linux/drivers/fsi/i2cr-scom.c
Eddie James c0b34bed0b fsi: Add I2C Responder SCOM driver
The I2CR has the capability to directly perform SCOM operations,
circumventing the need to drive the FSI2PIB engine. Add a new
driver to perform SCOM operations through the I2CR.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-15-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>
2023-08-11 13:32:14 +09:30

155 lines
3.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) IBM Corporation 2023 */
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/fsi.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include "fsi-master-i2cr.h"
#include "fsi-slave.h"
struct i2cr_scom {
struct device dev;
struct cdev cdev;
struct fsi_master_i2cr *i2cr;
};
static loff_t i2cr_scom_llseek(struct file *file, loff_t offset, int whence)
{
switch (whence) {
case SEEK_CUR:
break;
case SEEK_SET:
file->f_pos = offset;
break;
default:
return -EINVAL;
}
return offset;
}
static ssize_t i2cr_scom_read(struct file *filep, char __user *buf, size_t len, loff_t *offset)
{
struct i2cr_scom *scom = filep->private_data;
u64 data;
int ret;
if (len != sizeof(data))
return -EINVAL;
ret = fsi_master_i2cr_read(scom->i2cr, (u32)*offset, &data);
if (ret)
return ret;
ret = copy_to_user(buf, &data, len);
if (ret)
return ret;
return len;
}
static ssize_t i2cr_scom_write(struct file *filep, const char __user *buf, size_t len,
loff_t *offset)
{
struct i2cr_scom *scom = filep->private_data;
u64 data;
int ret;
if (len != sizeof(data))
return -EINVAL;
ret = copy_from_user(&data, buf, len);
if (ret)
return ret;
ret = fsi_master_i2cr_write(scom->i2cr, (u32)*offset, data);
if (ret)
return ret;
return len;
}
static const struct file_operations i2cr_scom_fops = {
.owner = THIS_MODULE,
.open = simple_open,
.llseek = i2cr_scom_llseek,
.read = i2cr_scom_read,
.write = i2cr_scom_write,
};
static int i2cr_scom_probe(struct device *dev)
{
struct fsi_device *fsi_dev = to_fsi_dev(dev);
struct i2cr_scom *scom;
int didx;
int ret;
if (!is_fsi_master_i2cr(fsi_dev->slave->master))
return -ENODEV;
scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
if (!scom)
return -ENOMEM;
scom->i2cr = to_fsi_master_i2cr(fsi_dev->slave->master);
dev_set_drvdata(dev, scom);
scom->dev.type = &fsi_cdev_type;
scom->dev.parent = dev;
device_initialize(&scom->dev);
ret = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
if (ret)
return ret;
dev_set_name(&scom->dev, "scom%d", didx);
cdev_init(&scom->cdev, &i2cr_scom_fops);
ret = cdev_device_add(&scom->cdev, &scom->dev);
if (ret)
fsi_free_minor(scom->dev.devt);
return ret;
}
static int i2cr_scom_remove(struct device *dev)
{
struct i2cr_scom *scom = dev_get_drvdata(dev);
cdev_device_del(&scom->cdev, &scom->dev);
fsi_free_minor(scom->dev.devt);
return 0;
}
static const struct of_device_id i2cr_scom_of_ids[] = {
{ .compatible = "ibm,i2cr-scom" },
{ }
};
MODULE_DEVICE_TABLE(of, i2cr_scom_of_ids);
static const struct fsi_device_id i2cr_scom_ids[] = {
{ 0x5, FSI_VERSION_ANY },
{ }
};
static struct fsi_driver i2cr_scom_driver = {
.id_table = i2cr_scom_ids,
.drv = {
.name = "i2cr_scom",
.bus = &fsi_bus_type,
.of_match_table = i2cr_scom_of_ids,
.probe = i2cr_scom_probe,
.remove = i2cr_scom_remove,
}
};
module_fsi_driver(i2cr_scom_driver);
MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("IBM I2C Responder SCOM driver");
MODULE_LICENSE("GPL");