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 #include <linux/mod_devicetable.h>
10
11 #include "fsi-master-i2cr.h"
12 #include "fsi-slave.h"
13
14 struct i2cr_scom {
15 struct device dev;
16 struct cdev cdev;
17 struct fsi_master_i2cr *i2cr;
18 };
19
i2cr_scom_llseek(struct file * file,loff_t offset,int whence)20 static loff_t i2cr_scom_llseek(struct file *file, loff_t offset, int whence)
21 {
22 switch (whence) {
23 case SEEK_CUR:
24 break;
25 case SEEK_SET:
26 file->f_pos = offset;
27 break;
28 default:
29 return -EINVAL;
30 }
31
32 return offset;
33 }
34
i2cr_scom_read(struct file * filep,char __user * buf,size_t len,loff_t * offset)35 static ssize_t i2cr_scom_read(struct file *filep, char __user *buf, size_t len, loff_t *offset)
36 {
37 struct i2cr_scom *scom = filep->private_data;
38 u64 data;
39 int ret;
40
41 if (len != sizeof(data))
42 return -EINVAL;
43
44 ret = fsi_master_i2cr_read(scom->i2cr, (u32)*offset, &data);
45 if (ret)
46 return ret;
47
48 ret = copy_to_user(buf, &data, len);
49 if (ret)
50 return ret;
51
52 return len;
53 }
54
i2cr_scom_write(struct file * filep,const char __user * buf,size_t len,loff_t * offset)55 static ssize_t i2cr_scom_write(struct file *filep, const char __user *buf, size_t len,
56 loff_t *offset)
57 {
58 struct i2cr_scom *scom = filep->private_data;
59 u64 data;
60 int ret;
61
62 if (len != sizeof(data))
63 return -EINVAL;
64
65 ret = copy_from_user(&data, buf, len);
66 if (ret)
67 return ret;
68
69 ret = fsi_master_i2cr_write(scom->i2cr, (u32)*offset, data);
70 if (ret)
71 return ret;
72
73 return len;
74 }
75
76 static const struct file_operations i2cr_scom_fops = {
77 .owner = THIS_MODULE,
78 .open = simple_open,
79 .llseek = i2cr_scom_llseek,
80 .read = i2cr_scom_read,
81 .write = i2cr_scom_write,
82 };
83
i2cr_scom_probe(struct device * dev)84 static int i2cr_scom_probe(struct device *dev)
85 {
86 struct fsi_device *fsi_dev = to_fsi_dev(dev);
87 struct i2cr_scom *scom;
88 int didx;
89 int ret;
90
91 if (!is_fsi_master_i2cr(fsi_dev->slave->master))
92 return -ENODEV;
93
94 scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
95 if (!scom)
96 return -ENOMEM;
97
98 scom->i2cr = to_fsi_master_i2cr(fsi_dev->slave->master);
99 dev_set_drvdata(dev, scom);
100
101 scom->dev.type = &fsi_cdev_type;
102 scom->dev.parent = dev;
103 device_initialize(&scom->dev);
104
105 ret = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
106 if (ret)
107 return ret;
108
109 dev_set_name(&scom->dev, "scom%d", didx);
110 cdev_init(&scom->cdev, &i2cr_scom_fops);
111 ret = cdev_device_add(&scom->cdev, &scom->dev);
112 if (ret)
113 fsi_free_minor(scom->dev.devt);
114
115 return ret;
116 }
117
i2cr_scom_remove(struct device * dev)118 static int i2cr_scom_remove(struct device *dev)
119 {
120 struct i2cr_scom *scom = dev_get_drvdata(dev);
121
122 cdev_device_del(&scom->cdev, &scom->dev);
123 fsi_free_minor(scom->dev.devt);
124
125 return 0;
126 }
127
128 static const struct of_device_id i2cr_scom_of_ids[] = {
129 { .compatible = "ibm,i2cr-scom" },
130 { }
131 };
132 MODULE_DEVICE_TABLE(of, i2cr_scom_of_ids);
133
134 static const struct fsi_device_id i2cr_scom_ids[] = {
135 { 0x5, FSI_VERSION_ANY },
136 { }
137 };
138
139 static struct fsi_driver i2cr_scom_driver = {
140 .id_table = i2cr_scom_ids,
141 .drv = {
142 .name = "i2cr_scom",
143 .bus = &fsi_bus_type,
144 .of_match_table = i2cr_scom_of_ids,
145 .probe = i2cr_scom_probe,
146 .remove = i2cr_scom_remove,
147 }
148 };
149
150 module_fsi_driver(i2cr_scom_driver);
151
152 MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
153 MODULE_DESCRIPTION("IBM I2C Responder SCOM driver");
154 MODULE_LICENSE("GPL");
155