linux_kernel/drivers/media/platform/cros-ec-cec/cros-ec-cec.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * CEC driver for ChromeOS Embedded Controller
 *
 * Copyright (c) 2018 BayLibre, SAS
 * Author: Neil Armstrong <narmstrong@baylibre.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/dmi.h>
#include <linux/pci.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
 * @rx_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);

	/* FW takes care of all retries, tell core to avoid more retries */
	if (events & EC_MKBP_CEC_SEND_FAILED)
		cec_transmit_attempt_done(cros_ec_cec->adap,
					  CEC_TX_STATUS_MAX_RETRIES |
					  CEC_TX_STATUS_NACK);
}

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_EVENT_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;

	msg.msg.command = EC_CMD_CEC_SET;
	msg.msg.outsize = sizeof(msg.data);
	msg.data.cmd = CEC_CMD_LOGICAL_ADDRESS;
	msg.data.val = 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;

	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 writing 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;

	msg.msg.command = EC_CMD_CEC_SET;
	msg.msg.outsize = sizeof(msg.data);
	msg.data.cmd = CEC_CMD_ENABLE;
	msg.data.val = 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);

#if IS_ENABLED(CONFIG_PCI) && IS_ENABLED(CONFIG_DMI)

/*
 * The Firmware only handles a single CEC interface tied to a single HDMI
 * connector we specify along with the DRM device name handling the HDMI output
 */

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", "Port B" },
};

static int cros_ec_cec_get_notifier(struct device *dev,
				    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)) {
			struct device *d;

			/* Find the device, bail out if not yet registered */
			d = bus_find_device_by_name(&pci_bus_type, NULL,
						    m->devname);
			if (!d)
				return -EPROBE_DEFER;

			*notify = cec_notifier_get_conn(d, m->conn);
			return 0;
		}
	}

	/* Hardware support must be added in the cec_dmi_match_table */
	dev_warn(dev, "CEC notifier not configured for this hardware\n");

	return -ENODEV;
}

#else

static int cros_ec_cec_get_notifier(struct device *dev,
				    struct cec_notifier **notify)
{
	return -ENODEV;
}

#endif

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;
	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(&pdev->dev, &cros_ec_cec->notify);
	if (ret)
		return ret;

	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_CAP_DEFAULTS, 1);
	if (IS_ERR(cros_ec_cec->adap))
		return PTR_ERR(cros_ec_cec->adap);

	/* 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 ChromeOS ECs");
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);