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