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Subject[PATCH v4 2/3] i2c: add support for Diolan DLN-2 USB-I2C adapter
Date
From: Laurentiu Palcu <laurentiu.palcu@intel.com>

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@intel.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
drivers/i2c/busses/Kconfig | 10 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-dln2.c | 390 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 401 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-dln2.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2ac87fa..6afc17e 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1021,4 +1021,14 @@ config SCx200_ACB
This support is also available as a module. If so, the module
will be called scx200_acb.

+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.
+
endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 49bf07e..3118fea 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -100,5 +100,6 @@ obj-$(CONFIG_I2C_ELEKTOR) += i2c-elektor.o
obj-$(CONFIG_I2C_PCA_ISA) += i2c-pca-isa.o
obj-$(CONFIG_I2C_SIBYTE) += i2c-sibyte.o
obj-$(CONFIG_SCx200_ACB) += scx200_acb.o
+obj-$(CONFIG_I2C_DLN2) += i2c-dln2.o

ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
new file mode 100644
index 0000000..ac09ec4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-dln2.c
@@ -0,0 +1,390 @@
+/*
+ * 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/errno.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 DRIVER_NAME "dln2-i2c"
+
+#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_SET_FREQUENCY DLN2_I2C_CMD(0x04)
+#define DLN2_I2C_GET_FREQUENCY DLN2_I2C_CMD(0x05)
+#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_GET_MIN_FREQUENCY DLN2_I2C_CMD(0x40)
+#define DLN2_I2C_GET_MAX_FREQUENCY DLN2_I2C_CMD(0x41)
+
+#define DLN2_I2C_FREQ_STD 100000
+
+#define DLN2_I2C_MAX_XFER_SIZE 256
+
+struct dln2_i2c {
+ struct platform_device *pdev;
+ struct i2c_adapter adapter;
+ uint32_t freq;
+ uint32_t min_freq;
+ uint32_t max_freq;
+ /*
+ * 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.
+ */
+ union {
+ struct {
+ u8 port;
+ u8 addr;
+ u8 mem_addr_len;
+ __le32 mem_addr;
+ __le16 buf_len;
+ u8 buf[DLN2_I2C_MAX_XFER_SIZE];
+ } __packed tx;
+ struct {
+ __le16 buf_len;
+ u8 buf[DLN2_I2C_MAX_XFER_SIZE];
+ } __packed rx;
+ } buf;
+};
+
+static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
+{
+ struct dln2_platform_data *pdata = dev_get_platdata(&dln2->pdev->dev);
+ int ret;
+ u8 port;
+ u16 cmd;
+
+ port = pdata->i2c.port;
+
+ if (enable)
+ cmd = DLN2_I2C_ENABLE;
+ else
+ cmd = DLN2_I2C_DISABLE;
+
+ ret = dln2_transfer(dln2->pdev, cmd, &port, sizeof(port), NULL, NULL);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int dln2_i2c_set_frequency(struct dln2_i2c *dln2, u32 freq)
+{
+ int ret;
+ struct tx_data {
+ u8 port;
+ __le32 freq;
+ } __packed tx;
+ struct dln2_platform_data *pdata = dev_get_platdata(&dln2->pdev->dev);
+
+ tx.port = pdata->i2c.port;
+ tx.freq = cpu_to_le32(freq);
+
+ ret = dln2_transfer(dln2->pdev, DLN2_I2C_SET_FREQUENCY, &tx, sizeof(tx),
+ NULL, NULL);
+ if (ret < 0)
+ return ret;
+
+ dln2->freq = freq;
+
+ return 0;
+}
+
+static int dln2_i2c_get_freq(struct dln2_i2c *dln2, u16 cmd, uint32_t *res)
+{
+ int ret;
+ struct dln2_platform_data *pdata = dev_get_platdata(&dln2->pdev->dev);
+ u8 port = pdata->i2c.port;
+ __le32 freq;
+ unsigned len = sizeof(freq);
+
+ ret = dln2_transfer(dln2->pdev, cmd, &port, sizeof(port),
+ &freq, &len);
+ if (ret < 0)
+ return ret;
+ if (len < sizeof(freq))
+ return -EPROTO;
+
+ *res = le32_to_cpu(freq);
+
+ return 0;
+}
+
+static int dln2_i2c_setup(struct dln2_i2c *dln2)
+{
+ int ret;
+
+ ret = dln2_i2c_enable(dln2, false);
+ if (ret < 0)
+ return ret;
+
+ ret = dln2_i2c_get_freq(dln2, DLN2_I2C_GET_MIN_FREQUENCY,
+ &dln2->min_freq);
+ if (ret < 0)
+ return 0;
+
+ ret = dln2_i2c_get_freq(dln2, DLN2_I2C_GET_MAX_FREQUENCY,
+ &dln2->max_freq);
+ if (ret < 0)
+ return 0;
+
+ ret = dln2_i2c_set_frequency(dln2, DLN2_I2C_FREQ_STD);
+ if (ret < 0)
+ return ret;
+
+ ret = dln2_i2c_enable(dln2, true);
+
+ return ret;
+}
+
+static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
+ u8 *data, u16 data_len)
+{
+ struct dln2_platform_data *pdata = dev_get_platdata(&dln2->pdev->dev);
+ int ret;
+ unsigned len;
+
+ dln2->buf.tx.port = pdata->i2c.port;
+ dln2->buf.tx.addr = addr;
+ dln2->buf.tx.mem_addr_len = 0;
+ dln2->buf.tx.mem_addr = 0;
+ dln2->buf.tx.buf_len = cpu_to_le16(data_len);
+ memcpy(dln2->buf.tx.buf, data, data_len);
+
+ len = sizeof(dln2->buf.tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;
+ ret = dln2_transfer(dln2->pdev, DLN2_I2C_WRITE, &dln2->buf.tx, len,
+ 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)
+{
+ struct dln2_platform_data *pdata = dev_get_platdata(&dln2->pdev->dev);
+ int ret;
+ struct {
+ u8 port;
+ u8 addr;
+ u8 mem_addr_len;
+ __le32 mem_addr;
+ __le16 buf_len;
+ } __packed tx;
+ unsigned rx_len, rx_buf_len;
+
+ tx.port = pdata->i2c.port;
+ tx.addr = addr;
+ tx.mem_addr_len = 0;
+ tx.mem_addr = 0;
+ tx.buf_len = cpu_to_le16(data_len);
+
+ rx_len = sizeof(dln2->buf.rx);
+
+ ret = dln2_transfer(dln2->pdev, DLN2_I2C_READ, &tx, sizeof(tx),
+ &dln2->buf.rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < 2)
+ return -EPROTO;
+
+ rx_buf_len = le16_to_cpu(dln2->buf.rx.buf_len);
+ if (rx_len < rx_buf_len + sizeof(dln2->buf.rx.buf_len))
+ return -EPROTO;
+
+ if (data_len > rx_buf_len)
+ data_len = rx_buf_len;
+
+ memcpy(data, dln2->buf.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->len > DLN2_I2C_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ 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 ssize_t dln2_i2c_freq_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dln2_i2c *dln2 = dev_get_drvdata(dev);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", dln2->freq);
+}
+
+static ssize_t dln2_i2c_freq_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dln2_i2c *dln2 = dev_get_drvdata(dev);
+ unsigned long freq;
+ int ret;
+
+ if (kstrtoul(buf, 0, &freq) || freq < dln2->min_freq ||
+ freq > dln2->max_freq)
+ return -EINVAL;
+
+ ret = dln2_i2c_enable(dln2, false);
+ if (ret < 0)
+ return ret;
+
+ ret = dln2_i2c_set_frequency(dln2, freq);
+ if (ret < 0)
+ return ret;
+
+ ret = dln2_i2c_enable(dln2, true);
+
+ return count;
+}
+
+static DEVICE_ATTR(freq, S_IRUGO|S_IWUSR, dln2_i2c_freq_show,
+ dln2_i2c_freq_store);
+
+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->pdev = pdev;
+
+ /* 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",
+ DRIVER_NAME, dev_name(pdev->dev.parent), pdata->i2c.port);
+
+ platform_set_drvdata(pdev, dln2);
+
+ ret = device_create_file(dev, &dev_attr_freq);
+ if (ret < 0) {
+ dev_err(dev, "failed to add freq attribute\n");
+ return ret;
+ }
+
+ /* initialize the i2c interface */
+ ret = dln2_i2c_setup(dln2);
+ if (ret < 0) {
+ dev_err(dev, "failed to initialize adapter: %d\n", ret);
+ goto out_remove_freq_attr;
+ }
+
+ /* 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);
+out_remove_freq_attr:
+ device_remove_file(dev, &dev_attr_freq);
+
+ return ret;
+}
+
+static int dln2_i2c_remove(struct platform_device *pdev)
+{
+ struct dln2_i2c *dln2 = platform_get_drvdata(pdev);
+
+ device_remove_file(&pdev->dev, &dev_attr_freq);
+ i2c_del_adapter(&dln2->adapter);
+ dln2_i2c_enable(dln2, false);
+
+ return 0;
+}
+
+static struct platform_driver dln2_i2c_driver = {
+ .driver.name = DRIVER_NAME,
+ .driver.owner = THIS_MODULE,
+ .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_NAME " driver");
+MODULE_LICENSE("GPL");
--
1.9.1


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