Date:   Fri, 16 Sep 2016 16:09:59 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org
Cc:     Johan Hovold <johan@...oldconsulting.com>,
        Rui Miguel Silva <rmfrfs@...il.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Sandeep Patil <sspatil@...gle.com>,
        Matt Porter <mporter@...nel.crashing.org>,
        John Stultz <john.stultz@...aro.org>,
        Rob Herring <robh@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Alex Elder <elder@...aro.org>, David Lin <dtwlin@...gle.com>,
        Bryan O'Donoghue <pure.logic@...us-software.ie>,
        Vaibhav Agarwal <vaibhav.agarwal@...aro.org>,
        Mark Greer <mgreer@...malcreek.com>
Subject: [patch 13/32] greybus: HID driver


This driver implements the Greybus HID protocol.

Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/greybus/hid.c |  536 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 536 insertions(+)

--- /dev/null
+++ b/drivers/greybus/hid.c
@@ -0,0 +1,536 @@
+/*
+ * HID class driver for the Greybus.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/bitops.h>
+#include <linux/hid.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include "greybus.h"
+
+/* Greybus HID device's structure */
+struct gb_hid {
+	struct gb_bundle *bundle;
+	struct gb_connection		*connection;
+
+	struct hid_device		*hid;
+	struct gb_hid_desc_response	hdesc;
+
+	unsigned long			flags;
+#define GB_HID_STARTED			0x01
+#define GB_HID_READ_PENDING		0x04
+
+	unsigned int			bufsize;
+	char				*inbuf;
+};
+
+static DEFINE_MUTEX(gb_hid_open_mutex);
+
+/* Routines to get controller's information over greybus */
+
+/* Operations performed on greybus */
+static int gb_hid_get_desc(struct gb_hid *ghid)
+{
+	return gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_DESC, NULL,
+				 0, &ghid->hdesc, sizeof(ghid->hdesc));
+}
+
+static int gb_hid_get_report_desc(struct gb_hid *ghid, char *rdesc)
+{
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT_DESC,
+				 NULL, 0, rdesc,
+				 le16_to_cpu(ghid->hdesc.wReportDescLength));
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_set_power(struct gb_hid *ghid, int type)
+{
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	ret = gb_operation_sync(ghid->connection, type, NULL, 0, NULL, 0);
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_get_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
+			     unsigned char *buf, int len)
+{
+	struct gb_hid_get_report_request request;
+	int ret;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	request.report_type = report_type;
+	request.report_id = report_id;
+
+	ret = gb_operation_sync(ghid->connection, GB_HID_TYPE_GET_REPORT,
+				 &request, sizeof(request), buf, len);
+
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_set_report(struct gb_hid *ghid, u8 report_type, u8 report_id,
+			     unsigned char *buf, int len)
+{
+	struct gb_hid_set_report_request *request;
+	struct gb_operation *operation;
+	int ret, size = sizeof(*request) + len - 1;
+
+	ret = gb_pm_runtime_get_sync(ghid->bundle);
+	if (ret)
+		return ret;
+
+	operation = gb_operation_create(ghid->connection,
+					GB_HID_TYPE_SET_REPORT, size, 0,
+					GFP_KERNEL);
+	if (!operation) {
+		gb_pm_runtime_put_autosuspend(ghid->bundle);
+		return -ENOMEM;
+	}
+
+	request = operation->request->payload;
+	request->report_type = report_type;
+	request->report_id = report_id;
+	memcpy(request->report, buf, len);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret) {
+		dev_err(&operation->connection->bundle->dev,
+			"failed to set report: %d\n", ret);
+	} else {
+		ret = len;
+	}
+
+	gb_operation_put(operation);
+	gb_pm_runtime_put_autosuspend(ghid->bundle);
+
+	return ret;
+}
+
+static int gb_hid_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_hid *ghid = gb_connection_get_data(connection);
+	struct gb_hid_input_report_request *request = op->request->payload;
+
+	if (op->type != GB_HID_TYPE_IRQ_EVENT) {
+		dev_err(&connection->bundle->dev,
+			"unsupported unsolicited request\n");
+		return -EINVAL;
+	}
+
+	if (test_bit(GB_HID_STARTED, &ghid->flags))
+		hid_input_report(ghid->hid, HID_INPUT_REPORT,
+				 request->report, op->request->payload_size, 1);
+
+	return 0;
+}
+
+static int gb_hid_report_len(struct hid_report *report)
+{
+	return ((report->size - 1) >> 3) + 1 +
+		report->device->report_enum[report->type].numbered;
+}
+
+static void gb_hid_find_max_report(struct hid_device *hid, unsigned int type,
+				   unsigned int *max)
+{
+	struct hid_report *report;
+	unsigned int size;
+
+	list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
+		size = gb_hid_report_len(report);
+		if (*max < size)
+			*max = size;
+	}
+}
+
+static void gb_hid_free_buffers(struct gb_hid *ghid)
+{
+	kfree(ghid->inbuf);
+	ghid->inbuf = NULL;
+	ghid->bufsize = 0;
+}
+
+static int gb_hid_alloc_buffers(struct gb_hid *ghid, size_t bufsize)
+{
+	ghid->inbuf = kzalloc(bufsize, GFP_KERNEL);
+	if (!ghid->inbuf)
+		return -ENOMEM;
+
+	ghid->bufsize = bufsize;
+
+	return 0;
+}
+
+/* Routines dealing with reports */
+static void gb_hid_init_report(struct gb_hid *ghid, struct hid_report *report)
+{
+	unsigned int size;
+
+	size = gb_hid_report_len(report);
+	if (gb_hid_get_report(ghid, report->type, report->id, ghid->inbuf,
+			      size))
+		return;
+
+	/*
+	 * hid->driver_lock is held as we are in probe function,
+	 * we just need to setup the input fields, so using
+	 * hid_report_raw_event is safe.
+	 */
+	hid_report_raw_event(ghid->hid, report->type, ghid->inbuf, size, 1);
+}
+
+static void gb_hid_init_reports(struct gb_hid *ghid)
+{
+	struct hid_device *hid = ghid->hid;
+	struct hid_report *report;
+
+	list_for_each_entry(report,
+		&hid->report_enum[HID_INPUT_REPORT].report_list, list)
+		gb_hid_init_report(ghid, report);
+
+	list_for_each_entry(report,
+		&hid->report_enum[HID_FEATURE_REPORT].report_list, list)
+		gb_hid_init_report(ghid, report);
+}
+
+static int __gb_hid_get_raw_report(struct hid_device *hid,
+		unsigned char report_number, __u8 *buf, size_t count,
+		unsigned char report_type)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret;
+
+	if (report_type == HID_OUTPUT_REPORT)
+		return -EINVAL;
+
+	ret = gb_hid_get_report(ghid, report_type, report_number, buf, count);
+	if (!ret)
+		ret = count;
+
+	return ret;
+}
+
+static int __gb_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
+				      size_t len, unsigned char report_type)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int report_id = buf[0];
+	int ret;
+
+	if (report_type == HID_INPUT_REPORT)
+		return -EINVAL;
+
+	if (report_id) {
+		buf++;
+		len--;
+	}
+
+	ret = gb_hid_set_report(ghid, report_type, report_id, buf, len);
+	if (report_id && ret >= 0)
+		ret++; /* add report_id to the number of transfered bytes */
+
+	return 0;
+}
+
+static int gb_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
+			       __u8 *buf, size_t len, unsigned char rtype,
+			       int reqtype)
+{
+	switch (reqtype) {
+	case HID_REQ_GET_REPORT:
+		return __gb_hid_get_raw_report(hid, reportnum, buf, len, rtype);
+	case HID_REQ_SET_REPORT:
+		if (buf[0] != reportnum)
+			return -EINVAL;
+		return __gb_hid_output_raw_report(hid, buf, len, rtype);
+	default:
+		return -EIO;
+	}
+}
+
+/* HID Callbacks */
+static int gb_hid_parse(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	unsigned int rsize;
+	char *rdesc;
+	int ret;
+
+	rsize = le16_to_cpu(ghid->hdesc.wReportDescLength);
+	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
+		dbg_hid("weird size of report descriptor (%u)\n", rsize);
+		return -EINVAL;
+	}
+
+	rdesc = kzalloc(rsize, GFP_KERNEL);
+	if (!rdesc) {
+		dbg_hid("couldn't allocate rdesc memory\n");
+		return -ENOMEM;
+	}
+
+	ret = gb_hid_get_report_desc(ghid, rdesc);
+	if (ret) {
+		hid_err(hid, "reading report descriptor failed\n");
+		goto free_rdesc;
+	}
+
+	ret = hid_parse_report(hid, rdesc, rsize);
+	if (ret)
+		dbg_hid("parsing report descriptor failed\n");
+
+free_rdesc:
+	kfree(rdesc);
+
+	return ret;
+}
+
+static int gb_hid_start(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	unsigned int bufsize = HID_MIN_BUFFER_SIZE;
+	int ret;
+
+	gb_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
+	gb_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
+	gb_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
+
+	if (bufsize > HID_MAX_BUFFER_SIZE)
+		bufsize = HID_MAX_BUFFER_SIZE;
+
+	ret = gb_hid_alloc_buffers(ghid, bufsize);
+	if (ret)
+		return ret;
+
+	if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
+		gb_hid_init_reports(ghid);
+
+	return 0;
+}
+
+static void gb_hid_stop(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+
+	gb_hid_free_buffers(ghid);
+}
+
+static int gb_hid_open(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret = 0;
+
+	mutex_lock(&gb_hid_open_mutex);
+	if (!hid->open++) {
+		ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
+		if (ret < 0)
+			hid->open--;
+		else
+			set_bit(GB_HID_STARTED, &ghid->flags);
+	}
+	mutex_unlock(&gb_hid_open_mutex);
+
+	return ret;
+}
+
+static void gb_hid_close(struct hid_device *hid)
+{
+	struct gb_hid *ghid = hid->driver_data;
+	int ret;
+
+	/*
+	 * Protecting hid->open to make sure we don't restart data acquistion
+	 * due to a resumption we no longer care about..
+	 */
+	mutex_lock(&gb_hid_open_mutex);
+	if (!--hid->open) {
+		clear_bit(GB_HID_STARTED, &ghid->flags);
+
+		/* Save some power */
+		ret = gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
+		if (ret)
+			dev_err(&ghid->connection->bundle->dev,
+				"failed to power off (%d)\n", ret);
+	}
+	mutex_unlock(&gb_hid_open_mutex);
+}
+
+static int gb_hid_power(struct hid_device *hid, int lvl)
+{
+	struct gb_hid *ghid = hid->driver_data;
+
+	switch (lvl) {
+	case PM_HINT_FULLON:
+		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_ON);
+	case PM_HINT_NORMAL:
+		return gb_hid_set_power(ghid, GB_HID_TYPE_PWR_OFF);
+	}
+
+	return 0;
+}
+
+/* HID structure to pass callbacks */
+static struct hid_ll_driver gb_hid_ll_driver = {
+	.parse = gb_hid_parse,
+	.start = gb_hid_start,
+	.stop = gb_hid_stop,
+	.open = gb_hid_open,
+	.close = gb_hid_close,
+	.power = gb_hid_power,
+	.raw_request = gb_hid_raw_request,
+};
+
+static int gb_hid_init(struct gb_hid *ghid)
+{
+	struct hid_device *hid = ghid->hid;
+	int ret;
+
+	ret = gb_hid_get_desc(ghid);
+	if (ret)
+		return ret;
+
+	hid->version = le16_to_cpu(ghid->hdesc.bcdHID);
+	hid->vendor = le16_to_cpu(ghid->hdesc.wVendorID);
+	hid->product = le16_to_cpu(ghid->hdesc.wProductID);
+	hid->country = ghid->hdesc.bCountryCode;
+
+	hid->driver_data = ghid;
+	hid->ll_driver = &gb_hid_ll_driver;
+	hid->dev.parent = &ghid->connection->bundle->dev;
+//	hid->bus = BUS_GREYBUS; /* Need a bustype for GREYBUS in <linux/input.h> */
+
+	/* Set HID device's name */
+	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
+		 dev_name(&ghid->connection->bundle->dev),
+		 hid->vendor, hid->product);
+
+	return 0;
+}
+
+static int gb_hid_probe(struct gb_bundle *bundle,
+			const struct greybus_bundle_id *id)
+{
+	struct greybus_descriptor_cport *cport_desc;
+	struct gb_connection *connection;
+	struct hid_device *hid;
+	struct gb_hid *ghid;
+	int ret;
+
+	if (bundle->num_cports != 1)
+		return -ENODEV;
+
+	cport_desc = &bundle->cport_desc[0];
+	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_HID)
+		return -ENODEV;
+
+	ghid = kzalloc(sizeof(*ghid), GFP_KERNEL);
+	if (!ghid)
+		return -ENOMEM;
+
+	connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
+						gb_hid_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto err_free_ghid;
+	}
+
+	gb_connection_set_data(connection, ghid);
+	ghid->connection = connection;
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid)) {
+		ret = PTR_ERR(hid);
+		goto err_connection_destroy;
+	}
+
+	ghid->hid = hid;
+	ghid->bundle = bundle;
+
+	greybus_set_drvdata(bundle, ghid);
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto err_destroy_hid;
+
+	ret = gb_hid_init(ghid);
+	if (ret)
+		goto err_connection_disable;
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		hid_err(hid, "can't add hid device: %d\n", ret);
+		goto err_connection_disable;
+	}
+
+	gb_pm_runtime_put_autosuspend(bundle);
+
+	return 0;
+
+err_connection_disable:
+	gb_connection_disable(connection);
+err_destroy_hid:
+	hid_destroy_device(hid);
+err_connection_destroy:
+	gb_connection_destroy(connection);
+err_free_ghid:
+	kfree(ghid);
+
+	return ret;
+}
+
+static void gb_hid_disconnect(struct gb_bundle *bundle)
+{
+	struct gb_hid *ghid = greybus_get_drvdata(bundle);
+
+	if (gb_pm_runtime_get_sync(bundle))
+		gb_pm_runtime_get_noresume(bundle);
+
+	hid_destroy_device(ghid->hid);
+	gb_connection_disable(ghid->connection);
+	gb_connection_destroy(ghid->connection);
+	kfree(ghid);
+}
+
+static const struct greybus_bundle_id gb_hid_id_table[] = {
+	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_HID) },
+	{ }
+};
+MODULE_DEVICE_TABLE(greybus, gb_hid_id_table);
+
+static struct greybus_driver gb_hid_driver = {
+	.name		= "hid",
+	.probe		= gb_hid_probe,
+	.disconnect	= gb_hid_disconnect,
+	.id_table	= gb_hid_id_table,
+};
+module_greybus_driver(gb_hid_driver);
+
+MODULE_LICENSE("GPL v2");

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