media: cec: i2c: ch7322: Add ch7322 CEC controller driver

Add a CEC device driver for the Chrontel ch7322 CEC conroller.
This is an I2C device capable of sending and receiving CEC messages.
Signed-off-by: Jeff Chase <jnchase@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

MAINTAINERS

@@ -4107,6 +4107,7 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 T:	git git://linuxtv.org/media_tree.git
 F:	Documentation/devicetree/bindings/media/i2c/chontel,ch7322.yaml
+F:	drivers/media/cec/i2c/ch7322.c
 
 CIRRUS LOGIC AUDIO CODEC DRIVERS
 M:	James Schulman <james.schulman@cirrus.com>

drivers/media/cec/Kconfig

@@ -33,6 +33,7 @@ menuconfig MEDIA_CEC_SUPPORT
 	  adapter that supports HDMI CEC.
 
 if MEDIA_CEC_SUPPORT
+source "drivers/media/cec/i2c/Kconfig"
 source "drivers/media/cec/platform/Kconfig"
 source "drivers/media/cec/usb/Kconfig"
 endif

drivers/media/cec/Makefile

 # SPDX-License-Identifier: GPL-2.0
-obj-y += core/ platform/ usb/
+obj-y += core/ i2c/ platform/ usb/

drivers/media/cec/i2c/Kconfig

+# SPDX-License-Identifier: GPL-2.0
+#
+# I2C drivers
+
+config CEC_CH7322
+	tristate "Chrontel CH7322 CEC controller"
+	depends on I2C
+	select REGMAP_I2C
+	select CEC_CORE
+	help
+	  This is a driver for the Chrontel CH7322 CEC controller. It uses the
+	  generic CEC framework interface.
+	  CEC bus is present in the HDMI connector and enables communication
+	  between compatible devices.

drivers/media/cec/i2c/Makefile

+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the CEC I2C device drivers.
+#
+obj-$(CONFIG_CEC_CH7322) += ch7322.o

drivers/media/cec/i2c/ch7322.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the Chrontel CH7322 CEC Controller
+ *
+ * Copyright 2020 Google LLC.
+ */
+
+/*
+ * Notes
+ *
+ * - This device powers on in Auto Mode which has limited functionality. This
+ *   driver disables Auto Mode when it attaches.
+ *
+ */
+
+#include <linux/cec.h>
+#include <linux/dmi.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/regmap.h>
+#include <media/cec.h>
+#include <media/cec-notifier.h>
+
+#define CH7322_WRITE		0x00
+#define CH7322_WRITE_MSENT		0x80
+#define CH7322_WRITE_BOK		0x40
+#define CH7322_WRITE_NMASK		0x0f
+
+/* Write buffer is 0x01-0x10 */
+#define CH7322_WRBUF		0x01
+#define CH7322_WRBUF_LEN	0x10
+
+#define CH7322_READ		0x40
+#define CH7322_READ_NRDT		0x80
+#define CH7322_READ_MSENT		0x20
+#define CH7322_READ_NMASK		0x0f
+
+/* Read buffer is 0x41-0x50 */
+#define CH7322_RDBUF		0x41
+#define CH7322_RDBUF_LEN	0x10
+
+#define CH7322_MODE		0x11
+#define CH7322_MODE_AUTO		0x78
+#define CH7322_MODE_SW			0xb5
+
+#define CH7322_RESET		0x12
+#define CH7322_RESET_RST		0x00
+
+#define CH7322_POWER		0x13
+#define CH7322_POWER_FPD		0x04
+
+#define CH7322_CFG0		0x17
+#define CH7322_CFG0_EOBEN		0x40
+#define CH7322_CFG0_PEOB		0x20
+#define CH7322_CFG0_CLRSPP		0x10
+#define CH7322_CFG0_FLOW		0x08
+
+#define CH7322_CFG1		0x1a
+#define CH7322_CFG1_STDBYO		0x04
+#define CH7322_CFG1_HPBP		0x02
+#define CH7322_CFG1_PIO			0x01
+
+#define CH7322_INTCTL		0x1b
+#define CH7322_INTCTL_INTPB		0x80
+#define CH7322_INTCTL_STDBY		0x40
+#define CH7322_INTCTL_HPDFALL		0x20
+#define CH7322_INTCTL_HPDRISE		0x10
+#define CH7322_INTCTL_RXMSG		0x08
+#define CH7322_INTCTL_TXMSG		0x04
+#define CH7322_INTCTL_NEWPHA		0x02
+#define CH7322_INTCTL_ERROR		0x01
+
+#define CH7322_DVCLKFNH	0x1d
+#define CH7322_DVCLKFNL	0x1e
+
+#define CH7322_CTL		0x31
+#define CH7322_CTL_FSTDBY		0x80
+#define CH7322_CTL_PLSEN		0x40
+#define CH7322_CTL_PLSPB		0x20
+#define CH7322_CTL_SPADL		0x10
+#define CH7322_CTL_HINIT		0x08
+#define CH7322_CTL_WPHYA		0x04
+#define CH7322_CTL_H1T			0x02
+#define CH7322_CTL_S1T			0x01
+
+#define CH7322_PAWH		0x32
+#define CH7322_PAWL		0x33
+
+#define CH7322_ADDLW		0x34
+#define CH7322_ADDLW_MASK	0xf0
+
+#define CH7322_ADDLR		0x3d
+#define CH7322_ADDLR_HPD		0x80
+#define CH7322_ADDLR_MASK		0x0f
+
+#define CH7322_INTDATA		0x3e
+#define CH7322_INTDATA_MODE		0x80
+#define CH7322_INTDATA_STDBY		0x40
+#define CH7322_INTDATA_HPDFALL		0x20
+#define CH7322_INTDATA_HPDRISE		0x10
+#define CH7322_INTDATA_RXMSG		0x08
+#define CH7322_INTDATA_TXMSG		0x04
+#define CH7322_INTDATA_NEWPHA		0x02
+#define CH7322_INTDATA_ERROR		0x01
+
+#define CH7322_EVENT		0x3f
+#define CH7322_EVENT_TXERR		0x80
+#define CH7322_EVENT_HRST		0x40
+#define CH7322_EVENT_HFST		0x20
+#define CH7322_EVENT_PHACHG		0x10
+#define CH7322_EVENT_ACTST		0x08
+#define CH7322_EVENT_PHARDY		0x04
+#define CH7322_EVENT_BSOK		0x02
+#define CH7322_EVENT_ERRADCF		0x01
+
+#define CH7322_DID		0x51
+#define CH7322_DID_CH7322		0x5b
+#define CH7322_DID_CH7323		0x5f
+
+#define CH7322_REVISIONID	0x52
+
+#define CH7322_PARH		0x53
+#define CH7322_PARL		0x54
+
+#define CH7322_IOCFG2		0x75
+#define CH7322_IOCFG_CIO		0x80
+#define CH7322_IOCFG_IOCFGMASK		0x78
+#define CH7322_IOCFG_AUDIO		0x04
+#define CH7322_IOCFG_SPAMST		0x02
+#define CH7322_IOCFG_SPAMSP		0x01
+
+#define CH7322_CTL3		0x7b
+#define CH7322_CTL3_SWENA		0x80
+#define CH7322_CTL3_FC_INIT		0x40
+#define CH7322_CTL3_SML_FL		0x20
+#define CH7322_CTL3_SM_RDST		0x10
+#define CH7322_CTL3_SPP_CIAH		0x08
+#define CH7322_CTL3_SPP_CIAL		0x04
+#define CH7322_CTL3_SPP_ACTH		0x02
+#define CH7322_CTL3_SPP_ACTL		0x01
+
+/* BOK status means NACK */
+#define CH7322_TX_FLAG_NACK	BIT(0)
+/* Device will retry automatically */
+#define CH7322_TX_FLAG_RETRY	BIT(1)
+
+struct ch7322 {
+	struct i2c_client *i2c;
+	struct regmap *regmap;
+	struct cec_adapter *cec;
+	struct mutex mutex;	/* device access mutex */
+	u8 tx_flags;
+};
+
+static const struct regmap_config ch7322_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x7f,
+	.disable_locking = true,
+};
+
+static int ch7322_send_message(struct ch7322 *ch7322, const struct cec_msg *msg)
+{
+	unsigned int val;
+	unsigned int len = msg->len;
+	int ret;
+	int i;
+
+	WARN_ON(!mutex_is_locked(&ch7322->mutex));
+
+	if (len > CH7322_WRBUF_LEN || len < 1)
+		return -EINVAL;
+
+	ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
+	if (ret)
+		return ret;
+
+	/* Buffer not ready */
+	if (!(val & CH7322_WRITE_MSENT))
+		return -EBUSY;
+
+	if (cec_msg_opcode(msg) == -1 &&
+	    cec_msg_initiator(msg) == cec_msg_destination(msg)) {
+		ch7322->tx_flags = CH7322_TX_FLAG_NACK | CH7322_TX_FLAG_RETRY;
+	} else if (cec_msg_is_broadcast(msg)) {
+		ch7322->tx_flags = CH7322_TX_FLAG_NACK;
+	} else {
+		ch7322->tx_flags = CH7322_TX_FLAG_RETRY;
+	}
+
+	ret = regmap_write(ch7322->regmap, CH7322_WRITE, len - 1);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < len; i++) {
+		ret = regmap_write(ch7322->regmap,
+				   CH7322_WRBUF + i, msg->msg[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ch7322_receive_message(struct ch7322 *ch7322, struct cec_msg *msg)
+{
+	unsigned int val;
+	int ret = 0;
+	int i;
+
+	WARN_ON(!mutex_is_locked(&ch7322->mutex));
+
+	ret = regmap_read(ch7322->regmap, CH7322_READ, &val);
+	if (ret)
+		return ret;
+
+	/* Message not ready */
+	if (!(val & CH7322_READ_NRDT))
+		return -EIO;
+
+	msg->len = (val & CH7322_READ_NMASK) + 1;
+
+	/* Read entire RDBUF to clear state */
+	for (i = 0; i < CH7322_RDBUF_LEN; i++) {
+		ret = regmap_read(ch7322->regmap, CH7322_RDBUF + i, &val);
+		if (ret)
+			return ret;
+		msg->msg[i] = (u8)val;
+	}
+
+	return 0;
+}
+
+static void ch7322_tx_done(struct ch7322 *ch7322)
+{
+	int ret;
+	unsigned int val;
+	u8 status, flags;
+
+	mutex_lock(&ch7322->mutex);
+	ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
+	flags = ch7322->tx_flags;
+	mutex_unlock(&ch7322->mutex);
+
+	/*
+	 * The device returns a one-bit OK status which usually means ACK but
+	 * actually means NACK when sending a logical address query or a
+	 * broadcast.
+	 */
+	if (ret)
+		status = CEC_TX_STATUS_ERROR;
+	else if ((val & CH7322_WRITE_BOK) && (flags & CH7322_TX_FLAG_NACK))
+		status = CEC_TX_STATUS_NACK;
+	else if (val & CH7322_WRITE_BOK)
+		status = CEC_TX_STATUS_OK;
+	else if (flags & CH7322_TX_FLAG_NACK)
+		status = CEC_TX_STATUS_OK;
+	else
+		status = CEC_TX_STATUS_NACK;
+
+	if (status == CEC_TX_STATUS_NACK && (flags & CH7322_TX_FLAG_RETRY))
+		status |= CEC_TX_STATUS_MAX_RETRIES;
+
+	cec_transmit_attempt_done(ch7322->cec, status);
+}
+
+static void ch7322_rx_done(struct ch7322 *ch7322)
+{
+	struct cec_msg msg;
+	int ret;
+
+	mutex_lock(&ch7322->mutex);
+	ret = ch7322_receive_message(ch7322, &msg);
+	mutex_unlock(&ch7322->mutex);
+
+	if (ret)
+		dev_err(&ch7322->i2c->dev, "cec receive error: %d\n", ret);
+	else
+		cec_received_msg(ch7322->cec, &msg);
+}
+
+/*
+ * This device can either monitor the DDC lines to obtain the physical address
+ * or it can allow the host to program it. This driver lets the device obtain
+ * it.
+ */
+static void ch7322_phys_addr(struct ch7322 *ch7322)
+{
+	unsigned int pah, pal;
+	int ret = 0;
+
+	mutex_lock(&ch7322->mutex);
+	ret |= regmap_read(ch7322->regmap, CH7322_PARH, &pah);
+	ret |= regmap_read(ch7322->regmap, CH7322_PARL, &pal);
+	mutex_unlock(&ch7322->mutex);
+
+	if (ret)
+		dev_err(&ch7322->i2c->dev, "phys addr error\n");
+	else
+		cec_s_phys_addr(ch7322->cec, pal | (pah << 8), false);
+}
+
+static irqreturn_t ch7322_irq(int irq, void *dev)
+{
+	struct ch7322 *ch7322 = dev;
+	unsigned int data = 0;
+
+	mutex_lock(&ch7322->mutex);
+	regmap_read(ch7322->regmap, CH7322_INTDATA, &data);
+	regmap_write(ch7322->regmap, CH7322_INTDATA, data);
+	mutex_unlock(&ch7322->mutex);
+
+	if (data & CH7322_INTDATA_HPDFALL)
+		cec_phys_addr_invalidate(ch7322->cec);
+
+	if (data & CH7322_INTDATA_TXMSG)
+		ch7322_tx_done(ch7322);
+
+	if (data & CH7322_INTDATA_RXMSG)
+		ch7322_rx_done(ch7322);
+
+	if (data & CH7322_INTDATA_NEWPHA)
+		ch7322_phys_addr(ch7322);
+
+	if (data & CH7322_INTDATA_ERROR)
+		dev_dbg(&ch7322->i2c->dev, "unknown error\n");
+
+	return IRQ_HANDLED;
+}
+
+/* This device is always enabled */
+static int ch7322_cec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	return 0;
+}
+
+static int ch7322_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
+{
+	struct ch7322 *ch7322 = cec_get_drvdata(adap);
+	int ret;
+
+	mutex_lock(&ch7322->mutex);
+	ret = regmap_update_bits(ch7322->regmap, CH7322_ADDLW,
+				 CH7322_ADDLW_MASK, log_addr << 4);
+	mutex_unlock(&ch7322->mutex);
+
+	return ret;
+}
+
+static int ch7322_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
+				    u32 signal_free_time, struct cec_msg *msg)
+{
+	struct ch7322 *ch7322 = cec_get_drvdata(adap);
+	int ret;
+
+	mutex_lock(&ch7322->mutex);
+	ret = ch7322_send_message(ch7322, msg);
+	mutex_unlock(&ch7322->mutex);
+
+	return ret;
+}
+
+static const struct cec_adap_ops ch7322_cec_adap_ops = {
+	.adap_enable = ch7322_cec_adap_enable,
+	.adap_log_addr = ch7322_cec_adap_log_addr,
+	.adap_transmit = ch7322_cec_adap_transmit,
+};
+
+#if IS_ENABLED(CONFIG_PCI) && IS_ENABLED(CONFIG_DMI)
+
+struct ch7322_conn_match {
+	const char *dev_name;
+	const char *pci_name;
+	const char *port_name;
+};
+
+static struct ch7322_conn_match google_endeavour[] = {
+	{ "i2c-PRP0001:00", "0000:00:02.0", "Port B" },
+	{ "i2c-PRP0001:01", "0000:00:02.0", "Port C" },
+	{ },
+};
+
+static const struct dmi_system_id ch7322_dmi_table[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
+			DMI_MATCH(DMI_BOARD_NAME, "Endeavour"),
+		},
+		.driver_data = google_endeavour,
+	},
+	{ },
+};
+
+/* Make a best-effort attempt to locate a matching HDMI port */
+static int ch7322_get_port(struct i2c_client *client,
+			   struct device **dev,
+			   const char **port)
+{
+	const struct dmi_system_id *system;
+	const struct ch7322_conn_match *conn;
+
+	*dev = NULL;
+	*port = NULL;
+
+	system = dmi_first_match(ch7322_dmi_table);
+	if (!system)
+		return 0;
+
+	for (conn = system->driver_data; conn->dev_name; conn++) {
+		if (!strcmp(dev_name(&client->dev), conn->dev_name)) {
+			struct device *d;
+
+			d = bus_find_device_by_name(&pci_bus_type, NULL,
+						    conn->pci_name);
+			if (!d)
+				return -EPROBE_DEFER;
+
+			put_device(d);
+
+			*dev = d;
+			*port = conn->port_name;
+
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+#else
+
+static int ch7322_get_port(struct i2c_client *client,
+			   struct device **dev,
+			   const char **port)
+{
+	*dev = NULL;
+	*port = NULL;
+
+	return 0;
+}
+
+#endif
+
+static int ch7322_probe(struct i2c_client *client)
+{
+	struct device *hdmi_dev;
+	const char *port_name;
+	struct ch7322 *ch7322;
+	struct cec_notifier *notifier = NULL;
+	u32 caps = CEC_CAP_DEFAULTS;
+	int ret;
+	unsigned int val;
+
+	ret = ch7322_get_port(client, &hdmi_dev, &port_name);
+	if (ret)
+		return ret;
+
+	if (hdmi_dev)
+		caps |= CEC_CAP_CONNECTOR_INFO;
+
+	ch7322 = devm_kzalloc(&client->dev, sizeof(*ch7322), GFP_KERNEL);
+	if (!ch7322)
+		return -ENOMEM;
+
+	ch7322->regmap = devm_regmap_init_i2c(client, &ch7322_regmap);
+	if (IS_ERR(ch7322->regmap))
+		return PTR_ERR(ch7322->regmap);
+
+	ret = regmap_read(ch7322->regmap, CH7322_DID, &val);
+	if (ret)
+		return ret;
+
+	if (val != CH7322_DID_CH7322)
+		return -EOPNOTSUPP;
+
+	mutex_init(&ch7322->mutex);
+	ch7322->i2c = client;
+	ch7322->tx_flags = 0;
+
+	i2c_set_clientdata(client, ch7322);
+
+	/* Disable auto mode */
+	ret = regmap_write(ch7322->regmap, CH7322_MODE, CH7322_MODE_SW);
+	if (ret)
+		goto err_mutex;
+
+	/* Enable logical address register */
+	ret = regmap_update_bits(ch7322->regmap, CH7322_CTL,
+				 CH7322_CTL_SPADL, CH7322_CTL_SPADL);
+	if (ret)
+		goto err_mutex;
+
+	ch7322->cec = cec_allocate_adapter(&ch7322_cec_adap_ops, ch7322,
+					   dev_name(&client->dev),
+					   caps, 1);
+
+	if (IS_ERR(ch7322->cec)) {
+		ret = PTR_ERR(ch7322->cec);
+		goto err_mutex;
+	}
+
+	ch7322->cec->adap_controls_phys_addr = true;
+
+	if (hdmi_dev) {
+		notifier = cec_notifier_cec_adap_register(hdmi_dev,
+							  port_name,
+							  ch7322->cec);
+		if (!notifier) {
+			ret = -ENOMEM;
+			goto err_cec;
+		}
+	}
+
+	/* Configure, mask, and clear interrupt */
+	ret = regmap_write(ch7322->regmap, CH7322_CFG1, 0);
+	if (ret)
+		goto err_notifier;
+	ret = regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
+	if (ret)
+		goto err_notifier;
+	ret = regmap_write(ch7322->regmap, CH7322_INTDATA, 0xff);
+	if (ret)
+		goto err_notifier;
+
+	/* If HPD is up read physical address */
+	ret = regmap_read(ch7322->regmap, CH7322_ADDLR, &val);
+	if (ret)
+		goto err_notifier;
+	if (val & CH7322_ADDLR_HPD)
+		ch7322_phys_addr(ch7322);
+
+	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+					ch7322_irq,
+					IRQF_ONESHOT | IRQF_TRIGGER_RISING,
+					client->name, ch7322);
+	if (ret)
+		goto err_notifier;
+
+	/* Unmask interrupt */
+	mutex_lock(&ch7322->mutex);
+	ret = regmap_write(ch7322->regmap, CH7322_INTCTL, 0xff);
+	mutex_unlock(&ch7322->mutex);
+
+	if (ret)
+		goto err_notifier;
+
+	ret = cec_register_adapter(ch7322->cec, &client->dev);
+	if (ret)
+		goto err_notifier;
+
+	dev_info(&client->dev, "device registered\n");
+
+	return 0;
+
+err_notifier:
+	if (notifier)
+		cec_notifier_cec_adap_unregister(notifier, ch7322->cec);
+err_cec:
+	cec_delete_adapter(ch7322->cec);
+err_mutex:
+	mutex_destroy(&ch7322->mutex);
+	return ret;
+}
+
+static int ch7322_remove(struct i2c_client *client)
+{
+	struct ch7322 *ch7322 = i2c_get_clientdata(client);
+
+	/* Mask interrupt */
+	mutex_lock(&ch7322->mutex);
+	regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
+	mutex_unlock(&ch7322->mutex);
+
+	cec_unregister_adapter(ch7322->cec);
+	mutex_destroy(&ch7322->mutex);
+
+	dev_info(&client->dev, "device unregistered\n");
+
+	return 0;
+}
+
+static const struct of_device_id ch7322_of_match[] = {
+	{ .compatible = "chrontel,ch7322", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ch7322_of_match);
+
+static struct i2c_driver ch7322_i2c_driver = {
+	.driver = {
+		.name = "ch7322",
+		.of_match_table = of_match_ptr(ch7322_of_match),
+	},
+	.probe_new	= ch7322_probe,
+	.remove		= ch7322_remove,
+};
+
+module_i2c_driver(ch7322_i2c_driver);
+
+MODULE_DESCRIPTION("Chrontel CH7322 CEC Controller Driver");
+MODULE_AUTHOR("Jeff Chase <jnchase@google.com>");
+MODULE_LICENSE("GPL");