1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Mellanox register access driver
4 *
5 * Copyright (C) 2018 Mellanox Technologies
6 * Copyright (C) 2018 Vadim Pasternak <vadimp@mellanox.com>
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/device.h>
11 #include <linux/hwmon.h>
12 #include <linux/hwmon-sysfs.h>
13 #include <linux/module.h>
14 #include <linux/platform_data/mlxreg.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17
18 /* Attribute parameters. */
19 #define MLXREG_IO_ATT_SIZE 10
20 #define MLXREG_IO_ATT_NUM 96
21
22 /**
23 * struct mlxreg_io_priv_data - driver's private data:
24 *
25 * @pdev: platform device;
26 * @pdata: platform data;
27 * @hwmon: hwmon device;
28 * @mlxreg_io_attr: sysfs attributes array;
29 * @mlxreg_io_dev_attr: sysfs sensor device attribute array;
30 * @group: sysfs attribute group;
31 * @groups: list of sysfs attribute group for hwmon registration;
32 * @regsize: size of a register value;
33 * @io_lock: user access locking;
34 */
35 struct mlxreg_io_priv_data {
36 struct platform_device *pdev;
37 struct mlxreg_core_platform_data *pdata;
38 struct device *hwmon;
39 struct attribute *mlxreg_io_attr[MLXREG_IO_ATT_NUM + 1];
40 struct sensor_device_attribute mlxreg_io_dev_attr[MLXREG_IO_ATT_NUM];
41 struct attribute_group group;
42 const struct attribute_group *groups[2];
43 int regsize;
44 struct mutex io_lock; /* Protects user access. */
45 };
46
47 static int
mlxreg_io_get_reg(void * regmap,struct mlxreg_core_data * data,u32 in_val,bool rw_flag,int regsize,u32 * regval)48 mlxreg_io_get_reg(void *regmap, struct mlxreg_core_data *data, u32 in_val,
49 bool rw_flag, int regsize, u32 *regval)
50 {
51 int i, val, ret;
52
53 ret = regmap_read(regmap, data->reg, regval);
54 if (ret)
55 goto access_error;
56
57 /*
58 * There are four kinds of attributes: single bit, full register's
59 * bits, bit sequence, bits in few registers For the first kind field
60 * mask indicates which bits are not related and field bit is set zero.
61 * For the second kind field mask is set to zero and field bit is set
62 * with all bits one. No special handling for such kind of attributes -
63 * pass value as is. For the third kind, the field mask indicates which
64 * bits are related and the field bit is set to the first bit number
65 * (from 1 to 32) is the bit sequence. For the fourth kind - the number
66 * of registers which should be read for getting an attribute are
67 * specified through 'data->regnum' field.
68 */
69 if (!data->bit) {
70 /* Single bit. */
71 if (rw_flag) {
72 /* For show: expose effective bit value as 0 or 1. */
73 *regval = !!(*regval & ~data->mask);
74 } else {
75 /* For store: set effective bit value. */
76 *regval &= data->mask;
77 if (in_val)
78 *regval |= ~data->mask;
79 }
80 } else if (data->mask) {
81 /* Bit sequence. */
82 if (rw_flag) {
83 /* For show: mask and shift right. */
84 *regval = ror32(*regval & data->mask, (data->bit - 1));
85 } else {
86 /* For store: shift to the position and mask. */
87 in_val = rol32(in_val, data->bit - 1) & data->mask;
88 /* Clear relevant bits and set them to new value. */
89 *regval = (*regval & ~data->mask) | in_val;
90 }
91 } else {
92 /*
93 * Some attributes could occupied few registers in case regmap
94 * bit size is 8 or 16. Compose such attributes from 'regnum'
95 * registers. Such attributes contain read-only data.
96 */
97 for (i = 1; i < data->regnum; i++) {
98 ret = regmap_read(regmap, data->reg + i, &val);
99 if (ret)
100 goto access_error;
101
102 *regval |= rol32(val, regsize * i * 8);
103 }
104 }
105
106 access_error:
107 return ret;
108 }
109
110 static ssize_t
mlxreg_io_attr_show(struct device * dev,struct device_attribute * attr,char * buf)111 mlxreg_io_attr_show(struct device *dev, struct device_attribute *attr,
112 char *buf)
113 {
114 struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
115 int index = to_sensor_dev_attr(attr)->index;
116 struct mlxreg_core_data *data = priv->pdata->data + index;
117 u32 regval = 0;
118 int ret;
119
120 mutex_lock(&priv->io_lock);
121
122 ret = mlxreg_io_get_reg(priv->pdata->regmap, data, 0, true,
123 priv->regsize, ®val);
124 if (ret)
125 goto access_error;
126
127 mutex_unlock(&priv->io_lock);
128
129 return sprintf(buf, "%u\n", regval);
130
131 access_error:
132 mutex_unlock(&priv->io_lock);
133 return ret;
134 }
135
136 static ssize_t
mlxreg_io_attr_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)137 mlxreg_io_attr_store(struct device *dev, struct device_attribute *attr,
138 const char *buf, size_t len)
139 {
140 struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
141 int index = to_sensor_dev_attr(attr)->index;
142 struct mlxreg_core_data *data = priv->pdata->data + index;
143 u32 input_val, regval;
144 int ret;
145
146 if (len > MLXREG_IO_ATT_SIZE)
147 return -EINVAL;
148
149 /* Convert buffer to input value. */
150 ret = kstrtou32(buf, 0, &input_val);
151 if (ret)
152 return ret;
153
154 mutex_lock(&priv->io_lock);
155
156 ret = mlxreg_io_get_reg(priv->pdata->regmap, data, input_val, false,
157 priv->regsize, ®val);
158 if (ret)
159 goto access_error;
160
161 ret = regmap_write(priv->pdata->regmap, data->reg, regval);
162 if (ret)
163 goto access_error;
164
165 mutex_unlock(&priv->io_lock);
166
167 return len;
168
169 access_error:
170 mutex_unlock(&priv->io_lock);
171 dev_err(&priv->pdev->dev, "Bus access error\n");
172 return ret;
173 }
174
175 static struct device_attribute mlxreg_io_devattr_rw = {
176 .show = mlxreg_io_attr_show,
177 .store = mlxreg_io_attr_store,
178 };
179
mlxreg_io_attr_init(struct mlxreg_io_priv_data * priv)180 static int mlxreg_io_attr_init(struct mlxreg_io_priv_data *priv)
181 {
182 int i;
183
184 priv->group.attrs = devm_kcalloc(&priv->pdev->dev,
185 priv->pdata->counter,
186 sizeof(struct attribute *),
187 GFP_KERNEL);
188 if (!priv->group.attrs)
189 return -ENOMEM;
190
191 for (i = 0; i < priv->pdata->counter; i++) {
192 priv->mlxreg_io_attr[i] =
193 &priv->mlxreg_io_dev_attr[i].dev_attr.attr;
194 memcpy(&priv->mlxreg_io_dev_attr[i].dev_attr,
195 &mlxreg_io_devattr_rw, sizeof(struct device_attribute));
196
197 /* Set attribute name as a label. */
198 priv->mlxreg_io_attr[i]->name =
199 devm_kasprintf(&priv->pdev->dev, GFP_KERNEL,
200 priv->pdata->data[i].label);
201
202 if (!priv->mlxreg_io_attr[i]->name) {
203 dev_err(&priv->pdev->dev, "Memory allocation failed for sysfs attribute %d.\n",
204 i + 1);
205 return -ENOMEM;
206 }
207
208 priv->mlxreg_io_dev_attr[i].dev_attr.attr.mode =
209 priv->pdata->data[i].mode;
210 priv->mlxreg_io_dev_attr[i].dev_attr.attr.name =
211 priv->mlxreg_io_attr[i]->name;
212 priv->mlxreg_io_dev_attr[i].index = i;
213 sysfs_attr_init(&priv->mlxreg_io_dev_attr[i].dev_attr.attr);
214 }
215
216 priv->group.attrs = priv->mlxreg_io_attr;
217 priv->groups[0] = &priv->group;
218 priv->groups[1] = NULL;
219
220 return 0;
221 }
222
mlxreg_io_probe(struct platform_device * pdev)223 static int mlxreg_io_probe(struct platform_device *pdev)
224 {
225 struct mlxreg_io_priv_data *priv;
226 int err;
227
228 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
229 if (!priv)
230 return -ENOMEM;
231
232 priv->pdata = dev_get_platdata(&pdev->dev);
233 if (!priv->pdata) {
234 dev_err(&pdev->dev, "Failed to get platform data.\n");
235 return -EINVAL;
236 }
237
238 priv->pdev = pdev;
239 priv->regsize = regmap_get_val_bytes(priv->pdata->regmap);
240 if (priv->regsize < 0)
241 return priv->regsize;
242
243 err = mlxreg_io_attr_init(priv);
244 if (err) {
245 dev_err(&priv->pdev->dev, "Failed to allocate attributes: %d\n",
246 err);
247 return err;
248 }
249
250 priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev,
251 "mlxreg_io",
252 priv,
253 priv->groups);
254 if (IS_ERR(priv->hwmon)) {
255 dev_err(&pdev->dev, "Failed to register hwmon device %ld\n",
256 PTR_ERR(priv->hwmon));
257 return PTR_ERR(priv->hwmon);
258 }
259
260 mutex_init(&priv->io_lock);
261 dev_set_drvdata(&pdev->dev, priv);
262
263 return 0;
264 }
265
mlxreg_io_remove(struct platform_device * pdev)266 static int mlxreg_io_remove(struct platform_device *pdev)
267 {
268 struct mlxreg_io_priv_data *priv = dev_get_drvdata(&pdev->dev);
269
270 mutex_destroy(&priv->io_lock);
271
272 return 0;
273 }
274
275 static struct platform_driver mlxreg_io_driver = {
276 .driver = {
277 .name = "mlxreg-io",
278 },
279 .probe = mlxreg_io_probe,
280 .remove = mlxreg_io_remove,
281 };
282
283 module_platform_driver(mlxreg_io_driver);
284
285 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
286 MODULE_DESCRIPTION("Mellanox regmap I/O access driver");
287 MODULE_LICENSE("GPL");
288 MODULE_ALIAS("platform:mlxreg-io");
289