i2c: virtual i2c adapter support
Hi, Rodolfo
I've tried your patches with linux-2.6.27 kernel running on custom board with 460EX PowerPC. This board has two i2c buses and pca9548 switch on bus 0.
The 954x driver (compiled into the kernel) creates 8 virtual buses just fine. However devices behind the mux are not detected if I use the "recommended" way of doing things.
I have RTC (ds1338) and temp sensor (ds1625) on mux channel 4 (i.e virtual bus 6). What I did initially to add the following code to board init code:
struct board_i2c_info {
int bus;
int addr;
char *id;
};static struct board_i2c_info board_i2c_devices[] = {
/* Bus Addr ID */
{6, 0x68, "ds1338"},
{6, 0x49, "ds1625"},
};static int board_i2c_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(board_i2c_devices); i++) {
struct i2c_board_info info = {};
info.irq = -1;
info.addr = board_i2c_devices[i].addr;
if (strlcpy(info.type, board_i2c_devices[i].id,
I2C_NAME_SIZE) >= I2C_NAME_SIZE)
return -ENOMEM;
i2c_register_board_info(board_i2c_devices[i].bus, &info, 1);
}
}arch_initcall(board_i2c_init);
This code is invoked by kernel before i2c bus and mux detection, but, as I said, RTC and sensor are not identified.
If I invoke the following code after creation of virtual adapters, things start working, but I don't like this solution
static int board_i2c_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(board_i2c_devices); i++) {
struct i2c_board_info info = {};
struct i2c_adapter *adap;
info.irq = -1;
info.addr = board_i2c_devices[i].addr;
if (strlcpy(info.type, board_i2c_devices[i].id,
I2C_NAME_SIZE) >= I2C_NAME_SIZE)
return -ENOMEM;
adap = i2c_get_adapter(board_i2c_devices[i].bus);
i2c_new_device(adap, &info);
}
}My question is: how can I register board i2c devices behind the mux in board init code, and make them properly identified when relevant drivers are loaded.
Thanks a lot.
Felix.
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Quoted 5 lines · Felix Radensky
Hi, Rodolfo
I've tried your patches with linux-2.6.27 kernel running on custom board with 460EX PowerPC. This board has two i2c buses and pca9548 switch on bus 0.
Please, consider thay my patch has been *not* accepted into main line due a mutex problem... :'(
Quoted 3 lines
My question is: how can I register board i2c devices behind the mux in board init code, and make them properly identified when relevant drivers are loaded.
I have just defined the i2c devices behind the mux as connected to the new virtual adapters:
static int wr1100_adap_ids[] = {
2, 3,
};static struct pca954x_platform_data wr1100_i2cmux_adap_ids = {
.adap_ids = wr1100_adap_ids,
.len = ARRAY_SIZE(wr1100_adap_ids),
};static struct i2c_board_info __initdata wr1100_i2c_devices[] = {
{
I2C_BOARD_INFO("pca9540", 0x70),
.platform_data = &wr1100_i2cmux_adap_ids,
},
};static struct i2c_board_info __initdata wr1100_i2c_mux_devices[] = {
{
I2C_BOARD_INFO("bq27200", 0x55),
},
};Then into machine startup code:
i2c_register_board_info(0, wr1100_i2c_devices,
ARRAY_SIZE(wr1100_i2c_devices));
i2c_register_board_info(2, wr1100_i2c_mux_devices,
ARRAY_SIZE(wr1100_i2c_mux_devices));
i2c_register_board_info(3, wr1100_i2c_mux_devices,
ARRAY_SIZE(wr1100_i2c_mux_devices));Ciao,
Rodolfo
Signature · 4 lines
GNU/Linux Solutions e-mail: giometti-AVVDYK/kqiJWk0Htik3J/[email protected] Linux Device Driver [email protected] Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
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Hi, Rodolfo
Quoted 4 lines · Rodolfo Giometti
Quoted 2 lines · Felix Radensky
Hi, Rodolfo
Quoted 9 lines
Quoted 4 lines
I've tried your patches with linux-2.6.27 kernel running on custom board with 460EX PowerPC. This board has two i2c buses and pca9548 switch on bus 0.
Please, consider thay my patch has been *not* accepted into main line due a mutex problem... :'(
I didn't find any discussion on the mailing list. What mutex problem exactly ?
I find your patches very useful, and the concept of virtual buses very elegant.
Hopefully you can rework your patches and get them into mainline. I'm willing
to test new patch versions.
Quoted 30 lines
Quoted 4 lines
My question is: how can I register board i2c devices behind the mux in board init code, and make them properly identified when relevant drivers are loaded.
I have just defined the i2c devices behind the mux as connected to the new virtual adapters:
static int wr1100_adap_ids[] = { 2, 3, };static struct pca954x_platform_data wr1100_i2cmux_adap_ids = { .adap_ids = wr1100_adap_ids, .len = ARRAY_SIZE(wr1100_adap_ids), };static struct i2c_board_info __initdata wr1100_i2c_devices[] = { { I2C_BOARD_INFO("pca9540", 0x70), .platform_data = &wr1100_i2cmux_adap_ids, }, };static struct i2c_board_info __initdata wr1100_i2c_mux_devices[] = { { I2C_BOARD_INFO("bq27200", 0x55), }, };
Quoted 10 lines
Then into machine startup code:
i2c_register_board_info(0, wr1100_i2c_devices, ARRAY_SIZE(wr1100_i2c_devices)); i2c_register_board_info(2, wr1100_i2c_mux_devices, ARRAY_SIZE(wr1100_i2c_mux_devices)); i2c_register_board_info(3, wr1100_i2c_mux_devices, ARRAY_SIZE(wr1100_i2c_mux_devices));
That works fine in my setup too. Thanks a lot for your help !!!
Quoted 5 lines
Ciao,
Rodolfo
Felix.
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Hi, Rodolfo
Quoted 4 lines · Rodolfo Giometti
Quoted 2 lines · Felix Radensky
Hi, Rodolfo
Quoted 9 lines
Quoted 4 lines
I've tried your patches with linux-2.6.27 kernel running on custom board with 460EX PowerPC. This board has two i2c buses and pca9548 switch on bus 0.
Please, consider thay my patch has been *not* accepted into main line due a mutex problem... :'(
I didn't find any discussion on the mailing list. What mutex problem exactly ?
I find your patches very useful, and the concept of virtual buses very elegant.
Hopefully you can rework your patches and get them into mainline. I'm willing
to test new patch versions.
Quoted 30 lines
Quoted 4 lines
My question is: how can I register board i2c devices behind the mux in board init code, and make them properly identified when relevant drivers are loaded.
I have just defined the i2c devices behind the mux as connected to the new virtual adapters:
static int wr1100_adap_ids[] = { 2, 3, };static struct pca954x_platform_data wr1100_i2cmux_adap_ids = { .adap_ids = wr1100_adap_ids, .len = ARRAY_SIZE(wr1100_adap_ids), };static struct i2c_board_info __initdata wr1100_i2c_devices[] = { { I2C_BOARD_INFO("pca9540", 0x70), .platform_data = &wr1100_i2cmux_adap_ids, }, };static struct i2c_board_info __initdata wr1100_i2c_mux_devices[] = { { I2C_BOARD_INFO("bq27200", 0x55), }, };
Quoted 10 lines
Then into machine startup code:
i2c_register_board_info(0, wr1100_i2c_devices, ARRAY_SIZE(wr1100_i2c_devices)); i2c_register_board_info(2, wr1100_i2c_mux_devices, ARRAY_SIZE(wr1100_i2c_mux_devices)); i2c_register_board_info(3, wr1100_i2c_mux_devices, ARRAY_SIZE(wr1100_i2c_mux_devices));
That works fine in my setup too. Thanks a lot for your help !!!
Quoted 5 lines
Ciao,
Rodolfo
Felix.
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Quoted 3 lines · Felix Radensky
Quoted 1 line
I didn't find any discussion on the mailing list. What mutex problem exactly ?
See this thread:
http://www.mail-archive.com/[email protected]/msg01535.html
Quoted 5 lines
I find your patches very useful, and the concept of virtual buses very elegant.
Hopefully you can rework your patches and get them into mainline. I'm willing
to test new patch versions.
No time to dedicate to... :'( maybe you can try to solve the issue! :P
Ciao,
Rodolfo
Signature · 4 lines
GNU/Linux Solutions e-mail: giometti-AVVDYK/kqiJWk0Htik3J/[email protected] Linux Device Driver [email protected] Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
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