media: add SECO cec driver

This patch adds support to the CEC device implemented with a STM32
microcontroller in X86 SECO Boards, including UDOO X86.

The communication is achieved via Braswell integrated SMBus
(i2c-i801). The driver use direct access to the PCI addresses, due to
the limitations of the specific driver in presence of ACPI calls.

The basic functionalities are tested with success with cec-ctl and
cec-compliance.

Inspired by cros-ec-cec implementation, attaches to i915 driver
cec-notifier.

Signed-off-by: Ettore Chimenti <ek5.chimenti@gmail.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 672 insertions, 0 deletions

diff --git a/drivers/media/platform/seco-cec/seco-cec.c b/drivers/media/platform/seco-cec/seco-cec.c
new file mode 100644
index 000000000000..85ef161742d8
--- /dev/null
+++ b/drivers/media/platform/seco-cec/seco-cec.c
@@ -0,0 +1,672 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * CEC driver for SECO X86 Boards
+ *
+ * Author:  Ettore Chimenti <ek5.chimenti@gmail.com>
+ * Copyright (C) 2018, SECO SpA.
+ * Copyright (C) 2018, Aidilab Srl.
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/dmi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+
+/* CEC Framework */
+#include <media/cec.h>
+
+#include "seco-cec.h"
+
+struct secocec_data {
+	struct device *dev;
+	struct platform_device *pdev;
+	struct cec_adapter *cec_adap;
+	struct cec_notifier *notifier;
+	int irq;
+};
+
+#define smb_wr16(cmd, data) smb_word_op(CMD_WORD_DATA, SECOCEC_MICRO_ADDRESS, \
+					     cmd, data, SMBUS_WRITE, NULL)
+#define smb_rd16(cmd, res) smb_word_op(CMD_WORD_DATA, SECOCEC_MICRO_ADDRESS, \
+				       cmd, 0, SMBUS_READ, res)
+
+static int smb_word_op(short data_format, u16 slave_addr, u8 cmd, u16 data,
+		       u8 operation, u16 *result)
+{
+	unsigned int count;
+	short _data_format;
+	int status = 0;
+
+	switch (data_format) {
+	case CMD_BYTE_DATA:
+		_data_format = BRA_SMB_CMD_BYTE_DATA;
+		break;
+	case CMD_WORD_DATA:
+		_data_format = BRA_SMB_CMD_WORD_DATA;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Active wait until ready */
+	for (count = 0; count <= SMBTIMEOUT; ++count) {
+		if (!(inb(HSTS) & BRA_INUSE_STS))
+			break;
+		udelay(SMB_POLL_UDELAY);
+	}
+
+	if (count > SMBTIMEOUT)
+		/* Reset the lock instead of failing */
+		outb(0xff, HSTS);
+
+	outb(0x00, HCNT);
+	outb((u8)(slave_addr & 0xfe) | operation, XMIT_SLVA);
+	outb(cmd, HCMD);
+	inb(HCNT);
+
+	if (operation == SMBUS_WRITE) {
+		outb((u8)data, HDAT0);
+		outb((u8)(data >> 8), HDAT1);
+	}
+
+	outb(BRA_START + _data_format, HCNT);
+
+	for (count = 0; count <= SMBTIMEOUT; count++) {
+		if (!(inb(HSTS) & BRA_HOST_BUSY))
+			break;
+		udelay(SMB_POLL_UDELAY);
+	}
+
+	if (count > SMBTIMEOUT) {
+		status = -EBUSY;
+		goto err;
+	}
+
+	if (inb(HSTS) & BRA_HSTS_ERR_MASK) {
+		status = -EIO;
+		goto err;
+	}
+
+	if (operation == SMBUS_READ)
+		*result = ((inb(HDAT0) & 0xff) + ((inb(HDAT1) & 0xff) << 8));
+
+err:
+	outb(0xff, HSTS);
+	return status;
+}
+
+static int secocec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	struct secocec_data *cec = cec_get_drvdata(adap);
+	struct device *dev = cec->dev;
+	u16 val = 0;
+	int status;
+
+	if (enable) {
+		/* Clear the status register */
+		status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
+		if (status)
+			goto err;
+
+		status = smb_wr16(SECOCEC_STATUS_REG_1, val);
+		if (status)
+			goto err;
+
+		/* Enable the interrupts */
+		status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
+		if (status)
+			goto err;
+
+		status = smb_wr16(SECOCEC_ENABLE_REG_1,
+				  val | SECOCEC_ENABLE_REG_1_CEC);
+		if (status)
+			goto err;
+
+		dev_dbg(dev, "Device enabled");
+	} else {
+		/* Clear the status register */
+		status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
+		status = smb_wr16(SECOCEC_STATUS_REG_1, val);
+
+		/* Disable the interrupts */
+		status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
+		status = smb_wr16(SECOCEC_ENABLE_REG_1, val &
+				  ~SECOCEC_ENABLE_REG_1_CEC &
+				  ~SECOCEC_ENABLE_REG_1_IR);
+
+		dev_dbg(dev, "Device disabled");
+	}
+
+	return 0;
+err:
+	return status;
+}
+
+static int secocec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
+{
+	u16 enable_val = 0;
+	int status;
+
+	/* Disable device */
+	status = smb_rd16(SECOCEC_ENABLE_REG_1, &enable_val);
+	if (status)
+		return status;
+
+	status = smb_wr16(SECOCEC_ENABLE_REG_1,
+			  enable_val & ~SECOCEC_ENABLE_REG_1_CEC);
+	if (status)
+		return status;
+
+	/* Write logical address
+	 * NOTE: CEC_LOG_ADDR_INVALID is mapped to the 'Unregistered' LA
+	 */
+	status = smb_wr16(SECOCEC_DEVICE_LA, logical_addr & 0xf);
+	if (status)
+		return status;
+
+	/* Re-enable device */
+	status = smb_wr16(SECOCEC_ENABLE_REG_1,
+			  enable_val | SECOCEC_ENABLE_REG_1_CEC);
+	if (status)
+		return status;
+
+	return 0;
+}
+
+static int secocec_adap_transmit(struct cec_adapter *adap, u8 attempts,
+				 u32 signal_free_time, struct cec_msg *msg)
+{
+	u16 payload_len, payload_id_len, destination, val = 0;
+	u8 *payload_msg;
+	int status;
+	u8 i;
+
+	/* Device msg len already accounts for header */
+	payload_id_len = msg->len - 1;
+
+	/* Send data length */
+	status = smb_wr16(SECOCEC_WRITE_DATA_LENGTH, payload_id_len);
+	if (status)
+		goto err;
+
+	/* Send Operation ID if present */
+	if (payload_id_len > 0) {
+		status = smb_wr16(SECOCEC_WRITE_OPERATION_ID, msg->msg[1]);
+		if (status)
+			goto err;
+	}
+	/* Send data if present */
+	if (payload_id_len > 1) {
+		/* Only data; */
+		payload_len = msg->len - 2;
+		payload_msg = &msg->msg[2];
+
+		/* Copy message into registers */
+		for (i = 0; i < payload_len; i += 2) {
+			/* hi byte */
+			val = payload_msg[i + 1] << 8;
+
+			/* lo byte */
+			val |= payload_msg[i];
+
+			status = smb_wr16(SECOCEC_WRITE_DATA_00 + i / 2, val);
+			if (status)
+				goto err;
+		}
+	}
+	/* Send msg source/destination and fire msg */
+	destination = msg->msg[0];
+	status = smb_wr16(SECOCEC_WRITE_BYTE0, destination);
+	if (status)
+		goto err;
+
+	return 0;
+
+err:
+	return status;
+}
+
+static void secocec_tx_done(struct cec_adapter *adap, u16 status_val)
+{
+	if (status_val & SECOCEC_STATUS_TX_ERROR_MASK) {
+		if (status_val & SECOCEC_STATUS_TX_NACK_ERROR)
+			cec_transmit_attempt_done(adap, CEC_TX_STATUS_NACK);
+		else
+			cec_transmit_attempt_done(adap, CEC_TX_STATUS_ERROR);
+	} else {
+		cec_transmit_attempt_done(adap, CEC_TX_STATUS_OK);
+	}
+
+	/* Reset status reg */
+	status_val = SECOCEC_STATUS_TX_ERROR_MASK |
+		SECOCEC_STATUS_MSG_SENT_MASK |
+		SECOCEC_STATUS_TX_NACK_ERROR;
+	smb_wr16(SECOCEC_STATUS, status_val);
+}
+
+static void secocec_rx_done(struct cec_adapter *adap, u16 status_val)
+{
+	struct secocec_data *cec = cec_get_drvdata(adap);
+	struct device *dev = cec->dev;
+	struct cec_msg msg = { };
+	bool flag_overflow = false;
+	u8 payload_len, i = 0;
+	u8 *payload_msg;
+	u16 val = 0;
+	int status;
+
+	if (status_val & SECOCEC_STATUS_RX_OVERFLOW_MASK) {
+		/* NOTE: Untested, it also might not be necessary */
+		dev_warn(dev, "Received more than 16 bytes. Discarding");
+		flag_overflow = true;
+	}
+
+	if (status_val & SECOCEC_STATUS_RX_ERROR_MASK) {
+		dev_warn(dev, "Message received with errors. Discarding");
+		status = -EIO;
+		goto rxerr;
+	}
+
+	/* Read message length */
+	status = smb_rd16(SECOCEC_READ_DATA_LENGTH, &val);
+	if (status)
+		return;
+
+	/* Device msg len already accounts for the header */
+	msg.len = min(val + 1, CEC_MAX_MSG_SIZE);
+
+	/* Read logical address */
+	status = smb_rd16(SECOCEC_READ_BYTE0, &val);
+	if (status)
+		return;
+
+	/* device stores source LA and destination */
+	msg.msg[0] = val;
+
+	/* Read operation ID */
+	status = smb_rd16(SECOCEC_READ_OPERATION_ID, &val);
+	if (status)
+		return;
+
+	msg.msg[1] = val;
+
+	/* Read data if present */
+	if (msg.len > 1) {
+		payload_len = msg.len - 2;
+		payload_msg = &msg.msg[2];
+
+		/* device stores 2 bytes in every 16-bit val */
+		for (i = 0; i < payload_len; i += 2) {
+			status = smb_rd16(SECOCEC_READ_DATA_00 + i / 2, &val);
+			if (status)
+				return;
+
+			/* low byte, skipping header */
+			payload_msg[i] = val & 0x00ff;
+
+			/* hi byte */
+			payload_msg[i + 1] = (val & 0xff00) >> 8;
+		}
+	}
+
+	cec_received_msg(cec->cec_adap, &msg);
+
+	/* Reset status reg */
+	status_val = SECOCEC_STATUS_MSG_RECEIVED_MASK;
+	if (flag_overflow)
+		status_val |= SECOCEC_STATUS_RX_OVERFLOW_MASK;
+
+	status = smb_wr16(SECOCEC_STATUS, status_val);
+
+	return;
+
+rxerr:
+	/* Reset error reg */
+	status_val = SECOCEC_STATUS_MSG_RECEIVED_MASK |
+		SECOCEC_STATUS_RX_ERROR_MASK;
+	if (flag_overflow)
+		status_val |= SECOCEC_STATUS_RX_OVERFLOW_MASK;
+	smb_wr16(SECOCEC_STATUS, status_val);
+}
+
+struct cec_adap_ops secocec_cec_adap_ops = {
+	/* Low-level callbacks */
+	.adap_enable = secocec_adap_enable,
+	.adap_log_addr = secocec_adap_log_addr,
+	.adap_transmit = secocec_adap_transmit,
+};
+
+static irqreturn_t secocec_irq_handler(int irq, void *priv)
+{
+	struct secocec_data *cec = priv;
+	struct device *dev = cec->dev;
+	u16 status_val, cec_val, val = 0;
+	int status;
+
+	/*  Read status register */
+	status = smb_rd16(SECOCEC_STATUS_REG_1, &status_val);
+	if (status)
+		goto err;
+
+	if (status_val & SECOCEC_STATUS_REG_1_CEC) {
+		/* Read CEC status register */
+		status = smb_rd16(SECOCEC_STATUS, &cec_val);
+		if (status)
+			goto err;
+
+		if (cec_val & SECOCEC_STATUS_MSG_RECEIVED_MASK)
+			secocec_rx_done(cec->cec_adap, cec_val);
+
+		if (cec_val & SECOCEC_STATUS_MSG_SENT_MASK)
+			secocec_tx_done(cec->cec_adap, cec_val);
+
+		if ((~cec_val & SECOCEC_STATUS_MSG_SENT_MASK) &&
+		    (~cec_val & SECOCEC_STATUS_MSG_RECEIVED_MASK))
+			dev_warn_once(dev,
+				      "Message not received or sent, but interrupt fired");
+
+		val = SECOCEC_STATUS_REG_1_CEC;
+	}
+
+	if (status_val & SECOCEC_STATUS_REG_1_IR) {
+		val |= SECOCEC_STATUS_REG_1_IR;
+		/* TODO IRDA RX */
+	}
+
+	/*  Reset status register */
+	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
+	if (status)
+		goto err;
+
+	return IRQ_HANDLED;
+
+err:
+	dev_err_once(dev, "IRQ: R/W SMBus operation failed (%d)", status);
+
+	/*  Reset status register */
+	val = SECOCEC_STATUS_REG_1_CEC | SECOCEC_STATUS_REG_1_IR;
+	smb_wr16(SECOCEC_STATUS_REG_1, val);
+
+	return IRQ_HANDLED;
+}
+
+struct cec_dmi_match {
+	char *sys_vendor;
+	char *product_name;
+	char *devname;
+	char *conn;
+};
+
+static const struct cec_dmi_match secocec_dmi_match_table[] = {
+	/* UDOO X86 */
+	{ "SECO", "UDOO x86", "0000:00:02.0", "Port B" },
+};
+
+static int secocec_cec_get_notifier(struct cec_notifier **notify)
+{
+	int i;
+
+	for (i = 0 ; i < ARRAY_SIZE(secocec_dmi_match_table) ; ++i) {
+		const struct cec_dmi_match *m = &secocec_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;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int secocec_acpi_probe(struct secocec_data *sdev)
+{
+	struct device *dev = sdev->dev;
+	struct gpio_desc *gpio;
+	int irq = 0;
+
+	gpio = devm_gpiod_get(dev, NULL, GPIOF_IN);
+	if (IS_ERR(gpio)) {
+		dev_err(dev, "Cannot request interrupt gpio");
+		return PTR_ERR(gpio);
+	}
+
+	irq = gpiod_to_irq(gpio);
+	if (irq < 0) {
+		dev_err(dev, "Cannot find valid irq");
+		return -ENODEV;
+	}
+	dev_dbg(dev, "irq-gpio is bound to IRQ %d", irq);
+
+	sdev->irq = irq;
+
+	return 0;
+}
+
+static int secocec_probe(struct platform_device *pdev)
+{
+	struct secocec_data *secocec;
+	struct device *dev = &pdev->dev;
+	int ret;
+	u16 val;
+
+	secocec = devm_kzalloc(dev, sizeof(*secocec), GFP_KERNEL);
+	if (!secocec)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, secocec);
+
+	/* Request SMBus regions */
+	if (!request_muxed_region(BRA_SMB_BASE_ADDR, 7, "CEC00001")) {
+		dev_err(dev, "Request memory region failed");
+		return -ENXIO;
+	}
+
+	secocec->pdev = pdev;
+	secocec->dev = dev;
+
+	if (!has_acpi_companion(dev)) {
+		dev_dbg(dev, "Cannot find any ACPI companion");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	ret = secocec_acpi_probe(secocec);
+	if (ret) {
+		dev_err(dev, "Cannot assign gpio to IRQ");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	/* Firmware version check */
+	ret = smb_rd16(SECOCEC_VERSION, &val);
+	if (ret) {
+		dev_err(dev, "Cannot check fw version");
+		goto err;
+	}
+	if (val < SECOCEC_LATEST_FW) {
+		dev_err(dev, "CEC Firmware not supported (v.%04x). Use ver > v.%04x",
+			val, SECOCEC_LATEST_FW);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = secocec_cec_get_notifier(&secocec->notifier);
+	if (ret) {
+		dev_err(dev, "no CEC notifier available\n");
+		goto err;
+	}
+
+	ret = devm_request_threaded_irq(dev,
+					secocec->irq,
+					NULL,
+					secocec_irq_handler,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					dev_name(&pdev->dev), secocec);
+
+	if (ret) {
+		dev_err(dev, "Cannot request IRQ %d", secocec->irq);
+		ret = -EIO;
+		goto err;
+	}
+
+	/* Allocate CEC adapter */
+	secocec->cec_adap = cec_allocate_adapter(&secocec_cec_adap_ops,
+						 secocec,
+						 dev_name(dev),
+						 CEC_CAP_DEFAULTS,
+						 SECOCEC_MAX_ADDRS);
+
+	if (IS_ERR(secocec->cec_adap)) {
+		ret = PTR_ERR(secocec->cec_adap);
+		goto err;
+	}
+
+	ret = cec_register_adapter(secocec->cec_adap, dev);
+	if (ret)
+		goto err_delete_adapter;
+
+	if (secocec->notifier)
+		cec_register_cec_notifier(secocec->cec_adap, secocec->notifier);
+
+	platform_set_drvdata(pdev, secocec);
+
+	dev_dbg(dev, "Device registered");
+
+	return ret;
+
+err_delete_adapter:
+	cec_delete_adapter(secocec->cec_adap);
+err:
+	dev_err(dev, "%s device probe failed\n", dev_name(dev));
+
+	return ret;
+}
+
+static int secocec_remove(struct platform_device *pdev)
+{
+	struct secocec_data *secocec = platform_get_drvdata(pdev);
+
+	cec_unregister_adapter(secocec->cec_adap);
+
+	if (secocec->notifier)
+		cec_notifier_put(secocec->notifier);
+
+	release_region(BRA_SMB_BASE_ADDR, 7);
+
+	dev_dbg(&pdev->dev, "CEC device removed");
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int secocec_suspend(struct device *dev)
+{
+	int status;
+	u16 val;
+
+	dev_dbg(dev, "Device going to suspend, disabling");
+
+	/* Clear the status register */
+	status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
+	if (status)
+		goto err;
+
+	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
+	if (status)
+		goto err;
+
+	/* Disable the interrupts */
+	status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
+	if (status)
+		goto err;
+
+	status = smb_wr16(SECOCEC_ENABLE_REG_1, val &
+			  ~SECOCEC_ENABLE_REG_1_CEC & ~SECOCEC_ENABLE_REG_1_IR);
+	if (status)
+		goto err;
+
+	return 0;
+
+err:
+	dev_err(dev, "Suspend failed (err: %d)", status);
+	return status;
+}
+
+static int secocec_resume(struct device *dev)
+{
+	int status;
+	u16 val;
+
+	dev_dbg(dev, "Resuming device from suspend");
+
+	/* Clear the status register */
+	status = smb_rd16(SECOCEC_STATUS_REG_1, &val);
+	if (status)
+		goto err;
+
+	status = smb_wr16(SECOCEC_STATUS_REG_1, val);
+	if (status)
+		goto err;
+
+	/* Enable the interrupts */
+	status = smb_rd16(SECOCEC_ENABLE_REG_1, &val);
+	if (status)
+		goto err;
+
+	status = smb_wr16(SECOCEC_ENABLE_REG_1, val | SECOCEC_ENABLE_REG_1_CEC);
+	if (status)
+		goto err;
+
+	dev_dbg(dev, "Device resumed from suspend");
+
+	return 0;
+
+err:
+	dev_err(dev, "Resume failed (err: %d)", status);
+	return status;
+}
+
+static SIMPLE_DEV_PM_OPS(secocec_pm_ops, secocec_suspend, secocec_resume);
+#define SECOCEC_PM_OPS (&secocec_pm_ops)
+#else
+#define SECOCEC_PM_OPS NULL
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id secocec_acpi_match[] = {
+	{"CEC00001", 0},
+	{},
+};
+
+MODULE_DEVICE_TABLE(acpi, secocec_acpi_match);
+#endif
+
+static struct platform_driver secocec_driver = {
+	.driver = {
+		   .name = SECOCEC_DEV_NAME,
+		   .acpi_match_table = ACPI_PTR(secocec_acpi_match),
+		   .pm = SECOCEC_PM_OPS,
+	},
+	.probe = secocec_probe,
+	.remove = secocec_remove,
+};
+
+module_platform_driver(secocec_driver);
+
+MODULE_DESCRIPTION("SECO CEC X86 Driver");
+MODULE_AUTHOR("Ettore Chimenti <ek5.chimenti@gmail.com>");
+MODULE_LICENSE("Dual BSD/GPL");