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/*
* Driver for the Diolan DLN-2 USB-I2C adapter
*
* Copyright (c) 2014 Intel Corporation
*
* Derived from:
* i2c-diolan-u2c.c
* Copyright (c) 2010-2011 Ericsson AB
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/mfd/dln2.h>
#define DLN2_I2C_MODULE_ID 0x03
#define DLN2_I2C_CMD(cmd) DLN2_CMD(cmd, DLN2_I2C_MODULE_ID)
/* I2C commands */
#define DLN2_I2C_GET_PORT_COUNT DLN2_I2C_CMD(0x00)
#define DLN2_I2C_ENABLE DLN2_I2C_CMD(0x01)
#define DLN2_I2C_DISABLE DLN2_I2C_CMD(0x02)
#define DLN2_I2C_IS_ENABLED DLN2_I2C_CMD(0x03)
#define DLN2_I2C_WRITE DLN2_I2C_CMD(0x06)
#define DLN2_I2C_READ DLN2_I2C_CMD(0x07)
#define DLN2_I2C_SCAN_DEVICES DLN2_I2C_CMD(0x08)
#define DLN2_I2C_PULLUP_ENABLE DLN2_I2C_CMD(0x09)
#define DLN2_I2C_PULLUP_DISABLE DLN2_I2C_CMD(0x0A)
#define DLN2_I2C_PULLUP_IS_ENABLED DLN2_I2C_CMD(0x0B)
#define DLN2_I2C_TRANSFER DLN2_I2C_CMD(0x0C)
#define DLN2_I2C_SET_MAX_REPLY_COUNT DLN2_I2C_CMD(0x0D)
#define DLN2_I2C_GET_MAX_REPLY_COUNT DLN2_I2C_CMD(0x0E)
#define DLN2_I2C_MAX_XFER_SIZE 256
#define DLN2_I2C_BUF_SIZE (DLN2_I2C_MAX_XFER_SIZE + 16)
struct dln2_i2c {
struct platform_device *pdev;
struct i2c_adapter adapter;
u8 port;
/*
* Buffer to hold the packet for read or write transfers. One is enough
* since we can't have multiple transfers in parallel on the i2c bus.
*/
void *buf;
};
static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
{
u16 cmd;
struct {
u8 port;
} tx;
tx.port = dln2->port;
if (enable)
cmd = DLN2_I2C_ENABLE;
else
cmd = DLN2_I2C_DISABLE;
return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
}
static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
u8 *data, u16 data_len)
{
int ret;
struct {
u8 port;
u8 addr;
u8 mem_addr_len;
__le32 mem_addr;
__le16 buf_len;
u8 buf[DLN2_I2C_MAX_XFER_SIZE];
} __packed *tx = dln2->buf;
unsigned len;
BUILD_BUG_ON(sizeof(*tx) > DLN2_I2C_BUF_SIZE);
tx->port = dln2->port;
tx->addr = addr;
tx->mem_addr_len = 0;
tx->mem_addr = 0;
tx->buf_len = cpu_to_le16(data_len);
memcpy(tx->buf, data, data_len);
len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
ret = dln2_transfer_tx(dln2->pdev, DLN2_I2C_WRITE, tx, len);
if (ret < 0)
return ret;
return data_len;
}
static int dln2_i2c_read(struct dln2_i2c *dln2, u16 addr, u8 *data,
u16 data_len)
{
int ret;
struct {
u8 port;
u8 addr;
u8 mem_addr_len;
__le32 mem_addr;
__le16 buf_len;
} __packed tx;
struct {
__le16 buf_len;
u8 buf[DLN2_I2C_MAX_XFER_SIZE];
} __packed *rx = dln2->buf;
unsigned rx_len = sizeof(*rx);
BUILD_BUG_ON(sizeof(*rx) > DLN2_I2C_BUF_SIZE);
tx.port = dln2->port;
tx.addr = addr;
tx.mem_addr_len = 0;
tx.mem_addr = 0;
tx.buf_len = cpu_to_le16(data_len);
ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
rx, &rx_len);
if (ret < 0)
return ret;
if (rx_len < sizeof(rx->buf_len) + data_len)
return -EPROTO;
if (le16_to_cpu(rx->buf_len) != data_len)
return -EPROTO;
memcpy(data, rx->buf, data_len);
return data_len;
}
static int dln2_i2c_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
struct dln2_i2c *dln2 = i2c_get_adapdata(adapter);
struct i2c_msg *pmsg;
int i;
for (i = 0; i < num; i++) {
int ret;
pmsg = &msgs[i];
if (pmsg->flags & I2C_M_RD) {
ret = dln2_i2c_read(dln2, pmsg->addr, pmsg->buf,
pmsg->len);
if (ret < 0)
return ret;
pmsg->len = ret;
} else {
ret = dln2_i2c_write(dln2, pmsg->addr, pmsg->buf,
pmsg->len);
if (ret != pmsg->len)
return -EPROTO;
}
}
return num;
}
static u32 dln2_i2c_func(struct i2c_adapter *a)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
I2C_FUNC_SMBUS_I2C_BLOCK;
}
static const struct i2c_algorithm dln2_i2c_usb_algorithm = {
.master_xfer = dln2_i2c_xfer,
.functionality = dln2_i2c_func,
};
static struct i2c_adapter_quirks dln2_i2c_quirks = {
.max_read_len = DLN2_I2C_MAX_XFER_SIZE,
.max_write_len = DLN2_I2C_MAX_XFER_SIZE,
};
static int dln2_i2c_probe(struct platform_device *pdev)
{
int ret;
struct dln2_i2c *dln2;
struct device *dev = &pdev->dev;
struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
dln2 = devm_kzalloc(dev, sizeof(*dln2), GFP_KERNEL);
if (!dln2)
return -ENOMEM;
dln2->buf = devm_kmalloc(dev, DLN2_I2C_BUF_SIZE, GFP_KERNEL);
if (!dln2->buf)
return -ENOMEM;
dln2->pdev = pdev;
dln2->port = pdata->port;
/* setup i2c adapter description */
dln2->adapter.owner = THIS_MODULE;
dln2->adapter.class = I2C_CLASS_HWMON;
dln2->adapter.algo = &dln2_i2c_usb_algorithm;
dln2->adapter.quirks = &dln2_i2c_quirks;
dln2->adapter.dev.parent = dev;
dln2->adapter.dev.of_node = dev->of_node;
i2c_set_adapdata(&dln2->adapter, dln2);
snprintf(dln2->adapter.name, sizeof(dln2->adapter.name), "%s-%s-%d",
"dln2-i2c", dev_name(pdev->dev.parent), dln2->port);
platform_set_drvdata(pdev, dln2);
/* initialize the i2c interface */
ret = dln2_i2c_enable(dln2, true);
if (ret < 0) {
dev_err(dev, "failed to initialize adapter: %d\n", ret);
return ret;
}
/* and finally attach to i2c layer */
ret = i2c_add_adapter(&dln2->adapter);
if (ret < 0) {
dev_err(dev, "failed to add I2C adapter: %d\n", ret);
goto out_disable;
}
return 0;
out_disable:
dln2_i2c_enable(dln2, false);
return ret;
}
static int dln2_i2c_remove(struct platform_device *pdev)
{
struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
i2c_del_adapter(&dln2->adapter);
dln2_i2c_enable(dln2, false);
return 0;
}
static struct platform_driver dln2_i2c_driver = {
.driver.name = "dln2-i2c",
.probe = dln2_i2c_probe,
.remove = dln2_i2c_remove,
};
module_platform_driver(dln2_i2c_driver);
MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:dln2-i2c");
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