i2c/busses/i2c-dln2.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Driver for the Diolan DLN-2 USB-I2C adapter
0004  *
0005  * Copyright (c) 2014 Intel Corporation
0006  *
0007  * Derived from:
0008  *  i2c-diolan-u2c.c
0009  *  Copyright (c) 2010-2011 Ericsson AB
0010  */
0011
0012 #include <linux/kernel.h>
0013 #include <linux/module.h>
0014 #include <linux/types.h>
0015 #include <linux/slab.h>
0016 #include <linux/i2c.h>
0017 #include <linux/platform_device.h>
0018 #include <linux/mfd/dln2.h>
0019 #include <linux/acpi.h>
0020
0021 #define DLN2_I2C_MODULE_ID      0x03
0022 #define DLN2_I2C_CMD(cmd)       DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
0023
0024 /* I2C commands */
0025 #define DLN2_I2C_GET_PORT_COUNT     DLN2_I2C_CMD(0x00)
0026 #define DLN2_I2C_ENABLE         DLN2_I2C_CMD(0x01)
0027 #define DLN2_I2C_DISABLE        DLN2_I2C_CMD(0x02)
0028 #define DLN2_I2C_IS_ENABLED     DLN2_I2C_CMD(0x03)
0029 #define DLN2_I2C_WRITE          DLN2_I2C_CMD(0x06)
0030 #define DLN2_I2C_READ           DLN2_I2C_CMD(0x07)
0031 #define DLN2_I2C_SCAN_DEVICES       DLN2_I2C_CMD(0x08)
0032 #define DLN2_I2C_PULLUP_ENABLE      DLN2_I2C_CMD(0x09)
0033 #define DLN2_I2C_PULLUP_DISABLE     DLN2_I2C_CMD(0x0A)
0034 #define DLN2_I2C_PULLUP_IS_ENABLED  DLN2_I2C_CMD(0x0B)
0035 #define DLN2_I2C_TRANSFER       DLN2_I2C_CMD(0x0C)
0036 #define DLN2_I2C_SET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0D)
0037 #define DLN2_I2C_GET_MAX_REPLY_COUNT    DLN2_I2C_CMD(0x0E)
0038
0039 #define DLN2_I2C_MAX_XFER_SIZE      256
0040 #define DLN2_I2C_BUF_SIZE       (DLN2_I2C_MAX_XFER_SIZE + 16)
0041
0042 struct dln2_i2c {
0043     struct platform_device *pdev;
0044     struct i2c_adapter adapter;
0045     u8 port;
0046     /*
0047      * Buffer to hold the packet for read or write transfers. One is enough
0048      * since we can't have multiple transfers in parallel on the i2c bus.
0049      */
0050     void *buf;
0051 };
0052
0053 static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
0054 {
0055     u16 cmd;
0056     struct {
0057         u8 port;
0058     } tx;
0059
0060     tx.port = dln2->port;
0061
0062     if (enable)
0063         cmd = DLN2_I2C_ENABLE;
0064     else
0065         cmd = DLN2_I2C_DISABLE;
0066
0067     return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
0068 }
0069
0070 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
0071               u8 *data, u16 data_len)
0072 {
0073     int ret;
0074     struct {
0075         u8 port;
0076         u8 addr;
0077         u8 mem_addr_len;
0078         __le32 mem_addr;
0079         __le16 buf_len;
0080         u8 buf[DLN2_I2C_MAX_XFER_SIZE];
0081     } __packed *tx = dln2->buf;
0082     unsigned len;
0083
0084     BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
0085
0086     tx->port = dln2->port;
0087     tx->addr = addr;
0088     tx->mem_addr_len = 0;
0089     tx->mem_addr = 0;
0090     tx->buf_len = cpu_to_le16(data_len);
0091     memcpy(tx->buf, data, data_len);
0092
0093     len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
0094     ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
0095     if (ret < 0)
0096         return ret;
0097
0098     return data_len;
0099 }
0100
0101 static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
0102              u16 data_len)
0103 {
0104     int ret;
0105     struct {
0106         u8 port;
0107         u8 addr;
0108         u8 mem_addr_len;
0109         __le32 mem_addr;
0110         __le16 buf_len;
0111     } __packed tx;
0112     struct {
0113         __le16 buf_len;
0114         u8 buf[DLN2_I2C_MAX_XFER_SIZE];
0115     } __packed *rx = dln2->buf;
0116     unsigned rx_len = sizeof(*rx);
0117
0118     BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
0119
0120     tx.port = dln2->port;
0121     tx.addr = addr;
0122     tx.mem_addr_len = 0;
0123     tx.mem_addr = 0;
0124     tx.buf_len = cpu_to_le16(data_len);
0125
0126     ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
0127                 rx, &rx_len);
0128     if (ret < 0)
0129         return ret;
0130     if (rx_len < sizeof(rx->buf_len) + data_len)
0131         return -EPROTO;
0132     if (le16_to_cpu(rx->buf_len) != data_len)
0133         return -EPROTO;
0134
0135     memcpy(data, rx->buf, data_len);
0136
0137     return data_len;
0138 }
0139
0140 static int dln2_i2c_xfer(struct i2c_adapter *adapter,
0141              struct i2c_msg *msgs, int num)
0142 {
0143     struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
0144     struct i2c_msg *pmsg;
0145     int i;
0146
0147     for (i = 0; i < num; i++) {
0148         int ret;
0149
0150         pmsg = &msgs[i];
0151
0152         if (pmsg->flags & I2C_M_RD) {
0153             ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
0154                         pmsg->len);
0155             if (ret < 0)
0156                 return ret;
0157
0158             pmsg->len = ret;
0159         } else {
0160             ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
0161                          pmsg->len);
0162             if (ret != pmsg->len)
0163                 return -EPROTO;
0164         }
0165     }
0166
0167     return num;
0168 }
0169
0170 static u32 dln2_i2c_func(struct i2c_adapter *a)
0171 {
0172     return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
0173         I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
0174         I2C_FUNC_SMBUS_I2C_BLOCK;
0175 }
0176
0177 static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
0178     .master_xfer = dln2_i2c_xfer,
0179     .functionality = dln2_i2c_func,
0180 };
0181
0182 static const struct i2c_adapter_quirks dln2_i2c_quirks = {
0183     .max_read_len = DLN2_I2C_MAX_XFER_SIZE,
0184     .max_write_len = DLN2_I2C_MAX_XFER_SIZE,
0185 };
0186
0187 static int dln2_i2c_probe(struct platform_device *pdev)
0188 {
0189     int ret;
0190     struct dln2_i2c *dln2;
0191     struct device *dev = &pdev->dev;
0192     struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
0193
0194     dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
0195     if (!dln2)
0196         return -ENOMEM;
0197
0198     dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
0199     if (!dln2->buf)
0200         return -ENOMEM;
0201
0202     dln2->pdev = pdev;
0203     dln2->port = pdata->port;
0204
0205     /* setup i2c adapter description */
0206     dln2->adapter.owner = THIS_MODULE;
0207     dln2->adapter.class = I2C_CLASS_HWMON;
0208     dln2->adapter.algo = &dln2_i2c_usb_algorithm;
0209     dln2->adapter.quirks = &dln2_i2c_quirks;
0210     dln2->adapter.dev.parent = dev;
0211     ACPI_COMPANION_SET(&dln2->adapter.dev, ACPI_COMPANION(&pdev->dev));
0212     dln2->adapter.dev.of_node = dev->of_node;
0213     i2c_set_adapdata(&dln2->adapter, dln2);
0214     snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
0215          "dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
0216
0217     platform_set_drvdata(pdev, dln2);
0218
0219     /* initialize the i2c interface */
0220     ret = dln2_i2c_enable(dln2, true);
0221     if (ret < 0) {
0222         dev_err(dev, "failed to initialize adapter: %d\n", ret);
0223         return ret;
0224     }
0225
0226     /* and finally attach to i2c layer */
0227     ret = i2c_add_adapter(&dln2->adapter);
0228     if (ret < 0)
0229         goto out_disable;
0230
0231     return 0;
0232
0233 out_disable:
0234     dln2_i2c_enable(dln2, false);
0235
0236     return ret;
0237 }
0238
0239 static int dln2_i2c_remove(struct platform_device *pdev)
0240 {
0241     struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
0242
0243     i2c_del_adapter(&dln2->adapter);
0244     dln2_i2c_enable(dln2, false);
0245
0246     return 0;
0247 }
0248
0249 static struct platform_driver dln2_i2c_driver = {
0250     .driver.name    = "dln2-i2c",
0251     .probe      = dln2_i2c_probe,
0252     .remove     = dln2_i2c_remove,
0253 };
0254
0255 module_platform_driver(dln2_i2c_driver);
0256
0257 MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
0258 MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
0259 MODULE_LICENSE("GPL v2");
0260 MODULE_ALIAS("platform:dln2-i2c");