[PATCH v8 2/4] i2c: add support for Diolan DLN-2 USB-I2C adapter

From: Octavian Purdila
Date: Wed Oct 15 2014 - 10:49:19 EST

From: Laurentiu Palcu <laurentiu.palcu@xxxxxxxxx>

This patch adds support for the Diolan DLN-2 I2C master module. Due
to hardware limitations it does not support SMBUS quick commands.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 6.2.2 for the I2C
master module commands and responses.

[1] https://www.diolan.com/downloads/dln-api-manual.pdf

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@xxxxxxxxx>
Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
---
drivers/i2c/busses/Kconfig | 10 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-dln2.c | 270 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 281 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-dln2.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2ac87fa..2f3f371 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -858,6 +858,16 @@ config I2C_DIOLAN_U2C
This driver can also be built as a module. If so, the module
will be called i2c-diolan-u2c.

+config I2C_DLN2
+ tristate "Diolan DLN-2 USB I2C adapter"
+ depends on MFD_DLN2
+ help
+ If you say yes to this option, support will be included for Diolan
+ DLN2, a USB to I2C interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-dln2.
+
config I2C_PARPORT
tristate "Parallel port adapter"
depends on PARPORT
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 49bf07e..4755f79 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -85,6 +85,7 @@ obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o

# External I2C/SMBus adapter drivers
obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
+obj-$(CONFIG_I2C_DLN2) += i2c-dln2.o
obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o
obj-$(CONFIG_I2C_ROBOTFUZZ_OSIF) += i2c-robotfuzz-osif.o
diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
new file mode 100644
index 0000000..62c38cd
--- /dev/null
+++ b/drivers/i2c/busses/i2c-dln2.c
@@ -0,0 +1,270 @@
+/*
+ * 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 adapter.
+ */
+ 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(dln2->pdev, cmd, &tx, sizeof(tx),
+ NULL, NULL, NULL);
+ 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(dln2->pdev, DLN2_I2C_WRITE, tx, len,
+ NULL, NULL, NULL);
+ 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, NULL);
+ 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->pdev->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@xxxxxxxxx>");
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 I2C master interface");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-i2c");
--
1.9.1

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