1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for the Diolan DLN-2 USB-I2C adapter
  4 *
  5 * Copyright (c) 2014 Intel Corporation
  6 *
  7 * Derived from:
  8 *  i2c-diolan-u2c.c
  9 *  Copyright (c) 2010-2011 Ericsson AB
 10 */
 11
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/types.h>
 15#include <linux/slab.h>
 16#include <linux/i2c.h>
 17#include <linux/platform_device.h>
 18#include <linux/mfd/dln2.h>
 19#include <linux/acpi.h>
 20
 21#define DLN2_I2C_MODULE_ID		0x03
 22#define DLN2_I2C_CMD(cmd)		DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
 23
 24/* I2C commands */
 25#define DLN2_I2C_GET_PORT_COUNT		DLN2_I2C_CMD(0x00)
 26#define DLN2_I2C_ENABLE			DLN2_I2C_CMD(0x01)
 27#define DLN2_I2C_DISABLE		DLN2_I2C_CMD(0x02)
 28#define DLN2_I2C_IS_ENABLED		DLN2_I2C_CMD(0x03)
 29#define DLN2_I2C_WRITE			DLN2_I2C_CMD(0x06)
 30#define DLN2_I2C_READ			DLN2_I2C_CMD(0x07)
 31#define DLN2_I2C_SCAN_DEVICES		DLN2_I2C_CMD(0x08)
 32#define DLN2_I2C_PULLUP_ENABLE		DLN2_I2C_CMD(0x09)
 33#define DLN2_I2C_PULLUP_DISABLE		DLN2_I2C_CMD(0x0A)
 34#define DLN2_I2C_PULLUP_IS_ENABLED	DLN2_I2C_CMD(0x0B)
 35#define DLN2_I2C_TRANSFER		DLN2_I2C_CMD(0x0C)
 36#define DLN2_I2C_SET_MAX_REPLY_COUNT	DLN2_I2C_CMD(0x0D)
 37#define DLN2_I2C_GET_MAX_REPLY_COUNT	DLN2_I2C_CMD(0x0E)
 38
 39#define DLN2_I2C_MAX_XFER_SIZE		256
 40#define DLN2_I2C_BUF_SIZE		(DLN2_I2C_MAX_XFER_SIZE + 16)
 41
 42struct dln2_i2c {
 43	struct platform_device *pdev;
 44	struct i2c_adapter adapter;
 45	u8 port;
 46	/*
 47	 * Buffer to hold the packet for read or write transfers. One is enough
 48	 * since we can't have multiple transfers in parallel on the i2c bus.
 49	 */
 50	void *buf;
 51};
 52
 53static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
 54{
 55	u16 cmd;
 56	struct {
 57		u8 port;
 58	} tx;
 59
 60	tx.port = dln2->port;
 61
 62	if (enable)
 63		cmd = DLN2_I2C_ENABLE;
 64	else
 65		cmd = DLN2_I2C_DISABLE;
 66
 67	return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
 68}
 69
 70static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
 71			  u8 *data, u16 data_len)
 72{
 73	int ret;
 74	struct {
 75		u8 port;
 76		u8 addr;
 77		u8 mem_addr_len;
 78		__le32 mem_addr;
 79		__le16 buf_len;
 80		u8 buf[DLN2_I2C_MAX_XFER_SIZE];
 81	} __packed *tx = dln2->buf;
 82	unsigned len;
 83
 84	BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
 85
 86	tx->port = dln2->port;
 87	tx->addr = addr;
 88	tx->mem_addr_len = 0;
 89	tx->mem_addr = 0;
 90	tx->buf_len = cpu_to_le16(data_len);
 91	memcpy(tx->buf, data, data_len);
 92
 93	len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
 94	ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
 95	if (ret < 0)
 96		return ret;
 97
 98	return data_len;
 99}
100
101static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
102			 u16 data_len)
103{
104	int ret;
105	struct {
106		u8 port;
107		u8 addr;
108		u8 mem_addr_len;
109		__le32 mem_addr;
110		__le16 buf_len;
111	} __packed tx;
112	struct {
113		__le16 buf_len;
114		u8 buf[DLN2_I2C_MAX_XFER_SIZE];
115	} __packed *rx = dln2->buf;
116	unsigned rx_len = sizeof(*rx);
117
118	BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
119
120	tx.port = dln2->port;
121	tx.addr = addr;
122	tx.mem_addr_len = 0;
123	tx.mem_addr = 0;
124	tx.buf_len = cpu_to_le16(data_len);
125
126	ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
127			    rx, &rx_len);
128	if (ret < 0)
129		return ret;
130	if (rx_len < sizeof(rx->buf_len) + data_len)
131		return -EPROTO;
132	if (le16_to_cpu(rx->buf_len) != data_len)
133		return -EPROTO;
134
135	memcpy(data, rx->buf, data_len);
136
137	return data_len;
138}
139
140static int dln2_i2c_xfer(struct i2c_adapter *adapter,
141			 struct i2c_msg *msgs, int num)
142{
143	struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
144	struct i2c_msg *pmsg;
145	int i;
146
147	for (i = 0; i < num; i++) {
148		int ret;
149
150		pmsg = &msgs[i];
151
152		if (pmsg->flags & I2C_M_RD) {
153			ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
154					    pmsg->len);
155			if (ret < 0)
156				return ret;
157
158			pmsg->len = ret;
159		} else {
160			ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
161					     pmsg->len);
162			if (ret != pmsg->len)
163				return -EPROTO;
164		}
165	}
166
167	return num;
168}
169
170static u32 dln2_i2c_func(struct i2c_adapter *a)
171{
172	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
173		I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
174		I2C_FUNC_SMBUS_I2C_BLOCK;
175}
176
177static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
178	.xfer = dln2_i2c_xfer,
179	.functionality = dln2_i2c_func,
180};
181
182static const struct i2c_adapter_quirks dln2_i2c_quirks = {
183	.max_read_len = DLN2_I2C_MAX_XFER_SIZE,
184	.max_write_len = DLN2_I2C_MAX_XFER_SIZE,
185};
186
187static int dln2_i2c_probe(struct platform_device *pdev)
188{
189	int ret;
190	struct dln2_i2c *dln2;
191	struct device *dev = &pdev->dev;
192	struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
193
194	dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
195	if (!dln2)
196		return -ENOMEM;
197
198	dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
199	if (!dln2->buf)
200		return -ENOMEM;
201
202	dln2->pdev = pdev;
203	dln2->port = pdata->port;
204
205	/* setup i2c adapter description */
206	dln2->adapter.owner = THIS_MODULE;
207	dln2->adapter.class = I2C_CLASS_HWMON;
208	dln2->adapter.algo = &dln2_i2c_usb_algorithm;
209	dln2->adapter.quirks = &dln2_i2c_quirks;
210	dln2->adapter.dev.parent = dev;
211	ACPI_COMPANION_SET(&dln2->adapter.dev, ACPI_COMPANION(&pdev->dev));
212	dln2->adapter.dev.of_node = dev->of_node;
213	i2c_set_adapdata(&dln2->adapter, dln2);
214	snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
215		 "dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
216
217	platform_set_drvdata(pdev, dln2);
218
219	/* initialize the i2c interface */
220	ret = dln2_i2c_enable(dln2, true);
221	if (ret < 0)
222		return dev_err_probe(dev, ret, "failed to initialize adapter\n");
223
224	/* and finally attach to i2c layer */
225	ret = i2c_add_adapter(&dln2->adapter);
226	if (ret < 0)
227		goto out_disable;
228
229	return 0;
230
231out_disable:
232	dln2_i2c_enable(dln2, false);
233
234	return ret;
235}
236
237static void dln2_i2c_remove(struct platform_device *pdev)
238{
239	struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
240
241	i2c_del_adapter(&dln2->adapter);
242	dln2_i2c_enable(dln2, false);
243}
244
245static struct platform_driver dln2_i2c_driver = {
246	.driver.name	= "dln2-i2c",
247	.probe		= dln2_i2c_probe,
248	.remove		= dln2_i2c_remove,
249};
250
251module_platform_driver(dln2_i2c_driver);
252
253MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
254MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C controller interface");
255MODULE_LICENSE("GPL v2");
256MODULE_ALIAS("platform:dln2-i2c");