Commit c0b34bed authored by Eddie James's avatar Eddie James Committed by Joel Stanley
Browse files

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: default avatarEddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-15-eajames@linux.ibm.com


Signed-off-by: default avatarJoel Stanley <joel@jms.id.au>
parent 53e89e3e

drivers/fsi/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -94,4 +94,12 @@ config FSI_OCC 
	provide the raw sensor data as well as perform thermal and power

	management on the system.



config I2CR_SCOM

	tristate "IBM I2C Responder SCOM driver"

	depends on FSI_MASTER_I2CR

	help

	  This option enables an I2C Responder based SCOM device driver. The

	  I2CR has the capability to directly perform SCOM operations instead

	  of using the FSI2PIB engine.



endif

drivers/fsi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,3 +9,4 @@ obj-$(CONFIG_FSI_MASTER_AST_CF) += fsi-master-ast-cf.o 
obj-$(CONFIG_FSI_SCOM) += fsi-scom.o

obj-$(CONFIG_FSI_SBEFIFO) += fsi-sbefifo.o

obj-$(CONFIG_FSI_OCC) += fsi-occ.o

obj-$(CONFIG_I2CR_SCOM) += i2cr-scom.o

drivers/fsi/i2cr-scom.c

0 → 100644
+154 −0
Original line number Diff line number Diff line 
// 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");