Re: [PATCH v4 3/6] usb: typec: ucsi: add Lenovo Yoga C630 glue driver

[Dmitry Baryshkov]

On Wed, May 29, 2024 at 04:41:40PM +0100, Bryan O'Donoghue wrote:
> On 28/05/2024 21:44, Dmitry Baryshkov wrote:
> > The Lenovo Yoga C630 WOS laptop provides implements UCSI interface in
> > the onboard EC. Add glue driver to interface the platform's UCSI
> > implementation.
> > 
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> >   drivers/usb/typec/ucsi/Kconfig          |   9 ++
> >   drivers/usb/typec/ucsi/Makefile         |   1 +
> >   drivers/usb/typec/ucsi/ucsi_yoga_c630.c | 189 ++++++++++++++++++++++++++++++++
> >   3 files changed, 199 insertions(+)
> > 
> > diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
> > index bdcb1764cfae..680e1b87b152 100644
> > --- a/drivers/usb/typec/ucsi/Kconfig
> > +++ b/drivers/usb/typec/ucsi/Kconfig
> > @@ -69,4 +69,13 @@ config UCSI_PMIC_GLINK
> >   	  To compile the driver as a module, choose M here: the module will be
> >   	  called ucsi_glink.
> > +config UCSI_LENOVO_YOGA_C630
> > +	tristate "UCSI Interface Driver for Lenovo Yoga C630"
> > +	depends on EC_LENOVO_YOGA_C630
> > +	help
> > +	  This driver enables UCSI support on the Lenovo Yoga C630 laptop.
> > +
> > +	  To compile the driver as a module, choose M here: the module will be
> > +	  called ucsi_yoga_c630.
> > +
> >   endif
> > diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
> > index b4679f94696b..aed41d23887b 100644
> > --- a/drivers/usb/typec/ucsi/Makefile
> > +++ b/drivers/usb/typec/ucsi/Makefile
> > @@ -21,3 +21,4 @@ obj-$(CONFIG_UCSI_ACPI)			+= ucsi_acpi.o
> >   obj-$(CONFIG_UCSI_CCG)			+= ucsi_ccg.o
> >   obj-$(CONFIG_UCSI_STM32G0)		+= ucsi_stm32g0.o
> >   obj-$(CONFIG_UCSI_PMIC_GLINK)		+= ucsi_glink.o
> > +obj-$(CONFIG_UCSI_LENOVO_YOGA_C630)	+= ucsi_yoga_c630.o
> > diff --git a/drivers/usb/typec/ucsi/ucsi_yoga_c630.c b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> > new file mode 100644
> > index 000000000000..ca1ab5c81b87
> > --- /dev/null
> > +++ b/drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> > @@ -0,0 +1,189 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright (c) 2022-2024, Linaro Ltd
> > + * Authors:
> > + *    Bjorn Andersson
> > + *    Dmitry Baryshkov
> > + */
> > +#include <linux/auxiliary_bus.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_data/lenovo-yoga-c630.h>
> > +
> > +#include "ucsi.h"
> > +
> > +struct yoga_c630_ucsi {
> > +	struct yoga_c630_ec *ec;
> > +	struct ucsi *ucsi;
> > +	struct notifier_block nb;
> > +	struct completion complete;
> > +	unsigned long flags;
> > +#define UCSI_C630_COMMAND_PENDING	0
> > +#define UCSI_C630_ACK_PENDING		1
> > +	u16 version;
> > +};
> > +
> > +static  int yoga_c630_ucsi_read(struct ucsi *ucsi, unsigned int offset,
> > +				void *val, size_t val_len)
> > +{
> > +	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +	u8 buf[YOGA_C630_UCSI_READ_SIZE];
> > +	int ret;
> > +
> > +	ret = yoga_c630_ec_ucsi_read(uec->ec, buf);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (offset == UCSI_VERSION) {
> > +		memcpy(val, &uec->version, min(val_len, sizeof(uec->version)));
> > +		return 0;
> > +	}
> > +
> > +	if (offset == UCSI_CCI)
> > +		memcpy(val, buf,
> > +		       min(val_len, YOGA_C630_UCSI_CCI_SIZE));
> > +	else if (offset == UCSI_MESSAGE_IN)
> > +		memcpy(val, buf + YOGA_C630_UCSI_CCI_SIZE,
> > +		       min(val_len, YOGA_C630_UCSI_DATA_SIZE));
> 
> For some reason I believe multi-lines like this, including function calls
> that are split over lines should be encapsulated with {}
> 
> else if(x) {
>     memcpy(x,y,
>            z);
> }
> 
> If checkpatch doesn't complain about it feel free not to do that though.

No, checkpatch --strict doesn't complain

> 
> > +	else
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> > +
> > +static  int yoga_c630_ucsi_async_write(struct ucsi *ucsi, unsigned int offset,
> > +				       const void *val, size_t val_len)
> > +{
> > +	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +
> > +	if (offset != UCSI_CONTROL ||
> > +	    val_len != YOGA_C630_UCSI_WRITE_SIZE)
> > +		return -EINVAL;
> > +
> > +	return yoga_c630_ec_ucsi_write(uec->ec, val);
> > +}
> > +
> > +static  int yoga_c630_ucsi_sync_write(struct ucsi *ucsi, unsigned int offset,
> > +				      const void *val, size_t val_len)
> > +{
> > +	struct yoga_c630_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +	bool ack = UCSI_COMMAND(*(u64 *)val) == UCSI_ACK_CC_CI;
> > +	int ret;
> > +
> > +	if (ack)
> > +		set_bit(UCSI_C630_ACK_PENDING, &uec->flags);
> > +	else
> > +		set_bit(UCSI_C630_COMMAND_PENDING, &uec->flags);
> > +
> > +	reinit_completion(&uec->complete);
> > +
> > +	ret = yoga_c630_ucsi_async_write(ucsi, offset, val, val_len);
> > +	if (ret)
> > +		goto out_clear_bit;
> > +
> > +	if (!wait_for_completion_timeout(&uec->complete, 5 * HZ))
> > +		ret = -ETIMEDOUT;
> > +
> > +out_clear_bit:
> > +	if (ack)
> > +		clear_bit(UCSI_C630_ACK_PENDING, &uec->flags);
> > +	else
> > +		clear_bit(UCSI_C630_COMMAND_PENDING, &uec->flags);
> > +
> > +	return ret;
> > +}
> > +
> > +const struct ucsi_operations yoga_c630_ucsi_ops = {
> > +	.read = yoga_c630_ucsi_read,
> > +	.sync_write = yoga_c630_ucsi_sync_write,
> > +	.async_write = yoga_c630_ucsi_async_write,
> > +};
> > +
> > +static int yoga_c630_ucsi_notify(struct notifier_block *nb,
> > +				 unsigned long action, void *data)
> > +{
> > +	struct yoga_c630_ucsi *uec = container_of(nb, struct yoga_c630_ucsi, nb);
> > +	u32 cci;
> > +	int ret;
> > +
> > +	if (action == LENOVO_EC_EVENT_USB || action == LENOVO_EC_EVENT_HPD) {
> > +		ucsi_connector_change(uec->ucsi, 1);
> > +		return NOTIFY_OK;
> > +	}
> > +
> > +	if (action != LENOVO_EC_EVENT_UCSI)
> > +		return NOTIFY_DONE;
> 
> Is this disjunction on action a good candidate for a switch(){}

Ack, refactored the function by extracting the UCSI notification code
and then using the switch-case.

> > +
> > +	ret = uec->ucsi->ops->read(uec->ucsi, UCSI_CCI, &cci, sizeof(cci));
> > +	if (ret)
> > +		return NOTIFY_DONE;
> > +
> > +	if (UCSI_CCI_CONNECTOR(cci))
> > +		ucsi_connector_change(uec->ucsi, UCSI_CCI_CONNECTOR(cci));
> > +
> > +	if (cci & UCSI_CCI_ACK_COMPLETE &&
> > +	    test_bit(UCSI_C630_ACK_PENDING, &uec->flags))
> > +		complete(&uec->complete);
> > +	if (cci & UCSI_CCI_COMMAND_COMPLETE &&
> > +	    test_bit(UCSI_C630_COMMAND_PENDING, &uec->flags))
> > +		complete(&uec->complete);
> 
> IMO these multi-line clauses should end up with a {} around the complete
> even though its not required.
> 
> Emphasis on the O.

I added an empty line inbetween, then it's easier to comprehent event
without curly brackets.

> 
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>

-- 
With best wishes
Dmitry