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Date:   Tue, 17 Oct 2023 11:34:09 +0300
From:   Heikki Krogerus <heikki.krogerus@linux.intel.com>
To:     Luca Weiss <luca.weiss@fairphone.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        ~postmarketos/upstreaming@lists.sr.ht, phone-devel@vger.kernel.org,
        linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 2/2] usb: typec: add support for PTN36502 redriver
Message-ID: <ZS5HAQrUObdhHSdV@kuha.fi.intel.com>
References: <20231013-ptn36502-v1-0-98109a430efc@fairphone.com>
 <20231013-ptn36502-v1-2-98109a430efc@fairphone.com>
MIME-Version: 1.0
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In-Reply-To: <20231013-ptn36502-v1-2-98109a430efc@fairphone.com>
Precedence: bulk

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@fairphone.com>

Looks OK to me, but couple of nitpicks below. With those fixed:

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.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@fairphone.com>
> + *
> + * Based on NB7VPQ904M driver:
> + * Copyright (C) 2023 Dmitry Baryshkov <dmitry.baryshkov@linaro.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 >>.

> +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@fairphone.com>");
> +MODULE_DESCRIPTION("NXP PTN36502 Type-C driver");
> +MODULE_LICENSE("GPL");

thanks,

-- 
heikki