[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Ajay Gupta]

Hi Peter,

> -----Original Message-----
> From: Peter Rosin <peda@axentia.se>
> Sent: Friday, September 7, 2018 2:13 AM
> To: Ajay Gupta <ajayg@nvidia.com>; wsa@the-dreams.de;
> heikki.krogerus@linux.intel.com
> Cc: linux-usb@vger.kernel.org; linux-i2c@vger.kernel.org
> Subject: Re: [PATCH v9 2/2] usb: typec: ucsi: add support for Cypress CCGx
> 
> On 2018-09-07 01:56, 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>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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
> >
> >  drivers/usb/typec/ucsi/Kconfig    |  10 ++
> >  drivers/usb/typec/ucsi/Makefile   |   2 +
> >  drivers/usb/typec/ucsi/ucsi_ccg.c | 335
> > ++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 347 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 e36d6c7..7811888 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 7afbea5..2f4900b 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 0000000..387b6fd
> > --- /dev/null
> > +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> > @@ -0,0 +1,335 @@
> > +// 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;
> > +	int irq;
> > +};
> > +
> > +#define CCGX_I2C_RAB_DEVICE_MODE			0x00
> > +#define CCGX_I2C_RAB_READ_SILICON_ID			0x2
> > +#define CCGX_I2C_RAB_INTR_REG				0x06
> > +#define CCGX_I2C_RAB_FW1_VERSION			0x28
> > +#define CCGX_I2C_RAB_FW2_VERSION			0x20
> > +#define CCGX_I2C_RAB_UCSI_CONTROL			0x39
> > +#define CCGX_I2C_RAB_UCSI_CONTROL_START			BIT(0)
> > +#define CCGX_I2C_RAB_UCSI_CONTROL_STOP			BIT(1)
> > +#define CCGX_I2C_RAB_RESPONSE_REG			0x7E
> > +#define CCGX_I2C_RAB_UCSI_DATA_BLOCK			0xf000
> > +
> > +static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
> > +{
> > +	struct i2c_client *client = uc->client;
> > +	unsigned char buf[2];
> > +	struct i2c_msg msgs[] = {
> > +		{
> > +			.addr	= client->addr,
> > +			.flags  = 0x0,
> > +			.len	= 0x2,
> > +			.buf	= buf,
> > +		},
> > +		{
> > +			.addr	= client->addr,
> > +			.flags  = I2C_M_RD,
> > +			.buf	= data,
> > +		},
> > +	};
> > +	u32 rlen, rem_len = len;
> > +	int status;
> > +
> > +	while (rem_len > 0) {
> > +		msgs[1].buf = &data[len - rem_len];
> > +		rlen = min_t(u16, rem_len, 4);
> > +		msgs[1].len = rlen;
> > +		put_unaligned_le16(rab, buf);
> 
> Why not simply do whichever is correct of
> 
> 	buf[0] = rab >> 8;
> 	buf[1] = rab;
> 
> and
> 
> 	buf[0] = rab;
> 	buf[1] = rab >> 8;
> 
> and feed rab as a cpu-native value and get rid of the endianess crap.
It was like that but was changed to put_unaligned_le16() in one of
review comments from Andy at
https://marc.info/?l=linux-usb&m=153561689418696&w=2

I would rather stay with put_unaligned_le16() which looks better to me
and is similar to your suggestion of using i2c_8bit_addr_from_msg() in 1/2 
patch of series.
 
> > +		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[2];
> > +	struct i2c_msg msgs[] = {
> > +		{
> > +			.addr	= client->addr,
> > +			.flags  = 0x0,
> > +			.len	= 0x2,
> > +			.buf	= buf,
> > +		},
> > +		{
> > +			.addr	= client->addr,
> > +			.flags  = 0x0,
> > +			.buf	= data,
> > +			.len	= len,
> > +		},
> > +	};
> > +	int status;
> > +
> > +	put_unaligned_le16(rab, buf);
> 
> Dito.
See above.
> 
> > +	status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
> > +	if (status < 0) {
> > +		dev_err(uc->dev, "i2c_transfer failed %d\n", status);
> > +		return status;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int ucsi_ccg_init(struct ucsi_ccg *uc) {
> > +	struct device *dev = uc->dev;
> > +	unsigned int count = 10;
> > +	u8 data[64];
> > +	int status;
> > +
> > +	/*
> > +	 * Selectively issue device reset
> > +	 * - if RESPONSE register is RESET_COMPLETE, do not issue device
> reset
> > +	 *   (will cause usb device disconnect / reconnect)
> > +	 * - if RESPONSE register is not RESET_COMPLETE, issue device reset
> > +	 *   (causes PPC to resync device connect state by re-issuing
> > +	 *   set mux command)
> > +	 */
> > +	data[0] = 0x00;
> > +	data[1] = 0x00;
> 
> Why do you need these assigments? Will not ccg_read just overwrite this
> anyway?
ok
> 
> > +
> > +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> > +	if (status < 0)
> > +		return status;
> > +
> > +	memset(data, 0, sizeof(data));
> 
> Dito.
ok
> 
> > +	status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data,
> sizeof(data));
> > +	if (status < 0)
> > +		return status;
> > +
> > +	dev_dbg(dev, "Silicon id %2ph", data +
> CCGX_I2C_RAB_READ_SILICON_ID);
> > +	dev_dbg(dev, "FW1 version %8ph\n", data +
> CCGX_I2C_RAB_FW1_VERSION);
> > +	dev_dbg(dev, "FW2 version %8ph\n", data +
> CCGX_I2C_RAB_FW2_VERSION);
> > +
> > +	data[0] = 0x0;
> > +	data[1] = 0x0;
> 
> Dito.
ok
> 
> > +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> > +	if (status < 0)
> > +		return status;
> > +
> > +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
> > +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> > +	if (status < 0)
> > +		return status;
> > +
> > +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
> > +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> > +	if (status < 0)
> > +		return status;
> > +
> > +	/*
> > +	 * Flush CCGx RESPONSE queue by acking interrupts
> > +	 * - above ucsi control register write will push response
> > +	 * which must be flushed
> > +	 * - affects f/w update which reads response register
> > +	 */
> > +	data[0] = 0xff;
> > +	do {
> > +		status = ccg_write(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> > +		if (status < 0)
> > +			return status;
> > +
> > +		usleep_range(10000, 11000);
> > +
> > +		status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> > +		if (status < 0)
> > +			return status;
> > +	} while ((data[0] != 0x00) && count--);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ucsi_ccg_send_data(struct ucsi_ccg *uc) {
> > +	int status;
> > +	unsigned char buf[4] = {
> > +		0x20, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> > +		0x8, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> > +	};
> > +	unsigned char buf1[16];
> > +	unsigned char buf2[8];
> > +
> > +	memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
> > +	memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
> > +
> > +	status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));
> 
> This seems to be endian-dependent. May I suggest that you do as suggested
> above for ccg_read, and then somthing like
> 
> #define CCGX_I2C_RAB_USCI_DATA_BLOCK(xxx) (0xf000 | ((xxx) & <mask>))
> 
> where you of course use an appropriate value for <mask> (perhaps 0xff, or
> 0xfff, what do I know) and a better name for the field than xxx (perhaps len,
> what do I know), and then finally do
> 
> 	status = ccg_write(uc, CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20), ...
> 
> Also, the 0x20 and 0x8 are repeated and are some magic numbers that really
> should be given a name or some explanation. They appear to be data lengths,
> but again, what do I know?
I will check on this.

> > +	if (status < 0)
> > +		return status;
> > +
> > +	return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2)); }
> > +
> > +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc) {
> > +	u8 *ppm = (u8 *)uc->ppm.data;
> > +	int status;
> > +	unsigned char buf[6] = {
> > +		0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> > +		0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> > +		0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> > +	};
> > +
> > +	status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);
> 
> There are plenty magic numbers, but this call does not follow the pattern.
> Should perhaps buf[0] be 0x2, or should perhaps the last 0x2 argument be
> 0x0? All other ...DATA_BLOCK calls seem to have the len in the other byte of
> the rab argument. Why does this call not follow the pattern?
We are reading message IN data from Type-C controller in response to a
UCSI command. You can find details at
https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/usb-type-c-ucsi-spec.pdf
 
> > +	if (status < 0)
> > +		return status;
> > +
> > +	status = ccg_read(uc, *(u16 *)(buf + 2), ppm + 0x4, 0x4);
> > +	if (status < 0)
> > +		return status;
> > +
> > +	return ccg_read(uc, *(u16 *)(buf + 4), ppm + 0x10, 0x10); }
> > +
> > +static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc) {
> > +	int status;
> > +	unsigned char buf[2] = {
> > +		CCGX_I2C_RAB_INTR_REG, CCGX_I2C_RAB_INTR_REG >> 8};
> > +	unsigned char buf2[1] = {0x0};
> > +
> > +	status = ccg_read(uc, *(u16 *)buf, buf2, 0x1);
> 
> This becomes
> 	status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, buf2, 0x1); and you
> can drop the buf variable (or perhaps rename buf2 to buf)
> 
> [time passes]
> 
> Hmm, you already do it like that in ucsi_ccg_init, so this function can be
> cleaned up regardless of any endian cleanup.
Ok

Thanks
Ajay
--
nvpublic
--
> 
> Cheers,
> Peter
> 
> > +	if (status < 0)
> > +		return status;
> > +
> > +	return ccg_write(uc, *(u16 *)buf, buf2, 0x1); }
> > +
> > +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;
> > +
> > +	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;
> > +	}
> > +
> > +	uc->irq = client->irq;
> > +
> > +	status = devm_request_threaded_irq(dev, uc->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);
> > +	}
> > +
> > +	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");
> >

[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Ajay Gupta]

Hi Peter,

> >>> +	memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
> >>> +	memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
> >>> +
> >>> +	status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));
> >>
> >> This seems to be endian-dependent. May I suggest that you do as
> >> suggested above for ccg_read, and then somthing like
> >>
> >> #define CCGX_I2C_RAB_USCI_DATA_BLOCK(xxx) (0xf000 | ((xxx) &
> <mask>))
> >>
> >> where you of course use an appropriate value for <mask> (perhaps
> >> 0xff, or 0xfff, what do I know) and a better name for the field than
> >> xxx (perhaps len, what do I know), and then finally do
> >>
> >> 	status = ccg_write(uc, CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20), ...
> >>
> >> Also, the 0x20 and 0x8 are repeated and are some magic numbers that
> >> really should be given a name or some explanation. They appear to be
> >> data lengths, but again, what do I know?
> > I will check on this.
> 
> From the below reference, it's
> 
> 0x8 is USBC_CONTROL with USBC_CONTROL_SIZE 0x8 (64/8)
> 0x20 is USBC_MESSAGE_OUT with USBC_MESSAGE_OUT_SIZE 0x10 (128/8)
> 
> You could do
> #define USBC_MESSAGE_OUT CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20)
> #define USBC_MESSAGE_OUT_SIZE (128/8)
> etc, so that it becomes
> 
> unsigned char buf1[USBC_MESSAGE_OUT_SIZE]; ...
> status = ccg_write(uc, USBC_MESSAGE_OUT, buf1, sizeof(buf1));
> 
> Which is a whole lot more readable IMHO.
Sure.
 
> >>> +	if (status < 0)
> >>> +		return status;
> >>> +
> >>> +	return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2)); }
> >>> +
> >>> +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc) {
> >>> +	u8 *ppm = (u8 *)uc->ppm.data;
> >>> +	int status;
> >>> +	unsigned char buf[6] = {
> >>> +		0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> >>> +		0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> >>> +		0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> >>> +	};
> >>> +
> >>> +	status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);
> >>
> >> There are plenty magic numbers, but this call does not follow the pattern.
> >> Should perhaps buf[0] be 0x2, or should perhaps the last 0x2 argument
> >> be 0x0? All other ...DATA_BLOCK calls seem to have the len in the
> >> other byte of the rab argument. Why does this call not follow the pattern?
> > We are reading message IN data from Type-C controller in response to a
> > UCSI command. You can find details at
> >
> https://www.intel.com/content/dam/www/public/us/en/documents/technica
> l
> > -specifications/usb-type-c-ucsi-spec.pdf
> 
> So, according to table 3-1,
> 0x0 is UCSI_VERSION with UCSI_VERSION_SIZE 0x2 (16/8)
> 0x4 is USBC_CCI (connector change indication) with USBC_CCI_SIZE 0x4 (32/8)
> 0x10 is USBC_MESSAGE_IN with USBC_MESSAGE_IN_SIZE 0x10 (128/8)
> 
> The pattern for 0x4 and 0x10 was a accidental, but again, *please* use defines
> for all these magic numbers.
Will fix in next version.

Thanks
Ajay

--
nvpublic

[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Peter Rosin]

On 2018-09-07 19:28, Ajay Gupta wrote:
> Hi Peter,
> 
>> -----Original Message-----
>> From: Peter Rosin <peda@axentia.se>
>> Sent: Friday, September 7, 2018 2:13 AM
>> To: Ajay Gupta <ajayg@nvidia.com>; wsa@the-dreams.de;
>> heikki.krogerus@linux.intel.com
>> Cc: linux-usb@vger.kernel.org; linux-i2c@vger.kernel.org
>> Subject: Re: [PATCH v9 2/2] usb: typec: ucsi: add support for Cypress CCGx
>>
>> On 2018-09-07 01:56, 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>
>>> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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
>>>
>>>  drivers/usb/typec/ucsi/Kconfig    |  10 ++
>>>  drivers/usb/typec/ucsi/Makefile   |   2 +
>>>  drivers/usb/typec/ucsi/ucsi_ccg.c | 335
>>> ++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 347 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 e36d6c7..7811888 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 7afbea5..2f4900b 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 0000000..387b6fd
>>> --- /dev/null
>>> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
>>> @@ -0,0 +1,335 @@
>>> +// 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;
>>> +	int irq;
>>> +};
>>> +
>>> +#define CCGX_I2C_RAB_DEVICE_MODE			0x00
>>> +#define CCGX_I2C_RAB_READ_SILICON_ID			0x2
>>> +#define CCGX_I2C_RAB_INTR_REG				0x06
>>> +#define CCGX_I2C_RAB_FW1_VERSION			0x28
>>> +#define CCGX_I2C_RAB_FW2_VERSION			0x20
>>> +#define CCGX_I2C_RAB_UCSI_CONTROL			0x39
>>> +#define CCGX_I2C_RAB_UCSI_CONTROL_START			BIT(0)
>>> +#define CCGX_I2C_RAB_UCSI_CONTROL_STOP			BIT(1)
>>> +#define CCGX_I2C_RAB_RESPONSE_REG			0x7E
>>> +#define CCGX_I2C_RAB_UCSI_DATA_BLOCK			0xf000
>>> +
>>> +static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
>>> +{
>>> +	struct i2c_client *client = uc->client;
>>> +	unsigned char buf[2];
>>> +	struct i2c_msg msgs[] = {
>>> +		{
>>> +			.addr	= client->addr,
>>> +			.flags  = 0x0,
>>> +			.len	= 0x2,
>>> +			.buf	= buf,
>>> +		},
>>> +		{
>>> +			.addr	= client->addr,
>>> +			.flags  = I2C_M_RD,
>>> +			.buf	= data,
>>> +		},
>>> +	};
>>> +	u32 rlen, rem_len = len;
>>> +	int status;
>>> +
>>> +	while (rem_len > 0) {
>>> +		msgs[1].buf = &data[len - rem_len];
>>> +		rlen = min_t(u16, rem_len, 4);
>>> +		msgs[1].len = rlen;
>>> +		put_unaligned_le16(rab, buf);
>>
>> Why not simply do whichever is correct of
>>
>> 	buf[0] = rab >> 8;
>> 	buf[1] = rab;
>>
>> and
>>
>> 	buf[0] = rab;
>> 	buf[1] = rab >> 8;
>>
>> and feed rab as a cpu-native value and get rid of the endianess crap.
> It was like that but was changed to put_unaligned_le16() in one of
> review comments from Andy at
> https://marc.info/?l=linux-usb&m=153561689418696&w=2
> 
> I would rather stay with put_unaligned_le16() which looks better to me
> and is similar to your suggestion of using i2c_8bit_addr_from_msg() in 1/2 
> patch of series.

Right, put_unaligned_le16 is the correct thing to do if rab is cpu-native.
I was confused by the fact that some users of ccg_read/ccg_write do
not call with a cpu-native rab. But since I also suggested that rab
should be made cpu-native for those cases, I guess I'm still to blame...
Sorry about that!

>>> +		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[2];
>>> +	struct i2c_msg msgs[] = {
>>> +		{
>>> +			.addr	= client->addr,
>>> +			.flags  = 0x0,
>>> +			.len	= 0x2,
>>> +			.buf	= buf,
>>> +		},
>>> +		{
>>> +			.addr	= client->addr,
>>> +			.flags  = 0x0,
>>> +			.buf	= data,
>>> +			.len	= len,
>>> +		},
>>> +	};
>>> +	int status;
>>> +
>>> +	put_unaligned_le16(rab, buf);
>>
>> Dito.
> See above.
>>
>>> +	status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
>>> +	if (status < 0) {
>>> +		dev_err(uc->dev, "i2c_transfer failed %d\n", status);
>>> +		return status;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int ucsi_ccg_init(struct ucsi_ccg *uc) {
>>> +	struct device *dev = uc->dev;
>>> +	unsigned int count = 10;
>>> +	u8 data[64];
>>> +	int status;
>>> +
>>> +	/*
>>> +	 * Selectively issue device reset
>>> +	 * - if RESPONSE register is RESET_COMPLETE, do not issue device
>> reset
>>> +	 *   (will cause usb device disconnect / reconnect)
>>> +	 * - if RESPONSE register is not RESET_COMPLETE, issue device reset
>>> +	 *   (causes PPC to resync device connect state by re-issuing
>>> +	 *   set mux command)
>>> +	 */
>>> +	data[0] = 0x00;
>>> +	data[1] = 0x00;
>>
>> Why do you need these assigments? Will not ccg_read just overwrite this
>> anyway?
> ok
>>
>>> +
>>> +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	memset(data, 0, sizeof(data));
>>
>> Dito.
> ok
>>
>>> +	status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data,
>> sizeof(data));
>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	dev_dbg(dev, "Silicon id %2ph", data +
>> CCGX_I2C_RAB_READ_SILICON_ID);
>>> +	dev_dbg(dev, "FW1 version %8ph\n", data +
>> CCGX_I2C_RAB_FW1_VERSION);
>>> +	dev_dbg(dev, "FW2 version %8ph\n", data +
>> CCGX_I2C_RAB_FW2_VERSION);
>>> +
>>> +	data[0] = 0x0;
>>> +	data[1] = 0x0;
>>
>> Dito.
> ok
>>
>>> +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
>>> +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
>>> +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	/*
>>> +	 * Flush CCGx RESPONSE queue by acking interrupts
>>> +	 * - above ucsi control register write will push response
>>> +	 * which must be flushed
>>> +	 * - affects f/w update which reads response register
>>> +	 */
>>> +	data[0] = 0xff;
>>> +	do {
>>> +		status = ccg_write(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
>>> +		if (status < 0)
>>> +			return status;
>>> +
>>> +		usleep_range(10000, 11000);
>>> +
>>> +		status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
>>> +		if (status < 0)
>>> +			return status;
>>> +	} while ((data[0] != 0x00) && count--);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int ucsi_ccg_send_data(struct ucsi_ccg *uc) {
>>> +	int status;
>>> +	unsigned char buf[4] = {
>>> +		0x20, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
>>> +		0x8, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
>>> +	};
>>> +	unsigned char buf1[16];
>>> +	unsigned char buf2[8];
>>> +
>>> +	memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
>>> +	memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
>>> +
>>> +	status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));
>>
>> This seems to be endian-dependent. May I suggest that you do as suggested
>> above for ccg_read, and then somthing like
>>
>> #define CCGX_I2C_RAB_USCI_DATA_BLOCK(xxx) (0xf000 | ((xxx) & <mask>))
>>
>> where you of course use an appropriate value for <mask> (perhaps 0xff, or
>> 0xfff, what do I know) and a better name for the field than xxx (perhaps len,
>> what do I know), and then finally do
>>
>> 	status = ccg_write(uc, CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20), ...
>>
>> Also, the 0x20 and 0x8 are repeated and are some magic numbers that really
>> should be given a name or some explanation. They appear to be data lengths,
>> but again, what do I know?
> I will check on this.

From the below reference, it's

0x8 is USBC_CONTROL with USBC_CONTROL_SIZE 0x8 (64/8)
0x20 is USBC_MESSAGE_OUT with USBC_MESSAGE_OUT_SIZE 0x10 (128/8)

You could do
#define USBC_MESSAGE_OUT CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20)
#define USBC_MESSAGE_OUT_SIZE (128/8)
etc, so that it becomes

unsigned char buf1[USBC_MESSAGE_OUT_SIZE];
...
status = ccg_write(uc, USBC_MESSAGE_OUT, buf1, sizeof(buf1));

Which is a whole lot more readable IMHO.

>>> +	if (status < 0)
>>> +		return status;
>>> +
>>> +	return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2)); }
>>> +
>>> +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc) {
>>> +	u8 *ppm = (u8 *)uc->ppm.data;
>>> +	int status;
>>> +	unsigned char buf[6] = {
>>> +		0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
>>> +		0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
>>> +		0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
>>> +	};
>>> +
>>> +	status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);
>>
>> There are plenty magic numbers, but this call does not follow the pattern.
>> Should perhaps buf[0] be 0x2, or should perhaps the last 0x2 argument be
>> 0x0? All other ...DATA_BLOCK calls seem to have the len in the other byte of
>> the rab argument. Why does this call not follow the pattern?
> We are reading message IN data from Type-C controller in response to a
> UCSI command. You can find details at
> https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/usb-type-c-ucsi-spec.pdf

So, according to table 3-1,
0x0 is UCSI_VERSION with UCSI_VERSION_SIZE 0x2 (16/8)
0x4 is USBC_CCI (connector change indication) with USBC_CCI_SIZE 0x4 (32/8)
0x10 is USBC_MESSAGE_IN with USBC_MESSAGE_IN_SIZE 0x10 (128/8)

The pattern for 0x4 and 0x10 was a accidental, but again, *please* use
defines for all these magic numbers.

Cheers,
Peter

[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Peter Rosin]

On 2018-09-07 01:56, 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>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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
> 
>  drivers/usb/typec/ucsi/Kconfig    |  10 ++
>  drivers/usb/typec/ucsi/Makefile   |   2 +
>  drivers/usb/typec/ucsi/ucsi_ccg.c | 335 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 347 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 e36d6c7..7811888 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 7afbea5..2f4900b 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 0000000..387b6fd
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -0,0 +1,335 @@
> +// 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;
> +	int irq;
> +};
> +
> +#define CCGX_I2C_RAB_DEVICE_MODE			0x00
> +#define CCGX_I2C_RAB_READ_SILICON_ID			0x2
> +#define CCGX_I2C_RAB_INTR_REG				0x06
> +#define CCGX_I2C_RAB_FW1_VERSION			0x28
> +#define CCGX_I2C_RAB_FW2_VERSION			0x20
> +#define CCGX_I2C_RAB_UCSI_CONTROL			0x39
> +#define CCGX_I2C_RAB_UCSI_CONTROL_START			BIT(0)
> +#define CCGX_I2C_RAB_UCSI_CONTROL_STOP			BIT(1)
> +#define CCGX_I2C_RAB_RESPONSE_REG			0x7E
> +#define CCGX_I2C_RAB_UCSI_DATA_BLOCK			0xf000
> +
> +static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
> +{
> +	struct i2c_client *client = uc->client;
> +	unsigned char buf[2];
> +	struct i2c_msg msgs[] = {
> +		{
> +			.addr	= client->addr,
> +			.flags  = 0x0,
> +			.len	= 0x2,
> +			.buf	= buf,
> +		},
> +		{
> +			.addr	= client->addr,
> +			.flags  = I2C_M_RD,
> +			.buf	= data,
> +		},
> +	};
> +	u32 rlen, rem_len = len;
> +	int status;
> +
> +	while (rem_len > 0) {
> +		msgs[1].buf = &data[len - rem_len];
> +		rlen = min_t(u16, rem_len, 4);
> +		msgs[1].len = rlen;
> +		put_unaligned_le16(rab, buf);

Why not simply do whichever is correct of

	buf[0] = rab >> 8;
	buf[1] = rab;

and

	buf[0] = rab;
	buf[1] = rab >> 8;

and feed rab as a cpu-native value and get rid of the endianess crap.

> +		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[2];
> +	struct i2c_msg msgs[] = {
> +		{
> +			.addr	= client->addr,
> +			.flags  = 0x0,
> +			.len	= 0x2,
> +			.buf	= buf,
> +		},
> +		{
> +			.addr	= client->addr,
> +			.flags  = 0x0,
> +			.buf	= data,
> +			.len	= len,
> +		},
> +	};
> +	int status;
> +
> +	put_unaligned_le16(rab, buf);

Dito.

> +	status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
> +	if (status < 0) {
> +		dev_err(uc->dev, "i2c_transfer failed %d\n", status);
> +		return status;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ucsi_ccg_init(struct ucsi_ccg *uc)
> +{
> +	struct device *dev = uc->dev;
> +	unsigned int count = 10;
> +	u8 data[64];
> +	int status;
> +
> +	/*
> +	 * Selectively issue device reset
> +	 * - if RESPONSE register is RESET_COMPLETE, do not issue device reset
> +	 *   (will cause usb device disconnect / reconnect)
> +	 * - if RESPONSE register is not RESET_COMPLETE, issue device reset
> +	 *   (causes PPC to resync device connect state by re-issuing
> +	 *   set mux command)
> +	 */
> +	data[0] = 0x00;
> +	data[1] = 0x00;

Why do you need these assigments? Will not ccg_read just overwrite this
anyway?

> +
> +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> +	if (status < 0)
> +		return status;
> +
> +	memset(data, 0, sizeof(data));

Dito.

> +	status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data, sizeof(data));
> +	if (status < 0)
> +		return status;
> +
> +	dev_dbg(dev, "Silicon id %2ph", data + CCGX_I2C_RAB_READ_SILICON_ID);
> +	dev_dbg(dev, "FW1 version %8ph\n", data + CCGX_I2C_RAB_FW1_VERSION);
> +	dev_dbg(dev, "FW2 version %8ph\n", data + CCGX_I2C_RAB_FW2_VERSION);
> +
> +	data[0] = 0x0;
> +	data[1] = 0x0;

Dito.

> +	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> +	if (status < 0)
> +		return status;
> +
> +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
> +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> +	if (status < 0)
> +		return status;
> +
> +	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
> +	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> +	if (status < 0)
> +		return status;
> +
> +	/*
> +	 * Flush CCGx RESPONSE queue by acking interrupts
> +	 * - above ucsi control register write will push response
> +	 * which must be flushed
> +	 * - affects f/w update which reads response register
> +	 */
> +	data[0] = 0xff;
> +	do {
> +		status = ccg_write(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> +		if (status < 0)
> +			return status;
> +
> +		usleep_range(10000, 11000);
> +
> +		status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> +		if (status < 0)
> +			return status;
> +	} while ((data[0] != 0x00) && count--);
> +
> +	return 0;
> +}
> +
> +static int ucsi_ccg_send_data(struct ucsi_ccg *uc)
> +{
> +	int status;
> +	unsigned char buf[4] = {
> +		0x20, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> +		0x8, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> +	};
> +	unsigned char buf1[16];
> +	unsigned char buf2[8];
> +
> +	memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
> +	memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
> +
> +	status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));

This seems to be endian-dependent. May I suggest that you do as suggested
above for ccg_read, and then somthing like

#define CCGX_I2C_RAB_USCI_DATA_BLOCK(xxx) (0xf000 | ((xxx) & <mask>))

where you of course use an appropriate value for <mask> (perhaps 0xff, or
0xfff, what do I know) and a better name for the field than xxx (perhaps
len, what do I know), and then finally do

	status = ccg_write(uc, CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20), ...

Also, the 0x20 and 0x8 are repeated and are some magic numbers that
really should be given a name or some explanation. They appear to be
data lengths, but again, what do I know?

> +	if (status < 0)
> +		return status;
> +
> +	return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2));
> +}
> +
> +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc)
> +{
> +	u8 *ppm = (u8 *)uc->ppm.data;
> +	int status;
> +	unsigned char buf[6] = {
> +		0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> +		0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> +		0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> +	};
> +
> +	status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);

There are plenty magic numbers, but this call does not follow the
pattern. Should perhaps buf[0] be 0x2, or should perhaps the
last 0x2 argument be 0x0? All other ...DATA_BLOCK calls seem to
have the len in the other byte of the rab argument. Why does
this call not follow the pattern?

> +	if (status < 0)
> +		return status;
> +
> +	status = ccg_read(uc, *(u16 *)(buf + 2), ppm + 0x4, 0x4);
> +	if (status < 0)
> +		return status;
> +
> +	return ccg_read(uc, *(u16 *)(buf + 4), ppm + 0x10, 0x10);
> +}
> +
> +static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc)
> +{
> +	int status;
> +	unsigned char buf[2] = {
> +		CCGX_I2C_RAB_INTR_REG, CCGX_I2C_RAB_INTR_REG >> 8};
> +	unsigned char buf2[1] = {0x0};
> +
> +	status = ccg_read(uc, *(u16 *)buf, buf2, 0x1);

This becomes
	status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, buf2, 0x1);
and you can drop the buf variable (or perhaps rename buf2 to buf)

[time passes]

Hmm, you already do it like that in ucsi_ccg_init, so this function
can be cleaned up regardless of any endian cleanup.

Cheers,
Peter

> +	if (status < 0)
> +		return status;
> +
> +	return ccg_write(uc, *(u16 *)buf, buf2, 0x1);
> +}
> +
> +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;
> +
> +	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;
> +	}
> +
> +	uc->irq = client->irq;
> +
> +	status = devm_request_threaded_irq(dev, uc->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);
> +	}
> +
> +	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");
>

[v9,2/2] usb: typec: ucsi: add support for Cypress CCGx

[Ajay Gupta]

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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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

 drivers/usb/typec/ucsi/Kconfig    |  10 ++
 drivers/usb/typec/ucsi/Makefile   |   2 +
 drivers/usb/typec/ucsi/ucsi_ccg.c | 335 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 347 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 e36d6c7..7811888 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 7afbea5..2f4900b 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 0000000..387b6fd
--- /dev/null
+++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
@@ -0,0 +1,335 @@
+// 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;
+	int irq;
+};
+
+#define CCGX_I2C_RAB_DEVICE_MODE			0x00
+#define CCGX_I2C_RAB_READ_SILICON_ID			0x2
+#define CCGX_I2C_RAB_INTR_REG				0x06
+#define CCGX_I2C_RAB_FW1_VERSION			0x28
+#define CCGX_I2C_RAB_FW2_VERSION			0x20
+#define CCGX_I2C_RAB_UCSI_CONTROL			0x39
+#define CCGX_I2C_RAB_UCSI_CONTROL_START			BIT(0)
+#define CCGX_I2C_RAB_UCSI_CONTROL_STOP			BIT(1)
+#define CCGX_I2C_RAB_RESPONSE_REG			0x7E
+#define CCGX_I2C_RAB_UCSI_DATA_BLOCK			0xf000
+
+static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32 len)
+{
+	struct i2c_client *client = uc->client;
+	unsigned char buf[2];
+	struct i2c_msg msgs[] = {
+		{
+			.addr	= client->addr,
+			.flags  = 0x0,
+			.len	= 0x2,
+			.buf	= buf,
+		},
+		{
+			.addr	= client->addr,
+			.flags  = I2C_M_RD,
+			.buf	= data,
+		},
+	};
+	u32 rlen, rem_len = len;
+	int status;
+
+	while (rem_len > 0) {
+		msgs[1].buf = &data[len - rem_len];
+		rlen = min_t(u16, rem_len, 4);
+		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[2];
+	struct i2c_msg msgs[] = {
+		{
+			.addr	= client->addr,
+			.flags  = 0x0,
+			.len	= 0x2,
+			.buf	= buf,
+		},
+		{
+			.addr	= client->addr,
+			.flags  = 0x0,
+			.buf	= data,
+			.len	= len,
+		},
+	};
+	int status;
+
+	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;
+	}
+
+	return 0;
+}
+
+static int ucsi_ccg_init(struct ucsi_ccg *uc)
+{
+	struct device *dev = uc->dev;
+	unsigned int count = 10;
+	u8 data[64];
+	int status;
+
+	/*
+	 * Selectively issue device reset
+	 * - if RESPONSE register is RESET_COMPLETE, do not issue device reset
+	 *   (will cause usb device disconnect / reconnect)
+	 * - if RESPONSE register is not RESET_COMPLETE, issue device reset
+	 *   (causes PPC to resync device connect state by re-issuing
+	 *   set mux command)
+	 */
+	data[0] = 0x00;
+	data[1] = 0x00;
+
+	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
+	if (status < 0)
+		return status;
+
+	memset(data, 0, sizeof(data));
+	status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data, sizeof(data));
+	if (status < 0)
+		return status;
+
+	dev_dbg(dev, "Silicon id %2ph", data + CCGX_I2C_RAB_READ_SILICON_ID);
+	dev_dbg(dev, "FW1 version %8ph\n", data + CCGX_I2C_RAB_FW1_VERSION);
+	dev_dbg(dev, "FW2 version %8ph\n", data + CCGX_I2C_RAB_FW2_VERSION);
+
+	data[0] = 0x0;
+	data[1] = 0x0;
+	status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
+	if (status < 0)
+		return status;
+
+	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
+	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
+	if (status < 0)
+		return status;
+
+	data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
+	status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
+	if (status < 0)
+		return status;
+
+	/*
+	 * Flush CCGx RESPONSE queue by acking interrupts
+	 * - above ucsi control register write will push response
+	 * which must be flushed
+	 * - affects f/w update which reads response register
+	 */
+	data[0] = 0xff;
+	do {
+		status = ccg_write(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
+		if (status < 0)
+			return status;
+
+		usleep_range(10000, 11000);
+
+		status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
+		if (status < 0)
+			return status;
+	} while ((data[0] != 0x00) && count--);
+
+	return 0;
+}
+
+static int ucsi_ccg_send_data(struct ucsi_ccg *uc)
+{
+	int status;
+	unsigned char buf[4] = {
+		0x20, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
+		0x8, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
+	};
+	unsigned char buf1[16];
+	unsigned char buf2[8];
+
+	memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
+	memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
+
+	status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));
+	if (status < 0)
+		return status;
+
+	return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2));
+}
+
+static int ucsi_ccg_recv_data(struct ucsi_ccg *uc)
+{
+	u8 *ppm = (u8 *)uc->ppm.data;
+	int status;
+	unsigned char buf[6] = {
+		0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
+		0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
+		0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
+	};
+
+	status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);
+	if (status < 0)
+		return status;
+
+	status = ccg_read(uc, *(u16 *)(buf + 2), ppm + 0x4, 0x4);
+	if (status < 0)
+		return status;
+
+	return ccg_read(uc, *(u16 *)(buf + 4), ppm + 0x10, 0x10);
+}
+
+static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc)
+{
+	int status;
+	unsigned char buf[2] = {
+		CCGX_I2C_RAB_INTR_REG, CCGX_I2C_RAB_INTR_REG >> 8};
+	unsigned char buf2[1] = {0x0};
+
+	status = ccg_read(uc, *(u16 *)buf, buf2, 0x1);
+	if (status < 0)
+		return status;
+
+	return ccg_write(uc, *(u16 *)buf, buf2, 0x1);
+}
+
+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;
+
+	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;
+	}
+
+	uc->irq = client->irq;
+
+	status = devm_request_threaded_irq(dev, uc->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);
+	}
+
+	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");