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