diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-dln2.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-dln2.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c new file mode 100644 index 000000000000..010a5fa8c883 --- /dev/null +++ b/drivers/i2c/busses/i2c-dln2.c @@ -0,0 +1,267 @@ +/* + * 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) +{ + int ret; + u16 cmd; + struct { + u8 port; + } tx; + + tx.port = dln2->port; + + if (enable) + cmd = DLN2_I2C_ENABLE; + else + cmd = DLN2_I2C_DISABLE; + + ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx)); + if (ret < 0) + return ret; + + return 0; +} + +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; + struct device *dev = &dln2->adapter.dev; + int i; + + for (i = 0; i < num; i++) { + int ret; + + pmsg = &msgs[i]; + + if (pmsg->len > DLN2_I2C_MAX_XFER_SIZE) { + dev_warn(dev, "maximum transfer size exceeded\n"); + return -EOPNOTSUPP; + } + + 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 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.dev.parent = dev; + 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"); |