Message-Id: <CWD1MKL68P2V.1QBJXJ0E5U171@fairphone.com>
Date:   Fri, 20 Oct 2023 08:13:05 +0200
From:   "Luca Weiss" <luca.weiss@...rphone.com>
To:     "Heikki Krogerus" <heikki.krogerus@...ux.intel.com>
Cc:     "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        "Rob Herring" <robh+dt@...nel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@...aro.org>,
        "Conor Dooley" <conor+dt@...nel.org>,
        "Liam Girdwood" <lgirdwood@...il.com>,
        "Mark Brown" <broonie@...nel.org>,
        "Dmitry Baryshkov" <dmitry.baryshkov@...aro.org>,
        <~postmarketos/upstreaming@...ts.sr.ht>,
        <phone-devel@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 2/2] usb: typec: add support for PTN36502 redriver

On Tue Oct 17, 2023 at 10:34 AM CEST, Heikki Krogerus wrote:
> Hi,
>
> On Fri, Oct 13, 2023 at 04:24:48PM +0200, Luca Weiss wrote:
> > Add a driver for the NXP PTN36502 Type-C USB 3.1 Gen 1 and DisplayPort
> > v1.2 combo redriver.
> > 
> > Signed-off-by: Luca Weiss <luca.weiss@...rphone.com>
>
> Looks OK to me, but couple of nitpicks below. With those fixed:
>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
>
> > ---
> >  drivers/usb/typec/mux/Kconfig    |  10 +
> >  drivers/usb/typec/mux/Makefile   |   1 +
> >  drivers/usb/typec/mux/ptn36502.c | 421 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 432 insertions(+)
> > 
> > diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
> > index 65da61150ba7..816b9bd08355 100644
> > --- a/drivers/usb/typec/mux/Kconfig
> > +++ b/drivers/usb/typec/mux/Kconfig
> > @@ -46,4 +46,14 @@ 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_PTN36502
> > +	tristate "NXP PTN36502 Type-C redriver driver"
> > +	depends on I2C
> > +	depends on DRM || DRM=n
> > +	select DRM_PANEL_BRIDGE if DRM
> > +	select REGMAP_I2C
> > +	help
> > +	  Say Y or M if your system has a NXP PTN36502 Type-C redriver chip
> > +	  found on some devices with a Type-C port.
> > +
> >  endmenu
> > diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
> > index 76196096ef41..9d6a5557b0bd 100644
> > --- a/drivers/usb/typec/mux/Makefile
> > +++ b/drivers/usb/typec/mux/Makefile
> > @@ -5,3 +5,4 @@ obj-$(CONFIG_TYPEC_MUX_GPIO_SBU)	+= gpio-sbu-mux.o
> >  obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
> >  obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
> >  obj-$(CONFIG_TYPEC_MUX_NB7VPQ904M)	+= nb7vpq904m.o
> > +obj-$(CONFIG_TYPEC_MUX_PTN36502)	+= ptn36502.o
> > diff --git a/drivers/usb/typec/mux/ptn36502.c b/drivers/usb/typec/mux/ptn36502.c
> > new file mode 100644
> > index 000000000000..91684a856f3a
> > --- /dev/null
> > +++ b/drivers/usb/typec/mux/ptn36502.c
> > @@ -0,0 +1,421 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * NXP PTN36502 Type-C driver
> > + *
> > + * Copyright (C) 2023 Luca Weiss <luca.weiss@...rphone.com>
> > + *
> > + * Based on NB7VPQ904M driver:
> > + * Copyright (C) 2023 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > + */
> > +
> > +#include <drm/drm_bridge.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/i2c.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/regmap.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/usb/typec_dp.h>
> > +#include <linux/usb/typec_mux.h>
> > +#include <linux/usb/typec_retimer.h>
> > +
> > +#define PTN36502_CHIP_ID_REG				0x00
> > +#define PTN36502_CHIP_ID				0x02
> > +
> > +#define PTN36502_CHIP_REVISION_REG			0x01
> > +#define PTN36502_CHIP_REVISION_BASE(val)		FIELD_GET(GENMASK(7, 4), (val))
> > +#define PTN36502_CHIP_REVISION_METAL(val)		FIELD_GET(GENMASK(3, 0), (val))
> > +
> > +#define PTN36502_DP_LINK_CTRL_REG			0x06
> > +#define PTN36502_DP_LINK_CTRL_LANES_2			(2 << 2)
> > +#define PTN36502_DP_LINK_CTRL_LANES_4			(3 << 2)
> > +#define PTN36502_DP_LINK_CTRL_LINK_RATE_5_4GBPS		(2 << 0)
> > +
> > +/* Registers for lane 0 (0x07) to lane 3 (0x0a) have the same layout */
> > +#define PTN36502_DP_LANE_CTRL_REG(n)			(0x07 + (n))
> > +#define PTN36502_DP_LANE_CTRL_RX_GAIN_3DB		(2<<4)
> > +#define PTN36502_DP_LANE_CTRL_TX_SWING_800MVPPD		(2<<2)
> > +#define PTN36502_DP_LANE_CTRL_PRE_EMPHASIS_3_5DB	(1<<0)
> > +
> > +#define PTN36502_MODE_CTRL1_REG				0x0b
> > +#define PTN36502_MODE_CTRL1_PLUG_ORIENT_REVERSE		(1<<5)
> > +#define PTN36502_MODE_CTRL1_AUX_CROSSBAR_SW_ON		(1<<3)
> > +#define PTN36502_MODE_CTRL1_MODE_OFF			(0<<0)
> > +#define PTN36502_MODE_CTRL1_MODE_USB_ONLY		(1<<0)
> > +#define PTN36502_MODE_CTRL1_MODE_USB_DP			(2<<0)
> > +#define PTN36502_MODE_CTRL1_MODE_DP			(3<<0)
> > +
> > +#define PTN36502_DEVICE_CTRL_REG			0x0d
> > +#define PTN36502_DEVICE_CTRL_AUX_MONITORING_EN		(1<<7)
>
> You have couple of different styles here. Please try to always use
> BIT() and GENMASK() macros when possible. At the very least put spaces
> around << and >>.

Hi Heikki,

I was wondering when writing that whether GENMASK was actually proper
use for values you write to registers, when not actually used as a
bitmask.

Since the datasheet refers to e.g. with TX_SWING_800MVPPD (2<<2) that
you write a '2' to the correct bits of this register. But when using
BIT(3) kind of hides this relationship if someone refers back to the
datasheet. Or same with "3<<2" -> GENMASK(3, 2) or whatever.

Let me know what you think.

Regards
Luca

>
> > +struct ptn36502 {
> > +	struct i2c_client *client;
> > +	struct regulator *vdd18_supply;
> > +	struct regmap *regmap;
> > +	struct typec_switch_dev *sw;
> > +	struct typec_retimer *retimer;
> > +
> > +	struct typec_switch *typec_switch;
> > +
> > +	struct drm_bridge bridge;
> > +
> > +	struct mutex lock; /* protect non-concurrent retimer & switch */
> > +
> > +	enum typec_orientation orientation;
> > +	unsigned long mode;
> > +	unsigned int svid;
> > +};
> > +
> > +static int ptn36502_set(struct ptn36502 *ptn)
> > +{
> > +	bool reverse = (ptn->orientation == TYPEC_ORIENTATION_REVERSE);
> > +	unsigned int ctrl1_val = 0;
> > +	unsigned int lane_ctrl_val = 0;
> > +	unsigned int link_ctrl_val = 0;
> > +
> > +	switch (ptn->mode) {
> > +	case TYPEC_STATE_SAFE:
> > +		/* Deep power saving state */
> > +		regmap_write(ptn->regmap, PTN36502_MODE_CTRL1_REG,
> > +			     PTN36502_MODE_CTRL1_MODE_OFF);
> > +		return 0;
> > +
> > +	case TYPEC_STATE_USB:
> > +		/*
> > +		 * Normal Orientation (CC1)
> > +		 * A -> USB RX
> > +		 * B -> USB TX
> > +		 * C -> X
> > +		 * D -> X
> > +		 * Flipped Orientation (CC2)
> > +		 * A -> X
> > +		 * B -> X
> > +		 * C -> USB TX
> > +		 * D -> USB RX
> > +		 */
> > +
> > +		/* USB 3.1 Gen 1 only */
> > +		ctrl1_val = PTN36502_MODE_CTRL1_MODE_USB_ONLY;
> > +		if (reverse)
> > +			ctrl1_val |= PTN36502_MODE_CTRL1_PLUG_ORIENT_REVERSE;
> > +
> > +		regmap_write(ptn->regmap, PTN36502_MODE_CTRL1_REG, ctrl1_val);
> > +		return 0;
> > +
> > +	default:
> > +		if (ptn->svid != USB_TYPEC_DP_SID)
> > +			return -EINVAL;
> > +
> > +		break;
> > +	}
> > +
> > +	/* DP Altmode Setup */
> > +
> > +	switch (ptn->mode) {
> > +	case TYPEC_DP_STATE_C:
> > +	case TYPEC_DP_STATE_E:
> > +		/*
> > +		 * Normal Orientation (CC1)
> > +		 * A -> DP3
> > +		 * B -> DP2
> > +		 * C -> DP1
> > +		 * D -> DP0
> > +		 * Flipped Orientation (CC2)
> > +		 * A -> DP0
> > +		 * B -> DP1
> > +		 * C -> DP2
> > +		 * D -> DP3
> > +		 */
> > +
> > +		/* 4-lane DP */
> > +		ctrl1_val |= PTN36502_MODE_CTRL1_MODE_DP;
> > +		link_ctrl_val |= PTN36502_DP_LINK_CTRL_LANES_4;
> > +		break;
> > +
> > +	case TYPEC_DP_STATE_D:
> > +	case TYPEC_DP_STATE_F: /* State F is deprecated */
> > +		/*
> > +		 * Normal Orientation (CC1)
> > +		 * A -> USB RX
> > +		 * B -> USB TX
> > +		 * C -> DP1
> > +		 * D -> DP0
> > +		 * Flipped Orientation (CC2)
> > +		 * A -> DP0
> > +		 * B -> DP1
> > +		 * C -> USB TX
> > +		 * D -> USB RX
> > +		 */
> > +
> > +		/* USB 3.1 Gen 1 and 2-lane DP */
> > +		ctrl1_val |= PTN36502_MODE_CTRL1_MODE_USB_DP;
> > +		link_ctrl_val |= PTN36502_DP_LINK_CTRL_LANES_2;
> > +		break;
> > +
> > +	default:
> > +		return -EOPNOTSUPP;
> > +	}
> > +
> > +	/* Enable AUX monitoring */
> > +	regmap_write(ptn->regmap, PTN36502_DEVICE_CTRL_REG,
> > +		     PTN36502_DEVICE_CTRL_AUX_MONITORING_EN);
> > +
> > +	/* Enable AUX switch path */
> > +	ctrl1_val |= PTN36502_MODE_CTRL1_AUX_CROSSBAR_SW_ON;
> > +	if (reverse)
> > +		ctrl1_val |= PTN36502_MODE_CTRL1_PLUG_ORIENT_REVERSE;
> > +	regmap_write(ptn->regmap, PTN36502_MODE_CTRL1_REG, ctrl1_val);
> > +
> > +	/* DP Link rate: 5.4 Gbps (HBR2) */
> > +	link_ctrl_val |= PTN36502_DP_LINK_CTRL_LINK_RATE_5_4GBPS;
> > +	regmap_write(ptn->regmap, PTN36502_DP_LINK_CTRL_REG, link_ctrl_val);
> > +
> > +	/*
> > +	 * For all lanes:
> > +	 * - Rx equivalization gain: 3 dB
> > +	 * - TX output swing control: 800 mVppd
> > +	 * - Pre-emphasis control: 3.5 dB
> > +	 */
> > +	lane_ctrl_val = PTN36502_DP_LANE_CTRL_RX_GAIN_3DB |
> > +			PTN36502_DP_LANE_CTRL_TX_SWING_800MVPPD |
> > +			PTN36502_DP_LANE_CTRL_PRE_EMPHASIS_3_5DB;
> > +	regmap_write(ptn->regmap, PTN36502_DP_LANE_CTRL_REG(0), lane_ctrl_val);
> > +	regmap_write(ptn->regmap, PTN36502_DP_LANE_CTRL_REG(1), lane_ctrl_val);
> > +	regmap_write(ptn->regmap, PTN36502_DP_LANE_CTRL_REG(2), lane_ctrl_val);
> > +	regmap_write(ptn->regmap, PTN36502_DP_LANE_CTRL_REG(3), lane_ctrl_val);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ptn36502_sw_set(struct typec_switch_dev *sw, enum typec_orientation orientation)
> > +{
> > +	struct ptn36502 *ptn = typec_switch_get_drvdata(sw);
> > +	int ret;
> > +
> > +	ret = typec_switch_set(ptn->typec_switch, orientation);
> > +	if (ret)
> > +		return ret;
> > +
> > +	mutex_lock(&ptn->lock);
> > +
> > +	if (ptn->orientation != orientation) {
> > +		ptn->orientation = orientation;
> > +
> > +		ret = ptn36502_set(ptn);
> > +	}
> > +
> > +	mutex_unlock(&ptn->lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static int ptn36502_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
> > +{
> > +	struct ptn36502 *ptn = typec_retimer_get_drvdata(retimer);
> > +	int ret = 0;
> > +
> > +	mutex_lock(&ptn->lock);
> > +
> > +	if (ptn->mode != state->mode) {
> > +		ptn->mode = state->mode;
> > +
> > +		if (state->alt)
> > +			ptn->svid = state->alt->svid;
> > +		else
> > +			ptn->svid = 0; // No SVID
> > +
> > +		ret = ptn36502_set(ptn);
> > +	}
> > +
> > +	mutex_unlock(&ptn->lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static int ptn36502_detect(struct ptn36502 *ptn)
> > +{
> > +	struct device *dev = &ptn->client->dev;
> > +	unsigned int reg_val;
> > +	int ret;
> > +
> > +	ret = regmap_read(ptn->regmap, PTN36502_CHIP_ID_REG,
> > +			  &reg_val);
> > +	if (ret < 0)
> > +		return dev_err_probe(dev, ret, "Failed to read chip ID\n");
> > +
> > +	if (reg_val != PTN36502_CHIP_ID)
> > +		return dev_err_probe(dev, -ENODEV, "Unexpected chip ID: %x\n", reg_val);
> > +
> > +	ret = regmap_read(ptn->regmap, PTN36502_CHIP_REVISION_REG,
> > +			  &reg_val);
> > +	if (ret < 0)
> > +		return dev_err_probe(dev, ret, "Failed to read chip revision\n");
> > +
> > +	dev_dbg(dev, "Chip revision: base layer version %lx, metal layer version %lx\n",
> > +		PTN36502_CHIP_REVISION_BASE(reg_val),
> > +		PTN36502_CHIP_REVISION_METAL(reg_val));
> > +
> > +	return 0;
> > +}
> > +
> > +#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)
> > +static int ptn36502_bridge_attach(struct drm_bridge *bridge,
> > +				    enum drm_bridge_attach_flags flags)
>
> I applied this patch and realised that that's not correctly aligned.
> There are couple of extra spaces.
>
> > +{
> > +	struct ptn36502 *ptn = container_of(bridge, struct ptn36502, bridge);
> > +	struct drm_bridge *next_bridge;
> > +
> > +	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
> > +		return -EINVAL;
> > +
> > +	next_bridge = devm_drm_of_get_bridge(&ptn->client->dev, ptn->client->dev.of_node, 0, 0);
> > +	if (IS_ERR(next_bridge)) {
> > +		dev_err(&ptn->client->dev, "failed to acquire drm_bridge: %pe\n", next_bridge);
> > +		return PTR_ERR(next_bridge);
> > +	}
> > +
> > +	return drm_bridge_attach(bridge->encoder, next_bridge, bridge,
> > +				 DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > +}
> > +
> > +static const struct drm_bridge_funcs ptn36502_bridge_funcs = {
> > +	.attach	= ptn36502_bridge_attach,
> > +};
> > +
> > +static int ptn36502_register_bridge(struct ptn36502 *ptn)
> > +{
> > +	ptn->bridge.funcs = &ptn36502_bridge_funcs;
> > +	ptn->bridge.of_node = ptn->client->dev.of_node;
> > +
> > +	return devm_drm_bridge_add(&ptn->client->dev, &ptn->bridge);
> > +}
> > +#else
> > +static int ptn36502_register_bridge(struct ptn36502 *ptn)
> > +{
> > +	return 0;
> > +}
> > +#endif
> > +
> > +static const struct regmap_config ptn36502_regmap = {
> > +	.max_register = 0x0d,
> > +	.reg_bits = 8,
> > +	.val_bits = 8,
> > +};
> > +
> > +static int ptn36502_probe(struct i2c_client *client)
> > +{
> > +	struct device *dev = &client->dev;
> > +	struct typec_switch_desc sw_desc = { };
> > +	struct typec_retimer_desc retimer_desc = { };
> > +	struct ptn36502 *ptn;
> > +	int ret;
> > +
> > +	ptn = devm_kzalloc(dev, sizeof(*ptn), GFP_KERNEL);
> > +	if (!ptn)
> > +		return -ENOMEM;
> > +
> > +	ptn->client = client;
> > +
> > +	ptn->regmap = devm_regmap_init_i2c(client, &ptn36502_regmap);
> > +	if (IS_ERR(ptn->regmap)) {
> > +		dev_err(&client->dev, "Failed to allocate register map\n");
> > +		return PTR_ERR(ptn->regmap);
> > +	}
> > +
> > +	ptn->mode = TYPEC_STATE_SAFE;
> > +	ptn->orientation = TYPEC_ORIENTATION_NONE;
> > +
> > +	mutex_init(&ptn->lock);
> > +
> > +	ptn->vdd18_supply = devm_regulator_get_optional(dev, "vdd18");
> > +	if (IS_ERR(ptn->vdd18_supply))
> > +		return PTR_ERR(ptn->vdd18_supply);
> > +
> > +	ptn->typec_switch = fwnode_typec_switch_get(dev->fwnode);
> > +	if (IS_ERR(ptn->typec_switch))
> > +		return dev_err_probe(dev, PTR_ERR(ptn->typec_switch),
> > +				     "Failed to acquire orientation-switch\n");
> > +
> > +	ret = regulator_enable(ptn->vdd18_supply);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret, "Failed to enable vdd18\n");
> > +
> > +	ret = ptn36502_detect(ptn);
> > +	if (ret)
> > +		goto err_disable_regulator;
> > +
> > +	ret = ptn36502_register_bridge(ptn);
> > +	if (ret)
> > +		goto err_disable_regulator;
> > +
> > +	sw_desc.drvdata = ptn;
> > +	sw_desc.fwnode = dev->fwnode;
> > +	sw_desc.set = ptn36502_sw_set;
> > +
> > +	ptn->sw = typec_switch_register(dev, &sw_desc);
> > +	if (IS_ERR(ptn->sw)) {
> > +		ret = dev_err_probe(dev, PTR_ERR(ptn->sw),
> > +				    "Failed to register typec switch\n");
> > +		goto err_disable_regulator;
> > +	}
> > +
> > +	retimer_desc.drvdata = ptn;
> > +	retimer_desc.fwnode = dev->fwnode;
> > +	retimer_desc.set = ptn36502_retimer_set;
> > +
> > +	ptn->retimer = typec_retimer_register(dev, &retimer_desc);
> > +	if (IS_ERR(ptn->retimer)) {
> > +		ret = dev_err_probe(dev, PTR_ERR(ptn->retimer),
> > +				    "Failed to register typec retimer\n");
> > +		goto err_switch_unregister;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_switch_unregister:
> > +	typec_switch_unregister(ptn->sw);
> > +
> > +err_disable_regulator:
> > +	regulator_disable(ptn->vdd18_supply);
> > +
> > +	return ret;
> > +}
> > +
> > +static void ptn36502_remove(struct i2c_client *client)
> > +{
> > +	struct ptn36502 *ptn = i2c_get_clientdata(client);
> > +
> > +	typec_retimer_unregister(ptn->retimer);
> > +	typec_switch_unregister(ptn->sw);
> > +
> > +	regulator_disable(ptn->vdd18_supply);
> > +}
> > +
> > +static const struct i2c_device_id ptn36502_table[] = {
> > +	{ "ptn36502" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, ptn36502_table);
> > +
> > +static const struct of_device_id ptn36502_of_table[] = {
> > +	{ .compatible = "nxp,ptn36502" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, ptn36502_of_table);
> > +
> > +static struct i2c_driver ptn36502_driver = {
> > +	.driver = {
> > +		.name = "ptn36502",
> > +		.of_match_table = ptn36502_of_table,
> > +	},
> > +	.probe		= ptn36502_probe,
> > +	.remove		= ptn36502_remove,
> > +	.id_table	= ptn36502_table,
> > +};
> > +module_i2c_driver(ptn36502_driver);
> > +
> > +MODULE_AUTHOR("Luca Weiss <luca.weiss@...rphone.com>");
> > +MODULE_DESCRIPTION("NXP PTN36502 Type-C driver");
> > +MODULE_LICENSE("GPL");
>
> thanks,

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