(val >> 8) & 0xff, val & 0xff,
};
struct i2c_msg msg = {
.addr = mst->i2c_addr, .flags = 0, .buf = b, .len = 4
};
return i2c_transfer(mst->i2c_adap, &msg, 1) != 1 ? -EREMOTEIO : 0;
}
static int dibx000_i2c_select_interface(struct dibx000_i2c_master *mst, enum dibx000_i2c_interface intf)
{
if (mst->device_rev > DIB3000MC && mst->selected_interface != intf) {
dprintk("selecting interface: %d\n",intf);
mst->selected_interface = intf;
return dibx000_write_word(mst, mst->base_reg + 4, intf);
}
return 0;
}
static int dibx000_i2c_gate_ctrl(struct dibx000_i2c_master *mst, u8 tx[4], u8 addr, int onoff)
{
u16 val;
if (onoff)
val = addr << 8; // bit 7 = use master or not, if 0, the gate is open
else
val = 1 << 7;
if (mst->device_rev > DIB7000)
val <<= 1;
tx[0] = (((mst->base_reg + 1) >> 8) & 0xff);
tx[1] = ( (mst->base_reg + 1) & 0xff);
tx[2] = val >> 8;
tx[3] = val & 0xff;
return 0;
}
static u32 dibx000_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C;
}
static int dibx000_i2c_gated_tuner_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msg[], int num)
{
struct dibx000_i2c_master *mst = i2c_get_adapdata(i2c_adap);
struct i2c_msg m[2 + num];
u8 tx_open[4], tx_close[4];
memset(m,0, sizeof(struct i2c_msg) * (2 + num));
dibx000_i2c_select_interface(mst, DIBX000_I2C_INTERFACE_TUNER);
dibx000_i2c_gate_ctrl(mst, tx_open, msg[0].addr, 1);
m[0].addr = mst->i2c_addr;
m[0].buf = tx_open;
m[0].len = 4;
memcpy(&m[1], msg, sizeof(struct i2c_msg) * num);
dibx000_i2c_gate_ctrl(mst, tx_close, 0, 0);
m[num+1].addr = mst->i2c_addr;
m[num+1].buf = tx_close;
m[num+1].len = 4;
return i2c_transfer(mst->i2c_adap, m, 2+num) == 2 + num ? num : -EIO;
}
static struct i2c_algorithm dibx000_i2c_gated_tuner_algo = {
.master_xfer = dibx000_i2c_gated_tuner_xfer,
.functionality = dibx000_i2c_func,
};
struct i2c_adapter * dibx000_get_i2c_adapter(struct dibx000_i2c_master *mst, enum dibx000_i2c_interface intf, int gating)
{
struct i2c_adapter *i2c = NULL;
switch (intf) {
case DIBX000_I2C_INTERFACE_TUNER:
if (gating)
i2c = &mst->gated_tuner_i2c_adap;
break;
default:
printk(KERN_ERR "DiBX000: incorrect I2C interface selected\n");
break;
}
return i2c;
}
EXPORT_SYMBOL(dibx000_get_i2c_adapter);
static int i2c_adapter_init(struct i2c_adapter *i2c_adap, struct i2c_algorithm *algo, const char *name, struct dibx000_i2c_master *mst)
{
strncpy(i2c_adap->name, name, sizeof(i2c_adap->name));
i2c_adap->class = I2C_CLASS_TV_DIGITAL,
i2c_adap->algo = algo;
i2c_adap->algo_data = NULL;
i2c_set_adapdata(i2c_adap, mst);
if (i2c_add_adapter(i2c_adap) < 0)
return -ENODEV;
return 0;
}
int dibx000_init_i2c_master(struct dibx000_i2c_master *mst, u16 device_rev, struct i2c_adapter *i2c_adap, u8 i2c_addr)
{
u8 tx[4];
struct i2c_msg m = { .addr = i2c_addr >> 1, .buf = tx, .len = 4 };
mst->device_rev = device_rev;
mst->i2c_adap = i2c_adap;
mst->i2c_addr = i2c_addr >> 1;
if (device_rev == DIB7000P)
mst->base_reg = 1024;
else
mst->base_reg = 768;
if (i2c_adapter_init(&mst->gated_tuner_i2c_adap, &dibx000_i2c_gated_tuner_algo, "DiBX000 tuner I2C bus", mst) != 0)
printk(KERN_ERR "DiBX000: could not initialize the tuner i2c_adapter\n");
/* initialize the i2c-master by closing the gate */
dibx000_i2c_gate_ctrl(mst, tx, 0, 0);
return i2c_transfer(i2c_adap, &m, 1) == 1;
}
EXPORT_SYMBOL(dibx000_init_i2c_master);
void dibx000_exit_i2c_master(struct dibx000_i2c_master *mst)
{
i2c_del_adapter(&mst->gated_tuner_i2c_adap);
}
EXPORT_SYMBOL(dibx000_exit_i2c_master);
MODULE_AUTHOR("Patrick Boettcher <pboettcher@dibcom.fr>");
MODULE_DESCRIPTION("Common function the DiBcom demodulator family");
MODULE_LICENSE("GPL");