[v15,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Fri, Oct 26, 2018 at 09:36:59AM -0700, Ajay Gupta wrote:
> 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: Ajay Gupta <ajayg@nvidia.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> Changes from v1 -> v2
> 	Fixed identation in drivers/usb/typec/ucsi/Kconfig
> Changes from v2 -> v3
> 	Fixed most of comments from Heikki
> 	Rename ucsi_i2c_ccg.c -> ucsi_ccg.c
> Changes from v3 -> v4
> 	Fixed comments from Andy
> Changes from v4 -> v5
> 	Fixed comments from Andy
> Changes from v5 -> v6
> 	Fixed review comments from Greg 
> Changes from v6 -> v7
> 	None
> Changes from v7 -> v8
> 	Fixed review comments from Peter 
> 	- Removed empty STOP message
> 	- Using stack memory for i2c_transfer()
> Changes from v8 -> v9
> 	None
> Changes from v9 -> v10
> 	Fixed review comments from Peter 
> 	- Use UCSI macros
> 	- Cleanups
> Changes from v10 -> v11
> 	Fixed review comments from Peter 
> 	- Combined two writes into one
> 	- Used offsetof() for ucsi_data struct
> Changes from v11 -> v12
> 	- some cleanup
> Changes from v12 -> v13
> 	- changed "u8 buf[1]" -> "u8 data"
> Changes from v13 -> v14
> 	- Fixed commend from Heikki and Andy
> 	- Added i2c adapters quirks check in ccg_read
> 	- Removed "irq" field from struct ucsi_ccg
> 	- Reorganize do {} while (); loop
> Changes from v14 -> v15
> 	- Fix unnecessary check for "data" in while () condition
> 
>  drivers/usb/typec/ucsi/Kconfig    |  10 +
>  drivers/usb/typec/ucsi/Makefile   |   2 +
>  drivers/usb/typec/ucsi/ucsi_ccg.c | 307 ++++++++++++++++++++++++++++++
>  3 files changed, 319 insertions(+)
>  create mode 100644 drivers/usb/typec/ucsi/ucsi_ccg.c
> 
> diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
> index e36d6c73c4a4..78118883f96c 100644
> --- a/drivers/usb/typec/ucsi/Kconfig
> +++ b/drivers/usb/typec/ucsi/Kconfig
> @@ -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
> diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
> index 7afbea512207..2f4900b26210 100644
> --- a/drivers/usb/typec/ucsi/Makefile
> +++ b/drivers/usb/typec/ucsi/Makefile
> @@ -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
> diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
> new file mode 100644
> index 000000000000..de8a43bdff68
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -0,0 +1,307 @@
> +// 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");
> -- 
> 2.17.1

thanks,