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 */
 34struct mlxreg_io_priv_data {
 35	struct platform_device *pdev;
 36	struct mlxreg_core_platform_data *pdata;
 37	struct device *hwmon;
 38	struct attribute *mlxreg_io_attr[MLXREG_IO_ATT_NUM + 1];
 39	struct sensor_device_attribute mlxreg_io_dev_attr[MLXREG_IO_ATT_NUM];
 40	struct attribute_group group;
 41	const struct attribute_group *groups[2];
 42};
 43
 44static int
 45mlxreg_io_get_reg(void *regmap, struct mlxreg_core_data *data, u32 in_val,
 46		  bool rw_flag, u32 *regval)
 47{
 48	int ret;
 49
 50	ret = regmap_read(regmap, data->reg, regval);
 51	if (ret)
 52		goto access_error;
 53
 54	/*
 55	 * There are three kinds of attributes: single bit, full register's
 56	 * bits and bit sequence. For the first kind field mask indicates which
 57	 * bits are not related and field bit is set zero. For the second kind
 58	 * field mask is set to zero and field bit is set with all bits one.
 59	 * No special handling for such kind of attributes - pass value as is.
 60	 * For the third kind, field mask indicates which bits are related and
 61	 * field bit is set to the first bit number (from 1 to 32) is the bit
 62	 * sequence.
 63	 */
 64	if (!data->bit) {
 65		/* Single bit. */
 66		if (rw_flag) {
 67			/* For show: expose effective bit value as 0 or 1. */
 68			*regval = !!(*regval & ~data->mask);
 69		} else {
 70			/* For store: set effective bit value. */
 71			*regval &= data->mask;
 72			if (in_val)
 73				*regval |= ~data->mask;
 74		}
 75	} else if (data->mask) {
 76		/* Bit sequence. */
 77		if (rw_flag) {
 78			/* For show: mask and shift right. */
 79			*regval = ror32(*regval & data->mask, (data->bit - 1));
 80		} else {
 81			/* For store: shift to the position and mask. */
 82			in_val = rol32(in_val, data->bit - 1) & data->mask;
 83			/* Clear relevant bits and set them to new value. */
 84			*regval = (*regval & ~data->mask) | in_val;
 85		}
 86	}
 87
 88access_error:
 89	return ret;
 90}
 91
 92static ssize_t
 93mlxreg_io_attr_show(struct device *dev, struct device_attribute *attr,
 94		    char *buf)
 95{
 96	struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
 97	int index = to_sensor_dev_attr(attr)->index;
 98	struct mlxreg_core_data *data = priv->pdata->data + index;
 99	u32 regval = 0;
100	int ret;
101
102	ret = mlxreg_io_get_reg(priv->pdata->regmap, data, 0, true, &regval);
103	if (ret)
104		goto access_error;
105
106	return sprintf(buf, "%u\n", regval);
107
108access_error:
109	return ret;
110}
111
112static ssize_t
113mlxreg_io_attr_store(struct device *dev, struct device_attribute *attr,
114		     const char *buf, size_t len)
115{
116	struct mlxreg_io_priv_data *priv = dev_get_drvdata(dev);
117	int index = to_sensor_dev_attr(attr)->index;
118	struct mlxreg_core_data *data = priv->pdata->data + index;
119	u32 input_val, regval;
120	int ret;
121
122	if (len > MLXREG_IO_ATT_SIZE)
123		return -EINVAL;
124
125	/* Convert buffer to input value. */
126	ret = kstrtou32(buf, len, &input_val);
127	if (ret)
128		return ret;
129
130	ret = mlxreg_io_get_reg(priv->pdata->regmap, data, input_val, false,
131				&regval);
132	if (ret)
133		goto access_error;
134
135	ret = regmap_write(priv->pdata->regmap, data->reg, regval);
136	if (ret)
137		goto access_error;
138
139	return len;
140
141access_error:
142	dev_err(&priv->pdev->dev, "Bus access error\n");
143	return ret;
144}
145
146static struct device_attribute mlxreg_io_devattr_rw = {
147	.show	= mlxreg_io_attr_show,
148	.store	= mlxreg_io_attr_store,
149};
150
151static int mlxreg_io_attr_init(struct mlxreg_io_priv_data *priv)
152{
153	int i;
154
155	priv->group.attrs = devm_kcalloc(&priv->pdev->dev,
156					 priv->pdata->counter,
157					 sizeof(struct attribute *),
158					 GFP_KERNEL);
159	if (!priv->group.attrs)
160		return -ENOMEM;
161
162	for (i = 0; i < priv->pdata->counter; i++) {
163		priv->mlxreg_io_attr[i] =
164				&priv->mlxreg_io_dev_attr[i].dev_attr.attr;
165		memcpy(&priv->mlxreg_io_dev_attr[i].dev_attr,
166		       &mlxreg_io_devattr_rw, sizeof(struct device_attribute));
167
168		/* Set attribute name as a label. */
169		priv->mlxreg_io_attr[i]->name =
170				devm_kasprintf(&priv->pdev->dev, GFP_KERNEL,
171					       priv->pdata->data[i].label);
172
173		if (!priv->mlxreg_io_attr[i]->name) {
174			dev_err(&priv->pdev->dev, "Memory allocation failed for sysfs attribute %d.\n",
175				i + 1);
176			return -ENOMEM;
177		}
178
179		priv->mlxreg_io_dev_attr[i].dev_attr.attr.mode =
180						priv->pdata->data[i].mode;
181		priv->mlxreg_io_dev_attr[i].dev_attr.attr.name =
182					priv->mlxreg_io_attr[i]->name;
183		priv->mlxreg_io_dev_attr[i].index = i;
184		sysfs_attr_init(&priv->mlxreg_io_dev_attr[i].dev_attr.attr);
185	}
186
187	priv->group.attrs = priv->mlxreg_io_attr;
188	priv->groups[0] = &priv->group;
189	priv->groups[1] = NULL;
190
191	return 0;
192}
193
194static int mlxreg_io_probe(struct platform_device *pdev)
195{
196	struct mlxreg_io_priv_data *priv;
197	int err;
198
199	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
200	if (!priv)
201		return -ENOMEM;
202
203	priv->pdata = dev_get_platdata(&pdev->dev);
204	if (!priv->pdata) {
205		dev_err(&pdev->dev, "Failed to get platform data.\n");
206		return -EINVAL;
207	}
208
209	priv->pdev = pdev;
210
211	err = mlxreg_io_attr_init(priv);
212	if (err) {
213		dev_err(&priv->pdev->dev, "Failed to allocate attributes: %d\n",
214			err);
215		return err;
216	}
217
218	priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev,
219							     "mlxreg_io",
220							      priv,
221							      priv->groups);
222	if (IS_ERR(priv->hwmon)) {
223		dev_err(&pdev->dev, "Failed to register hwmon device %ld\n",
224			PTR_ERR(priv->hwmon));
225		return PTR_ERR(priv->hwmon);
226	}
227
228	dev_set_drvdata(&pdev->dev, priv);
229
230	return 0;
231}
232
233static struct platform_driver mlxreg_io_driver = {
234	.driver = {
235	    .name = "mlxreg-io",
236	},
237	.probe = mlxreg_io_probe,
238};
239
240module_platform_driver(mlxreg_io_driver);
241
242MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
243MODULE_DESCRIPTION("Mellanox regmap I/O access driver");
244MODULE_LICENSE("GPL");
245MODULE_ALIAS("platform:mlxreg-io");