[PATCH v9 04/15] usb: typec: tcpci_maxim: Chip level TCPC driver

[Badhri Jagan Sridharan <badhri@google.com>]

Chip level TCPC driver for Maxim's TCPCI implementation.
This TCPC implementation does not support the following
commands: COMMAND.SinkVbus, COMMAND.SourceVbusDefaultVoltage,
COMMAND.SourceVbusHighVoltage. Instead the sinking and sourcing
from vbus is supported by writes to custom registers.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
Changes since v1:
- Changing patch version to v6 to fix version number confusion.
- Removed setting USB_PSY and terminating description with period as
  suggested by Randy.

Changes since v6:
- Addressed Heikki comments:
  - Removed TX discarded message
  - Removed the redundant TCPC_POWER_STATUS_UNINIT check
- Cleaned up irq setup routine

Changes since v7:
- Added reviewed-by: Heikki

Changes since v8:
- None
---
 drivers/usb/typec/tcpm/Kconfig       |   6 +
 drivers/usb/typec/tcpm/Makefile      |  15 +-
 drivers/usb/typec/tcpm/tcpci.h       |   1 +
 drivers/usb/typec/tcpm/tcpci_maxim.c | 461 +++++++++++++++++++++++++++
 4 files changed, 476 insertions(+), 7 deletions(-)
 create mode 100644 drivers/usb/typec/tcpm/tcpci_maxim.c

diff --git a/drivers/usb/typec/tcpm/Kconfig b/drivers/usb/typec/tcpm/Kconfig
index 58a64e1bf627..557f392fe24d 100644
--- a/drivers/usb/typec/tcpm/Kconfig
+++ b/drivers/usb/typec/tcpm/Kconfig
@@ -35,6 +35,12 @@ config TYPEC_MT6360
 	  USB Type-C. It works with Type-C Port Controller Manager
 	  to provide USB PD and USB Type-C functionalities.
 
+config TYPEC_TCPCI_MAXIM
+	tristate "Maxim TCPCI based Type-C chip driver"
+	help
+	  MAXIM TCPCI based Type-C/PD chip driver. Works with
+	  with Type-C Port Controller Manager.
+
 endif # TYPEC_TCPCI
 
 config TYPEC_FUSB302
diff --git a/drivers/usb/typec/tcpm/Makefile b/drivers/usb/typec/tcpm/Makefile
index 7592ccb8c526..7d499f3569fd 100644
--- a/drivers/usb/typec/tcpm/Makefile
+++ b/drivers/usb/typec/tcpm/Makefile
@@ -1,8 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
-obj-$(CONFIG_TYPEC_FUSB302)	+= fusb302.o
-obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
-typec_wcove-y			:= wcove.o
-obj-$(CONFIG_TYPEC_TCPCI)	+= tcpci.o
-obj-$(CONFIG_TYPEC_RT1711H)	+= tcpci_rt1711h.o
-obj-$(CONFIG_TYPEC_MT6360)	+= tcpci_mt6360.o
+obj-$(CONFIG_TYPEC_TCPM)		+= tcpm.o
+obj-$(CONFIG_TYPEC_FUSB302)		+= fusb302.o
+obj-$(CONFIG_TYPEC_WCOVE)		+= typec_wcove.o
+typec_wcove-y				:= wcove.o
+obj-$(CONFIG_TYPEC_TCPCI)		+= tcpci.o
+obj-$(CONFIG_TYPEC_RT1711H)		+= tcpci_rt1711h.o
+obj-$(CONFIG_TYPEC_MT6360)		+= tcpci_mt6360.o
+obj-$(CONFIG_TYPEC_TCPCI_MAXIM)		+= tcpci_maxim.o
diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
index 4d441bdf24d5..82f021a82456 100644
--- a/drivers/usb/typec/tcpm/tcpci.h
+++ b/drivers/usb/typec/tcpm/tcpci.h
@@ -109,6 +109,7 @@
 
 #define TCPC_RX_BYTE_CNT		0x30
 #define TCPC_RX_BUF_FRAME_TYPE		0x31
+#define TCPC_RX_BUF_FRAME_TYPE_SOP	0
 #define TCPC_RX_HDR			0x32
 #define TCPC_RX_DATA			0x34 /* through 0x4f */
 
diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.c b/drivers/usb/typec/tcpm/tcpci_maxim.c
new file mode 100644
index 000000000000..91337ddb4962
--- /dev/null
+++ b/drivers/usb/typec/tcpm/tcpci_maxim.c
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Google LLC
+ *
+ * MAXIM TCPCI based TCPC driver
+ */
+
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/usb/pd.h>
+#include <linux/usb/tcpm.h>
+#include <linux/usb/typec.h>
+
+#include "tcpci.h"
+
+#define PD_ACTIVITY_TIMEOUT_MS				10000
+
+#define TCPC_VENDOR_ALERT				0x80
+
+#define TCPC_RECEIVE_BUFFER_COUNT_OFFSET		0
+#define TCPC_RECEIVE_BUFFER_FRAME_TYPE_OFFSET		1
+#define TCPC_RECEIVE_BUFFER_RX_BYTE_BUF_OFFSET		2
+
+/*
+ * LongMessage not supported, hence 32 bytes for buf to be read from RECEIVE_BUFFER.
+ * DEVICE_CAPABILITIES_2.LongMessage = 0, the value in READABLE_BYTE_COUNT reg shall be
+ * less than or equal to 31. Since, RECEIVE_BUFFER len = 31 + 1(READABLE_BYTE_COUNT).
+ */
+#define TCPC_RECEIVE_BUFFER_LEN				32
+
+#define MAX_BUCK_BOOST_SID				0x69
+#define MAX_BUCK_BOOST_OP				0xb9
+#define MAX_BUCK_BOOST_OFF				0
+#define MAX_BUCK_BOOST_SOURCE				0xa
+#define MAX_BUCK_BOOST_SINK				0x5
+
+struct max_tcpci_chip {
+	struct tcpci_data data;
+	struct tcpci *tcpci;
+	struct device *dev;
+	struct i2c_client *client;
+	struct tcpm_port *port;
+};
+
+static const struct regmap_range max_tcpci_tcpci_range[] = {
+	regmap_reg_range(0x00, 0x95)
+};
+
+const struct regmap_access_table max_tcpci_tcpci_write_table = {
+	.yes_ranges = max_tcpci_tcpci_range,
+	.n_yes_ranges = ARRAY_SIZE(max_tcpci_tcpci_range),
+};
+
+static const struct regmap_config max_tcpci_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x95,
+	.wr_table = &max_tcpci_tcpci_write_table,
+};
+
+static struct max_tcpci_chip *tdata_to_max_tcpci(struct tcpci_data *tdata)
+{
+	return container_of(tdata, struct max_tcpci_chip, data);
+}
+
+static int max_tcpci_read16(struct max_tcpci_chip *chip, unsigned int reg, u16 *val)
+{
+	return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u16));
+}
+
+static int max_tcpci_write16(struct max_tcpci_chip *chip, unsigned int reg, u16 val)
+{
+	return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u16));
+}
+
+static int max_tcpci_read8(struct max_tcpci_chip *chip, unsigned int reg, u8 *val)
+{
+	return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u8));
+}
+
+static int max_tcpci_write8(struct max_tcpci_chip *chip, unsigned int reg, u8 val)
+{
+	return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u8));
+}
+
+static void max_tcpci_init_regs(struct max_tcpci_chip *chip)
+{
+	u16 alert_mask = 0;
+	int ret;
+
+	ret = max_tcpci_write16(chip, TCPC_ALERT, 0xffff);
+	if (ret < 0) {
+		dev_err(chip->dev, "Error writing to TCPC_ALERT ret:%d\n", ret);
+		return;
+	}
+
+	ret = max_tcpci_write16(chip, TCPC_VENDOR_ALERT, 0xffff);
+	if (ret < 0) {
+		dev_err(chip->dev, "Error writing to TCPC_VENDOR_ALERT ret:%d\n", ret);
+		return;
+	}
+
+	alert_mask = TCPC_ALERT_TX_SUCCESS | TCPC_ALERT_TX_DISCARDED | TCPC_ALERT_TX_FAILED |
+		TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_RX_STATUS | TCPC_ALERT_CC_STATUS |
+		TCPC_ALERT_VBUS_DISCNCT | TCPC_ALERT_RX_BUF_OVF | TCPC_ALERT_POWER_STATUS;
+
+	ret = max_tcpci_write16(chip, TCPC_ALERT_MASK, alert_mask);
+	if (ret < 0) {
+		dev_err(chip->dev, "Error writing to TCPC_ALERT_MASK ret:%d\n", ret);
+		return;
+	}
+
+	/* Enable vbus voltage monitoring and voltage alerts */
+	ret = max_tcpci_write8(chip, TCPC_POWER_CTRL, 0);
+	if (ret < 0) {
+		dev_err(chip->dev, "Error writing to TCPC_POWER_CTRL ret:%d\n", ret);
+		return;
+	}
+}
+
+static void process_rx(struct max_tcpci_chip *chip, u16 status)
+{
+	struct pd_message msg;
+	u8 count, frame_type, rx_buf[TCPC_RECEIVE_BUFFER_LEN];
+	int ret, payload_index;
+	u8 *rx_buf_ptr;
+
+	/*
+	 * READABLE_BYTE_COUNT: Indicates the number of bytes in the RX_BUF_BYTE_x registers
+	 * plus one (for the RX_BUF_FRAME_TYPE) Table 4-36.
+	 * Read the count and frame type.
+	 */
+	ret = regmap_raw_read(chip->data.regmap, TCPC_RX_BYTE_CNT, rx_buf, 2);
+	if (ret < 0) {
+		dev_err(chip->dev, "TCPC_RX_BYTE_CNT read failed ret:%d", ret);
+		return;
+	}
+
+	count = rx_buf[TCPC_RECEIVE_BUFFER_COUNT_OFFSET];
+	frame_type = rx_buf[TCPC_RECEIVE_BUFFER_FRAME_TYPE_OFFSET];
+
+	if (count == 0 || frame_type != TCPC_RX_BUF_FRAME_TYPE_SOP) {
+		max_tcpci_write16(chip, TCPC_ALERT, TCPC_ALERT_RX_STATUS);
+		dev_err(chip->dev, "%s", count ==  0 ? "error: count is 0" :
+			"error frame_type is not SOP");
+		return;
+	}
+
+	if (count > sizeof(struct pd_message) || count + 1 > TCPC_RECEIVE_BUFFER_LEN) {
+		dev_err(chip->dev, "Invalid TCPC_RX_BYTE_CNT %d", count);
+		return;
+	}
+
+	/*
+	 * Read count + 1 as RX_BUF_BYTE_x is hidden and can only be read through
+	 * TCPC_RX_BYTE_CNT
+	 */
+	count += 1;
+	ret = regmap_raw_read(chip->data.regmap, TCPC_RX_BYTE_CNT, rx_buf, count);
+	if (ret < 0) {
+		dev_err(chip->dev, "Error: TCPC_RX_BYTE_CNT read failed: %d", ret);
+		return;
+	}
+
+	rx_buf_ptr = rx_buf + TCPC_RECEIVE_BUFFER_RX_BYTE_BUF_OFFSET;
+	msg.header = cpu_to_le16(*(u16 *)rx_buf_ptr);
+	rx_buf_ptr = rx_buf_ptr + sizeof(msg.header);
+	for (payload_index = 0; payload_index < pd_header_cnt_le(msg.header); payload_index++,
+	     rx_buf_ptr += sizeof(msg.payload[0]))
+		msg.payload[payload_index] = cpu_to_le32(*(u32 *)rx_buf_ptr);
+
+	/*
+	 * Read complete, clear RX status alert bit.
+	 * Clear overflow as well if set.
+	 */
+	ret = max_tcpci_write16(chip, TCPC_ALERT, status & TCPC_ALERT_RX_BUF_OVF ?
+				TCPC_ALERT_RX_STATUS | TCPC_ALERT_RX_BUF_OVF :
+				TCPC_ALERT_RX_STATUS);
+	if (ret < 0)
+		return;
+
+	tcpm_pd_receive(chip->port, &msg);
+}
+
+static int max_tcpci_set_vbus(struct tcpci *tcpci, struct tcpci_data *tdata, bool source, bool sink)
+{
+	struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
+	u8 buffer_source[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_SOURCE};
+	u8 buffer_sink[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_SINK};
+	u8 buffer_none[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_OFF};
+	struct i2c_client *i2c = chip->client;
+	int ret;
+
+	struct i2c_msg msgs[] = {
+		{
+			.addr = MAX_BUCK_BOOST_SID,
+			.flags = i2c->flags & I2C_M_TEN,
+			.len = 2,
+			.buf = source ? buffer_source : sink ? buffer_sink : buffer_none,
+		},
+	};
+
+	if (source && sink) {
+		dev_err(chip->dev, "Both source and sink set\n");
+		return -EINVAL;
+	}
+
+	ret = i2c_transfer(i2c->adapter, msgs, 1);
+
+	return  ret < 0 ? ret : 1;
+}
+
+static void process_power_status(struct max_tcpci_chip *chip)
+{
+	u8 pwr_status;
+	int ret;
+
+	ret = max_tcpci_read8(chip, TCPC_POWER_STATUS, &pwr_status);
+	if (ret < 0)
+		return;
+
+	if (pwr_status == 0xff)
+		max_tcpci_init_regs(chip);
+	else
+		tcpm_vbus_change(chip->port);
+}
+
+static void process_tx(struct max_tcpci_chip *chip, u16 status)
+{
+	if (status & TCPC_ALERT_TX_SUCCESS)
+		tcpm_pd_transmit_complete(chip->port, TCPC_TX_SUCCESS);
+	else if (status & TCPC_ALERT_TX_DISCARDED)
+		tcpm_pd_transmit_complete(chip->port, TCPC_TX_DISCARDED);
+	else if (status & TCPC_ALERT_TX_FAILED)
+		tcpm_pd_transmit_complete(chip->port, TCPC_TX_FAILED);
+
+	/* Reinit regs as Hard reset sets them to default value */
+	if ((status & TCPC_ALERT_TX_SUCCESS) && (status & TCPC_ALERT_TX_FAILED))
+		max_tcpci_init_regs(chip);
+}
+
+static irqreturn_t _max_tcpci_irq(struct max_tcpci_chip *chip, u16 status)
+{
+	u16 mask;
+	int ret;
+
+	/*
+	 * Clear alert status for everything except RX_STATUS, which shouldn't
+	 * be cleared until we have successfully retrieved message.
+	 */
+	if (status & ~TCPC_ALERT_RX_STATUS) {
+		mask = status & TCPC_ALERT_RX_BUF_OVF ?
+			status & ~(TCPC_ALERT_RX_STATUS | TCPC_ALERT_RX_BUF_OVF) :
+			status & ~TCPC_ALERT_RX_STATUS;
+		ret = max_tcpci_write16(chip, TCPC_ALERT, mask);
+		if (ret < 0) {
+			dev_err(chip->dev, "ALERT clear failed\n");
+			return ret;
+		}
+	}
+
+	if (status & TCPC_ALERT_RX_BUF_OVF && !(status & TCPC_ALERT_RX_STATUS)) {
+		ret = max_tcpci_write16(chip, TCPC_ALERT, (TCPC_ALERT_RX_STATUS |
+							  TCPC_ALERT_RX_BUF_OVF));
+		if (ret < 0) {
+			dev_err(chip->dev, "ALERT clear failed\n");
+			return ret;
+		}
+	}
+
+	if (status & TCPC_ALERT_RX_STATUS)
+		process_rx(chip, status);
+
+	if (status & TCPC_ALERT_VBUS_DISCNCT)
+		tcpm_vbus_change(chip->port);
+
+	if (status & TCPC_ALERT_CC_STATUS)
+		tcpm_cc_change(chip->port);
+
+	if (status & TCPC_ALERT_POWER_STATUS)
+		process_power_status(chip);
+
+	if (status & TCPC_ALERT_RX_HARD_RST) {
+		tcpm_pd_hard_reset(chip->port);
+		max_tcpci_init_regs(chip);
+	}
+
+	if (status & TCPC_ALERT_TX_SUCCESS || status & TCPC_ALERT_TX_DISCARDED || status &
+	    TCPC_ALERT_TX_FAILED)
+		process_tx(chip, status);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t max_tcpci_irq(int irq, void *dev_id)
+{
+	struct max_tcpci_chip *chip = dev_id;
+	u16 status;
+	irqreturn_t irq_return;
+	int ret;
+
+	if (!chip->port)
+		return IRQ_HANDLED;
+
+	ret = max_tcpci_read16(chip, TCPC_ALERT, &status);
+	if (ret < 0) {
+		dev_err(chip->dev, "ALERT read failed\n");
+		return ret;
+	}
+	while (status) {
+		irq_return = _max_tcpci_irq(chip, status);
+		/* Do not return if the ALERT is already set. */
+		ret = max_tcpci_read16(chip, TCPC_ALERT, &status);
+		if (ret < 0)
+			break;
+	}
+
+	return irq_return;
+}
+
+static irqreturn_t max_tcpci_isr(int irq, void *dev_id)
+{
+	struct max_tcpci_chip *chip = dev_id;
+
+	pm_wakeup_event(chip->dev, PD_ACTIVITY_TIMEOUT_MS);
+
+	if (!chip->port)
+		return IRQ_HANDLED;
+
+	return IRQ_WAKE_THREAD;
+}
+
+static int max_tcpci_init_alert(struct max_tcpci_chip *chip, struct i2c_client *client)
+{
+	int ret;
+
+	ret = devm_request_threaded_irq(chip->dev, client->irq, max_tcpci_isr, max_tcpci_irq,
+					(IRQF_TRIGGER_LOW | IRQF_ONESHOT), dev_name(chip->dev),
+					chip);
+
+	if (ret < 0)
+		return ret;
+
+	enable_irq_wake(client->irq);
+	return 0;
+}
+
+static int max_tcpci_start_toggling(struct tcpci *tcpci, struct tcpci_data *tdata,
+				    enum typec_cc_status cc)
+{
+	struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
+
+	max_tcpci_init_regs(chip);
+
+	return 0;
+}
+
+static int tcpci_init(struct tcpci *tcpci, struct tcpci_data *data)
+{
+	/*
+	 * Generic TCPCI overwrites the regs once this driver initializes
+	 * them. Prevent this by returning -1.
+	 */
+	return -1;
+}
+
+static int max_tcpci_probe(struct i2c_client *client, const struct i2c_device_id *i2c_id)
+{
+	int ret;
+	struct max_tcpci_chip *chip;
+	u8 power_status;
+
+	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->client = client;
+	chip->data.regmap = devm_regmap_init_i2c(client, &max_tcpci_regmap_config);
+	if (IS_ERR(chip->data.regmap)) {
+		dev_err(&client->dev, "Regmap init failed\n");
+		return PTR_ERR(chip->data.regmap);
+	}
+
+	chip->dev = &client->dev;
+	i2c_set_clientdata(client, chip);
+
+	ret = max_tcpci_read8(chip, TCPC_POWER_STATUS, &power_status);
+	if (ret < 0)
+		return ret;
+
+	/* Chip level tcpci callbacks */
+	chip->data.set_vbus = max_tcpci_set_vbus;
+	chip->data.start_drp_toggling = max_tcpci_start_toggling;
+	chip->data.TX_BUF_BYTE_x_hidden = true;
+	chip->data.init = tcpci_init;
+
+	max_tcpci_init_regs(chip);
+	chip->tcpci = tcpci_register_port(chip->dev, &chip->data);
+	if (IS_ERR_OR_NULL(chip->tcpci)) {
+		dev_err(&client->dev, "TCPCI port registration failed");
+		ret = PTR_ERR(chip->tcpci);
+		return PTR_ERR(chip->tcpci);
+	}
+	chip->port = tcpci_get_tcpm_port(chip->tcpci);
+	ret = max_tcpci_init_alert(chip, client);
+	if (ret < 0)
+		goto unreg_port;
+
+	device_init_wakeup(chip->dev, true);
+	return 0;
+
+unreg_port:
+	tcpci_unregister_port(chip->tcpci);
+
+	return ret;
+}
+
+static int max_tcpci_remove(struct i2c_client *client)
+{
+	struct max_tcpci_chip *chip = i2c_get_clientdata(client);
+
+	if (!IS_ERR_OR_NULL(chip->tcpci))
+		tcpci_unregister_port(chip->tcpci);
+
+	return 0;
+}
+
+static const struct i2c_device_id max_tcpci_id[] = {
+	{ "maxtcpc", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max_tcpci_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id max_tcpci_of_match[] = {
+	{ .compatible = "maxim,tcpc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, max_tcpci_of_match);
+#endif
+
+static struct i2c_driver max_tcpci_i2c_driver = {
+	.driver = {
+		.name = "maxtcpc",
+		.of_match_table = of_match_ptr(max_tcpci_of_match),
+	},
+	.probe = max_tcpci_probe,
+	.remove = max_tcpci_remove,
+	.id_table = max_tcpci_id,
+};
+module_i2c_driver(max_tcpci_i2c_driver);
+
+MODULE_AUTHOR("Badhri Jagan Sridharan <badhri@google.com>");
+MODULE_DESCRIPTION("Maxim TCPCI based USB Type-C Port Controller Interface Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.28.0.709.gb0816b6eb0-goog