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/*
* 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 <jdelvare@suse.de>.
*
* 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/device.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/platform_data/pca954x.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define PCA954X_MAX_NCHANS 8
#define PCA954X_IRQ_OFFSET 4
enum pca_type {
pca_9540,
pca_9542,
pca_9543,
pca_9544,
pca_9545,
pca_9546,
pca_9547,
pca_9548,
};
struct chip_desc {
u8 nchans;
u8 enable; /* used for muxes only */
u8 has_irq;
enum muxtype {
pca954x_ismux = 0,
pca954x_isswi
} muxtype;
};
struct pca954x {
const struct chip_desc *chip;
u8 last_chan; /* last register value */
u8 deselect;
struct i2c_client *client;
struct irq_domain *irq;
unsigned int irq_mask;
raw_spinlock_t lock;
};
/* 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_9542] = {
.nchans = 2,
.enable = 0x4,
.has_irq = 1,
.muxtype = pca954x_ismux,
},
[pca_9543] = {
.nchans = 2,
.has_irq = 1,
.muxtype = pca954x_isswi,
},
[pca_9544] = {
.nchans = 4,
.enable = 0x4,
.has_irq = 1,
.muxtype = pca954x_ismux,
},
[pca_9545] = {
.nchans = 4,
.has_irq = 1,
.muxtype = pca954x_isswi,
},
[pca_9546] = {
.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_9542 },
{ "pca9543", pca_9543 },
{ "pca9544", pca_9544 },
{ "pca9545", pca_9545 },
{ "pca9546", pca_9546 },
{ "pca9547", pca_9547 },
{ "pca9548", pca_9548 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pca954x_id);
#ifdef CONFIG_OF
static const struct of_device_id pca954x_of_match[] = {
{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
{}
};
MODULE_DEVICE_TABLE(of, pca954x_of_match);
#endif
/* 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 = __i2c_transfer(adap, &msg, 1);
if (ret >= 0 && ret != 1)
ret = -EREMOTEIO;
} 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_mux_core *muxc, u32 chan)
{
struct pca954x *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
const struct chip_desc *chip = data->chip;
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(muxc->parent, client, regval);
data->last_chan = ret < 0 ? 0 : regval;
}
return ret;
}
static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
{
struct pca954x *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
if (!(data->deselect & (1 << chan)))
return 0;
/* Deselect active channel */
data->last_chan = 0;
return pca954x_reg_write(muxc->parent, client, data->last_chan);
}
static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
{
struct pca954x *data = dev_id;
unsigned int child_irq;
int ret, i, handled = 0;
ret = i2c_smbus_read_byte(data->client);
if (ret < 0)
return IRQ_NONE;
for (i = 0; i < data->chip->nchans; i++) {
if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
child_irq = irq_linear_revmap(data->irq, i);
handle_nested_irq(child_irq);
handled++;
}
}
return handled ? IRQ_HANDLED : IRQ_NONE;
}
static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
{
if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
return -EINVAL;
return 0;
}
static struct irq_chip pca954x_irq_chip = {
.<
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