Commit 247c554a authored by Ajay Gupta's avatar Ajay Gupta Committed by Wolfram Sang
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usb: typec: ucsi: add support for Cypress CCGx 



Latest NVIDIA GPU cards have a Cypress CCGx Type-C controller
over I2C interface.

This UCSI I2C driver uses I2C bus driver interface for communicating
with Type-C controller.

Signed-off-by: default avatarAjay Gupta <ajayg@nvidia.com>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent caccdcc5

drivers/usb/typec/ucsi/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -23,6 +23,16 @@ config TYPEC_UCSI 


if TYPEC_UCSI



config UCSI_CCG

	tristate "UCSI Interface Driver for Cypress CCGx"

	depends on I2C

	help

	  This driver enables UCSI support on platforms that expose a

	  Cypress CCGx Type-C controller over I2C interface.



	  To compile the driver as a module, choose M here: the module will be

	  called ucsi_ccg.



config UCSI_ACPI

	tristate "UCSI ACPI Interface Driver"

	depends on ACPI

drivers/usb/typec/ucsi/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -8,3 +8,5 @@ typec_ucsi-y := ucsi.o 
typec_ucsi-$(CONFIG_TRACING)	+= trace.o



obj-$(CONFIG_UCSI_ACPI)		+= ucsi_acpi.o



obj-$(CONFIG_UCSI_CCG)		+= ucsi_ccg.o

drivers/usb/typec/ucsi/ucsi_ccg.c

0 → 100644
+307 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * UCSI driver for Cypress CCGx Type-C controller

 *

 * Copyright (C) 2017-2018 NVIDIA Corporation. All rights reserved.

 * Author: Ajay Gupta <ajayg@nvidia.com>

 *

 * Some code borrowed from drivers/usb/typec/ucsi/ucsi_acpi.c

 */

#include <linux/acpi.h>

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/platform_device.h>



#include <asm/unaligned.h>

#include "ucsi.h"



struct ucsi_ccg {

	struct device *dev;

	struct ucsi *ucsi;

	struct ucsi_ppm ppm;

	struct i2c_client *client;

};



#define CCGX_RAB_INTR_REG			0x06

#define CCGX_RAB_UCSI_CONTROL			0x39

#define CCGX_RAB_UCSI_CONTROL_START		BIT(0)

#define CCGX_RAB_UCSI_CONTROL_STOP		BIT(1)

#define CCGX_RAB_UCSI_DATA_BLOCK(offset)	(0xf000 | ((offset) & 0xff))



static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)

{

	struct i2c_client *client = uc->client;

	const struct i2c_adapter_quirks *quirks = client->adapter->quirks;

	unsigned char buf[2];

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags  = 0x0,

			.len	= sizeof(buf),

			.buf	= buf,

		},

		{

			.addr	= client->addr,

			.flags  = I2C_M_RD,

			.buf	= data,

		},

	};

	u32 rlen, rem_len = len, max_read_len = len;

	int status;



	/* check any max_read_len limitation on i2c adapter */

	if (quirks && quirks->max_read_len)

		max_read_len = quirks->max_read_len;



	while (rem_len > 0) {

		msgs[1].buf = &data[len - rem_len];

		rlen = min_t(u16, rem_len, max_read_len);

		msgs[1].len = rlen;

		put_unaligned_le16(rab, buf);

		status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

		if (status < 0) {

			dev_err(uc->dev, "i2c_transfer failed %d\n", status);

			return status;

		}

		rab += rlen;

		rem_len -= rlen;

	}



	return 0;

}



static int ccg_write(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)

{

	struct i2c_client *client = uc->client;

	unsigned char *buf;

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags  = 0x0,

		}

	};

	int status;



	buf = kzalloc(len + sizeof(rab), GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	put_unaligned_le16(rab, buf);

	memcpy(buf + sizeof(rab), data, len);



	msgs[0].len = len + sizeof(rab);

	msgs[0].buf = buf;



	status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

	if (status < 0) {

		dev_err(uc->dev, "i2c_transfer failed %d\n", status);

		kfree(buf);

		return status;

	}



	kfree(buf);

	return 0;

}



static int ucsi_ccg_init(struct ucsi_ccg *uc)

{

	unsigned int count = 10;

	u8 data;

	int status;



	data = CCGX_RAB_UCSI_CONTROL_STOP;

	status = ccg_write(uc, CCGX_RAB_UCSI_CONTROL, &data, sizeof(data));

	if (status < 0)

		return status;



	data = CCGX_RAB_UCSI_CONTROL_START;

	status = ccg_write(uc, CCGX_RAB_UCSI_CONTROL, &data, sizeof(data));

	if (status < 0)

		return status;



	/*

	 * Flush CCGx RESPONSE queue by acking interrupts. Above ucsi control

	 * register write will push response which must be cleared.

	 */

	do {

		status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));

		if (status < 0)

			return status;



		if (!data)

			return 0;



		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));

		if (status < 0)

			return status;



		usleep_range(10000, 11000);

	} while (--count);



	return -ETIMEDOUT;

}



static int ucsi_ccg_send_data(struct ucsi_ccg *uc)

{

	u8 *ppm = (u8 *)uc->ppm.data;

	int status;

	u16 rab;



	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, message_out));

	status = ccg_write(uc, rab, ppm +

			   offsetof(struct ucsi_data, message_out),

			   sizeof(uc->ppm.data->message_out));

	if (status < 0)

		return status;



	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, ctrl));

	return ccg_write(uc, rab, ppm + offsetof(struct ucsi_data, ctrl),

			 sizeof(uc->ppm.data->ctrl));

}



static int ucsi_ccg_recv_data(struct ucsi_ccg *uc)

{

	u8 *ppm = (u8 *)uc->ppm.data;

	int status;

	u16 rab;



	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, cci));

	status = ccg_read(uc, rab, ppm + offsetof(struct ucsi_data, cci),

			  sizeof(uc->ppm.data->cci));

	if (status < 0)

		return status;



	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, message_in));

	return ccg_read(uc, rab, ppm + offsetof(struct ucsi_data, message_in),

			sizeof(uc->ppm.data->message_in));

}



static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc)

{

	int status;

	unsigned char data;



	status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));

	if (status < 0)

		return status;



	return ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));

}



static int ucsi_ccg_sync(struct ucsi_ppm *ppm)

{

	struct ucsi_ccg *uc = container_of(ppm, struct ucsi_ccg, ppm);

	int status;



	status = ucsi_ccg_recv_data(uc);

	if (status < 0)

		return status;



	/* ack interrupt to allow next command to run */

	return ucsi_ccg_ack_interrupt(uc);

}



static int ucsi_ccg_cmd(struct ucsi_ppm *ppm, struct ucsi_control *ctrl)

{

	struct ucsi_ccg *uc = container_of(ppm, struct ucsi_ccg, ppm);



	ppm->data->ctrl.raw_cmd = ctrl->raw_cmd;

	return ucsi_ccg_send_data(uc);

}



static irqreturn_t ccg_irq_handler(int irq, void *data)

{

	struct ucsi_ccg *uc = data;



	ucsi_notify(uc->ucsi);



	return IRQ_HANDLED;

}



static int ucsi_ccg_probe(struct i2c_client *client,

			  const struct i2c_device_id *id)

{

	struct device *dev = &client->dev;

	struct ucsi_ccg *uc;

	int status;

	u16 rab;



	uc = devm_kzalloc(dev, sizeof(*uc), GFP_KERNEL);

	if (!uc)

		return -ENOMEM;



	uc->ppm.data = devm_kzalloc(dev, sizeof(struct ucsi_data), GFP_KERNEL);

	if (!uc->ppm.data)

		return -ENOMEM;



	uc->ppm.cmd = ucsi_ccg_cmd;

	uc->ppm.sync = ucsi_ccg_sync;

	uc->dev = dev;

	uc->client = client;



	/* reset ccg device and initialize ucsi */

	status = ucsi_ccg_init(uc);

	if (status < 0) {

		dev_err(uc->dev, "ucsi_ccg_init failed - %d\n", status);

		return status;

	}



	status = devm_request_threaded_irq(dev, client->irq, NULL,

					   ccg_irq_handler,

					   IRQF_ONESHOT | IRQF_TRIGGER_HIGH,

					   dev_name(dev), uc);

	if (status < 0) {

		dev_err(uc->dev, "request_threaded_irq failed - %d\n", status);

		return status;

	}



	uc->ucsi = ucsi_register_ppm(dev, &uc->ppm);

	if (IS_ERR(uc->ucsi)) {

		dev_err(uc->dev, "ucsi_register_ppm failed\n");

		return PTR_ERR(uc->ucsi);

	}



	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, version));

	status = ccg_read(uc, rab, (u8 *)(uc->ppm.data) +

			  offsetof(struct ucsi_data, version),

			  sizeof(uc->ppm.data->version));

	if (status < 0) {

		ucsi_unregister_ppm(uc->ucsi);

		return status;

	}



	i2c_set_clientdata(client, uc);

	return 0;

}



static int ucsi_ccg_remove(struct i2c_client *client)

{

	struct ucsi_ccg *uc = i2c_get_clientdata(client);



	ucsi_unregister_ppm(uc->ucsi);



	return 0;

}



static const struct i2c_device_id ucsi_ccg_device_id[] = {

	{"ccgx-ucsi", 0},

	{}

};

MODULE_DEVICE_TABLE(i2c, ucsi_ccg_device_id);



static struct i2c_driver ucsi_ccg_driver = {

	.driver = {

		.name = "ucsi_ccg",

	},

	.probe = ucsi_ccg_probe,

	.remove = ucsi_ccg_remove,

	.id_table = ucsi_ccg_device_id,

};



module_i2c_driver(ucsi_ccg_driver);



MODULE_AUTHOR("Ajay Gupta <ajayg@nvidia.com>");

MODULE_DESCRIPTION("UCSI driver for Cypress CCGx Type-C controller");

MODULE_LICENSE("GPL v2");

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