1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) IBM Corporation 2023 */
3
4 #include <linux/cdev.h>
5 #include <linux/device.h>
6 #include <linux/fs.h>
7 #include <linux/fsi.h>
8 #include <linux/module.h>
9
10 #include "fsi-master-i2cr.h"
11 #include "fsi-slave.h"
12
13 struct i2cr_scom {
14 struct device dev;
15 struct cdev cdev;
16 struct fsi_master_i2cr *i2cr;
17 };
18
i2cr_scom_llseek(struct file * file,loff_t offset,int whence)19 static loff_t i2cr_scom_llseek(struct file *file, loff_t offset, int whence)
20 {
21 switch (whence) {
22 case SEEK_CUR:
23 break;
24 case SEEK_SET:
25 file->f_pos = offset;
26 break;
27 default:
28 return -EINVAL;
29 }
30
31 return offset;
32 }
33
i2cr_scom_read(struct file * filep,char __user * buf,size_t len,loff_t * offset)34 static ssize_t i2cr_scom_read(struct file *filep, char __user *buf, size_t len, loff_t *offset)
35 {
36 struct i2cr_scom *scom = filep->private_data;
37 u64 data;
38 int ret;
39
40 if (len != sizeof(data))
41 return -EINVAL;
42
43 ret = fsi_master_i2cr_read(scom->i2cr, (u32)*offset, &data);
44 if (ret)
45 return ret;
46
47 ret = copy_to_user(buf, &data, len);
48 if (ret)
49 return ret;
50
51 return len;
52 }
53
i2cr_scom_write(struct file * filep,const char __user * buf,size_t len,loff_t * offset)54 static ssize_t i2cr_scom_write(struct file *filep, const char __user *buf, size_t len,
55 loff_t *offset)
56 {
57 struct i2cr_scom *scom = filep->private_data;
58 u64 data;
59 int ret;
60
61 if (len != sizeof(data))
62 return -EINVAL;
63
64 ret = copy_from_user(&data, buf, len);
65 if (ret)
66 return ret;
67
68 ret = fsi_master_i2cr_write(scom->i2cr, (u32)*offset, data);
69 if (ret)
70 return ret;
71
72 return len;
73 }
74
75 static const struct file_operations i2cr_scom_fops = {
76 .owner = THIS_MODULE,
77 .open = simple_open,
78 .llseek = i2cr_scom_llseek,
79 .read = i2cr_scom_read,
80 .write = i2cr_scom_write,
81 };
82
i2cr_scom_probe(struct fsi_device * fsi_dev)83 static int i2cr_scom_probe(struct fsi_device *fsi_dev)
84 {
85 struct device *dev = &fsi_dev->dev;
86 struct i2cr_scom *scom;
87 int didx;
88 int ret;
89
90 if (!is_fsi_master_i2cr(fsi_dev->slave->master))
91 return -ENODEV;
92
93 scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
94 if (!scom)
95 return -ENOMEM;
96
97 scom->i2cr = to_fsi_master_i2cr(fsi_dev->slave->master);
98 dev_set_drvdata(dev, scom);
99
100 scom->dev.type = &fsi_cdev_type;
101 scom->dev.parent = dev;
102 device_initialize(&scom->dev);
103
104 ret = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
105 if (ret)
106 return ret;
107
108 dev_set_name(&scom->dev, "scom%d", didx);
109 cdev_init(&scom->cdev, &i2cr_scom_fops);
110 ret = cdev_device_add(&scom->cdev, &scom->dev);
111 if (ret)
112 fsi_free_minor(scom->dev.devt);
113
114 return ret;
115 }
116
i2cr_scom_remove(struct fsi_device * fsi_dev)117 static void i2cr_scom_remove(struct fsi_device *fsi_dev)
118 {
119 struct i2cr_scom *scom = dev_get_drvdata(&fsi_dev->dev);
120
121 cdev_device_del(&scom->cdev, &scom->dev);
122 fsi_free_minor(scom->dev.devt);
123 }
124
125 static const struct of_device_id i2cr_scom_of_ids[] = {
126 { .compatible = "ibm,i2cr-scom" },
127 { }
128 };
129 MODULE_DEVICE_TABLE(of, i2cr_scom_of_ids);
130
131 static const struct fsi_device_id i2cr_scom_ids[] = {
132 { 0x5, FSI_VERSION_ANY },
133 { }
134 };
135
136 static struct fsi_driver i2cr_scom_driver = {
137 .probe = i2cr_scom_probe,
138 .remove = i2cr_scom_remove,
139 .id_table = i2cr_scom_ids,
140 .drv = {
141 .name = "i2cr_scom",
142 .of_match_table = i2cr_scom_of_ids,
143 }
144 };
145
146 module_fsi_driver(i2cr_scom_driver);
147
148 MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
149 MODULE_DESCRIPTION("IBM I2C Responder SCOM driver");
150 MODULE_LICENSE("GPL");
151