Date:   Tue, 15 May 2018 00:40:39 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     airlied@...ux.ie, hans.verkuil@...co.com, lee.jones@...aro.org,
        olof@...om.net, seanpaul@...gle.com
Cc:     Neil Armstrong <narmstrong@...libre.com>, sadolfsson@...gle.com,
        felixe@...gle.com, bleung@...gle.com, darekm@...gle.com,
        marcheu@...omium.org, fparent@...libre.com,
        dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 5/5] media: platform: Add Chrome OS EC CEC driver

The Chrome OS Embedded Controller can expose a CEC bus, this patch add the
driver for such feature of the Embedded Controller.

This driver is part of the cros-ec MFD and will be add as a sub-device when
the feature bit is exposed by the EC.

The controller will only handle a single logical address and handles
all the messages retries and will only expose Success or Error.

When the logical address is invalid, the controller will act as a CEC sniffer
and transfer all messages on the bus.

Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/media/platform/Kconfig               |  11 +
 drivers/media/platform/Makefile              |   2 +
 drivers/media/platform/cros-ec/Makefile      |   1 +
 drivers/media/platform/cros-ec/cros-ec-cec.c | 331 +++++++++++++++++++++++++++
 4 files changed, 345 insertions(+)
 create mode 100644 drivers/media/platform/cros-ec/Makefile
 create mode 100644 drivers/media/platform/cros-ec/cros-ec-cec.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index c7a1cf8..e55a8ed2 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -546,6 +546,17 @@ menuconfig CEC_PLATFORM_DRIVERS
 
 if CEC_PLATFORM_DRIVERS
 
+config VIDEO_CROS_EC_CEC
+	tristate "Chrome OS EC CEC driver"
+	depends on MFD_CROS_EC || COMPILE_TEST
+	select CEC_CORE
+	select CEC_NOTIFIER
+	---help---
+	  If you say yes here you will get support for the
+	  Chrome OS Embedded Controller's CEC.
+	  The CEC bus is present in the HDMI connector and enables communication
+	  between compatible devices.
+
 config VIDEO_MESON_AO_CEC
 	tristate "Amlogic Meson AO CEC driver"
 	depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index 932515d..0e0582e 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -92,3 +92,5 @@ obj-$(CONFIG_VIDEO_QCOM_CAMSS)		+= qcom/camss-8x16/
 obj-$(CONFIG_VIDEO_QCOM_VENUS)		+= qcom/venus/
 
 obj-y					+= meson/
+
+obj-y					+= cros-ec/
diff --git a/drivers/media/platform/cros-ec/Makefile b/drivers/media/platform/cros-ec/Makefile
new file mode 100644
index 0000000..9ce97f9
--- /dev/null
+++ b/drivers/media/platform/cros-ec/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_VIDEO_CROS_EC_CEC) += cros-ec-cec.o
diff --git a/drivers/media/platform/cros-ec/cros-ec-cec.c b/drivers/media/platform/cros-ec/cros-ec-cec.c
new file mode 100644
index 0000000..fea90da
--- /dev/null
+++ b/drivers/media/platform/cros-ec/cros-ec-cec.c
@@ -0,0 +1,331 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * CEC driver for Chrome OS Embedded Controller
+ *
+ * Copyright (c) 2018 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@...libre.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dmi.h>
+#include <linux/cec.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <media/cec.h>
+#include <media/cec-notifier.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+
+#define DRV_NAME	"cros-ec-cec"
+
+/**
+ * struct cros_ec_cec - Driver data for EC CEC
+ *
+ * @cros_ec: Pointer to EC device
+ * @notifier: Notifier info for responding to EC events
+ * @adap: CEC adapter
+ * @notify: CEC notifier pointer
+ * @rc_msg: storage for a received message
+ */
+struct cros_ec_cec {
+	struct cros_ec_device *cros_ec;
+	struct notifier_block notifier;
+	struct cec_adapter *adap;
+	struct cec_notifier *notify;
+	struct cec_msg rx_msg;
+};
+
+static void handle_cec_message(struct cros_ec_cec *cros_ec_cec)
+{
+	struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
+	uint8_t *cec_message = cros_ec->event_data.data.cec_message;
+	unsigned int len = cros_ec->event_size;
+
+	cros_ec_cec->rx_msg.len = len;
+	memcpy(cros_ec_cec->rx_msg.msg, cec_message, len);
+
+	cec_received_msg(cros_ec_cec->adap, &cros_ec_cec->rx_msg);
+}
+
+static void handle_cec_event(struct cros_ec_cec *cros_ec_cec)
+{
+	struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
+	uint32_t events = cros_ec->event_data.data.cec_events;
+
+	if (events & EC_MKBP_CEC_SEND_OK)
+		cec_transmit_attempt_done(cros_ec_cec->adap,
+					  CEC_TX_STATUS_OK);
+
+	if (events & EC_MKBP_CEC_SEND_FAILED)
+		cec_transmit_attempt_done(cros_ec_cec->adap,
+					  CEC_TX_STATUS_ERROR);
+}
+
+static int cros_ec_cec_event(struct notifier_block *nb,
+	unsigned long queued_during_suspend, void *_notify)
+{
+	struct cros_ec_cec *cros_ec_cec;
+	struct cros_ec_device *cros_ec;
+
+	cros_ec_cec = container_of(nb, struct cros_ec_cec, notifier);
+	cros_ec = cros_ec_cec->cros_ec;
+
+	if (cros_ec->event_data.event_type == EC_MKBP_CEC_EVENT) {
+		handle_cec_event(cros_ec_cec);
+		return NOTIFY_OK;
+	}
+
+	if (cros_ec->event_data.event_type == EC_MKBP_EVENT_CEC_MESSAGE) {
+		handle_cec_message(cros_ec_cec);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int cros_ec_cec_set_log_addr(struct cec_adapter *adap, u8 logical_addr)
+{
+	struct cros_ec_cec *cros_ec_cec = adap->priv;
+	struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
+	struct {
+		struct cros_ec_command msg;
+		struct ec_params_cec_set data;
+	} __packed msg;
+	int ret = 0;
+
+	if (logical_addr == CEC_LOG_ADDR_INVALID)
+		return 0;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg.command = EC_CMD_CEC_SET;
+	msg.msg.outsize = sizeof(msg.data);
+	msg.data.cmd = CEC_CMD_LOGICAL_ADDRESS;
+	msg.data.address = logical_addr;
+
+	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
+	if (ret < 0) {
+		dev_err(cros_ec->dev,
+			"error setting CEC logical address on EC: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cros_ec_cec_transmit(struct cec_adapter *adap, u8 attempts,
+				u32 signal_free_time, struct cec_msg *cec_msg)
+{
+	struct cros_ec_cec *cros_ec_cec = adap->priv;
+	struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
+	struct {
+		struct cros_ec_command msg;
+		struct ec_params_cec_write data;
+	} __packed msg;
+	int ret = 0;
+
+	if (cec_msg->len > MAX_CEC_MSG_LEN)
+		return -EINVAL;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg.command = EC_CMD_CEC_WRITE_MSG;
+	msg.msg.outsize = cec_msg->len;
+	memcpy(msg.data.msg, cec_msg->msg, cec_msg->len);
+
+	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
+	if (ret < 0) {
+		dev_err(cros_ec->dev,
+			"error writting CEC msg on EC: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cros_ec_cec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	struct cros_ec_cec *cros_ec_cec = adap->priv;
+	struct cros_ec_device *cros_ec = cros_ec_cec->cros_ec;
+	struct {
+		struct cros_ec_command msg;
+		struct ec_params_cec_set data;
+	} __packed msg;
+	int ret = 0;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg.command = EC_CMD_CEC_SET;
+	msg.msg.outsize = sizeof(msg.data);
+	msg.data.cmd = CEC_CMD_ENABLE;
+	msg.data.enable = enable;
+
+	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
+	if (ret < 0) {
+		dev_err(cros_ec->dev,
+			"error %sabling CEC on EC: %d\n",
+			(enable ? "en" : "dis"), ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct cec_adap_ops cros_ec_cec_ops = {
+	.adap_enable = cros_ec_cec_adap_enable,
+	.adap_log_addr = cros_ec_cec_set_log_addr,
+	.adap_transmit = cros_ec_cec_transmit,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int cros_ec_cec_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct cros_ec_cec *cros_ec_cec = dev_get_drvdata(&pdev->dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(cros_ec_cec->cros_ec->irq);
+
+	return 0;
+}
+
+static int cros_ec_cec_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct cros_ec_cec *cros_ec_cec = dev_get_drvdata(&pdev->dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(cros_ec_cec->cros_ec->irq);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(cros_ec_cec_pm_ops,
+	cros_ec_cec_suspend, cros_ec_cec_resume);
+
+
+struct cec_dmi_match {
+	char *sys_vendor;
+	char *product_name;
+	char *devname;
+	char *conn;
+};
+
+static const struct cec_dmi_match cec_dmi_match_table[] = {
+	/* Google Fizz */
+	{ "Google", "Fizz", "0000:00:02.0", "HDMI-A-1" },
+};
+
+static int cros_ec_cec_get_notifier(struct cec_notifier **notify)
+{
+	int i;
+
+	for (i = 0 ; i < ARRAY_SIZE(cec_dmi_match_table) ; ++i) {
+		const struct cec_dmi_match *m = &cec_dmi_match_table[i];
+
+		if (dmi_match(DMI_SYS_VENDOR, m->sys_vendor) &&
+		    dmi_match(DMI_PRODUCT_NAME, m->product_name)) {
+			*notify = cec_notifier_get_byname(m->devname, m->conn);
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int cros_ec_cec_probe(struct platform_device *pdev)
+{
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
+	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
+	struct cros_ec_cec *cros_ec_cec;
+	unsigned int cec_caps = CEC_CAP_DEFAULTS;
+	int ret;
+
+	cros_ec_cec = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_cec),
+				   GFP_KERNEL);
+	if (!cros_ec_cec)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, cros_ec_cec);
+	cros_ec_cec->cros_ec = cros_ec;
+
+	ret = cros_ec_cec_get_notifier(&cros_ec_cec->notify);
+	if (ret) {
+		dev_warn(&pdev->dev, "no CEC notifier available\n");
+		cec_caps |= CEC_CAP_PHYS_ADDR;
+	} else if (!cros_ec_cec->notify) {
+		return -EPROBE_DEFER;
+	}
+
+	ret = device_init_wakeup(&pdev->dev, 1);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize wakeup\n");
+		return ret;
+	}
+
+	cros_ec_cec->adap = cec_allocate_adapter(&cros_ec_cec_ops, cros_ec_cec,
+						 DRV_NAME, cec_caps, 1);
+	if (IS_ERR(cros_ec_cec->adap))
+		return PTR_ERR(cros_ec_cec->adap);
+
+	cros_ec_cec->adap->owner = THIS_MODULE;
+
+	/* Get CEC events from the EC. */
+	cros_ec_cec->notifier.notifier_call = cros_ec_cec_event;
+	ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
+					       &cros_ec_cec->notifier);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register notifier\n");
+		cec_delete_adapter(cros_ec_cec->adap);
+		return ret;
+	}
+
+	ret = cec_register_adapter(cros_ec_cec->adap, &pdev->dev);
+	if (ret < 0) {
+		cec_delete_adapter(cros_ec_cec->adap);
+		return ret;
+	}
+
+	cec_register_cec_notifier(cros_ec_cec->adap, cros_ec_cec->notify);
+
+	return 0;
+}
+
+static int cros_ec_cec_remove(struct platform_device *pdev)
+{
+	struct cros_ec_cec *cros_ec_cec = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ret = blocking_notifier_chain_unregister(
+			&cros_ec_cec->cros_ec->event_notifier,
+			&cros_ec_cec->notifier);
+
+	if (ret) {
+		dev_err(dev, "failed to unregister notifier\n");
+		return ret;
+	}
+
+	cec_unregister_adapter(cros_ec_cec->adap);
+
+	if (cros_ec_cec->notify)
+		cec_notifier_put(cros_ec_cec->notify);
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_cec_driver = {
+	.probe = cros_ec_cec_probe,
+	.remove  = cros_ec_cec_remove,
+	.driver = {
+		.name = DRV_NAME,
+		.pm = &cros_ec_cec_pm_ops,
+	},
+};
+
+module_platform_driver(cros_ec_cec_driver);
+
+MODULE_DESCRIPTION("CEC driver for Chrome OS ECs");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@...libre.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
-- 
2.7.4

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