Re: [PATCH 2/2] usb: typec: add support for the nb7vpq904m Type-C Linear Redriver
From: neil . armstrong
Date: Thu Jun 01 2023 - 05:57:21 EST
On 01/06/2023 11:37, Dmitry Baryshkov wrote:
On 01/06/2023 12:21, neil.armstrong@xxxxxxxxxx wrote:
From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Add support for the ON Semiconductor NB7VPQ904M Type-C USB SuperSpeed
and DisplayPort ALT Mode Linear Redriver chip found on some devices
with a Type-C port.
The redriver compensates ultra High-Speeed DisplayPort and USB
Super Speed signal integrity losses mainly due to PCB & transmission
cables.
The redriver doesn't support SuperSpeed lines swapping, but
can support Type-C SBU lines swapping.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
drivers/usb/typec/mux/Kconfig | 8 +
drivers/usb/typec/mux/Makefile | 1 +
drivers/usb/typec/mux/nb7vpq904m.c | 526 +++++++++++++++++++++++++++++++++++++
3 files changed, 535 insertions(+)
diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index c46fa4f9d3df..8c4d6b8fb75c 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -35,4 +35,12 @@ config TYPEC_MUX_INTEL_PMC
control the USB role switch and also the multiplexer/demultiplexer
switches used with USB Type-C Alternate Modes.
+config TYPEC_MUX_NB7VPQ904M
+ tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ 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.
+
endmenu
diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index dda67e19b58b..76196096ef41 100644
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_TYPEC_MUX_FSA4480) += fsa4480.o
obj-$(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
diff --git a/drivers/usb/typec/mux/nb7vpq904m.c b/drivers/usb/typec/mux/nb7vpq904m.c
new file mode 100644
index 000000000000..2f85ad9e417a
--- /dev/null
+++ b/drivers/usb/typec/mux/nb7vpq904m.c
@@ -0,0 +1,526 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OnSemi NB7VPQ904M Type-C driver
+ *
+ * Copyright (C) 2023 Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
+ */
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/of_graph.h>
+#include <drm/drm_bridge.h>
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define NB7_CHNA 0
+#define NB7_CHNB 1
+#define NB7_CHNC 2
+#define NB7_CHND 3
+#define NB7_IS_CHAN_AD(channel) (channel == NB7_CHNA || channel == NB7_CHND)
+
+#define GEN_DEV_SET_REG 0x00
+
+#define GEN_DEV_SET_CHIP_EN BIT(0)
+#define GEN_DEV_SET_CHNA_EN BIT(4)
+#define GEN_DEV_SET_CHNB_EN BIT(5)
+#define GEN_DEV_SET_CHNC_EN BIT(6)
+#define GEN_DEV_SET_CHND_EN BIT(7)
+
+#define GEN_DEV_SET_OP_MODE_MASK GENMASK(3, 1)
+
+#define GEN_DEV_SET_OP_MODE_DP_CC2 0
+#define GEN_DEV_SET_OP_MODE_DP_CC1 1
+#define GEN_DEV_SET_OP_MODE_DP_4LANE 2
+#define GEN_DEV_SET_OP_MODE_USB 5
+
+#define EQ_SETTING_REG_BASE 0x01
+#define EQ_SETTING_REG(n) (EQ_SETTING_REG_BASE + (n) * 2)
+#define EQ_SETTING_MASK GENMASK(3, 1)
+
+#define OUTPUT_COMPRESSION_AND_POL_REG_BASE 0x02
+#define OUTPUT_COMPRESSION_AND_POL_REG(n) (OUTPUT_COMPRESSION_AND_POL_REG_BASE + (n) * 2)
+#define OUTPUT_COMPRESSION_MASK GENMASK(2, 1)
+
+#define FLAT_GAIN_REG_BASE 0x18
+#define FLAT_GAIN_REG(n) (FLAT_GAIN_REG_BASE + (n) * 2)
+#define FLAT_GAIN_MASK GENMASK(1, 0)
+
+#define LOSS_MATCH_REG_BASE 0x19
+#define LOSS_MATCH_REG(n) (LOSS_MATCH_REG_BASE + (n) * 2)
+#define LOSS_MATCH_MASK GENMASK(1, 0)
+
+#define AUX_CC_REG 0x09
+
+#define CHIP_VERSION_REG 0x17
+
+struct nb7vpq904m {
+ struct i2c_client *client;
+ struct gpio_desc *enable_gpio;
+ struct regulator *vcc_supply;
+ struct regmap *regmap;
+ struct typec_switch_dev *sw;
+ struct typec_mux_dev *mux;
+
+ bool swap_data_lanes;
+ struct typec_switch *typec_switch;
+
+ struct drm_bridge bridge;
+
+ struct mutex lock; /* protect non-concurrent mux & switch */
+
+ enum typec_orientation orientation;
+ unsigned long mode;
+ unsigned int svid;
+};
+
+static void nb7vpq904m_set_channel(struct nb7vpq904m *nb7, unsigned int channel, bool dp)
+{
+ u8 eq, out_comp, flat_gain, loss_match;
+
+ if (dp) {
+ eq = NB7_IS_CHAN_AD(channel) ? 0x6 : 0x4;
+ out_comp = 0x3;
+ flat_gain = NB7_IS_CHAN_AD(channel) ? 0x2 : 0x1;
+ loss_match = 0x3;
+ } else {
+ eq = 0x4;
+ out_comp = 0x3;
+ flat_gain = NB7_IS_CHAN_AD(channel) ? 0x3 : 0x1;
+ loss_match = NB7_IS_CHAN_AD(channel) ? 0x1 : 0x3;
+ }
+
+ regmap_update_bits(nb7->regmap, EQ_SETTING_REG(channel),
+ EQ_SETTING_MASK, FIELD_PREP(EQ_SETTING_MASK, eq));
+ regmap_update_bits(nb7->regmap, OUTPUT_COMPRESSION_AND_POL_REG(channel),
+ OUTPUT_COMPRESSION_MASK, FIELD_PREP(OUTPUT_COMPRESSION_MASK, out_comp));
+ regmap_update_bits(nb7->regmap, FLAT_GAIN_REG(channel),
+ FLAT_GAIN_MASK, FIELD_PREP(FLAT_GAIN_MASK, flat_gain));
+ regmap_update_bits(nb7->regmap, LOSS_MATCH_REG(channel),
+ LOSS_MATCH_MASK, FIELD_PREP(LOSS_MATCH_MASK, loss_match));
+}
+
+static int nb7vpq904m_set(struct nb7vpq904m *nb7)
+{
+ bool reverse = (nb7->orientation == TYPEC_ORIENTATION_REVERSE);
+
+ switch (nb7->mode) {
+ case TYPEC_STATE_SAFE:
+ regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+ GEN_DEV_SET_CHIP_EN |
+ GEN_DEV_SET_CHNA_EN |
+ GEN_DEV_SET_CHNB_EN |
+ GEN_DEV_SET_CHNC_EN |
+ GEN_DEV_SET_CHND_EN |
+ FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+ GEN_DEV_SET_OP_MODE_USB));
+ nb7vpq904m_set_channel(nb7, NB7_CHNA, false);
+ nb7vpq904m_set_channel(nb7, NB7_CHNB, false);
+ nb7vpq904m_set_channel(nb7, NB7_CHNC, false);
+ nb7vpq904m_set_channel(nb7, NB7_CHND, false);
+ regmap_write(nb7->regmap, AUX_CC_REG, 0x2);
+
+ 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
+ *
+ * Reversed if data lanes are swapped
+ */
+ if (reverse ^ nb7->swap_data_lanes) {
+ regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+ GEN_DEV_SET_CHIP_EN |
+ GEN_DEV_SET_CHNA_EN |
+ GEN_DEV_SET_CHNB_EN |
+ FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+ GEN_DEV_SET_OP_MODE_USB));
+ nb7vpq904m_set_channel(nb7, NB7_CHNA, false);
+ nb7vpq904m_set_channel(nb7, NB7_CHNB, false);
+ } else {
+ regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+ GEN_DEV_SET_CHIP_EN |
+ GEN_DEV_SET_CHNC_EN |
+ GEN_DEV_SET_CHND_EN |
+ FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+ GEN_DEV_SET_OP_MODE_USB));
+ nb7vpq904m_set_channel(nb7, NB7_CHNC, false);
+ nb7vpq904m_set_channel(nb7, NB7_CHND, false);
+ }
+ regmap_write(nb7->regmap, AUX_CC_REG, 0x2);
+
+ return 0;
+
+ default:
+ if (nb7->svid != USB_TYPEC_DP_SID)
+ return -EINVAL;
+
+ break;
+ }
+
+ /* DP Altmode Setup */
+
+ regmap_write(nb7->regmap, AUX_CC_REG, reverse ? 0x1 : 0x0);
+
+ switch (nb7->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
+ */
+ regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+ GEN_DEV_SET_CHIP_EN |
+ GEN_DEV_SET_CHNA_EN |
+ GEN_DEV_SET_CHNB_EN |
+ GEN_DEV_SET_CHNC_EN |
+ GEN_DEV_SET_CHND_EN |
+ FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+ GEN_DEV_SET_OP_MODE_DP_4LANE));
+ nb7vpq904m_set_channel(nb7, NB7_CHNA, true);
+ nb7vpq904m_set_channel(nb7, NB7_CHNB, true);
+ nb7vpq904m_set_channel(nb7, NB7_CHNC, true);
+ nb7vpq904m_set_channel(nb7, NB7_CHND, true);
+ break;
+
+ case TYPEC_DP_STATE_D:
+ case TYPEC_DP_STATE_F:
+ regmap_write(nb7->regmap, GEN_DEV_SET_REG,
+ GEN_DEV_SET_CHIP_EN |
+ GEN_DEV_SET_CHNA_EN |
+ GEN_DEV_SET_CHNB_EN |
+ GEN_DEV_SET_CHNC_EN |
+ GEN_DEV_SET_CHND_EN |
+ FIELD_PREP(GEN_DEV_SET_OP_MODE_MASK,
+ reverse ^ nb7->swap_data_lanes ?
+ GEN_DEV_SET_OP_MODE_DP_CC2
+ : GEN_DEV_SET_OP_MODE_DP_CC1));
+
+ /*
+ * 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
+ *
+ * Reversed if data lanes are swapped
+ */
+ if (nb7->swap_data_lanes) {
+ nb7vpq904m_set_channel(nb7, NB7_CHNA, !reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHNB, !reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHNC, reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHND, reverse);
+ } else {
+ nb7vpq904m_set_channel(nb7, NB7_CHNA, reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHNB, reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHNC, !reverse);
+ nb7vpq904m_set_channel(nb7, NB7_CHND, !reverse);
+ }
+ break;
+
+ default:
+ return -ENOTSUPP;
+ }
+
+ return 0;
+}
+
+static int nb7vpq904m_sw_set(struct typec_switch_dev *sw,
+ enum typec_orientation orientation)
+{
+ struct nb7vpq904m *nb7 = typec_switch_get_drvdata(sw);
+ int ret;
+
+ ret = typec_switch_set(nb7->typec_switch, orientation);
+ if (ret)
+ return ret;
+
+ mutex_lock(&nb7->lock);
+
+ if (nb7->orientation != orientation) {
+ nb7->orientation = orientation;
+
+ ret = nb7vpq904m_set(nb7);
+ }
+
+ mutex_unlock(&nb7->lock);
+
+ return ret;
+}
+
+static int nb7vpq904m_mux_set(struct typec_mux_dev *mux, struct typec_mux_state *state)
+{
+ struct nb7vpq904m *nb7 = typec_mux_get_drvdata(mux);
+ int ret = 0;
+
+ mutex_lock(&nb7->lock);
+
+ if (nb7->mode != state->mode) {
+ nb7->mode = state->mode;
+
+ if (state->alt)
+ nb7->svid = state->alt->svid;
+ else
+ nb7->svid = 0; // No SVID
+
+ ret = nb7vpq904m_set(nb7);
+ }
+
+ mutex_unlock(&nb7->lock);
+
+ return ret;
+}
+
+#if IS_ENABLED(CONFIG_DRM)
+static int nb7vpq904m_bridge_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct nb7vpq904m *nb7 = container_of(bridge, struct nb7vpq904m, bridge);
+ struct drm_bridge *next_bridge;
+
+ if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
+ return -EINVAL;
+
+ next_bridge = devm_drm_of_get_bridge(&nb7->client->dev, nb7->client->dev.of_node, 0, 0);
+ if (IS_ERR(next_bridge)) {
+ dev_err(&nb7->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 nb7vpq904m_bridge_funcs = {
+ .attach = nb7vpq904m_bridge_attach,
+};
+
+static int nb7vpq904m_register_bridge(struct nb7vpq904m *nb7)
+{
+ nb7->bridge.funcs = &nb7vpq904m_bridge_funcs;
+ nb7->bridge.of_node = nb7->client->dev.of_node;
+
+ return devm_drm_bridge_add(&nb7->client->dev, &nb7->bridge);
+}
+#else
+static int nb7vpq904m_register_bridge(struct nb7vpq904m *nb7)
+{
+ return 0;
+}
+#endif
This is what I feared of when we started mixing USB-C and drm bridges. A part of me still thinks that the proper solution should involve OOB notifications.
OOB looks nice, but as I lookes, it would require a large amount of changes.
The advantage of bridge chaining is we can add specific ops for prepare/enable/disable/unprepare
for each elements of the USB-C data path.
If we can expect a sizeable amount of such drivers, can we have a generic drm helper for such passthrough bridges?
Sure, we can add this to drm-bridge.c as a simple pass-throught bridge code
Neil
+
+static const struct regmap_config nb7_regmap = {
+ .max_register = 0x1f,
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+enum {
+ NORMAL_LANE_MAPPING,
+ INVERT_LANE_MAPPING,
+};
+
+#define DATA_LANES_COUNT 4
+
+static const int supported_data_lane_mapping[][DATA_LANES_COUNT] = {
+ [NORMAL_LANE_MAPPING] = { 0, 1, 2, 3 },
+ [INVERT_LANE_MAPPING] = { 2, 3, 0, 1 },
+};
+
+static int nb7vpq904m_parse_data_lanes_mapping(struct nb7vpq904m *nb7)
+{
+ struct device_node *ep;
+ u32 data_lanes[4];
+ int ret, i, j;
+
+ ep = of_graph_get_endpoint_by_regs(nb7->client->dev.of_node, 1, 0);
+
+ if (ep) {
+ ret = of_property_count_u32_elems(ep, "data-lanes");
+ if (ret == -EINVAL)
+ /* Property isn't here, consider default mapping */
+ goto out_done;
+ if (ret < 0)
+ goto out_error;
+
+ if (ret != DATA_LANES_COUNT) {
+ dev_err(&nb7->client->dev, "expected 4 data lanes\n");
+ ret = -EINVAL;
+ goto out_error;
+ }
+
+ ret = of_property_read_u32_array(ep, "data-lanes", data_lanes, DATA_LANES_COUNT);
+ if (ret)
+ goto out_error;
+
+ for (i = 0; i < ARRAY_SIZE(supported_data_lane_mapping); i++) {
+ for (j = 0; j < DATA_LANES_COUNT; j++) {
+ if (data_lanes[j] != supported_data_lane_mapping[i][j])
+ break;
+ }
+
+ if (j == DATA_LANES_COUNT)
+ break;
+ }
+
+ switch (i) {
+ case NORMAL_LANE_MAPPING:
+ break;
+ case INVERT_LANE_MAPPING:
+ nb7->swap_data_lanes = true;
+ dev_info(&nb7->client->dev, "using inverted data lanes mapping\n");
+ break;
+ default:
+ dev_err(&nb7->client->dev, "invalid data lanes mapping\n");
+ ret = -EINVAL;
+ goto out_error;
+ }
+ }
+
+out_done:
+ ret = 0;
+
+out_error:
+ of_node_put(ep);
+
+ return ret;
+}
+
+static int nb7vpq904m_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct typec_switch_desc sw_desc = { };
+ struct typec_mux_desc mux_desc = { };
+ struct nb7vpq904m *nb7;
+ int ret;
+
+ nb7 = devm_kzalloc(dev, sizeof(*nb7), GFP_KERNEL);
+ if (!nb7)
+ return -ENOMEM;
+
+ nb7->client = client;
+
+ nb7->regmap = devm_regmap_init_i2c(client, &nb7_regmap);
+ if (IS_ERR(nb7->regmap)) {
+ dev_err(&client->dev, "Failed to allocate register map\n");
+ return PTR_ERR(nb7->regmap);
+ }
+
+ nb7->mode = TYPEC_STATE_SAFE;
+ nb7->orientation = TYPEC_ORIENTATION_NONE;
+
+ mutex_init(&nb7->lock);
+
+ nb7->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
+ if (IS_ERR(nb7->enable_gpio))
+ return dev_err_probe(dev, PTR_ERR(nb7->enable_gpio),
+ "unable to acquire enable gpio\n");
+
+ nb7->vcc_supply = devm_regulator_get_optional(dev, "vcc");
+ if (IS_ERR(nb7->vcc_supply))
+ return PTR_ERR(nb7->vcc_supply);
+
+ nb7->typec_switch = fwnode_typec_switch_get(dev->fwnode);
+ if (IS_ERR(nb7->typec_switch))
+ return dev_err_probe(dev, PTR_ERR(nb7->typec_switch),
+ "failed to acquire orientation-switch\n");
+
+ ret = nb7vpq904m_parse_data_lanes_mapping(nb7);
+ if (ret)
+ return ret;
+
+ ret = regulator_enable(nb7->vcc_supply);
+ if (ret)
+ dev_warn(dev, "Failed to enable vcc: %d\n", ret);
+
+ gpiod_set_value(nb7->enable_gpio, 1);
+
+ ret = nb7vpq904m_register_bridge(nb7);
+ if (ret)
+ return ret;
+
+ sw_desc.drvdata = nb7;
+ sw_desc.fwnode = dev->fwnode;
+ sw_desc.set = nb7vpq904m_sw_set;
+
+ nb7->sw = typec_switch_register(dev, &sw_desc);
+ if (IS_ERR(nb7->sw))
+ return dev_err_probe(dev, PTR_ERR(nb7->sw), "Error registering typec switch\n");
+
+ mux_desc.drvdata = nb7;
+ mux_desc.fwnode = dev->fwnode;
+ mux_desc.set = nb7vpq904m_mux_set;
+
+ nb7->mux = typec_mux_register(dev, &mux_desc);
+ if (IS_ERR(nb7->mux)) {
+ typec_switch_unregister(nb7->sw);
+ return dev_err_probe(dev, PTR_ERR(nb7->mux), "Error registering typec mux\n");
+ }
+
+ return 0;
+}
+
+static void nb7vpq904m_remove(struct i2c_client *client)
+{
+ struct nb7vpq904m *nb7 = i2c_get_clientdata(client);
+
+ typec_mux_unregister(nb7->mux);
+ typec_switch_unregister(nb7->sw);
+
+ gpiod_set_value(nb7->enable_gpio, 0);
+
+ regulator_disable(nb7->vcc_supply);
+}
+
+static const struct i2c_device_id nb7vpq904m_table[] = {
+ { "nb7vpq904m" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, nb7vpq904m_table);
+
+static const struct of_device_id nb7vpq904m_of_table[] = {
+ { .compatible = "onnn,nb7vpq904m" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, nb7vpq904m_of_table);
+
+static struct i2c_driver nb7vpq904m_driver = {
+ .driver = {
+ .name = "nb7vpq904m",
+ .of_match_table = nb7vpq904m_of_table,
+ },
+ .probe_new = nb7vpq904m_probe,
+ .remove = nb7vpq904m_remove,
+ .id_table = nb7vpq904m_table,
+};
+
+module_i2c_driver(nb7vpq904m_driver);
+
+MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>");
+MODULE_DESCRIPTION("OnSemi NB7VPQ904M Type-C driver");
+MODULE_LICENSE("GPL");