Re: [PATCH v2 2/2] usb: typec: Add support for Parade PS8830 Type-C Retimer

[Abel Vesa <abel.vesa@linaro.org>]

On 24-10-06 18:40:51, Dmitry Baryshkov wrote:
> On Fri, Oct 04, 2024 at 04:57:38PM GMT, Abel Vesa wrote:
> > The Parade PS8830 is a Type-C muti-protocol retimer controlled over I2C.
> > It provides both altmode and orientation handling.
> > 
> > Add a driver with support for the following modes:
> >  - DP 4lanes
> >  - DP 2lanes + USB3
> >  - USB3
> > 
> > Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
> > ---
> >  drivers/usb/typec/mux/Kconfig  |  10 +
> >  drivers/usb/typec/mux/Makefile |   1 +
> >  drivers/usb/typec/mux/ps8830.c | 424 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 435 insertions(+)
> > 
> > diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
> > index ce7db6ad30572a0a74890f5f11944fb3ff07f635..48613b67f1c5dacd14d54baf91c3066377cf97be 100644
> > --- a/drivers/usb/typec/mux/Kconfig
> > +++ b/drivers/usb/typec/mux/Kconfig
> > @@ -56,6 +56,16 @@ config TYPEC_MUX_NB7VPQ904M
> >  	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
> >  	  redriver chip found on some devices with a Type-C port.
> >  
> > +config TYPEC_MUX_PS8830
> > +	tristate "Parade PS8830 Type-C retimer driver"
> > +	depends on I2C
> > +	depends on DRM || DRM=n
> > +	select DRM_AUX_BRIDGE if DRM_BRIDGE && OF
> > +	select REGMAP_I2C
> > +	help
> > +	  Say Y or M if your system has a Parade PS8830 Type-C retimer chip
> > +	  found on some devices with a Type-C port.
> > +
> >  config TYPEC_MUX_PTN36502
> >  	tristate "NXP PTN36502 Type-C redriver driver"
> >  	depends on I2C
> > diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
> > index bb96f30267af05b33b9277dcf1cc0e1527d2dcdd..4b23b12cfe45a0ff8a37f38c7ba050f572d556e7 100644
> > --- a/drivers/usb/typec/mux/Makefile
> > +++ b/drivers/usb/typec/mux/Makefile
> > @@ -6,5 +6,6 @@ obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
> >  obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
> >  obj-$(CONFIG_TYPEC_MUX_IT5205)		+= it5205.o
> >  obj-$(CONFIG_TYPEC_MUX_NB7VPQ904M)	+= nb7vpq904m.o
> > +obj-$(CONFIG_TYPEC_MUX_PS8830)		+= ps8830.o
> >  obj-$(CONFIG_TYPEC_MUX_PTN36502)	+= ptn36502.o
> >  obj-$(CONFIG_TYPEC_MUX_WCD939X_USBSS)	+= wcd939x-usbss.o
> > diff --git a/drivers/usb/typec/mux/ps8830.c b/drivers/usb/typec/mux/ps8830.c
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..58990f7860bf77ec12d00f0d3df3a40735bbf9d8
> > --- /dev/null
> > +++ b/drivers/usb/typec/mux/ps8830.c
> > @@ -0,0 +1,424 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Parade PS8830 usb retimer driver
> > + *
> > + * Copyright (C) 2024 Linaro Ltd.
> > + */
> > +
> > +#include <drm/bridge/aux-bridge.h>
> > +#include <linux/clk.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/regmap.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/usb/typec_altmode.h>
> > +#include <linux/usb/typec_dp.h>
> > +#include <linux/usb/typec_mux.h>
> > +#include <linux/usb/typec_retimer.h>
> > +
> > +struct ps8830_retimer {
> > +	struct i2c_client *client;
> > +	struct gpio_desc *reset_gpio;
> > +	struct regmap *regmap;
> > +	struct typec_switch_dev *sw;
> > +	struct typec_retimer *retimer;
> > +	struct clk *xo_clk;
> > +	struct regulator *vdd_supply;
> > +	struct regulator *vdd33_supply;
> > +	struct regulator *vdd33_cap_supply;
> > +	struct regulator *vddat_supply;
> > +	struct regulator *vddar_supply;
> > +	struct regulator *vddio_supply;
> > +
> > +	struct typec_switch *typec_switch;
> > +	struct typec_mux *typec_mux;
> > +
> > +	struct mutex lock; /* protect non-concurrent retimer & switch */
> > +
> > +	enum typec_orientation orientation;
> > +	unsigned long mode;
> > +	int cfg[3];
> > +};
> > +
> > +static void ps8830_write(struct ps8830_retimer *retimer, int cfg0, int cfg1, int cfg2)
> > +{
> > +	if (cfg0 == retimer->cfg[0] &&
> > +	    cfg1 == retimer->cfg[1] &&
> > +	    cfg2 == retimer->cfg[2])
> > +		return;
> > +
> > +	retimer->cfg[0] = cfg0;
> > +	retimer->cfg[1] = cfg1;
> > +	retimer->cfg[2] = cfg2;
> > +
> > +	regmap_write(retimer->regmap, 0x0, cfg0);
> > +	regmap_write(retimer->regmap, 0x1, cfg1);
> > +	regmap_write(retimer->regmap, 0x2, cfg2);
> > +}
> 
> This looks like a reimplementation of regcache. Is it really necessary?

Sure, will use regcache.

> 
> > +
> > +static void ps8830_configure(struct ps8830_retimer *retimer, int cfg0, int cfg1, int cfg2)
> > +{
> > +	/* Write safe-mode config before switching to new config */
> 
> Why is this required?

Data sheet says it needs to be configured into safe mode before
switching modes.

> 
> > +	ps8830_write(retimer, 0x1, 0x0, 0x0);
> > +
> > +	ps8830_write(retimer, cfg0, cfg1, cfg2);
> > +}
> > +
> > +static int ps8380_set(struct ps8830_retimer *retimer)
> > +{
> > +	int cfg0 = 0x00;
> > +	int cfg1 = 0x00;
> > +	int cfg2 = 0x00;
> > +
> > +	if (retimer->orientation == TYPEC_ORIENTATION_NONE ||
> > +	    retimer->mode == TYPEC_STATE_SAFE) {
> > +		ps8830_write(retimer, 0x1, 0x0, 0x0);
> > +		return 0;
> > +	}
> > +
> > +	if (retimer->orientation == TYPEC_ORIENTATION_NORMAL)
> > +		cfg0 = 0x01;
> > +	else
> > +		cfg0 = 0x03;
> > +
> > +	switch (retimer->mode) {
> > +	/* USB3 Only */
> > +	case TYPEC_STATE_USB:
> > +		cfg0 |= 0x20;
> > +		break;
> > +
> 
> The TYPEC_DP clauses should only be used if state->alt->swid is set to
> USB_TYPEC_DP_SID. Other altmodes share id space for their states.

Make sense. Will check svid for DP.

> 
> > +	/* DP Only */
> > +	case TYPEC_DP_STATE_C:
> > +		cfg1 = 0x85;
> > +		break;
> > +
> > +	case TYPEC_DP_STATE_E:
> > +		cfg1 = 0x81;
> > +		break;
> > +
> > +	/* DP + USB */
> > +	case TYPEC_DP_STATE_D:
> > +		cfg0 |= 0x20;
> > +		cfg1 = 0x85;
> > +		break;
> 
> CDE, please.

Will do.

> 
> > +
> > +	default:
> > +		return -EOPNOTSUPP;
> > +	}
> > +
> > +	ps8830_configure(retimer, cfg0, cfg1, cfg2);
> > +
> > +	return 0;
> > +}
> > +
> 
> -- 
> With best wishes
> Dmitry

Thanks for reviewing.

Abel