[PATCH v9 0/4] mfd: add support for Diolan DLN-2

[PATCH v9 0/4] mfd: add support for Diolan DLN-2

[Octavian Purdila]

This patch series adds support for Diolan USB-I2C/GPIO Master Adapter
DLN-2. Details about device can be found here:

https://www.diolan.com/i2c/i2c_interface.html.

This patch series is against the MFD tree branch
for-mfd-next-v3.19. It does include a gpiolib patch that was merged by
Linus W but it was not yet pulled into Lee's tree.

Changes since v8:

 * common: remove result parameter from dln2_transfer as it is not yet
   used in this patch set (we will add it later with the i2c change
   freq patches); fix comments to wrap to 80 columns instead of 70

 * MFD: add two variants for dln2_transfer: dln2_trasfer_rx and
   dln2_transfer_tx; use entry instead of new_cb in
   dln2_register_event_cb; rename dln2_rx_transfer to
   dln2_transfer_complete and add comment about the URB completion,
   also move the warning about late/missing responses here;

 * GPIO: use dln2_transfer_rx and dln2_transfer_tx where possible

 * I2C: use dln2_transfer_rx and dln2_transfer_tx where possible; use
   adapter's device instead of platform's device for
   dev_err/dev_info/etc prints


Daniel Baluta (1):
  gpio: add support for the Diolan DLN-2 USB GPIO driver

Laurentiu Palcu (1):
  i2c: add support for Diolan DLN-2 USB-I2C adapter

Octavian Purdila (2):
  mfd: add support for Diolan DLN-2 devices
  gpiolib: add irq_not_threaded flag to gpio_chip

 drivers/gpio/Kconfig          |  12 +
 drivers/gpio/Makefile         |   1 +
 drivers/gpio/gpio-dln2.c      | 553 ++++++++++++++++++++++++++++++
 drivers/gpio/gpiolib.c        |   2 +-
 drivers/i2c/busses/Kconfig    |  10 +
 drivers/i2c/busses/Makefile   |   1 +
 drivers/i2c/busses/i2c-dln2.c | 267 +++++++++++++++
 drivers/mfd/Kconfig           |  11 +
 drivers/mfd/Makefile          |   1 +
 drivers/mfd/dln2.c            | 761 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/gpio/driver.h   |   3 +
 include/linux/mfd/dln2.h      | 103 ++++++
 12 files changed, 1724 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpio/gpio-dln2.c
 create mode 100644 drivers/i2c/busses/i2c-dln2.c
 create mode 100644 drivers/mfd/dln2.c
 create mode 100644 include/linux/mfd/dln2.h

-- 
1.9.1

[PATCH v9 0/4] mfd: add support for Diolan DLN-2

[Octavian Purdila]

This patch series adds support for Diolan USB-I2C/GPIO Master Adapter
DLN-2. Details about device can be found here:

https://www.diolan.com/i2c/i2c_interface.html.

This patch series is against the MFD tree branch
for-mfd-next-v3.19. It does include a gpiolib patch that was merged by
Linus W but it was not yet pulled into Lee's tree.

Changes since v8:

 * common: remove result parameter from dln2_transfer as it is not yet
   used in this patch set (we will add it later with the i2c change
   freq patches); fix comments to wrap to 80 columns instead of 70

 * MFD: add two variants for dln2_transfer: dln2_trasfer_rx and
   dln2_transfer_tx; use entry instead of new_cb in
   dln2_register_event_cb; rename dln2_rx_transfer to
   dln2_transfer_complete and add comment about the URB completion,
   also move the warning about late/missing responses here;

 * GPIO: use dln2_transfer_rx and dln2_transfer_tx where possible

 * I2C: use dln2_transfer_rx and dln2_transfer_tx where possible; use
   adapter's device instead of platform's device for
   dev_err/dev_info/etc prints


Daniel Baluta (1):
  gpio: add support for the Diolan DLN-2 USB GPIO driver

Laurentiu Palcu (1):
  i2c: add support for Diolan DLN-2 USB-I2C adapter

Octavian Purdila (2):
  mfd: add support for Diolan DLN-2 devices
  gpiolib: add irq_not_threaded flag to gpio_chip

 drivers/gpio/Kconfig          |  12 +
 drivers/gpio/Makefile         |   1 +
 drivers/gpio/gpio-dln2.c      | 553 ++++++++++++++++++++++++++++++
 drivers/gpio/gpiolib.c        |   2 +-
 drivers/i2c/busses/Kconfig    |  10 +
 drivers/i2c/busses/Makefile   |   1 +
 drivers/i2c/busses/i2c-dln2.c | 267 +++++++++++++++
 drivers/mfd/Kconfig           |  11 +
 drivers/mfd/Makefile          |   1 +
 drivers/mfd/dln2.c            | 761 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/gpio/driver.h   |   3 +
 include/linux/mfd/dln2.h      | 103 ++++++
 12 files changed, 1724 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpio/gpio-dln2.c
 create mode 100644 drivers/i2c/busses/i2c-dln2.c
 create mode 100644 drivers/mfd/dln2.c
 create mode 100644 include/linux/mfd/dln2.h

-- 
1.9.1

[PATCH v9 1/4] mfd: add support for Diolan DLN-2 devices

[Octavian Purdila]

This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
Master Adapter DLN-2. Details about the device can be found here:

https://www.diolan.com/i2c/i2c_interface.html.

Information about the USB protocol can be found in the Programmer's
Reference Manual [1], see section 1.7.

Because the hardware has a single transmit endpoint and a single
receive endpoint the communication between the various DLN2 drivers
and the hardware will be muxed/demuxed by this driver.

Each DLN2 module will be identified by the handle field within the DLN2
message header. If a DLN2 module issues multiple commands in parallel
they will be identified by the echo counter field in the message header.

The DLN2 modules can use the dln2_transfer() function to issue a
command and wait for its response. They can also register a callback
that is going to be called when a specific event id is generated by
the device (e.g. GPIO interrupts). The device uses handle 0 for
sending events.

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

Signed-off-by: Octavian Purdila <octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/mfd/Kconfig      |  11 +
 drivers/mfd/Makefile     |   1 +
 drivers/mfd/dln2.c       | 761 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/dln2.h | 103 +++++++
 4 files changed, 876 insertions(+)
 create mode 100644 drivers/mfd/dln2.c
 create mode 100644 include/linux/mfd/dln2.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index c9200d3..4538815a 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -189,6 +189,17 @@ config MFD_DA9063
 	  Additional drivers must be enabled in order to use the functionality
 	  of the device.
 
+config MFD_DLN2
+	tristate "Diolan DLN2 support"
+	select MFD_CORE
+	depends on USB
+	help
+
+	  This adds support for Diolan USB-I2C/SPI/GPIO Master Adapter
+	  DLN-2. Additional drivers such as I2C_DLN2, GPIO_DLN2,
+	  etc. must be enabled in order to use the functionality of
+	  the device.
+
 config MFD_MC13XXX
 	tristate
 	depends on (SPI_MASTER || I2C)
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 61f8dbf..2cd7e74 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -175,6 +175,7 @@ obj-$(CONFIG_MFD_STW481X)	+= stw481x.o
 obj-$(CONFIG_MFD_IPAQ_MICRO)	+= ipaq-micro.o
 obj-$(CONFIG_MFD_MENF21BMC)	+= menf21bmc.o
 obj-$(CONFIG_MFD_HI6421_PMIC)	+= hi6421-pmic-core.o
+obj-$(CONFIG_MFD_DLN2)		+= dln2.o
 
 intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
new file mode 100644
index 0000000..b3946ef
--- /dev/null
+++ b/drivers/mfd/dln2.c
@@ -0,0 +1,761 @@
+/*
+ * Driver for the Diolan DLN-2 USB 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/usb.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/dln2.h>
+#include <linux/rculist.h>
+
+struct dln2_header {
+	__le16 size;
+	__le16 id;
+	__le16 echo;
+	__le16 handle;
+} __packed;
+
+struct dln2_response {
+	struct dln2_header hdr;
+	__le16 result;
+} __packed;
+
+#define DLN2_GENERIC_MODULE_ID		0x00
+#define DLN2_GENERIC_CMD(cmd)		DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)
+#define CMD_GET_DEVICE_VER		DLN2_GENERIC_CMD(0x30)
+#define CMD_GET_DEVICE_SN		DLN2_GENERIC_CMD(0x31)
+
+#define DLN2_HW_ID			0x200
+#define DLN2_USB_TIMEOUT		200	/* in ms */
+#define DLN2_MAX_RX_SLOTS		16
+#define DLN2_MAX_URBS			16
+#define DLN2_RX_BUF_SIZE		512
+
+enum dln2_handle {
+	DLN2_HANDLE_EVENT = 0,		/* don't change, hardware defined */
+	DLN2_HANDLE_CTRL,
+	DLN2_HANDLE_GPIO,
+	DLN2_HANDLE_I2C,
+	DLN2_HANDLES
+};
+
+/*
+ * Receive context used between the receive demultiplexer and the transfer
+ * routine. While sending a request the transfer routine will look for a free
+ * receive context and use it to wait for a response and to receive the URB and
+ * thus the response data.
+ */
+struct dln2_rx_context {
+	/* completion used to wait for a response */
+	struct completion done;
+
+	/* if non-NULL the URB contains the response */
+	struct urb *urb;
+
+	/* if true then this context is used to wait for a response */
+	bool in_use;
+};
+
+/*
+ * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the
+ * handle header field to identify the module in dln2_dev.mod_rx_slots and then
+ * the echo header field to index the slots field and find the receive context
+ * for a particular request.
+ */
+struct dln2_mod_rx_slots {
+	/* RX slots bitmap */
+	DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);
+
+	/* used to wait for a free RX slot */
+	wait_queue_head_t wq;
+
+	/* used to wait for an RX operation to complete */
+	struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];
+
+	/* avoid races between alloc/free_rx_slot and dln2_rx_transfer */
+	spinlock_t lock;
+};
+
+struct dln2_dev {
+	struct usb_device *usb_dev;
+	struct usb_interface *interface;
+	u8 ep_in;
+	u8 ep_out;
+
+	struct urb *rx_urb[DLN2_MAX_URBS];
+	void *rx_buf[DLN2_MAX_URBS];
+
+	struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];
+
+	struct list_head event_cb_list;
+	spinlock_t event_cb_lock;
+
+	bool disconnect;
+	int active_transfers;
+	wait_queue_head_t disconnect_wq;
+	spinlock_t disconnect_lock;
+};
+
+struct dln2_event_cb_entry {
+	struct list_head list;
+	u16 id;
+	struct platform_device *pdev;
+	dln2_event_cb_t callback;
+};
+
+int dln2_register_event_cb(struct platform_device *pdev, u16 id,
+			   dln2_event_cb_t event_cb)
+{
+	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
+	struct dln2_event_cb_entry *i, *entry;
+	unsigned long flags;
+	int ret = 0;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->id = id;
+	entry->callback = event_cb;
+	entry->pdev = pdev;
+
+	spin_lock_irqsave(&dln2->event_cb_lock, flags);
+
+	list_for_each_entry(i, &dln2->event_cb_list, list) {
+		if (i->id == id) {
+			ret = -EBUSY;
+			break;
+		}
+	}
+
+	if (!ret)
+		list_add_rcu(&entry->list, &dln2->event_cb_list);
+
+	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
+
+	if (ret)
+		kfree(entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(dln2_register_event_cb);
+
+void dln2_unregister_event_cb(struct platform_device *pdev, u16 id)
+{
+	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
+	struct dln2_event_cb_entry *i;
+	unsigned long flags;
+	bool found = false;
+
+	spin_lock_irqsave(&dln2->event_cb_lock, flags);
+
+	list_for_each_entry(i, &dln2->event_cb_list, list) {
+		if (i->id == id) {
+			list_del_rcu(&i->list);
+			found = true;
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
+
+	if (found) {
+		synchronize_rcu();
+		kfree(i);
+	}
+}
+EXPORT_SYMBOL(dln2_unregister_event_cb);
+
+/*
+ * Returns true if a valid transfer slot is found. In this case the URB must not
+ * be resubmitted imediately in dln2_rx as we need the data when dln2_transfer
+ * is woke up. It will be resubmitted there.
+ */
+static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
+				   u16 handle, u16 rx_slot)
+{
+	struct device *dev = &dln2->interface->dev;
+	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
+	struct dln2_rx_context *rxc;
+	bool valid_slot = false;
+
+	rxc = &rxs->slots[rx_slot];
+
+	/*
+	 * No need to disable interrupts as this lock is not taken in interrupt
+	 * context elsewhere in this driver. This function (or its callers) are
+	 * also not exported to other modules.
+	 */
+	spin_lock(&rxs->lock);
+	if (rxc->in_use && !rxc->urb) {
+		rxc->urb = urb;
+		complete(&rxc->done);
+		valid_slot = true;
+	}
+	spin_unlock(&rxs->lock);
+
+	if (!valid_slot)
+		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
+
+	return valid_slot;
+}
+
+static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
+				     void *data, int len)
+{
+	struct dln2_event_cb_entry *i;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(i, &dln2->event_cb_list, list)
+		if (i->id == id)
+			i->callback(i->pdev, echo, data, len);
+
+	rcu_read_unlock();
+}
+
+static void dln2_rx(struct urb *urb)
+{
+	struct dln2_dev *dln2 = urb->context;
+	struct dln2_header *hdr = urb->transfer_buffer;
+	struct device *dev = &dln2->interface->dev;
+	u16 id, echo, handle, size;
+	u8 *data;
+	int len;
+	int err;
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+	case -EPIPE:
+		/* this urb is terminated, clean up */
+		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
+		return;
+	default:
+		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
+		goto out;
+	}
+
+	if (urb->actual_length < sizeof(struct dln2_header)) {
+		dev_err(dev, "short response: %d\n", urb->actual_length);
+		goto out;
+	}
+
+	handle = le16_to_cpu(hdr->handle);
+	id = le16_to_cpu(hdr->id);
+	echo = le16_to_cpu(hdr->echo);
+	size = le16_to_cpu(hdr->size);
+
+	if (size != urb->actual_length) {
+		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
+			handle, id, echo, size, urb->actual_length);
+		goto out;
+	}
+
+	if (handle >= DLN2_HANDLES) {
+		dev_warn(dev, "RX: invalid handle %d\n", handle);
+		goto out;
+	}
+
+	data = urb->transfer_buffer + sizeof(struct dln2_header);
+	len = urb->actual_length - sizeof(struct dln2_header);
+
+	if (handle == DLN2_HANDLE_EVENT) {
+		dln2_run_event_callbacks(dln2, id, echo, data, len);
+	} else {
+		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
+		if (dln2_transfer_complete(dln2, urb, handle, echo))
+			return;
+	}
+
+out:
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err < 0)
+		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
+}
+
+static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
+			   int *obuf_len, gfp_t gfp)
+{
+	int len;
+	void *buf;
+	struct dln2_header *hdr;
+
+	len = *obuf_len + sizeof(*hdr);
+	buf = kmalloc(len, gfp);
+	if (!buf)
+		return NULL;
+
+	hdr = (struct dln2_header *)buf;
+	hdr->id = cpu_to_le16(cmd);
+	hdr->size = cpu_to_le16(len);
+	hdr->echo = cpu_to_le16(echo);
+	hdr->handle = cpu_to_le16(handle);
+
+	memcpy(buf + sizeof(*hdr), obuf, *obuf_len);
+
+	*obuf_len = len;
+
+	return buf;
+}
+
+static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
+			  const void *obuf, int obuf_len)
+{
+	int ret = 0;
+	int len = obuf_len;
+	void *buf;
+	int actual;
+
+	buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = usb_bulk_msg(dln2->usb_dev,
+			   usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
+			   buf, len, &actual, DLN2_USB_TIMEOUT);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
+{
+	struct dln2_mod_rx_slots *rxs;
+	unsigned long flags;
+
+	if (dln2->disconnect) {
+		*slot = -ENODEV;
+		return true;
+	}
+
+	rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock_irqsave(&rxs->lock, flags);
+
+	*slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);
+
+	if (*slot < DLN2_MAX_RX_SLOTS) {
+		struct dln2_rx_context *rxc = &rxs->slots[*slot];
+
+		set_bit(*slot, rxs->bmap);
+		rxc->in_use = true;
+	}
+
+	spin_unlock_irqrestore(&rxs->lock, flags);
+
+	return *slot < DLN2_MAX_RX_SLOTS;
+}
+
+static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
+{
+	int ret;
+	int slot;
+
+	/*
+	 * No need to timeout here, the wait is bounded by the timeout in
+	 * _dln2_transfer.
+	 */
+	ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
+				       find_free_slot(dln2, handle, &slot));
+	if (ret < 0)
+		return ret;
+
+	return slot;
+}
+
+static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
+{
+	struct dln2_mod_rx_slots *rxs;
+	struct urb *urb = NULL;
+	unsigned long flags;
+	struct dln2_rx_context *rxc;
+
+	rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock_irqsave(&rxs->lock, flags);
+
+	clear_bit(slot, rxs->bmap);
+
+	rxc = &rxs->slots[slot];
+	rxc->in_use = false;
+	urb = rxc->urb;
+	rxc->urb = NULL;
+	reinit_completion(&rxc->done);
+
+	spin_unlock_irqrestore(&rxs->lock, flags);
+
+	if (urb) {
+		int err;
+		struct device *dev = &dln2->interface->dev;
+
+		err = usb_submit_urb(urb, GFP_KERNEL);
+		if (err < 0)
+			dev_err(dev, "failed to resubmit RX URB: %d\n", err);
+	}
+
+	wake_up_interruptible(&rxs->wq);
+}
+
+static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
+			  const void *obuf, unsigned obuf_len,
+			  void *ibuf, unsigned *ibuf_len)
+{
+	int ret = 0;
+	int rx_slot;
+	struct dln2_response *rsp;
+	struct dln2_rx_context *rxc;
+	struct device *dev = &dln2->interface->dev;
+	const int timeout = DLN2_USB_TIMEOUT * HZ / 1000;
+	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock(&dln2->disconnect_lock);
+	if (!dln2->disconnect)
+		dln2->active_transfers++;
+	else
+		ret = -ENODEV;
+	spin_unlock(&dln2->disconnect_lock);
+
+	if (ret)
+		return ret;
+
+	rx_slot = alloc_rx_slot(dln2, handle);
+	if (rx_slot < 0) {
+		ret = rx_slot;
+		goto out_decr;
+	}
+
+	ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
+	if (ret < 0) {
+		dev_err(dev, "USB write failed: %d\n", ret);
+		goto out_free_rx_slot;
+	}
+
+	rxc = &rxs->slots[rx_slot];
+
+	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
+	if (ret <= 0) {
+		if (!ret)
+			ret = -ETIMEDOUT;
+		goto out_free_rx_slot;
+	}
+
+	if (dln2->disconnect) {
+		ret = -ENODEV;
+		goto out_free_rx_slot;
+	}
+
+	/* if we got here we know that the response header has been checked */
+	rsp = rxc->urb->transfer_buffer;
+
+	if (rsp->hdr.size < sizeof(*rsp)) {
+		ret = -EPROTO;
+		goto out_free_rx_slot;
+	}
+
+	if (le16_to_cpu(rsp->result) > 0x80) {
+		dev_dbg(dev, "%d received response with error %d\n",
+			handle, le16_to_cpu(rsp->result));
+		ret = -EREMOTEIO;
+		goto out_free_rx_slot;
+	}
+
+	if (!ibuf) {
+		ret = 0;
+		goto out_free_rx_slot;
+	}
+
+	if (*ibuf_len > rsp->hdr.size - sizeof(*rsp))
+		*ibuf_len = rsp->hdr.size - sizeof(*rsp);
+
+	memcpy(ibuf, rsp + 1, *ibuf_len);
+
+out_free_rx_slot:
+	free_rx_slot(dln2, handle, rx_slot);
+out_decr:
+	spin_lock(&dln2->disconnect_lock);
+	dln2->active_transfers--;
+	spin_unlock(&dln2->disconnect_lock);
+	if (dln2->disconnect)
+		wake_up(&dln2->disconnect_wq);
+
+	return ret;
+}
+
+int dln2_transfer(struct platform_device *pdev, u16 cmd,
+		  const void *obuf, unsigned obuf_len,
+		  void *ibuf, unsigned *ibuf_len)
+{
+	struct dln2_platform_data *dln2_pdata;
+	struct dln2_dev *dln2;
+	u16 handle;
+
+	dln2 = dev_get_drvdata(pdev->dev.parent);
+	dln2_pdata = dev_get_platdata(&pdev->dev);
+	handle = dln2_pdata->handle;
+
+	return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
+			      ibuf_len);
+}
+EXPORT_SYMBOL(dln2_transfer);
+
+static int dln2_check_hw(struct dln2_dev *dln2)
+{
+	int ret;
+	__le32 hw_type;
+	int len = sizeof(hw_type);
+
+	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
+			     NULL, 0, &hw_type, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(hw_type))
+		return -EREMOTEIO;
+
+	if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
+		dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
+			le32_to_cpu(hw_type));
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int dln2_print_serialno(struct dln2_dev *dln2)
+{
+	int ret;
+	__le32 serial_no;
+	int len = sizeof(serial_no);
+	struct device *dev = &dln2->interface->dev;
+
+	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
+			     &serial_no, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(serial_no))
+		return -EREMOTEIO;
+
+	dev_info(dev, "Diolan DLN2 serial 0x%x\n", le32_to_cpu(serial_no));
+
+	return 0;
+}
+
+static int dln2_hw_init(struct dln2_dev *dln2)
+{
+	int ret;
+
+	ret = dln2_check_hw(dln2);
+	if (ret < 0)
+		return ret;
+
+	return dln2_print_serialno(dln2);
+}
+
+static void dln2_free_rx_urbs(struct dln2_dev *dln2)
+{
+	int i;
+
+	for (i = 0; i < DLN2_MAX_URBS; i++) {
+		usb_kill_urb(dln2->rx_urb[i]);
+		usb_free_urb(dln2->rx_urb[i]);
+		kfree(dln2->rx_buf[i]);
+	}
+}
+
+static void dln2_free(struct dln2_dev *dln2)
+{
+	dln2_free_rx_urbs(dln2);
+	usb_put_dev(dln2->usb_dev);
+	kfree(dln2);
+}
+
+static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
+			      struct usb_host_interface *hostif)
+{
+	int i;
+	const int rx_max_size = DLN2_RX_BUF_SIZE;
+
+	for (i = 0; i < DLN2_MAX_URBS; i++) {
+		int ret;
+		struct device *dev = &dln2->interface->dev;
+
+		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
+		if (!dln2->rx_buf[i])
+			return -ENOMEM;
+
+		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+		if (!dln2->rx_urb[i])
+			return -ENOMEM;
+
+		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
+				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
+				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
+
+		ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL);
+		if (ret < 0) {
+			dev_err(dev, "failed to submit RX URB: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static struct dln2_platform_data dln2_pdata_gpio = {
+	.handle = DLN2_HANDLE_GPIO,
+};
+
+/* Only one I2C port seems to be supported on current hardware */
+static struct dln2_platform_data dln2_pdata_i2c = {
+	.handle = DLN2_HANDLE_I2C,
+	.port = 0,
+};
+
+static const struct mfd_cell dln2_devs[] = {
+	{
+		.name = "dln2-gpio",
+		.platform_data = &dln2_pdata_gpio,
+		.pdata_size = sizeof(struct dln2_platform_data),
+	},
+	{
+		.name = "dln2-i2c",
+		.platform_data = &dln2_pdata_i2c,
+		.pdata_size = sizeof(struct dln2_platform_data),
+	},
+};
+
+static void dln2_disconnect(struct usb_interface *interface)
+{
+	struct dln2_dev *dln2 = usb_get_intfdata(interface);
+	int i, j;
+
+	/* don't allow starting new transfers */
+	spin_lock(&dln2->disconnect_lock);
+	dln2->disconnect = true;
+	spin_unlock(&dln2->disconnect_lock);
+
+	/* cancel in progress transfers */
+	for (i = 0; i < DLN2_HANDLES; i++) {
+		struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
+		unsigned long flags;
+
+		spin_lock_irqsave(&rxs->lock, flags);
+
+		/* cancel all response waiters */
+		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
+			struct dln2_rx_context *rxc = &rxs->slots[j];
+
+			if (rxc->in_use)
+				complete(&rxc->done);
+		}
+
+		spin_unlock_irqrestore(&rxs->lock, flags);
+	}
+
+	/* wait for transfers to end */
+	wait_event(dln2->disconnect_wq, !dln2->active_transfers);
+
+	mfd_remove_devices(&interface->dev);
+
+	dln2_free(dln2);
+}
+
+static int dln2_probe(struct usb_interface *interface,
+		      const struct usb_device_id *usb_id)
+{
+	struct usb_host_interface *hostif = interface->cur_altsetting;
+	struct device *dev = &interface->dev;
+	struct dln2_dev *dln2;
+	int ret;
+	int i, j;
+
+	if (hostif->desc.bInterfaceNumber != 0 ||
+	    hostif->desc.bNumEndpoints < 2)
+		return -ENODEV;
+
+	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
+	if (!dln2)
+		return -ENOMEM;
+
+	dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
+	dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	dln2->interface = interface;
+	usb_set_intfdata(interface, dln2);
+	init_waitqueue_head(&dln2->disconnect_wq);
+
+	for (i = 0; i < DLN2_HANDLES; i++) {
+		init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
+		spin_lock_init(&dln2->mod_rx_slots[i].lock);
+		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
+			init_completion(&dln2->mod_rx_slots[i].slots[j].done);
+	}
+
+	spin_lock_init(&dln2->event_cb_lock);
+	spin_lock_init(&dln2->disconnect_lock);
+	INIT_LIST_HEAD(&dln2->event_cb_list);
+
+	ret = dln2_setup_rx_urbs(dln2, hostif);
+	if (ret)
+		goto out_cleanup;
+
+	ret = dln2_hw_init(dln2);
+	if (ret < 0) {
+		dev_err(dev, "failed to initialize hardware\n");
+		goto out_cleanup;
+	}
+
+	ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
+	if (ret != 0) {
+		dev_err(dev, "failed to add mfd devices to core\n");
+		goto out_cleanup;
+	}
+
+	return 0;
+
+out_cleanup:
+	dln2_free(dln2);
+
+	return ret;
+}
+
+static const struct usb_device_id dln2_table[] = {
+	{ USB_DEVICE(0xa257, 0x2013) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(usb, dln2_table);
+
+static struct usb_driver dln2_driver = {
+	.name = "dln2",
+	.probe = dln2_probe,
+	.disconnect = dln2_disconnect,
+	.id_table = dln2_table,
+};
+
+module_usb_driver(dln2_driver);
+
+MODULE_AUTHOR("Octavian Purdila <octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>");
+MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/dln2.h b/include/linux/mfd/dln2.h
new file mode 100644
index 0000000..1d12807
--- /dev/null
+++ b/include/linux/mfd/dln2.h
@@ -0,0 +1,103 @@
+#ifndef __LINUX_USB_DLN2_H
+#define __LINUX_USB_DLN2_H
+
+#define DLN2_CMD(cmd, id)		((cmd) | ((id) << 8))
+
+struct dln2_platform_data {
+	u16 handle;		/* sub-driver handle (internally used only) */
+	u8 port;		/* I2C/SPI port */
+};
+
+/**
+ * dln2_event_cb_t - event callback function signature
+ *
+ * @pdev - the sub-device that registered this callback
+ * @echo - the echo header field received in the message
+ * @data - the data payload
+ * @len  - the data payload length
+ *
+ * The callback function is called in interrupt context and the data payload is
+ * only valid during the call. If the user needs later access of the data, it
+ * must copy it.
+ */
+
+typedef void (*dln2_event_cb_t)(struct platform_device *pdev, u16 echo,
+				const void *data, int len);
+
+/**
+ * dl2n_register_event_cb - register a callback function for an event
+ *
+ * @pdev - the sub-device that registers the callback
+ * @event - the event for which to register a callback
+ * @event_cb - the callback function
+ *
+ * @return 0 in case of success, negative value in case of error
+ */
+int dln2_register_event_cb(struct platform_device *pdev, u16 event,
+			   dln2_event_cb_t event_cb);
+
+/**
+ * dln2_unregister_event_cb - unregister the callback function for an event
+ *
+ * @pdev - the sub-device that registered the callback
+ * @event - the event for which to register a callback
+ */
+void dln2_unregister_event_cb(struct platform_device *pdev, u16 event);
+
+/**
+ * dln2_transfer - issue a DLN2 command and wait for a response and the
+ * associated data
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @obuf - the buffer to be sent to the device; it can be NULL if the user
+ *	doesn't need to transmit data with this command
+ * @obuf_len - the size of the buffer to be sent to the device
+ * @ibuf - any data associated with the response will be copied here; it can be
+ *	NULL if the user doesn't need the response data
+ * @ibuf_len - must be initialized to the input buffer size; it will be modified
+ *	to indicate the actual data transfered;
+ *
+ * @return 0 for success, negative value for errors
+ */
+int dln2_transfer(struct platform_device *pdev, u16 cmd,
+		  const void *obuf, unsigned obuf_len,
+		  void *ibuf, unsigned *ibuf_len);
+
+/**
+ * dln2_transfer_rx - variant of @dln2_transfer() where TX buffer is not needed
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @ibuf - any data associated with the response will be copied here; it can be
+ *	NULL if the user doesn't need the response data
+ * @ibuf_len - must be initialized to the input buffer size; it will be modified
+ *	to indicate the actual data transfered;
+ *
+ * @return 0 for success, negative value for errors
+ */
+
+static inline int dln2_transfer_rx(struct platform_device *pdev, u16 cmd,
+				   void *ibuf, unsigned *ibuf_len)
+{
+	return dln2_transfer(pdev, cmd, NULL, 0, ibuf, ibuf_len);
+}
+
+/**
+ * dln2_transfer_tx - variant of @dln2_transfer() where RX buffer is not needed
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @obuf - the buffer to be sent to the device; it can be NULL if the
+ *	user doesn't need to transmit data with this command
+ * @obuf_len - the size of the buffer to be sent to the device
+ *
+ * @return 0 for success, negative value for errors
+ */
+static inline int dln2_transfer_tx(struct platform_device *pdev, u16 cmd,
+				   const void *obuf, unsigned obuf_len)
+{
+	return dln2_transfer(pdev, cmd, obuf, obuf_len, NULL, NULL);
+}
+
+#endif
-- 
1.9.1

[PATCH v9 1/4] mfd: add support for Diolan DLN-2 devices

[Octavian Purdila]

This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
Master Adapter DLN-2. Details about the device can be found here:

https://www.diolan.com/i2c/i2c_interface.html.

Information about the USB protocol can be found in the Programmer's
Reference Manual [1], see section 1.7.

Because the hardware has a single transmit endpoint and a single
receive endpoint the communication between the various DLN2 drivers
and the hardware will be muxed/demuxed by this driver.

Each DLN2 module will be identified by the handle field within the DLN2
message header. If a DLN2 module issues multiple commands in parallel
they will be identified by the echo counter field in the message header.

The DLN2 modules can use the dln2_transfer() function to issue a
command and wait for its response. They can also register a callback
that is going to be called when a specific event id is generated by
the device (e.g. GPIO interrupts). The device uses handle 0 for
sending events.

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

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/mfd/Kconfig      |  11 +
 drivers/mfd/Makefile     |   1 +
 drivers/mfd/dln2.c       | 761 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/dln2.h | 103 +++++++
 4 files changed, 876 insertions(+)
 create mode 100644 drivers/mfd/dln2.c
 create mode 100644 include/linux/mfd/dln2.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index c9200d3..4538815a 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -189,6 +189,17 @@ config MFD_DA9063
 	  Additional drivers must be enabled in order to use the functionality
 	  of the device.
 
+config MFD_DLN2
+	tristate "Diolan DLN2 support"
+	select MFD_CORE
+	depends on USB
+	help
+
+	  This adds support for Diolan USB-I2C/SPI/GPIO Master Adapter
+	  DLN-2. Additional drivers such as I2C_DLN2, GPIO_DLN2,
+	  etc. must be enabled in order to use the functionality of
+	  the device.
+
 config MFD_MC13XXX
 	tristate
 	depends on (SPI_MASTER || I2C)
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 61f8dbf..2cd7e74 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -175,6 +175,7 @@ obj-$(CONFIG_MFD_STW481X)	+= stw481x.o
 obj-$(CONFIG_MFD_IPAQ_MICRO)	+= ipaq-micro.o
 obj-$(CONFIG_MFD_MENF21BMC)	+= menf21bmc.o
 obj-$(CONFIG_MFD_HI6421_PMIC)	+= hi6421-pmic-core.o
+obj-$(CONFIG_MFD_DLN2)		+= dln2.o
 
 intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
new file mode 100644
index 0000000..b3946ef
--- /dev/null
+++ b/drivers/mfd/dln2.c
@@ -0,0 +1,761 @@
+/*
+ * Driver for the Diolan DLN-2 USB 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/usb.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/dln2.h>
+#include <linux/rculist.h>
+
+struct dln2_header {
+	__le16 size;
+	__le16 id;
+	__le16 echo;
+	__le16 handle;
+} __packed;
+
+struct dln2_response {
+	struct dln2_header hdr;
+	__le16 result;
+} __packed;
+
+#define DLN2_GENERIC_MODULE_ID		0x00
+#define DLN2_GENERIC_CMD(cmd)		DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)
+#define CMD_GET_DEVICE_VER		DLN2_GENERIC_CMD(0x30)
+#define CMD_GET_DEVICE_SN		DLN2_GENERIC_CMD(0x31)
+
+#define DLN2_HW_ID			0x200
+#define DLN2_USB_TIMEOUT		200	/* in ms */
+#define DLN2_MAX_RX_SLOTS		16
+#define DLN2_MAX_URBS			16
+#define DLN2_RX_BUF_SIZE		512
+
+enum dln2_handle {
+	DLN2_HANDLE_EVENT = 0,		/* don't change, hardware defined */
+	DLN2_HANDLE_CTRL,
+	DLN2_HANDLE_GPIO,
+	DLN2_HANDLE_I2C,
+	DLN2_HANDLES
+};
+
+/*
+ * Receive context used between the receive demultiplexer and the transfer
+ * routine. While sending a request the transfer routine will look for a free
+ * receive context and use it to wait for a response and to receive the URB and
+ * thus the response data.
+ */
+struct dln2_rx_context {
+	/* completion used to wait for a response */
+	struct completion done;
+
+	/* if non-NULL the URB contains the response */
+	struct urb *urb;
+
+	/* if true then this context is used to wait for a response */
+	bool in_use;
+};
+
+/*
+ * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the
+ * handle header field to identify the module in dln2_dev.mod_rx_slots and then
+ * the echo header field to index the slots field and find the receive context
+ * for a particular request.
+ */
+struct dln2_mod_rx_slots {
+	/* RX slots bitmap */
+	DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);
+
+	/* used to wait for a free RX slot */
+	wait_queue_head_t wq;
+
+	/* used to wait for an RX operation to complete */
+	struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];
+
+	/* avoid races between alloc/free_rx_slot and dln2_rx_transfer */
+	spinlock_t lock;
+};
+
+struct dln2_dev {
+	struct usb_device *usb_dev;
+	struct usb_interface *interface;
+	u8 ep_in;
+	u8 ep_out;
+
+	struct urb *rx_urb[DLN2_MAX_URBS];
+	void *rx_buf[DLN2_MAX_URBS];
+
+	struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];
+
+	struct list_head event_cb_list;
+	spinlock_t event_cb_lock;
+
+	bool disconnect;
+	int active_transfers;
+	wait_queue_head_t disconnect_wq;
+	spinlock_t disconnect_lock;
+};
+
+struct dln2_event_cb_entry {
+	struct list_head list;
+	u16 id;
+	struct platform_device *pdev;
+	dln2_event_cb_t callback;
+};
+
+int dln2_register_event_cb(struct platform_device *pdev, u16 id,
+			   dln2_event_cb_t event_cb)
+{
+	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
+	struct dln2_event_cb_entry *i, *entry;
+	unsigned long flags;
+	int ret = 0;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->id = id;
+	entry->callback = event_cb;
+	entry->pdev = pdev;
+
+	spin_lock_irqsave(&dln2->event_cb_lock, flags);
+
+	list_for_each_entry(i, &dln2->event_cb_list, list) {
+		if (i->id == id) {
+			ret = -EBUSY;
+			break;
+		}
+	}
+
+	if (!ret)
+		list_add_rcu(&entry->list, &dln2->event_cb_list);
+
+	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
+
+	if (ret)
+		kfree(entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(dln2_register_event_cb);
+
+void dln2_unregister_event_cb(struct platform_device *pdev, u16 id)
+{
+	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
+	struct dln2_event_cb_entry *i;
+	unsigned long flags;
+	bool found = false;
+
+	spin_lock_irqsave(&dln2->event_cb_lock, flags);
+
+	list_for_each_entry(i, &dln2->event_cb_list, list) {
+		if (i->id == id) {
+			list_del_rcu(&i->list);
+			found = true;
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
+
+	if (found) {
+		synchronize_rcu();
+		kfree(i);
+	}
+}
+EXPORT_SYMBOL(dln2_unregister_event_cb);
+
+/*
+ * Returns true if a valid transfer slot is found. In this case the URB must not
+ * be resubmitted imediately in dln2_rx as we need the data when dln2_transfer
+ * is woke up. It will be resubmitted there.
+ */
+static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
+				   u16 handle, u16 rx_slot)
+{
+	struct device *dev = &dln2->interface->dev;
+	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
+	struct dln2_rx_context *rxc;
+	bool valid_slot = false;
+
+	rxc = &rxs->slots[rx_slot];
+
+	/*
+	 * No need to disable interrupts as this lock is not taken in interrupt
+	 * context elsewhere in this driver. This function (or its callers) are
+	 * also not exported to other modules.
+	 */
+	spin_lock(&rxs->lock);
+	if (rxc->in_use && !rxc->urb) {
+		rxc->urb = urb;
+		complete(&rxc->done);
+		valid_slot = true;
+	}
+	spin_unlock(&rxs->lock);
+
+	if (!valid_slot)
+		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
+
+	return valid_slot;
+}
+
+static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
+				     void *data, int len)
+{
+	struct dln2_event_cb_entry *i;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(i, &dln2->event_cb_list, list)
+		if (i->id == id)
+			i->callback(i->pdev, echo, data, len);
+
+	rcu_read_unlock();
+}
+
+static void dln2_rx(struct urb *urb)
+{
+	struct dln2_dev *dln2 = urb->context;
+	struct dln2_header *hdr = urb->transfer_buffer;
+	struct device *dev = &dln2->interface->dev;
+	u16 id, echo, handle, size;
+	u8 *data;
+	int len;
+	int err;
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+	case -EPIPE:
+		/* this urb is terminated, clean up */
+		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
+		return;
+	default:
+		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
+		goto out;
+	}
+
+	if (urb->actual_length < sizeof(struct dln2_header)) {
+		dev_err(dev, "short response: %d\n", urb->actual_length);
+		goto out;
+	}
+
+	handle = le16_to_cpu(hdr->handle);
+	id = le16_to_cpu(hdr->id);
+	echo = le16_to_cpu(hdr->echo);
+	size = le16_to_cpu(hdr->size);
+
+	if (size != urb->actual_length) {
+		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
+			handle, id, echo, size, urb->actual_length);
+		goto out;
+	}
+
+	if (handle >= DLN2_HANDLES) {
+		dev_warn(dev, "RX: invalid handle %d\n", handle);
+		goto out;
+	}
+
+	data = urb->transfer_buffer + sizeof(struct dln2_header);
+	len = urb->actual_length - sizeof(struct dln2_header);
+
+	if (handle == DLN2_HANDLE_EVENT) {
+		dln2_run_event_callbacks(dln2, id, echo, data, len);
+	} else {
+		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
+		if (dln2_transfer_complete(dln2, urb, handle, echo))
+			return;
+	}
+
+out:
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err < 0)
+		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
+}
+
+static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
+			   int *obuf_len, gfp_t gfp)
+{
+	int len;
+	void *buf;
+	struct dln2_header *hdr;
+
+	len = *obuf_len + sizeof(*hdr);
+	buf = kmalloc(len, gfp);
+	if (!buf)
+		return NULL;
+
+	hdr = (struct dln2_header *)buf;
+	hdr->id = cpu_to_le16(cmd);
+	hdr->size = cpu_to_le16(len);
+	hdr->echo = cpu_to_le16(echo);
+	hdr->handle = cpu_to_le16(handle);
+
+	memcpy(buf + sizeof(*hdr), obuf, *obuf_len);
+
+	*obuf_len = len;
+
+	return buf;
+}
+
+static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
+			  const void *obuf, int obuf_len)
+{
+	int ret = 0;
+	int len = obuf_len;
+	void *buf;
+	int actual;
+
+	buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = usb_bulk_msg(dln2->usb_dev,
+			   usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
+			   buf, len, &actual, DLN2_USB_TIMEOUT);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
+{
+	struct dln2_mod_rx_slots *rxs;
+	unsigned long flags;
+
+	if (dln2->disconnect) {
+		*slot = -ENODEV;
+		return true;
+	}
+
+	rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock_irqsave(&rxs->lock, flags);
+
+	*slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);
+
+	if (*slot < DLN2_MAX_RX_SLOTS) {
+		struct dln2_rx_context *rxc = &rxs->slots[*slot];
+
+		set_bit(*slot, rxs->bmap);
+		rxc->in_use = true;
+	}
+
+	spin_unlock_irqrestore(&rxs->lock, flags);
+
+	return *slot < DLN2_MAX_RX_SLOTS;
+}
+
+static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
+{
+	int ret;
+	int slot;
+
+	/*
+	 * No need to timeout here, the wait is bounded by the timeout in
+	 * _dln2_transfer.
+	 */
+	ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
+				       find_free_slot(dln2, handle, &slot));
+	if (ret < 0)
+		return ret;
+
+	return slot;
+}
+
+static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
+{
+	struct dln2_mod_rx_slots *rxs;
+	struct urb *urb = NULL;
+	unsigned long flags;
+	struct dln2_rx_context *rxc;
+
+	rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock_irqsave(&rxs->lock, flags);
+
+	clear_bit(slot, rxs->bmap);
+
+	rxc = &rxs->slots[slot];
+	rxc->in_use = false;
+	urb = rxc->urb;
+	rxc->urb = NULL;
+	reinit_completion(&rxc->done);
+
+	spin_unlock_irqrestore(&rxs->lock, flags);
+
+	if (urb) {
+		int err;
+		struct device *dev = &dln2->interface->dev;
+
+		err = usb_submit_urb(urb, GFP_KERNEL);
+		if (err < 0)
+			dev_err(dev, "failed to resubmit RX URB: %d\n", err);
+	}
+
+	wake_up_interruptible(&rxs->wq);
+}
+
+static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
+			  const void *obuf, unsigned obuf_len,
+			  void *ibuf, unsigned *ibuf_len)
+{
+	int ret = 0;
+	int rx_slot;
+	struct dln2_response *rsp;
+	struct dln2_rx_context *rxc;
+	struct device *dev = &dln2->interface->dev;
+	const int timeout = DLN2_USB_TIMEOUT * HZ / 1000;
+	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
+
+	spin_lock(&dln2->disconnect_lock);
+	if (!dln2->disconnect)
+		dln2->active_transfers++;
+	else
+		ret = -ENODEV;
+	spin_unlock(&dln2->disconnect_lock);
+
+	if (ret)
+		return ret;
+
+	rx_slot = alloc_rx_slot(dln2, handle);
+	if (rx_slot < 0) {
+		ret = rx_slot;
+		goto out_decr;
+	}
+
+	ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
+	if (ret < 0) {
+		dev_err(dev, "USB write failed: %d\n", ret);
+		goto out_free_rx_slot;
+	}
+
+	rxc = &rxs->slots[rx_slot];
+
+	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
+	if (ret <= 0) {
+		if (!ret)
+			ret = -ETIMEDOUT;
+		goto out_free_rx_slot;
+	}
+
+	if (dln2->disconnect) {
+		ret = -ENODEV;
+		goto out_free_rx_slot;
+	}
+
+	/* if we got here we know that the response header has been checked */
+	rsp = rxc->urb->transfer_buffer;
+
+	if (rsp->hdr.size < sizeof(*rsp)) {
+		ret = -EPROTO;
+		goto out_free_rx_slot;
+	}
+
+	if (le16_to_cpu(rsp->result) > 0x80) {
+		dev_dbg(dev, "%d received response with error %d\n",
+			handle, le16_to_cpu(rsp->result));
+		ret = -EREMOTEIO;
+		goto out_free_rx_slot;
+	}
+
+	if (!ibuf) {
+		ret = 0;
+		goto out_free_rx_slot;
+	}
+
+	if (*ibuf_len > rsp->hdr.size - sizeof(*rsp))
+		*ibuf_len = rsp->hdr.size - sizeof(*rsp);
+
+	memcpy(ibuf, rsp + 1, *ibuf_len);
+
+out_free_rx_slot:
+	free_rx_slot(dln2, handle, rx_slot);
+out_decr:
+	spin_lock(&dln2->disconnect_lock);
+	dln2->active_transfers--;
+	spin_unlock(&dln2->disconnect_lock);
+	if (dln2->disconnect)
+		wake_up(&dln2->disconnect_wq);
+
+	return ret;
+}
+
+int dln2_transfer(struct platform_device *pdev, u16 cmd,
+		  const void *obuf, unsigned obuf_len,
+		  void *ibuf, unsigned *ibuf_len)
+{
+	struct dln2_platform_data *dln2_pdata;
+	struct dln2_dev *dln2;
+	u16 handle;
+
+	dln2 = dev_get_drvdata(pdev->dev.parent);
+	dln2_pdata = dev_get_platdata(&pdev->dev);
+	handle = dln2_pdata->handle;
+
+	return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
+			      ibuf_len);
+}
+EXPORT_SYMBOL(dln2_transfer);
+
+static int dln2_check_hw(struct dln2_dev *dln2)
+{
+	int ret;
+	__le32 hw_type;
+	int len = sizeof(hw_type);
+
+	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
+			     NULL, 0, &hw_type, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(hw_type))
+		return -EREMOTEIO;
+
+	if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
+		dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
+			le32_to_cpu(hw_type));
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int dln2_print_serialno(struct dln2_dev *dln2)
+{
+	int ret;
+	__le32 serial_no;
+	int len = sizeof(serial_no);
+	struct device *dev = &dln2->interface->dev;
+
+	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
+			     &serial_no, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(serial_no))
+		return -EREMOTEIO;
+
+	dev_info(dev, "Diolan DLN2 serial 0x%x\n", le32_to_cpu(serial_no));
+
+	return 0;
+}
+
+static int dln2_hw_init(struct dln2_dev *dln2)
+{
+	int ret;
+
+	ret = dln2_check_hw(dln2);
+	if (ret < 0)
+		return ret;
+
+	return dln2_print_serialno(dln2);
+}
+
+static void dln2_free_rx_urbs(struct dln2_dev *dln2)
+{
+	int i;
+
+	for (i = 0; i < DLN2_MAX_URBS; i++) {
+		usb_kill_urb(dln2->rx_urb[i]);
+		usb_free_urb(dln2->rx_urb[i]);
+		kfree(dln2->rx_buf[i]);
+	}
+}
+
+static void dln2_free(struct dln2_dev *dln2)
+{
+	dln2_free_rx_urbs(dln2);
+	usb_put_dev(dln2->usb_dev);
+	kfree(dln2);
+}
+
+static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
+			      struct usb_host_interface *hostif)
+{
+	int i;
+	const int rx_max_size = DLN2_RX_BUF_SIZE;
+
+	for (i = 0; i < DLN2_MAX_URBS; i++) {
+		int ret;
+		struct device *dev = &dln2->interface->dev;
+
+		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
+		if (!dln2->rx_buf[i])
+			return -ENOMEM;
+
+		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+		if (!dln2->rx_urb[i])
+			return -ENOMEM;
+
+		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
+				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
+				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
+
+		ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL);
+		if (ret < 0) {
+			dev_err(dev, "failed to submit RX URB: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static struct dln2_platform_data dln2_pdata_gpio = {
+	.handle = DLN2_HANDLE_GPIO,
+};
+
+/* Only one I2C port seems to be supported on current hardware */
+static struct dln2_platform_data dln2_pdata_i2c = {
+	.handle = DLN2_HANDLE_I2C,
+	.port = 0,
+};
+
+static const struct mfd_cell dln2_devs[] = {
+	{
+		.name = "dln2-gpio",
+		.platform_data = &dln2_pdata_gpio,
+		.pdata_size = sizeof(struct dln2_platform_data),
+	},
+	{
+		.name = "dln2-i2c",
+		.platform_data = &dln2_pdata_i2c,
+		.pdata_size = sizeof(struct dln2_platform_data),
+	},
+};
+
+static void dln2_disconnect(struct usb_interface *interface)
+{
+	struct dln2_dev *dln2 = usb_get_intfdata(interface);
+	int i, j;
+
+	/* don't allow starting new transfers */
+	spin_lock(&dln2->disconnect_lock);
+	dln2->disconnect = true;
+	spin_unlock(&dln2->disconnect_lock);
+
+	/* cancel in progress transfers */
+	for (i = 0; i < DLN2_HANDLES; i++) {
+		struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
+		unsigned long flags;
+
+		spin_lock_irqsave(&rxs->lock, flags);
+
+		/* cancel all response waiters */
+		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
+			struct dln2_rx_context *rxc = &rxs->slots[j];
+
+			if (rxc->in_use)
+				complete(&rxc->done);
+		}
+
+		spin_unlock_irqrestore(&rxs->lock, flags);
+	}
+
+	/* wait for transfers to end */
+	wait_event(dln2->disconnect_wq, !dln2->active_transfers);
+
+	mfd_remove_devices(&interface->dev);
+
+	dln2_free(dln2);
+}
+
+static int dln2_probe(struct usb_interface *interface,
+		      const struct usb_device_id *usb_id)
+{
+	struct usb_host_interface *hostif = interface->cur_altsetting;
+	struct device *dev = &interface->dev;
+	struct dln2_dev *dln2;
+	int ret;
+	int i, j;
+
+	if (hostif->desc.bInterfaceNumber != 0 ||
+	    hostif->desc.bNumEndpoints < 2)
+		return -ENODEV;
+
+	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
+	if (!dln2)
+		return -ENOMEM;
+
+	dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
+	dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	dln2->interface = interface;
+	usb_set_intfdata(interface, dln2);
+	init_waitqueue_head(&dln2->disconnect_wq);
+
+	for (i = 0; i < DLN2_HANDLES; i++) {
+		init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
+		spin_lock_init(&dln2->mod_rx_slots[i].lock);
+		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
+			init_completion(&dln2->mod_rx_slots[i].slots[j].done);
+	}
+
+	spin_lock_init(&dln2->event_cb_lock);
+	spin_lock_init(&dln2->disconnect_lock);
+	INIT_LIST_HEAD(&dln2->event_cb_list);
+
+	ret = dln2_setup_rx_urbs(dln2, hostif);
+	if (ret)
+		goto out_cleanup;
+
+	ret = dln2_hw_init(dln2);
+	if (ret < 0) {
+		dev_err(dev, "failed to initialize hardware\n");
+		goto out_cleanup;
+	}
+
+	ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
+	if (ret != 0) {
+		dev_err(dev, "failed to add mfd devices to core\n");
+		goto out_cleanup;
+	}
+
+	return 0;
+
+out_cleanup:
+	dln2_free(dln2);
+
+	return ret;
+}
+
+static const struct usb_device_id dln2_table[] = {
+	{ USB_DEVICE(0xa257, 0x2013) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(usb, dln2_table);
+
+static struct usb_driver dln2_driver = {
+	.name = "dln2",
+	.probe = dln2_probe,
+	.disconnect = dln2_disconnect,
+	.id_table = dln2_table,
+};
+
+module_usb_driver(dln2_driver);
+
+MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
+MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/dln2.h b/include/linux/mfd/dln2.h
new file mode 100644
index 0000000..1d12807
--- /dev/null
+++ b/include/linux/mfd/dln2.h
@@ -0,0 +1,103 @@
+#ifndef __LINUX_USB_DLN2_H
+#define __LINUX_USB_DLN2_H
+
+#define DLN2_CMD(cmd, id)		((cmd) | ((id) << 8))
+
+struct dln2_platform_data {
+	u16 handle;		/* sub-driver handle (internally used only) */
+	u8 port;		/* I2C/SPI port */
+};
+
+/**
+ * dln2_event_cb_t - event callback function signature
+ *
+ * @pdev - the sub-device that registered this callback
+ * @echo - the echo header field received in the message
+ * @data - the data payload
+ * @len  - the data payload length
+ *
+ * The callback function is called in interrupt context and the data payload is
+ * only valid during the call. If the user needs later access of the data, it
+ * must copy it.
+ */
+
+typedef void (*dln2_event_cb_t)(struct platform_device *pdev, u16 echo,
+				const void *data, int len);
+
+/**
+ * dl2n_register_event_cb - register a callback function for an event
+ *
+ * @pdev - the sub-device that registers the callback
+ * @event - the event for which to register a callback
+ * @event_cb - the callback function
+ *
+ * @return 0 in case of success, negative value in case of error
+ */
+int dln2_register_event_cb(struct platform_device *pdev, u16 event,
+			   dln2_event_cb_t event_cb);
+
+/**
+ * dln2_unregister_event_cb - unregister the callback function for an event
+ *
+ * @pdev - the sub-device that registered the callback
+ * @event - the event for which to register a callback
+ */
+void dln2_unregister_event_cb(struct platform_device *pdev, u16 event);
+
+/**
+ * dln2_transfer - issue a DLN2 command and wait for a response and the
+ * associated data
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @obuf - the buffer to be sent to the device; it can be NULL if the user
+ *	doesn't need to transmit data with this command
+ * @obuf_len - the size of the buffer to be sent to the device
+ * @ibuf - any data associated with the response will be copied here; it can be
+ *	NULL if the user doesn't need the response data
+ * @ibuf_len - must be initialized to the input buffer size; it will be modified
+ *	to indicate the actual data transfered;
+ *
+ * @return 0 for success, negative value for errors
+ */
+int dln2_transfer(struct platform_device *pdev, u16 cmd,
+		  const void *obuf, unsigned obuf_len,
+		  void *ibuf, unsigned *ibuf_len);
+
+/**
+ * dln2_transfer_rx - variant of @dln2_transfer() where TX buffer is not needed
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @ibuf - any data associated with the response will be copied here; it can be
+ *	NULL if the user doesn't need the response data
+ * @ibuf_len - must be initialized to the input buffer size; it will be modified
+ *	to indicate the actual data transfered;
+ *
+ * @return 0 for success, negative value for errors
+ */
+
+static inline int dln2_transfer_rx(struct platform_device *pdev, u16 cmd,
+				   void *ibuf, unsigned *ibuf_len)
+{
+	return dln2_transfer(pdev, cmd, NULL, 0, ibuf, ibuf_len);
+}
+
+/**
+ * dln2_transfer_tx - variant of @dln2_transfer() where RX buffer is not needed
+ *
+ * @pdev - the sub-device which is issuing this transfer
+ * @cmd - the command to be sent to the device
+ * @obuf - the buffer to be sent to the device; it can be NULL if the
+ *	user doesn't need to transmit data with this command
+ * @obuf_len - the size of the buffer to be sent to the device
+ *
+ * @return 0 for success, negative value for errors
+ */
+static inline int dln2_transfer_tx(struct platform_device *pdev, u16 cmd,
+				   const void *obuf, unsigned obuf_len)
+{
+	return dln2_transfer(pdev, cmd, obuf, obuf_len, NULL, NULL);
+}
+
+#endif
-- 
1.9.1

[PATCH v9 2/4] i2c: add support for Diolan DLN-2 USB-I2C adapter

[Octavian Purdila]

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 | 267 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 278 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..010a5fa
--- /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");
-- 
1.9.1

[PATCH v9 3/4] gpiolib: add irq_not_threaded flag to gpio_chip

[Octavian Purdila]

Some GPIO chips (e.g. the DLN2 USB adapter) have blocking get/set
operation but do not need a threaded irq handler.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/gpio/gpiolib.c      | 2 +-
 include/linux/gpio/driver.h | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 15cc0bb..3fa7e73 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -447,7 +447,7 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
 	irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
 	irq_set_chip_and_handler(irq, chip->irqchip, chip->irq_handler);
 	/* Chips that can sleep need nested thread handlers */
-	if (chip->can_sleep)
+	if (chip->can_sleep && !chip->irq_not_threaded)
 		irq_set_nested_thread(irq, 1);
 #ifdef CONFIG_ARM
 	set_irq_flags(irq, IRQF_VALID);
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index e78a237..44161ac 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -56,6 +56,8 @@ struct seq_file;
  *	as the chip access may sleep when e.g. reading out the IRQ status
  *	registers.
  * @exported: flags if the gpiochip is exported for use from sysfs. Private.
+ * @irq_not_threaded: flag must be set if @can_sleep is set but the
+ *	IRQs don't need to be threaded
  *
  * A gpio_chip can help platforms abstract various sources of GPIOs so
  * they can all be accessed through a common programing interface.
@@ -101,6 +103,7 @@ struct gpio_chip {
 	struct gpio_desc	*desc;
 	const char		*const *names;
 	bool			can_sleep;
+	bool			irq_not_threaded;
 	bool			exported;
 
 #ifdef CONFIG_GPIOLIB_IRQCHIP
-- 
1.9.1

[PATCH v9 4/4] gpio: add support for the Diolan DLN-2 USB GPIO driver

[Octavian Purdila]

From: Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 2.9 for the GPIO
module commands and responses.

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

Signed-off-by: Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Octavian Purdila <octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/gpio/Kconfig     |  12 +
 drivers/gpio/Makefile    |   1 +
 drivers/gpio/gpio-dln2.c | 553 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 566 insertions(+)
 create mode 100644 drivers/gpio/gpio-dln2.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9de1515..44ec206 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -897,4 +897,16 @@ config GPIO_VIPERBOARD
           River Tech's viperboard.h for detailed meaning
           of the module parameters.
 
+config GPIO_DLN2
+	tristate "Diolan DLN2 GPIO support"
+	depends on MFD_DLN2
+	select GPIOLIB_IRQCHIP
+
+	help
+	  Select this option to enable GPIO driver for the Diolan DLN2
+	  board.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called gpio-dln2.
+
 endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d024e3..eaa97a0 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_GPIO_CRYSTAL_COVE)	+= gpio-crystalcove.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
+obj-$(CONFIG_GPIO_DLN2)		+= gpio-dln2.o
 obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
diff --git a/drivers/gpio/gpio-dln2.c b/drivers/gpio/gpio-dln2.c
new file mode 100644
index 0000000..0e31d73
--- /dev/null
+++ b/drivers/gpio/gpio-dln2.c
@@ -0,0 +1,553 @@
+/*
+ * Driver for the Diolan DLN-2 USB-GPIO adapter
+ *
+ * Copyright (c) 2014 Intel Corporation
+ *
+ * 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/slab.h>
+#include <linux/types.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/dln2.h>
+
+#define DLN2_GPIO_ID			0x01
+
+#define DLN2_GPIO_GET_PIN_COUNT		DLN2_CMD(0x01, DLN2_GPIO_ID)
+#define DLN2_GPIO_SET_DEBOUNCE		DLN2_CMD(0x04, DLN2_GPIO_ID)
+#define DLN2_GPIO_GET_DEBOUNCE		DLN2_CMD(0x05, DLN2_GPIO_ID)
+#define DLN2_GPIO_PORT_GET_VAL		DLN2_CMD(0x06, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_VAL		DLN2_CMD(0x0B, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_OUT_VAL	DLN2_CMD(0x0C, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_OUT_VAL	DLN2_CMD(0x0D, DLN2_GPIO_ID)
+#define DLN2_GPIO_CONDITION_MET_EV	DLN2_CMD(0x0F, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_ENABLE		DLN2_CMD(0x10, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_DISABLE		DLN2_CMD(0x11, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_DIRECTION	DLN2_CMD(0x13, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_DIRECTION	DLN2_CMD(0x14, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_EVENT_CFG	DLN2_CMD(0x1E, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_EVENT_CFG	DLN2_CMD(0x1F, DLN2_GPIO_ID)
+
+#define DLN2_GPIO_EVENT_NONE		0
+#define DLN2_GPIO_EVENT_CHANGE		1
+#define DLN2_GPIO_EVENT_LVL_HIGH	2
+#define DLN2_GPIO_EVENT_LVL_LOW		3
+#define DLN2_GPIO_EVENT_CHANGE_RISING	0x11
+#define DLN2_GPIO_EVENT_CHANGE_FALLING  0x21
+#define DLN2_GPIO_EVENT_MASK		0x0F
+
+#define DLN2_GPIO_MAX_PINS 32
+
+struct dln2_irq_work {
+	struct work_struct work;
+	struct dln2_gpio *dln2;
+	int pin;
+	int type;
+};
+
+struct dln2_gpio {
+	struct platform_device *pdev;
+	struct gpio_chip gpio;
+
+	/*
+	 * Cache pin direction to save us one transfer, since the hardware has
+	 * separate commands to read the in and out values.
+	 */
+	DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS);
+
+	DECLARE_BITMAP(irqs_masked, DLN2_GPIO_MAX_PINS);
+	DECLARE_BITMAP(irqs_enabled, DLN2_GPIO_MAX_PINS);
+	DECLARE_BITMAP(irqs_pending, DLN2_GPIO_MAX_PINS);
+	struct dln2_irq_work *irq_work;
+};
+
+struct dln2_gpio_pin {
+	__le16 pin;
+};
+
+struct dln2_gpio_pin_val {
+	__le16 pin __packed;
+	u8 value;
+};
+
+static int dln2_gpio_get_pin_count(struct platform_device *pdev)
+{
+	int ret;
+	__le16 count;
+	int len = sizeof(count);
+
+	ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(count))
+		return -EPROTO;
+
+	return le16_to_cpu(count);
+}
+
+static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin)
+{
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(pin),
+	};
+
+	return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req));
+}
+
+static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin)
+{
+	int ret;
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(pin),
+	};
+	struct dln2_gpio_pin_val rsp;
+	int len = sizeof(rsp);
+
+	ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(rsp) || req.pin != rsp.pin)
+		return -EPROTO;
+
+	return rsp.value;
+}
+
+static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+	int ret;
+
+	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin);
+	if (ret < 0)
+		return ret;
+	return !!ret;
+}
+
+static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+	int ret;
+
+	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin);
+	if (ret < 0)
+		return ret;
+	return !!ret;
+}
+
+static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
+				      unsigned int pin, int value)
+{
+	struct dln2_gpio_pin_val req = {
+		.pin = cpu_to_le16(pin),
+		.value = cpu_to_le16(value),
+	};
+
+	dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
+			 sizeof(req));
+}
+
+#define DLN2_GPIO_DIRECTION_IN		0
+#define DLN2_GPIO_DIRECTION_OUT		1
+
+static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(offset),
+	};
+	struct dln2_gpio_pin_val rsp;
+	int len = sizeof(rsp);
+	int ret;
+
+	ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
+	if (ret < 0)
+		return ret;
+
+	/* cache the pin direction */
+	ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
+			    &req, sizeof(req), &rsp, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(rsp) || req.pin != rsp.pin) {
+		ret = -EPROTO;
+		goto out_disable;
+	}
+
+	switch (rsp.value) {
+	case DLN2_GPIO_DIRECTION_IN:
+		clear_bit(offset, dln2->output_enabled);
+		return 0;
+	case DLN2_GPIO_DIRECTION_OUT:
+		set_bit(offset, dln2->output_enabled);
+		return 0;
+	default:
+		ret = -EPROTO;
+		goto out_disable;
+	}
+
+out_disable:
+	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+	return ret;
+}
+
+static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+}
+
+static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	if (test_bit(offset, dln2->output_enabled))
+		return GPIOF_DIR_OUT;
+
+	return GPIOF_DIR_IN;
+}
+
+static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	int dir;
+
+	dir = dln2_gpio_get_direction(chip, offset);
+	if (dir < 0)
+		return dir;
+
+	if (dir == GPIOF_DIR_IN)
+		return dln2_gpio_pin_get_in_val(dln2, offset);
+
+	return dln2_gpio_pin_get_out_val(dln2, offset);
+}
+
+static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	dln2_gpio_pin_set_out_val(dln2, offset, value);
+}
+
+static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
+				   unsigned dir)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	struct dln2_gpio_pin_val req = {
+		.pin = cpu_to_le16(offset),
+		.value = cpu_to_le16(dir),
+	};
+	int ret;
+
+	ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION,
+			       &req, sizeof(req));
+	if (ret < 0)
+		return ret;
+
+	if (dir == DLN2_GPIO_DIRECTION_OUT)
+		set_bit(offset, dln2->output_enabled);
+	else
+		clear_bit(offset, dln2->output_enabled);
+
+	return ret;
+}
+
+static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN);
+}
+
+static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+				      int value)
+{
+	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
+}
+
+static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+				  unsigned debounce)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	__le32 duration = cpu_to_le32(debounce);
+
+	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE,
+				&duration, sizeof(duration));
+}
+
+static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin,
+				   unsigned type, unsigned period)
+{
+	struct {
+		__le16 pin;
+		u8 type;
+		__le16 period;
+	} __packed req = {
+		.pin = cpu_to_le16(pin),
+		.type = type,
+		.period = cpu_to_le16(period),
+	};
+
+	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG,
+				&req, sizeof(req));
+}
+
+static void dln2_irq_work(struct work_struct *w)
+{
+	struct dln2_irq_work *iw = container_of(w, struct dln2_irq_work, work);
+	struct dln2_gpio *dln2 = iw->dln2;
+	u8 type = iw->type & DLN2_GPIO_EVENT_MASK;
+
+	if (test_bit(iw->pin, dln2->irqs_enabled))
+		dln2_gpio_set_event_cfg(dln2, iw->pin, type, 0);
+	else
+		dln2_gpio_set_event_cfg(dln2, iw->pin, DLN2_GPIO_EVENT_NONE, 0);
+}
+
+static void dln2_irq_enable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	set_bit(pin, dln2->irqs_enabled);
+	schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_disable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	clear_bit(pin, dln2->irqs_enabled);
+	schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_mask(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	set_bit(pin, dln2->irqs_masked);
+}
+
+static void dln2_irq_unmask(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	struct device *dev = dln2->gpio.dev;
+	int pin = irqd_to_hwirq(irqd);
+
+	if (test_and_clear_bit(pin, dln2->irqs_pending)) {
+		int irq;
+
+		irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+		if (!irq) {
+			dev_err(dev, "pin %d not mapped to IRQ\n", pin);
+			return;
+		}
+
+		generic_handle_irq(irq);
+	}
+}
+
+static int dln2_irq_set_type(struct irq_data *irqd, unsigned type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	switch (type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_LOW;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_FALLING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct irq_chip dln2_gpio_irqchip = {
+	.name = "dln2-irq",
+	.irq_enable = dln2_irq_enable,
+	.irq_disable = dln2_irq_disable,
+	.irq_mask = dln2_irq_mask,
+	.irq_unmask = dln2_irq_unmask,
+	.irq_set_type = dln2_irq_set_type,
+};
+
+static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
+			    const void *data, int len)
+{
+	int pin, irq;
+	const struct {
+		__le16 count;
+		__u8 type;
+		__le16 pin;
+		__u8 value;
+	} __packed *event = data;
+	struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+
+	if (len < sizeof(*event)) {
+		dev_err(dln2->gpio.dev, "short event message\n");
+		return;
+	}
+
+	pin = le16_to_cpu(event->pin);
+	if (pin >= dln2->gpio.ngpio) {
+		dev_err(dln2->gpio.dev, "out of bounds pin %d\n", pin);
+		return;
+	}
+
+	irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+	if (!irq) {
+		dev_err(dln2->gpio.dev, "pin %d not mapped to IRQ\n", pin);
+		return;
+	}
+
+	if (!test_bit(pin, dln2->irqs_enabled))
+		return;
+	if (test_bit(pin, dln2->irqs_masked)) {
+		set_bit(pin, dln2->irqs_pending);
+		return;
+	}
+
+	switch (dln2->irq_work[pin].type) {
+	case DLN2_GPIO_EVENT_CHANGE_RISING:
+		if (event->value)
+			generic_handle_irq(irq);
+		break;
+	case DLN2_GPIO_EVENT_CHANGE_FALLING:
+		if (!event->value)
+			generic_handle_irq(irq);
+		break;
+	default:
+		generic_handle_irq(irq);
+	}
+}
+
+static int dln2_gpio_probe(struct platform_device *pdev)
+{
+	struct dln2_gpio *dln2;
+	struct device *dev = &pdev->dev;
+	int pins;
+	int i, ret;
+
+	pins = dln2_gpio_get_pin_count(pdev);
+	if (pins < 0) {
+		dev_err(dev, "failed to get pin count: %d\n", pins);
+		return pins;
+	}
+	if (pins > DLN2_GPIO_MAX_PINS) {
+		pins = DLN2_GPIO_MAX_PINS;
+		dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS);
+	}
+
+	dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL);
+	if (!dln2)
+		return -ENOMEM;
+
+	dln2->irq_work = devm_kcalloc(&pdev->dev, pins,
+				      sizeof(struct dln2_irq_work), GFP_KERNEL);
+	if (!dln2->irq_work)
+		return -ENOMEM;
+	for (i = 0; i < pins; i++) {
+		INIT_WORK(&dln2->irq_work[i].work, dln2_irq_work);
+		dln2->irq_work[i].pin = i;
+		dln2->irq_work[i].dln2 = dln2;
+	}
+
+	dln2->pdev = pdev;
+
+	dln2->gpio.label = "dln2";
+	dln2->gpio.dev = dev;
+	dln2->gpio.owner = THIS_MODULE;
+	dln2->gpio.base = -1;
+	dln2->gpio.ngpio = pins;
+	dln2->gpio.exported = true;
+	dln2->gpio.can_sleep = true;
+	dln2->gpio.irq_not_threaded = true;
+	dln2->gpio.set = dln2_gpio_set;
+	dln2->gpio.get = dln2_gpio_get;
+	dln2->gpio.request = dln2_gpio_request;
+	dln2->gpio.free = dln2_gpio_free;
+	dln2->gpio.get_direction = dln2_gpio_get_direction;
+	dln2->gpio.direction_input = dln2_gpio_direction_input;
+	dln2->gpio.direction_output = dln2_gpio_direction_output;
+	dln2->gpio.set_debounce = dln2_gpio_set_debounce;
+
+	platform_set_drvdata(pdev, dln2);
+
+	ret = gpiochip_add(&dln2->gpio);
+	if (ret < 0) {
+		dev_err(dev, "failed to add gpio chip: %d\n", ret);
+		goto out;
+	}
+
+	ret = gpiochip_irqchip_add(&dln2->gpio, &dln2_gpio_irqchip, 0,
+				   handle_simple_irq, IRQ_TYPE_NONE);
+	if (ret < 0) {
+		dev_err(dev, "failed to add irq chip: %d\n", ret);
+		goto out_gpiochip_remove;
+	}
+
+	ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV,
+				     dln2_gpio_event);
+	if (ret) {
+		dev_err(dev, "failed to register event cb: %d\n", ret);
+		goto out_gpiochip_remove;
+	}
+
+	return 0;
+
+out_gpiochip_remove:
+	gpiochip_remove(&dln2->gpio);
+out:
+	return ret;
+}
+
+static int dln2_gpio_remove(struct platform_device *pdev)
+{
+	struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+	int i;
+
+	dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
+	for (i = 0; i < dln2->gpio.ngpio; i++)
+		flush_work(&dln2->irq_work[i].work);
+	gpiochip_remove(&dln2->gpio);
+
+	return 0;
+}
+
+static struct platform_driver dln2_gpio_driver = {
+	.driver.name	= "dln2-gpio",
+	.probe		= dln2_gpio_probe,
+	.remove		= dln2_gpio_remove,
+};
+
+module_platform_driver(dln2_gpio_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org");
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-gpio");
-- 
1.9.1

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[PATCH v9 4/4] gpio: add support for the Diolan DLN-2 USB GPIO driver

[Octavian Purdila]

From: Daniel Baluta <daniel.baluta@intel.com>

This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 2.9 for the GPIO
module commands and responses.

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

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/gpio/Kconfig     |  12 +
 drivers/gpio/Makefile    |   1 +
 drivers/gpio/gpio-dln2.c | 553 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 566 insertions(+)
 create mode 100644 drivers/gpio/gpio-dln2.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9de1515..44ec206 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -897,4 +897,16 @@ config GPIO_VIPERBOARD
           River Tech's viperboard.h for detailed meaning
           of the module parameters.
 
+config GPIO_DLN2
+	tristate "Diolan DLN2 GPIO support"
+	depends on MFD_DLN2
+	select GPIOLIB_IRQCHIP
+
+	help
+	  Select this option to enable GPIO driver for the Diolan DLN2
+	  board.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called gpio-dln2.
+
 endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d024e3..eaa97a0 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_GPIO_CRYSTAL_COVE)	+= gpio-crystalcove.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
+obj-$(CONFIG_GPIO_DLN2)		+= gpio-dln2.o
 obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
 obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o
diff --git a/drivers/gpio/gpio-dln2.c b/drivers/gpio/gpio-dln2.c
new file mode 100644
index 0000000..0e31d73
--- /dev/null
+++ b/drivers/gpio/gpio-dln2.c
@@ -0,0 +1,553 @@
+/*
+ * Driver for the Diolan DLN-2 USB-GPIO adapter
+ *
+ * Copyright (c) 2014 Intel Corporation
+ *
+ * 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/slab.h>
+#include <linux/types.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/dln2.h>
+
+#define DLN2_GPIO_ID			0x01
+
+#define DLN2_GPIO_GET_PIN_COUNT		DLN2_CMD(0x01, DLN2_GPIO_ID)
+#define DLN2_GPIO_SET_DEBOUNCE		DLN2_CMD(0x04, DLN2_GPIO_ID)
+#define DLN2_GPIO_GET_DEBOUNCE		DLN2_CMD(0x05, DLN2_GPIO_ID)
+#define DLN2_GPIO_PORT_GET_VAL		DLN2_CMD(0x06, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_VAL		DLN2_CMD(0x0B, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_OUT_VAL	DLN2_CMD(0x0C, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_OUT_VAL	DLN2_CMD(0x0D, DLN2_GPIO_ID)
+#define DLN2_GPIO_CONDITION_MET_EV	DLN2_CMD(0x0F, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_ENABLE		DLN2_CMD(0x10, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_DISABLE		DLN2_CMD(0x11, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_DIRECTION	DLN2_CMD(0x13, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_DIRECTION	DLN2_CMD(0x14, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_EVENT_CFG	DLN2_CMD(0x1E, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_EVENT_CFG	DLN2_CMD(0x1F, DLN2_GPIO_ID)
+
+#define DLN2_GPIO_EVENT_NONE		0
+#define DLN2_GPIO_EVENT_CHANGE		1
+#define DLN2_GPIO_EVENT_LVL_HIGH	2
+#define DLN2_GPIO_EVENT_LVL_LOW		3
+#define DLN2_GPIO_EVENT_CHANGE_RISING	0x11
+#define DLN2_GPIO_EVENT_CHANGE_FALLING  0x21
+#define DLN2_GPIO_EVENT_MASK		0x0F
+
+#define DLN2_GPIO_MAX_PINS 32
+
+struct dln2_irq_work {
+	struct work_struct work;
+	struct dln2_gpio *dln2;
+	int pin;
+	int type;
+};
+
+struct dln2_gpio {
+	struct platform_device *pdev;
+	struct gpio_chip gpio;
+
+	/*
+	 * Cache pin direction to save us one transfer, since the hardware has
+	 * separate commands to read the in and out values.
+	 */
+	DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS);
+
+	DECLARE_BITMAP(irqs_masked, DLN2_GPIO_MAX_PINS);
+	DECLARE_BITMAP(irqs_enabled, DLN2_GPIO_MAX_PINS);
+	DECLARE_BITMAP(irqs_pending, DLN2_GPIO_MAX_PINS);
+	struct dln2_irq_work *irq_work;
+};
+
+struct dln2_gpio_pin {
+	__le16 pin;
+};
+
+struct dln2_gpio_pin_val {
+	__le16 pin __packed;
+	u8 value;
+};
+
+static int dln2_gpio_get_pin_count(struct platform_device *pdev)
+{
+	int ret;
+	__le16 count;
+	int len = sizeof(count);
+
+	ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(count))
+		return -EPROTO;
+
+	return le16_to_cpu(count);
+}
+
+static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin)
+{
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(pin),
+	};
+
+	return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req));
+}
+
+static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin)
+{
+	int ret;
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(pin),
+	};
+	struct dln2_gpio_pin_val rsp;
+	int len = sizeof(rsp);
+
+	ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(rsp) || req.pin != rsp.pin)
+		return -EPROTO;
+
+	return rsp.value;
+}
+
+static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+	int ret;
+
+	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin);
+	if (ret < 0)
+		return ret;
+	return !!ret;
+}
+
+static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+	int ret;
+
+	ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin);
+	if (ret < 0)
+		return ret;
+	return !!ret;
+}
+
+static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
+				      unsigned int pin, int value)
+{
+	struct dln2_gpio_pin_val req = {
+		.pin = cpu_to_le16(pin),
+		.value = cpu_to_le16(value),
+	};
+
+	dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
+			 sizeof(req));
+}
+
+#define DLN2_GPIO_DIRECTION_IN		0
+#define DLN2_GPIO_DIRECTION_OUT		1
+
+static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	struct dln2_gpio_pin req = {
+		.pin = cpu_to_le16(offset),
+	};
+	struct dln2_gpio_pin_val rsp;
+	int len = sizeof(rsp);
+	int ret;
+
+	ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
+	if (ret < 0)
+		return ret;
+
+	/* cache the pin direction */
+	ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
+			    &req, sizeof(req), &rsp, &len);
+	if (ret < 0)
+		return ret;
+	if (len < sizeof(rsp) || req.pin != rsp.pin) {
+		ret = -EPROTO;
+		goto out_disable;
+	}
+
+	switch (rsp.value) {
+	case DLN2_GPIO_DIRECTION_IN:
+		clear_bit(offset, dln2->output_enabled);
+		return 0;
+	case DLN2_GPIO_DIRECTION_OUT:
+		set_bit(offset, dln2->output_enabled);
+		return 0;
+	default:
+		ret = -EPROTO;
+		goto out_disable;
+	}
+
+out_disable:
+	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+	return ret;
+}
+
+static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+}
+
+static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	if (test_bit(offset, dln2->output_enabled))
+		return GPIOF_DIR_OUT;
+
+	return GPIOF_DIR_IN;
+}
+
+static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	int dir;
+
+	dir = dln2_gpio_get_direction(chip, offset);
+	if (dir < 0)
+		return dir;
+
+	if (dir == GPIOF_DIR_IN)
+		return dln2_gpio_pin_get_in_val(dln2, offset);
+
+	return dln2_gpio_pin_get_out_val(dln2, offset);
+}
+
+static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+	dln2_gpio_pin_set_out_val(dln2, offset, value);
+}
+
+static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
+				   unsigned dir)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	struct dln2_gpio_pin_val req = {
+		.pin = cpu_to_le16(offset),
+		.value = cpu_to_le16(dir),
+	};
+	int ret;
+
+	ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION,
+			       &req, sizeof(req));
+	if (ret < 0)
+		return ret;
+
+	if (dir == DLN2_GPIO_DIRECTION_OUT)
+		set_bit(offset, dln2->output_enabled);
+	else
+		clear_bit(offset, dln2->output_enabled);
+
+	return ret;
+}
+
+static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN);
+}
+
+static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+				      int value)
+{
+	return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
+}
+
+static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+				  unsigned debounce)
+{
+	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+	__le32 duration = cpu_to_le32(debounce);
+
+	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE,
+				&duration, sizeof(duration));
+}
+
+static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin,
+				   unsigned type, unsigned period)
+{
+	struct {
+		__le16 pin;
+		u8 type;
+		__le16 period;
+	} __packed req = {
+		.pin = cpu_to_le16(pin),
+		.type = type,
+		.period = cpu_to_le16(period),
+	};
+
+	return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG,
+				&req, sizeof(req));
+}
+
+static void dln2_irq_work(struct work_struct *w)
+{
+	struct dln2_irq_work *iw = container_of(w, struct dln2_irq_work, work);
+	struct dln2_gpio *dln2 = iw->dln2;
+	u8 type = iw->type & DLN2_GPIO_EVENT_MASK;
+
+	if (test_bit(iw->pin, dln2->irqs_enabled))
+		dln2_gpio_set_event_cfg(dln2, iw->pin, type, 0);
+	else
+		dln2_gpio_set_event_cfg(dln2, iw->pin, DLN2_GPIO_EVENT_NONE, 0);
+}
+
+static void dln2_irq_enable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	set_bit(pin, dln2->irqs_enabled);
+	schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_disable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	clear_bit(pin, dln2->irqs_enabled);
+	schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_mask(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	set_bit(pin, dln2->irqs_masked);
+}
+
+static void dln2_irq_unmask(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	struct device *dev = dln2->gpio.dev;
+	int pin = irqd_to_hwirq(irqd);
+
+	if (test_and_clear_bit(pin, dln2->irqs_pending)) {
+		int irq;
+
+		irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+		if (!irq) {
+			dev_err(dev, "pin %d not mapped to IRQ\n", pin);
+			return;
+		}
+
+		generic_handle_irq(irq);
+	}
+}
+
+static int dln2_irq_set_type(struct irq_data *irqd, unsigned type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+	int pin = irqd_to_hwirq(irqd);
+
+	switch (type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_LOW;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_FALLING;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct irq_chip dln2_gpio_irqchip = {
+	.name = "dln2-irq",
+	.irq_enable = dln2_irq_enable,
+	.irq_disable = dln2_irq_disable,
+	.irq_mask = dln2_irq_mask,
+	.irq_unmask = dln2_irq_unmask,
+	.irq_set_type = dln2_irq_set_type,
+};
+
+static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
+			    const void *data, int len)
+{
+	int pin, irq;
+	const struct {
+		__le16 count;
+		__u8 type;
+		__le16 pin;
+		__u8 value;
+	} __packed *event = data;
+	struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+
+	if (len < sizeof(*event)) {
+		dev_err(dln2->gpio.dev, "short event message\n");
+		return;
+	}
+
+	pin = le16_to_cpu(event->pin);
+	if (pin >= dln2->gpio.ngpio) {
+		dev_err(dln2->gpio.dev, "out of bounds pin %d\n", pin);
+		return;
+	}
+
+	irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+	if (!irq) {
+		dev_err(dln2->gpio.dev, "pin %d not mapped to IRQ\n", pin);
+		return;
+	}
+
+	if (!test_bit(pin, dln2->irqs_enabled))
+		return;
+	if (test_bit(pin, dln2->irqs_masked)) {
+		set_bit(pin, dln2->irqs_pending);
+		return;
+	}
+
+	switch (dln2->irq_work[pin].type) {
+	case DLN2_GPIO_EVENT_CHANGE_RISING:
+		if (event->value)
+			generic_handle_irq(irq);
+		break;
+	case DLN2_GPIO_EVENT_CHANGE_FALLING:
+		if (!event->value)
+			generic_handle_irq(irq);
+		break;
+	default:
+		generic_handle_irq(irq);
+	}
+}
+
+static int dln2_gpio_probe(struct platform_device *pdev)
+{
+	struct dln2_gpio *dln2;
+	struct device *dev = &pdev->dev;
+	int pins;
+	int i, ret;
+
+	pins = dln2_gpio_get_pin_count(pdev);
+	if (pins < 0) {
+		dev_err(dev, "failed to get pin count: %d\n", pins);
+		return pins;
+	}
+	if (pins > DLN2_GPIO_MAX_PINS) {
+		pins = DLN2_GPIO_MAX_PINS;
+		dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS);
+	}
+
+	dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL);
+	if (!dln2)
+		return -ENOMEM;
+
+	dln2->irq_work = devm_kcalloc(&pdev->dev, pins,
+				      sizeof(struct dln2_irq_work), GFP_KERNEL);
+	if (!dln2->irq_work)
+		return -ENOMEM;
+	for (i = 0; i < pins; i++) {
+		INIT_WORK(&dln2->irq_work[i].work, dln2_irq_work);
+		dln2->irq_work[i].pin = i;
+		dln2->irq_work[i].dln2 = dln2;
+	}
+
+	dln2->pdev = pdev;
+
+	dln2->gpio.label = "dln2";
+	dln2->gpio.dev = dev;
+	dln2->gpio.owner = THIS_MODULE;
+	dln2->gpio.base = -1;
+	dln2->gpio.ngpio = pins;
+	dln2->gpio.exported = true;
+	dln2->gpio.can_sleep = true;
+	dln2->gpio.irq_not_threaded = true;
+	dln2->gpio.set = dln2_gpio_set;
+	dln2->gpio.get = dln2_gpio_get;
+	dln2->gpio.request = dln2_gpio_request;
+	dln2->gpio.free = dln2_gpio_free;
+	dln2->gpio.get_direction = dln2_gpio_get_direction;
+	dln2->gpio.direction_input = dln2_gpio_direction_input;
+	dln2->gpio.direction_output = dln2_gpio_direction_output;
+	dln2->gpio.set_debounce = dln2_gpio_set_debounce;
+
+	platform_set_drvdata(pdev, dln2);
+
+	ret = gpiochip_add(&dln2->gpio);
+	if (ret < 0) {
+		dev_err(dev, "failed to add gpio chip: %d\n", ret);
+		goto out;
+	}
+
+	ret = gpiochip_irqchip_add(&dln2->gpio, &dln2_gpio_irqchip, 0,
+				   handle_simple_irq, IRQ_TYPE_NONE);
+	if (ret < 0) {
+		dev_err(dev, "failed to add irq chip: %d\n", ret);
+		goto out_gpiochip_remove;
+	}
+
+	ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV,
+				     dln2_gpio_event);
+	if (ret) {
+		dev_err(dev, "failed to register event cb: %d\n", ret);
+		goto out_gpiochip_remove;
+	}
+
+	return 0;
+
+out_gpiochip_remove:
+	gpiochip_remove(&dln2->gpio);
+out:
+	return ret;
+}
+
+static int dln2_gpio_remove(struct platform_device *pdev)
+{
+	struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+	int i;
+
+	dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
+	for (i = 0; i < dln2->gpio.ngpio; i++)
+		flush_work(&dln2->irq_work[i].work);
+	gpiochip_remove(&dln2->gpio);
+
+	return 0;
+}
+
+static struct platform_driver dln2_gpio_driver = {
+	.driver.name	= "dln2-gpio",
+	.probe		= dln2_gpio_probe,
+	.remove		= dln2_gpio_remove,
+};
+
+module_platform_driver(dln2_gpio_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-gpio");
-- 
1.9.1

Re: [PATCH v9 1/4] mfd: add support for Diolan DLN-2 devices

[Joe Perches]

On Mon, 2014-10-27 at 18:31 +0200, Octavian Purdila wrote:
> This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
> Master Adapter DLN-2. Details about the device can be found here:

trivia:

> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
[]
> +static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
> +			  const void *obuf, unsigned obuf_len,
> +			  void *ibuf, unsigned *ibuf_len)
> +{
> +	int ret = 0;
> +	int rx_slot;
> +	struct dln2_response *rsp;
> +	struct dln2_rx_context *rxc;
> +	struct device *dev = &dln2->interface->dev;
> +	const int timeout = DLN2_USB_TIMEOUT * HZ / 1000;

unsigned long timeout?

[]

> +	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
> +	if (ret <= 0) {
> +		if (!ret)
> +			ret = -ETIMEDOUT;
> +		goto out_free_rx_slot;
> +	}

[]

> +static int dln2_print_serialno(struct dln2_dev *dln2)
> +{
> +	int ret;
> +	__le32 serial_no;
> +	int len = sizeof(serial_no);
> +	struct device *dev = &dln2->interface->dev;
> +
> +	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
> +			     &serial_no, &len);
> +	if (ret < 0)
> +		return ret;
> +	if (len < sizeof(serial_no))
> +		return -EREMOTEIO;
> +
> +	dev_info(dev, "Diolan DLN2 serial 0x%x\n", le32_to_cpu(serial_no));

why a hex serial #?

Re: [PATCH v9 1/4] mfd: add support for Diolan DLN-2 devices

[Octavian Purdila]

On Mon, Oct 27, 2014 at 6:57 PM, Joe Perches <joe@perches.com> wrote:
> On Mon, 2014-10-27 at 18:31 +0200, Octavian Purdila wrote:
>> This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
>> Master Adapter DLN-2. Details about the device can be found here:
>
> trivia:
>

Thanks for the review Joe.

>> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> []
>> +static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
>> +                       const void *obuf, unsigned obuf_len,
>> +                       void *ibuf, unsigned *ibuf_len)
>> +{
>> +     int ret = 0;
>> +     int rx_slot;
>> +     struct dln2_response *rsp;
>> +     struct dln2_rx_context *rxc;
>> +     struct device *dev = &dln2->interface->dev;
>> +     const int timeout = DLN2_USB_TIMEOUT * HZ / 1000;
>
> unsigned long timeout?
>

Ok.

> []
>
>> +     ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
>> +     if (ret <= 0) {
>> +             if (!ret)
>> +                     ret = -ETIMEDOUT;
>> +             goto out_free_rx_slot;
>> +     }
>
> []

I think you forgot to add your comments here?

>
>> +static int dln2_print_serialno(struct dln2_dev *dln2)
>> +{
>> +     int ret;
>> +     __le32 serial_no;
>> +     int len = sizeof(serial_no);
>> +     struct device *dev = &dln2->interface->dev;
>> +
>> +     ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
>> +                          &serial_no, &len);
>> +     if (ret < 0)
>> +             return ret;
>> +     if (len < sizeof(serial_no))
>> +             return -EREMOTEIO;
>> +
>> +     dev_info(dev, "Diolan DLN2 serial 0x%x\n", le32_to_cpu(serial_no));
>
> why a hex serial #?
>

Good point, I will switch it to decimal.

Re: [PATCH v9 4/4] gpio: add support for the Diolan DLN-2 USB GPIO driver

[Johan Hovold]

On Mon, Oct 27, 2014 at 06:31:12PM +0200, Octavian Purdila wrote:
> From: Daniel Baluta <daniel.baluta-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

[...]

> +static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
> +				      unsigned int pin, int value)
> +{
> +	struct dln2_gpio_pin_val req = {
> +		.pin = cpu_to_le16(pin),
> +		.value = cpu_to_le16(value),

Drop cpu_to_le16 (value is u8).

> +	};
> +
> +	dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
> +			 sizeof(req));
> +}
> +
> +#define DLN2_GPIO_DIRECTION_IN		0
> +#define DLN2_GPIO_DIRECTION_OUT		1
> +
> +static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	struct dln2_gpio_pin req = {
> +		.pin = cpu_to_le16(offset),
> +	};
> +	struct dln2_gpio_pin_val rsp;
> +	int len = sizeof(rsp);
> +	int ret;
> +
> +	ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* cache the pin direction */
> +	ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
> +			    &req, sizeof(req), &rsp, &len);
> +	if (ret < 0)
> +		return ret;
> +	if (len < sizeof(rsp) || req.pin != rsp.pin) {
> +		ret = -EPROTO;
> +		goto out_disable;
> +	}
> +
> +	switch (rsp.value) {
> +	case DLN2_GPIO_DIRECTION_IN:
> +		clear_bit(offset, dln2->output_enabled);
> +		return 0;
> +	case DLN2_GPIO_DIRECTION_OUT:
> +		set_bit(offset, dln2->output_enabled);
> +		return 0;
> +	default:
> +		ret = -EPROTO;
> +		goto out_disable;
> +	}
> +
> +out_disable:
> +	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
> +	return ret;
> +}
> +
> +static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
> +}
> +
> +static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	if (test_bit(offset, dln2->output_enabled))
> +		return GPIOF_DIR_OUT;
> +
> +	return GPIOF_DIR_IN;
> +}
> +
> +static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	int dir;
> +
> +	dir = dln2_gpio_get_direction(chip, offset);
> +	if (dir < 0)
> +		return dir;
> +
> +	if (dir == GPIOF_DIR_IN)
> +		return dln2_gpio_pin_get_in_val(dln2, offset);
> +
> +	return dln2_gpio_pin_get_out_val(dln2, offset);
> +}
> +
> +static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	dln2_gpio_pin_set_out_val(dln2, offset, value);
> +}
> +
> +static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
> +				   unsigned dir)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	struct dln2_gpio_pin_val req = {
> +		.pin = cpu_to_le16(offset),
> +		.value = cpu_to_le16(dir),

Same here.

Johan

Re: [PATCH v9 4/4] gpio: add support for the Diolan DLN-2 USB GPIO driver

[Johan Hovold]

On Mon, Oct 27, 2014 at 06:31:12PM +0200, Octavian Purdila wrote:
> From: Daniel Baluta <daniel.baluta@intel.com>
> 
> This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

[...]

> +static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
> +				      unsigned int pin, int value)
> +{
> +	struct dln2_gpio_pin_val req = {
> +		.pin = cpu_to_le16(pin),
> +		.value = cpu_to_le16(value),

Drop cpu_to_le16 (value is u8).

> +	};
> +
> +	dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
> +			 sizeof(req));
> +}
> +
> +#define DLN2_GPIO_DIRECTION_IN		0
> +#define DLN2_GPIO_DIRECTION_OUT		1
> +
> +static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	struct dln2_gpio_pin req = {
> +		.pin = cpu_to_le16(offset),
> +	};
> +	struct dln2_gpio_pin_val rsp;
> +	int len = sizeof(rsp);
> +	int ret;
> +
> +	ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* cache the pin direction */
> +	ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
> +			    &req, sizeof(req), &rsp, &len);
> +	if (ret < 0)
> +		return ret;
> +	if (len < sizeof(rsp) || req.pin != rsp.pin) {
> +		ret = -EPROTO;
> +		goto out_disable;
> +	}
> +
> +	switch (rsp.value) {
> +	case DLN2_GPIO_DIRECTION_IN:
> +		clear_bit(offset, dln2->output_enabled);
> +		return 0;
> +	case DLN2_GPIO_DIRECTION_OUT:
> +		set_bit(offset, dln2->output_enabled);
> +		return 0;
> +	default:
> +		ret = -EPROTO;
> +		goto out_disable;
> +	}
> +
> +out_disable:
> +	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
> +	return ret;
> +}
> +
> +static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
> +}
> +
> +static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	if (test_bit(offset, dln2->output_enabled))
> +		return GPIOF_DIR_OUT;
> +
> +	return GPIOF_DIR_IN;
> +}
> +
> +static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	int dir;
> +
> +	dir = dln2_gpio_get_direction(chip, offset);
> +	if (dir < 0)
> +		return dir;
> +
> +	if (dir == GPIOF_DIR_IN)
> +		return dln2_gpio_pin_get_in_val(dln2, offset);
> +
> +	return dln2_gpio_pin_get_out_val(dln2, offset);
> +}
> +
> +static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +
> +	dln2_gpio_pin_set_out_val(dln2, offset, value);
> +}
> +
> +static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
> +				   unsigned dir)
> +{
> +	struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
> +	struct dln2_gpio_pin_val req = {
> +		.pin = cpu_to_le16(offset),
> +		.value = cpu_to_le16(dir),

Same here.

Johan

Re: [PATCH v9 1/4] mfd: add support for Diolan DLN-2 devices

[Johan Hovold]

On Mon, Oct 27, 2014 at 06:31:09PM +0200, Octavian Purdila wrote:
> This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
> Master Adapter DLN-2. Details about the device can be found here:
> 
> https://www.diolan.com/i2c/i2c_interface.html.
> 
> Information about the USB protocol can be found in the Programmer's
> Reference Manual [1], see section 1.7.
> 
> Because the hardware has a single transmit endpoint and a single
> receive endpoint the communication between the various DLN2 drivers
> and the hardware will be muxed/demuxed by this driver.
> 
> Each DLN2 module will be identified by the handle field within the DLN2
> message header. If a DLN2 module issues multiple commands in parallel
> they will be identified by the echo counter field in the message header.
> 
> The DLN2 modules can use the dln2_transfer() function to issue a
> command and wait for its response. They can also register a callback
> that is going to be called when a specific event id is generated by
> the device (e.g. GPIO interrupts). The device uses handle 0 for
> sending events.
> 
> [1] https://www.diolan.com/downloads/dln-api-manual.pdf
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> ---
>  drivers/mfd/Kconfig      |  11 +
>  drivers/mfd/Makefile     |   1 +
>  drivers/mfd/dln2.c       | 761 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/dln2.h | 103 +++++++
>  4 files changed, 876 insertions(+)
>  create mode 100644 drivers/mfd/dln2.c
>  create mode 100644 include/linux/mfd/dln2.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index c9200d3..4538815a 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -189,6 +189,17 @@ config MFD_DA9063
>  	  Additional drivers must be enabled in order to use the functionality
>  	  of the device.
>  
> +config MFD_DLN2
> +	tristate "Diolan DLN2 support"
> +	select MFD_CORE
> +	depends on USB
> +	help
> +
> +	  This adds support for Diolan USB-I2C/SPI/GPIO Master Adapter
> +	  DLN-2. Additional drivers such as I2C_DLN2, GPIO_DLN2,
> +	  etc. must be enabled in order to use the functionality of
> +	  the device.
> +
>  config MFD_MC13XXX
>  	tristate
>  	depends on (SPI_MASTER || I2C)
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 61f8dbf..2cd7e74 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -175,6 +175,7 @@ obj-$(CONFIG_MFD_STW481X)	+= stw481x.o
>  obj-$(CONFIG_MFD_IPAQ_MICRO)	+= ipaq-micro.o
>  obj-$(CONFIG_MFD_MENF21BMC)	+= menf21bmc.o
>  obj-$(CONFIG_MFD_HI6421_PMIC)	+= hi6421-pmic-core.o
> +obj-$(CONFIG_MFD_DLN2)		+= dln2.o
>  
>  intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
>  obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> new file mode 100644
> index 0000000..b3946ef
> --- /dev/null
> +++ b/drivers/mfd/dln2.c

[...]

> +struct dln2_header {
> +	__le16 size;
> +	__le16 id;
> +	__le16 echo;
> +	__le16 handle;
> +} __packed;
> +
> +struct dln2_response {
> +	struct dln2_header hdr;
> +	__le16 result;
> +} __packed;
> +

__packed not needed on either struct above.

[...]

> +/*
> + * Returns true if a valid transfer slot is found. In this case the URB must not
> + * be resubmitted imediately in dln2_rx as we need the data when dln2_transfer

s/imediately/immediately/

> + * is woke up. It will be resubmitted there.
> + */
> +static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
> +				   u16 handle, u16 rx_slot)
> +{
> +	struct device *dev = &dln2->interface->dev;
> +	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
> +	struct dln2_rx_context *rxc;
> +	bool valid_slot = false;
> +
> +	rxc = &rxs->slots[rx_slot];
> +
> +	/*
> +	 * No need to disable interrupts as this lock is not taken in interrupt
> +	 * context elsewhere in this driver. This function (or its callers) are
> +	 * also not exported to other modules.
> +	 */
> +	spin_lock(&rxs->lock);
> +	if (rxc->in_use && !rxc->urb) {
> +		rxc->urb = urb;
> +		complete(&rxc->done);
> +		valid_slot = true;
> +	}
> +	spin_unlock(&rxs->lock);
> +
> +	if (!valid_slot)
> +		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
> +
> +	return valid_slot;
> +}
> +
> +static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
> +				     void *data, int len)
> +{
> +	struct dln2_event_cb_entry *i;
> +
> +	rcu_read_lock();
> +
> +	list_for_each_entry_rcu(i, &dln2->event_cb_list, list)
> +		if (i->id == id)
> +			i->callback(i->pdev, echo, data, len);

No need to continue the search if id is found as it will be unique in
the list.

> +
> +	rcu_read_unlock();
> +}
> +
> +static void dln2_rx(struct urb *urb)
> +{
> +	struct dln2_dev *dln2 = urb->context;
> +	struct dln2_header *hdr = urb->transfer_buffer;
> +	struct device *dev = &dln2->interface->dev;
> +	u16 id, echo, handle, size;
> +	u8 *data;
> +	int len;
> +	int err;
> +
> +	switch (urb->status) {
> +	case 0:
> +		/* success */
> +		break;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +	case -EPIPE:
> +		/* this urb is terminated, clean up */
> +		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
> +		return;
> +	default:
> +		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
> +		goto out;
> +	}
> +
> +	if (urb->actual_length < sizeof(struct dln2_header)) {
> +		dev_err(dev, "short response: %d\n", urb->actual_length);
> +		goto out;
> +	}
> +
> +	handle = le16_to_cpu(hdr->handle);
> +	id = le16_to_cpu(hdr->id);
> +	echo = le16_to_cpu(hdr->echo);
> +	size = le16_to_cpu(hdr->size);
> +
> +	if (size != urb->actual_length) {
> +		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
> +			handle, id, echo, size, urb->actual_length);
> +		goto out;
> +	}
> +
> +	if (handle >= DLN2_HANDLES) {
> +		dev_warn(dev, "RX: invalid handle %d\n", handle);

Drop the RX: prefix for consistency.

> +		goto out;
> +	}
> +
> +	data = urb->transfer_buffer + sizeof(struct dln2_header);
> +	len = urb->actual_length - sizeof(struct dln2_header);
> +
> +	if (handle == DLN2_HANDLE_EVENT) {
> +		dln2_run_event_callbacks(dln2, id, echo, data, len);
> +	} else {
> +		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
> +		if (dln2_transfer_complete(dln2, urb, handle, echo))
> +			return;
> +	}
> +
> +out:
> +	err = usb_submit_urb(urb, GFP_ATOMIC);
> +	if (err < 0)
> +		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
> +}

[...]

> +static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
> +			      struct usb_host_interface *hostif)
> +{
> +	int i;
> +	const int rx_max_size = DLN2_RX_BUF_SIZE;
> +
> +	for (i = 0; i < DLN2_MAX_URBS; i++) {
> +		int ret;
> +		struct device *dev = &dln2->interface->dev;

Again, no need to keep these inside the for-loop.

> +
> +		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
> +		if (!dln2->rx_buf[i])
> +			return -ENOMEM;
> +
> +		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
> +		if (!dln2->rx_urb[i])
> +			return -ENOMEM;
> +
> +		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
> +				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
> +				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
> +
> +		ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to submit RX URB: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}

Looks good otherwise.

I'll respond with my reviewed by tag after you have addressed the above
and Joe's comments.

Johan

Re: [PATCH v9 2/4] i2c: add support for Diolan DLN-2 USB-I2C adapter

[Johan Hovold]

On Mon, Oct 27, 2014 at 06:31:10PM +0200, Octavian Purdila wrote:
> 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>

Reviewed-by: Johan Hovold <johan@kernel.org>

Johan