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, &regval);
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, &regval);
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");
267