i2c: I2C bus multiplexer driver pca954x
I2C driver for PCA954x I2C multiplexer series. Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
parent
0826374bff
commit
7f528135da
|
@ -58,6 +58,8 @@ config I2C_MUX
|
|||
This support is also available as a module. If so, the module
|
||||
will be called i2c-mux.
|
||||
|
||||
source drivers/i2c/muxes/Kconfig
|
||||
|
||||
config I2C_HELPER_AUTO
|
||||
bool "Autoselect pertinent helper modules"
|
||||
default y
|
||||
|
|
|
@ -7,7 +7,7 @@ obj-$(CONFIG_I2C) += i2c-core.o
|
|||
obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o
|
||||
obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o
|
||||
obj-$(CONFIG_I2C_MUX) += i2c-mux.o
|
||||
obj-y += algos/ busses/
|
||||
obj-y += algos/ busses/ muxes/
|
||||
|
||||
ifeq ($(CONFIG_I2C_DEBUG_CORE),y)
|
||||
EXTRA_CFLAGS += -DDEBUG
|
||||
|
|
18
drivers/i2c/muxes/Kconfig
Normal file
18
drivers/i2c/muxes/Kconfig
Normal file
|
@ -0,0 +1,18 @@
|
|||
#
|
||||
# Multiplexer I2C chip drivers configuration
|
||||
#
|
||||
|
||||
menu "Multiplexer I2C Chip support"
|
||||
depends on I2C_MUX
|
||||
|
||||
config I2C_MUX_PCA954x
|
||||
tristate "Philips PCA954x I2C Mux/switches"
|
||||
depends on EXPERIMENTAL
|
||||
help
|
||||
If you say yes here you get support for the Philips PCA954x
|
||||
I2C mux/switch devices.
|
||||
|
||||
This driver can also be built as a module. If so, the module
|
||||
will be called pca954x.
|
||||
|
||||
endmenu
|
8
drivers/i2c/muxes/Makefile
Normal file
8
drivers/i2c/muxes/Makefile
Normal file
|
@ -0,0 +1,8 @@
|
|||
#
|
||||
# Makefile for multiplexer I2C chip drivers.
|
||||
|
||||
obj-$(CONFIG_I2C_MUX_PCA954x) += pca954x.o
|
||||
|
||||
ifeq ($(CONFIG_I2C_DEBUG_BUS),y)
|
||||
EXTRA_CFLAGS += -DDEBUG
|
||||
endif
|
301
drivers/i2c/muxes/pca954x.c
Normal file
301
drivers/i2c/muxes/pca954x.c
Normal file
|
@ -0,0 +1,301 @@
|
|||
/*
|
||||
* I2C multiplexer
|
||||
*
|
||||
* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
|
||||
* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
|
||||
*
|
||||
* This module supports the PCA954x series of I2C multiplexer/switch chips
|
||||
* made by Philips Semiconductors.
|
||||
* This includes the:
|
||||
* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
|
||||
* and PCA9548.
|
||||
*
|
||||
* These chips are all controlled via the I2C bus itself, and all have a
|
||||
* single 8-bit register. The upstream "parent" bus fans out to two,
|
||||
* four, or eight downstream busses or channels; which of these
|
||||
* are selected is determined by the chip type and register contents. A
|
||||
* mux can select only one sub-bus at a time; a switch can select any
|
||||
* combination simultaneously.
|
||||
*
|
||||
* Based on:
|
||||
* pca954x.c from Kumar Gala <galak@kernel.crashing.org>
|
||||
* Copyright (C) 2006
|
||||
*
|
||||
* Based on:
|
||||
* pca954x.c from Ken Harrenstien
|
||||
* Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
|
||||
*
|
||||
* Based on:
|
||||
* i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
|
||||
* and
|
||||
* pca9540.c from Jean Delvare <khali@linux-fr.org>.
|
||||
*
|
||||
* This file is licensed under the terms of the GNU General Public
|
||||
* License version 2. This program is licensed "as is" without any
|
||||
* warranty of any kind, whether express or implied.
|
||||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/i2c-mux.h>
|
||||
|
||||
#include <linux/i2c/pca954x.h>
|
||||
|
||||
#define PCA954X_MAX_NCHANS 8
|
||||
|
||||
enum pca_type {
|
||||
pca_9540,
|
||||
pca_9542,
|
||||
pca_9543,
|
||||
pca_9544,
|
||||
pca_9545,
|
||||
pca_9546,
|
||||
pca_9547,
|
||||
pca_9548,
|
||||
};
|
||||
|
||||
struct pca954x {
|
||||
enum pca_type type;
|
||||
struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
|
||||
|
||||
u8 last_chan; /* last register value */
|
||||
};
|
||||
|
||||
struct chip_desc {
|
||||
u8 nchans;
|
||||
u8 enable; /* used for muxes only */
|
||||
enum muxtype {
|
||||
pca954x_ismux = 0,
|
||||
pca954x_isswi
|
||||
} muxtype;
|
||||
};
|
||||
|
||||
/* Provide specs for the PCA954x types we know about */
|
||||
static const struct chip_desc chips[] = {
|
||||
[pca_9540] = {
|
||||
.nchans = 2,
|
||||
.enable = 0x4,
|
||||
.muxtype = pca954x_ismux,
|
||||
},
|
||||
[pca_9543] = {
|
||||
.nchans = 2,
|
||||
.muxtype = pca954x_isswi,
|
||||
},
|
||||
[pca_9544] = {
|
||||
.nchans = 4,
|
||||
.enable = 0x4,
|
||||
.muxtype = pca954x_ismux,
|
||||
},
|
||||
[pca_9545] = {
|
||||
.nchans = 4,
|
||||
.muxtype = pca954x_isswi,
|
||||
},
|
||||
[pca_9547] = {
|
||||
.nchans = 8,
|
||||
.enable = 0x8,
|
||||
.muxtype = pca954x_ismux,
|
||||
},
|
||||
[pca_9548] = {
|
||||
.nchans = 8,
|
||||
.muxtype = pca954x_isswi,
|
||||
},
|
||||
};
|
||||
|
||||
static const struct i2c_device_id pca954x_id[] = {
|
||||
{ "pca9540", pca_9540 },
|
||||
{ "pca9542", pca_9540 },
|
||||
{ "pca9543", pca_9543 },
|
||||
{ "pca9544", pca_9544 },
|
||||
{ "pca9545", pca_9545 },
|
||||
{ "pca9546", pca_9545 },
|
||||
{ "pca9547", pca_9547 },
|
||||
{ "pca9548", pca_9548 },
|
||||
{ }
|
||||
};
|
||||
MODULE_DEVICE_TABLE(i2c, pca954x_id);
|
||||
|
||||
/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
|
||||
for this as they will try to lock adapter a second time */
|
||||
static int pca954x_reg_write(struct i2c_adapter *adap,
|
||||
struct i2c_client *client, u8 val)
|
||||
{
|
||||
int ret = -ENODEV;
|
||||
|
||||
if (adap->algo->master_xfer) {
|
||||
struct i2c_msg msg;
|
||||
char buf[1];
|
||||
|
||||
msg.addr = client->addr;
|
||||
msg.flags = 0;
|
||||
msg.len = 1;
|
||||
buf[0] = val;
|
||||
msg.buf = buf;
|
||||
ret = adap->algo->master_xfer(adap, &msg, 1);
|
||||
} else {
|
||||
union i2c_smbus_data data;
|
||||
ret = adap->algo->smbus_xfer(adap, client->addr,
|
||||
client->flags,
|
||||
I2C_SMBUS_WRITE,
|
||||
val, I2C_SMBUS_BYTE, &data);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int pca954x_select_chan(struct i2c_adapter *adap,
|
||||
void *client, u32 chan)
|
||||
{
|
||||
struct pca954x *data = i2c_get_clientdata(client);
|
||||
const struct chip_desc *chip = &chips[data->type];
|
||||
u8 regval;
|
||||
int ret = 0;
|
||||
|
||||
/* we make switches look like muxes, not sure how to be smarter */
|
||||
if (chip->muxtype == pca954x_ismux)
|
||||
regval = chan | chip->enable;
|
||||
else
|
||||
regval = 1 << chan;
|
||||
|
||||
/* Only select the channel if its different from the last channel */
|
||||
if (data->last_chan != regval) {
|
||||
ret = pca954x_reg_write(adap, client, regval);
|
||||
data->last_chan = regval;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int pca954x_deselect_mux(struct i2c_adapter *adap,
|
||||
void *client, u32 chan)
|
||||
{
|
||||
struct pca954x *data = i2c_get_clientdata(client);
|
||||
|
||||
/* Deselect active channel */
|
||||
data->last_chan = 0;
|
||||
return pca954x_reg_write(adap, client, data->last_chan);
|
||||
}
|
||||
|
||||
/*
|
||||
* I2C init/probing/exit functions
|
||||
*/
|
||||
static int __devinit pca954x_probe(struct i2c_client *client,
|
||||
const struct i2c_device_id *id)
|
||||
{
|
||||
struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
|
||||
struct pca954x_platform_data *pdata = client->dev.platform_data;
|
||||
int num, force;
|
||||
struct pca954x *data;
|
||||
int ret = -ENODEV;
|
||||
|
||||
if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
|
||||
goto err;
|
||||
|
||||
data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
|
||||
if (!data) {
|
||||
ret = -ENOMEM;
|
||||
goto err;
|
||||
}
|
||||
|
||||
i2c_set_clientdata(client, data);
|
||||
|
||||
/* Read the mux register at addr to verify
|
||||
* that the mux is in fact present.
|
||||
*/
|
||||
if (i2c_smbus_read_byte(client) < 0) {
|
||||
dev_warn(&client->dev, "probe failed\n");
|
||||
goto exit_free;
|
||||
}
|
||||
|
||||
data->type = id->driver_data;
|
||||
data->last_chan = 0; /* force the first selection */
|
||||
|
||||
/* Now create an adapter for each channel */
|
||||
for (num = 0; num < chips[data->type].nchans; num++) {
|
||||
force = 0; /* dynamic adap number */
|
||||
if (pdata) {
|
||||
if (num < pdata->num_modes)
|
||||
/* force static number */
|
||||
force = pdata->modes[num].adap_id;
|
||||
else
|
||||
/* discard unconfigured channels */
|
||||
break;
|
||||
}
|
||||
|
||||
data->virt_adaps[num] =
|
||||
i2c_add_mux_adapter(adap, client,
|
||||
force, num, pca954x_select_chan,
|
||||
(pdata && pdata->modes[num].deselect_on_exit)
|
||||
? pca954x_deselect_mux : NULL);
|
||||
|
||||
if (data->virt_adaps[num] == NULL) {
|
||||
ret = -ENODEV;
|
||||
dev_err(&client->dev,
|
||||
"failed to register multiplexed adapter"
|
||||
" %d as bus %d\n", num, force);
|
||||
goto virt_reg_failed;
|
||||
}
|
||||
}
|
||||
|
||||
dev_info(&client->dev,
|
||||
"registered %d multiplexed busses for I2C %s %s\n",
|
||||
num, chips[data->type].muxtype == pca954x_ismux
|
||||
? "mux" : "switch", client->name);
|
||||
|
||||
return 0;
|
||||
|
||||
virt_reg_failed:
|
||||
for (num--; num >= 0; num--)
|
||||
i2c_del_mux_adapter(data->virt_adaps[num]);
|
||||
exit_free:
|
||||
kfree(data);
|
||||
err:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int __devexit pca954x_remove(struct i2c_client *client)
|
||||
{
|
||||
struct pca954x *data = i2c_get_clientdata(client);
|
||||
const struct chip_desc *chip = &chips[data->type];
|
||||
int i, err;
|
||||
|
||||
for (i = 0; i < chip->nchans; ++i)
|
||||
if (data->virt_adaps[i]) {
|
||||
err = i2c_del_mux_adapter(data->virt_adaps[i]);
|
||||
if (err)
|
||||
return err;
|
||||
data->virt_adaps[i] = NULL;
|
||||
}
|
||||
|
||||
kfree(data);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct i2c_driver pca954x_driver = {
|
||||
.driver = {
|
||||
.name = "pca954x",
|
||||
.owner = THIS_MODULE,
|
||||
},
|
||||
.probe = pca954x_probe,
|
||||
.remove = __devexit_p(pca954x_remove),
|
||||
.id_table = pca954x_id,
|
||||
};
|
||||
|
||||
static int __init pca954x_init(void)
|
||||
{
|
||||
return i2c_add_driver(&pca954x_driver);
|
||||
}
|
||||
|
||||
static void __exit pca954x_exit(void)
|
||||
{
|
||||
i2c_del_driver(&pca954x_driver);
|
||||
}
|
||||
|
||||
module_init(pca954x_init);
|
||||
module_exit(pca954x_exit);
|
||||
|
||||
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
||||
MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
|
||||
MODULE_LICENSE("GPL v2");
|
47
include/linux/i2c/pca954x.h
Normal file
47
include/linux/i2c/pca954x.h
Normal file
|
@ -0,0 +1,47 @@
|
|||
/*
|
||||
*
|
||||
* pca954x.h - I2C multiplexer/switch support
|
||||
*
|
||||
* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
|
||||
* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
|
||||
* Michael Lawnick <michael.lawnick.ext@nsn.com>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
|
||||
#ifndef _LINUX_I2C_PCA954X_H
|
||||
#define _LINUX_I2C_PCA954X_H
|
||||
|
||||
/* Platform data for the PCA954x I2C multiplexers */
|
||||
|
||||
/* Per channel initialisation data:
|
||||
* @adap_id: bus number for the adapter. 0 = don't care
|
||||
* @deselect_on_exit: set this entry to 1, if your H/W needs deselection
|
||||
* of this channel after transaction.
|
||||
*
|
||||
*/
|
||||
struct pca954x_platform_mode {
|
||||
int adap_id;
|
||||
unsigned int deselect_on_exit:1;
|
||||
};
|
||||
|
||||
/* Per mux/switch data, used with i2c_register_board_info */
|
||||
struct pca954x_platform_data {
|
||||
struct pca954x_platform_mode *modes;
|
||||
int num_modes;
|
||||
};
|
||||
|
||||
#endif /* _LINUX_I2C_PCA954X_H */
|
Loading…
Reference in a new issue