kolibrios-gitea/drivers/video/drm/i2c/i2c-core.c

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/* i2c-core.c - a device driver for the iic-bus interface */
/* ------------------------------------------------------------------------- */
/* Copyright (C) 1995-99 Simon G. Vogl
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., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301 USA. */
/* ------------------------------------------------------------------------- */
/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
Jean Delvare <khali@linux-fr.org>
Mux support by Rodolfo Giometti <giometti@enneenne.com> and
Michael Lawnick <michael.lawnick.ext@nsn.com> */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <list.h>
#include <errno.h>
#include <linux/i2c.h>
#include <syscall.h>
#if 0
static ssize_t
show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
}
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
static struct attribute *i2c_dev_attrs[] = {
&dev_attr_name.attr,
/* modalias helps coldplug: modprobe $(cat .../modalias) */
&dev_attr_modalias.attr,
NULL
};
static struct attribute_group i2c_dev_attr_group = {
.attrs = i2c_dev_attrs,
};
static const struct attribute_group *i2c_dev_attr_groups[] = {
&i2c_dev_attr_group,
NULL
};
static const struct dev_pm_ops i2c_device_pm_ops = {
.suspend = i2c_device_pm_suspend,
.resume = i2c_device_pm_resume,
.freeze = i2c_device_pm_freeze,
.thaw = i2c_device_pm_thaw,
.poweroff = i2c_device_pm_poweroff,
.restore = i2c_device_pm_restore,
SET_RUNTIME_PM_OPS(
pm_generic_runtime_suspend,
pm_generic_runtime_resume,
pm_generic_runtime_idle
)
};
struct bus_type i2c_bus_type = {
.name = "i2c",
.match = i2c_device_match,
.probe = i2c_device_probe,
.remove = i2c_device_remove,
.shutdown = i2c_device_shutdown,
.pm = &i2c_device_pm_ops,
};
EXPORT_SYMBOL_GPL(i2c_bus_type);
static struct device_type i2c_client_type = {
.groups = i2c_dev_attr_groups,
.uevent = i2c_device_uevent,
.release = i2c_client_dev_release,
};
/**
* i2c_verify_client - return parameter as i2c_client, or NULL
* @dev: device, probably from some driver model iterator
*
* When traversing the driver model tree, perhaps using driver model
* iterators like @device_for_each_child(), you can't assume very much
* about the nodes you find. Use this function to avoid oopses caused
* by wrongly treating some non-I2C device as an i2c_client.
*/
struct i2c_client *i2c_verify_client(struct device *dev)
{
return (dev->type == &i2c_client_type)
? to_i2c_client(dev)
: NULL;
}
EXPORT_SYMBOL(i2c_verify_client);
/* This is a permissive address validity check, I2C address map constraints
* are purposely not enforced, except for the general call address. */
static int i2c_check_client_addr_validity(const struct i2c_client *client)
{
if (client->flags & I2C_CLIENT_TEN) {
/* 10-bit address, all values are valid */
if (client->addr > 0x3ff)
return -EINVAL;
} else {
/* 7-bit address, reject the general call address */
if (client->addr == 0x00 || client->addr > 0x7f)
return -EINVAL;
}
return 0;
}
/* And this is a strict address validity check, used when probing. If a
* device uses a reserved address, then it shouldn't be probed. 7-bit
* addressing is assumed, 10-bit address devices are rare and should be
* explicitly enumerated. */
static int i2c_check_addr_validity(unsigned short addr)
{
/*
* Reserved addresses per I2C specification:
* 0x00 General call address / START byte
* 0x01 CBUS address
* 0x02 Reserved for different bus format
* 0x03 Reserved for future purposes
* 0x04-0x07 Hs-mode master code
* 0x78-0x7b 10-bit slave addressing
* 0x7c-0x7f Reserved for future purposes
*/
if (addr < 0x08 || addr > 0x77)
return -EINVAL;
return 0;
}
static int __i2c_check_addr_busy(struct device *dev, void *addrp)
{
struct i2c_client *client = i2c_verify_client(dev);
int addr = *(int *)addrp;
if (client && client->addr == addr)
return -EBUSY;
return 0;
}
/* walk up mux tree */
static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
int result;
result = device_for_each_child(&adapter->dev, &addr,
__i2c_check_addr_busy);
if (!result && parent)
result = i2c_check_mux_parents(parent, addr);
return result;
}
/* recurse down mux tree */
static int i2c_check_mux_children(struct device *dev, void *addrp)
{
int result;
if (dev->type == &i2c_adapter_type)
result = device_for_each_child(dev, addrp,
i2c_check_mux_children);
else
result = __i2c_check_addr_busy(dev, addrp);
return result;
}
static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
int result = 0;
if (parent)
result = i2c_check_mux_parents(parent, addr);
if (!result)
result = device_for_each_child(&adapter->dev, &addr,
i2c_check_mux_children);
return result;
}
/**
* i2c_lock_adapter - Get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
*/
void i2c_lock_adapter(struct i2c_adapter *adapter)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
if (parent)
i2c_lock_adapter(parent);
else
rt_mutex_lock(&adapter->bus_lock);
}
EXPORT_SYMBOL_GPL(i2c_lock_adapter);
/**
* i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
*/
static int i2c_trylock_adapter(struct i2c_adapter *adapter)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
if (parent)
return i2c_trylock_adapter(parent);
else
return rt_mutex_trylock(&adapter->bus_lock);
}
/**
* i2c_unlock_adapter - Release exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
*/
void i2c_unlock_adapter(struct i2c_adapter *adapter)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
if (parent)
i2c_unlock_adapter(parent);
else
rt_mutex_unlock(&adapter->bus_lock);
}
EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
#endif
/**
* i2c_transfer - execute a single or combined I2C message
* @adap: Handle to I2C bus
* @msgs: One or more messages to execute before STOP is issued to
* terminate the operation; each message begins with a START.
* @num: Number of messages to be executed.
*
* Returns negative errno, else the number of messages executed.
*
* Note that there is no requirement that each message be sent to
* the same slave address, although that is the most common model.
*/
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
unsigned long orig_jiffies;
int ret, try;
/* REVISIT the fault reporting model here is weak:
*
* - When we get an error after receiving N bytes from a slave,
* there is no way to report "N".
*
* - When we get a NAK after transmitting N bytes to a slave,
* there is no way to report "N" ... or to let the master
* continue executing the rest of this combined message, if
* that's the appropriate response.
*
* - When for example "num" is two and we successfully complete
* the first message but get an error part way through the
* second, it's unclear whether that should be reported as
* one (discarding status on the second message) or errno
* (discarding status on the first one).
*/
if (adap->algo->master_xfer) {
/* Retry automatically on arbitration loss */
orig_jiffies = GetTimerTicks();
for (ret = 0, try = 0; try <= adap->retries; try++) {
ret = adap->algo->master_xfer(adap, msgs, num);
if (ret != -EAGAIN)
break;
if (time_after(GetTimerTicks(), orig_jiffies + adap->timeout))
break;
delay(1);
}
// mutex_unlock(&adap->bus_lock);
return ret;
} else {
dbgprintf("I2C level transfers not supported\n");
return -EOPNOTSUPP;
}
}
EXPORT_SYMBOL(i2c_transfer);
/**
* i2c_new_device - instantiate an i2c device
* @adap: the adapter managing the device
* @info: describes one I2C device; bus_num is ignored
* Context: can sleep
*
* Create an i2c device. Binding is handled through driver model
* probe()/remove() methods. A driver may be bound to this device when we
* return from this function, or any later moment (e.g. maybe hotplugging will
* load the driver module). This call is not appropriate for use by mainboard
* initialization logic, which usually runs during an arch_initcall() long
* before any i2c_adapter could exist.
*
* This returns the new i2c client, which may be saved for later use with
* i2c_unregister_device(); or NULL to indicate an error.
*/
struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
struct i2c_client *client;
int status;
client = kzalloc(sizeof *client, GFP_KERNEL);
if (!client)
return NULL;
client->adapter = adap;
client->flags = info->flags;
client->addr = info->addr;
client->irq = info->irq;
strlcpy(client->name, info->type, sizeof(client->name));
return client;
}