The tmds181 and sn65dp159 are "retimers" and hence can be considered
HDMI-to-HDMI bridges. Typical usage is to convert the output of an
FPGA into a valid HDMI signal, and it will typically be inserted
between an encoder and hdmi-connector.
Signed-off-by: Mike Looijmans <mike.looijm...@topic.nl>
---
Changes in v3:
Lower-case hex values and use defines for EYESCAN registers
Remove equalizer code (unlikely to be used)
Remove attributes (no longer useful, undocumented)
Fix build for 6.17 kernel
Use devm_drm_bridge_alloc
Sort includes and add linux/bitfield.h
Check chip type and complain on mismatch
Changes in v2:
Use atomic_enable/disable
Use #defines for bit fields in registers
Allow HDMI 2 compliance
Filter modes on clock range
Use cross-over pixel frequency instead of manual overides
Devicetree bindings according to standards
drivers/gpu/drm/bridge/Kconfig | 11 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/ti-tmds181.c | 409 ++++++++++++++++++++++++++++
3 files changed, 421 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/ti-tmds181.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index b9e0ca85226a..753177fc9b50 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -430,6 +430,17 @@ config DRM_TI_SN65DSI86
help
Texas Instruments SN65DSI86 DSI to eDP Bridge driver
+config DRM_TI_TMDS181
+ tristate "TI TMDS181 and SN65DP159 HDMI retimer bridge driver"
+ depends on OF
+ select DRM_KMS_HELPER
+ select REGMAP_I2C
+ help
+ Enable this to support the TI TMDS181 and SN65DP159 HDMI retimers.
+ The SN65DP159 provides output into a cable (source) whereas the
+ TMDS181 is meant to forward a cable signal into a PCB (sink). Either
+ can be set up as source or sink though.
+
config DRM_TI_TPD12S015
tristate "TI TPD12S015 HDMI level shifter and ESD protection"
depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 245e8a27e3fc..f4b5089e903c 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_DRM_TI_SN65DSI83) += ti-sn65dsi83.o
obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
obj-$(CONFIG_DRM_TI_TDP158) += ti-tdp158.o
obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
+obj-$(CONFIG_DRM_TI_TMDS181) += ti-tmds181.o
obj-$(CONFIG_DRM_TI_TPD12S015) += ti-tpd12s015.o
obj-$(CONFIG_DRM_NWL_MIPI_DSI) += nwl-dsi.o
obj-$(CONFIG_DRM_ITE_IT66121) += ite-it66121.o
diff --git a/drivers/gpu/drm/bridge/ti-tmds181.c
b/drivers/gpu/drm/bridge/ti-tmds181.c
new file mode 100644
index 000000000000..8ac3eb808d5b
--- /dev/null
+++ b/drivers/gpu/drm/bridge/ti-tmds181.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * TI tmds181 and sn65dp159 HDMI redriver and retimer chips
+ *
+ * Copyright (C) 2018 - 2025 Topic Embedded Products <www.topic.nl>
+ *
+ * based on code
+ * Copyright (C) 2007 Hans Verkuil
+ * Copyright (C) 2016, 2017 Leon Woestenberg <l...@sidebranch.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+
+MODULE_DESCRIPTION("I2C device driver for DP159 and TMDS181 redriver/retimer");
+MODULE_AUTHOR("Mike Looijmans");
+MODULE_LICENSE("GPL");
+
+#define TMDS181_REG_ID 0
+#define TMDS181_REG_REV 0x8
+#define TMDS181_REG_CTRL9 0x9
+/* Registers A and B have a volatile bit, but we don't use it, so cache is ok
*/
+#define TMDS181_REG_CTRLA 0xa
+#define TMDS181_REG_CTRLB 0xb
+#define TMDS181_REG_CTRLC 0xc
+#define TMDS181_REG_EQUALIZER 0xd
+/* EYESCAN registers don't appear to deserve separate names */
+#define TMDS181_REG_EYESCAN_E 0xe
+#define TMDS181_REG_EYESCAN_F 0xf
+#define TMDS181_REG_EYESCAN_15 0x15
+#define TMDS181_REG_EYESCAN_17 0x17
+#define TMDS181_REG_EYESCAN_1F 0x1f
+#define TMDS181_REG_AUX 0x20
+
+
+#define TMDS181_CTRL9_SIG_EN BIT(4)
+#define TMDS181_CTRL9_PD_EN BIT(3)
+#define TMDS181_CTRL9_HPD_AUTO_PWRDWN_DISABLE BIT(2)
+#define TMDS181_CTRL9_I2C_DR_CTL GENMASK(1, 0)
+
+#define TMDS181_CTRLA_MODE_SINK BIT(7)
+#define TMDS181_CTRLA_HPDSNK_GATE_EN BIT(6)
+#define TMDS181_CTRLA_EQ_ADA_EN BIT(5)
+#define TMDS181_CTRLA_EQ_EN BIT(4)
+#define TMDS181_CTRLA_AUX_BRG_EN BIT(3)
+#define TMDS181_CTRLA_APPLY BIT(2)
+#define TMDS181_CTRLA_DEV_FUNC_MODE GENMASK(1, 0)
+
+#define TMDS181_CTRLB_SLEW_CTL GENMASK(7, 6)
+#define TMDS181_CTRLB_HDMI_SEL_DVI BIT(5)
+#define TMDS181_CTRLB_TX_TERM_CTL GENMASK(4, 3)
+#define TMDS181_CTRLB_DDC_DR_SEL BIT(2)
+#define TMDS181_CTRLB_TMDS_CLOCK_RATIO_STATUS BIT(1)
+#define TMDS181_CTRLB_DDC_TRAIN_SET BIT(0)
+
+#define TMDS181_CTRLB_TX_TERM_150_300_OHMS 1
+#define TMDS181_CTRLB_TX_TERM_75_150_OHMS 3
+
+#define TMDS181_CTRLC_VSWING_DATA GENMASK(7, 5)
+#define TMDS181_CTRLC_VSWING_CLK GENMASK(4, 2)
+#define TMDS181_CTRLC_HDMI_TWPST1 GENMASK(1, 0)
+
+#define TMDS181_EQ_DATA_LANE GENMASK(5, 3)
+#define TMDS181_EQ_CLOCK_LANE GENMASK(2, 1)
+#define TMDS181_EQ_DIS_HDMI2_SWG BIT(0)
+
+/* Above this data rate HDMI2 standards apply (TX termination) */
+#define HDMI2_PIXEL_RATE_KHZ 340000
+
+enum tmds181_chip {
+ tmds181,
+ dp159,
+};
+
+struct tmds181_data {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct drm_bridge *next_bridge;
+ struct drm_bridge bridge;
+ u32 retimer_threshold_khz;
+};
+
+static inline struct tmds181_data *
+drm_bridge_to_tmds181_data(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct tmds181_data, bridge);
+}
+
+static int tmds181_attach(struct drm_bridge *bridge, struct drm_encoder
*encoder,
+ enum drm_bridge_attach_flags flags)
+{
+ struct tmds181_data *data = drm_bridge_to_tmds181_data(bridge);
+
+ return drm_bridge_attach(encoder, data->next_bridge, bridge, flags);
+}
+
+static enum drm_mode_status
+tmds181_mode_valid(struct drm_bridge *bridge, const struct drm_display_info
*info,
+ const struct drm_display_mode *mode)
+{
+ /* Clock limits: clk between 25 and 350 MHz, clk is 1/10 of bit clock */
+ if (mode->clock < 25000)
+ return MODE_CLOCK_LOW;
+
+ /* The actual HDMI clock (if provided) cannot exceed 350MHz */
+ if (mode->crtc_clock > 350000)
+ return MODE_CLOCK_HIGH;
+
+ /*
+ * When in HDMI 2 mode, the clock is 1/40th of the bitrate. The limit is
+ * then the data rate of 6Gbps, which would use a 600MHz pixel clock.
+ */
+ if (mode->clock > 600000)
+ return MODE_CLOCK_HIGH;
+
+ return MODE_OK;
+}
+
+static void tmds181_enable(struct drm_bridge *bridge, struct drm_atomic_state
*state)
+{
+ struct tmds181_data *data = drm_bridge_to_tmds181_data(bridge);
+ const struct drm_crtc_state *crtc_state;
+ const struct drm_display_mode *mode;
+ struct drm_connector *connector;
+ struct drm_crtc *crtc;
+ unsigned int val;
+
+ /*
+ * Retrieve the CRTC adjusted mode. This requires a little dance to go
+ * from the bridge to the encoder, to the connector and to the CRTC.
+ */
+ connector = drm_atomic_get_new_connector_for_encoder(state,
+ bridge->encoder);
+ crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
+ crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+ mode = &crtc_state->adjusted_mode;
+
+ /* Set retimer/redriver mode based on pixel clock */
+ val = mode->clock > data->retimer_threshold_khz ?
TMDS181_CTRLA_DEV_FUNC_MODE : 0;
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_DEV_FUNC_MODE, val);
+
+ /* Configure TX termination based on pixel clock */
+ val = mode->clock > HDMI2_PIXEL_RATE_KHZ ?
+ TMDS181_CTRLB_TX_TERM_75_150_OHMS :
+ TMDS181_CTRLB_TX_TERM_150_300_OHMS;
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLB,
+ TMDS181_CTRLB_TX_TERM_CTL,
+ FIELD_PREP(TMDS181_CTRLB_TX_TERM_CTL, val));
+
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRL9,
+ TMDS181_CTRL9_PD_EN, 0);
+}
+
+static void tmds181_disable(struct drm_bridge *bridge, struct drm_atomic_state
*state)
+{
+ struct tmds181_data *data = drm_bridge_to_tmds181_data(bridge);
+
+ /* Set the PD_EN bit */
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRL9,
+ TMDS181_CTRL9_PD_EN, TMDS181_CTRL9_PD_EN);
+}
+
+static const struct drm_bridge_funcs tmds181_bridge_funcs = {
+ .attach = tmds181_attach,
+ .mode_valid = tmds181_mode_valid,
+ .atomic_enable = tmds181_enable,
+ .atomic_disable = tmds181_disable,
+
+ .atomic_reset = drm_atomic_helper_bridge_reset,
+ .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+};
+
+static const u8 tmds181_id_tmds181[8] __nonstring = "TMDS181 ";
+static const u8 tmds181_id_dp159[8] __nonstring = "DP159 ";
+
+static int tmds181_check_id(struct tmds181_data *data, enum tmds181_chip *chip)
+{
+ int ret;
+ int retry;
+ u8 buffer[8];
+
+ for (retry = 0; retry < 20; ++retry) {
+ ret = regmap_bulk_read(data->regmap, TMDS181_REG_ID, buffer,
+ sizeof(buffer));
+ if (!ret)
+ break;
+
+ /* Compensate for very long OE power-up delays due to the cap */
+ usleep_range(5000, 10000);
+ }
+
+ if (ret) {
+ dev_err(&data->client->dev, "I2C read ID failed\n");
+ return ret;
+ }
+
+ if (memcmp(buffer, tmds181_id_tmds181, sizeof(buffer)) == 0) {
+ if (*chip != tmds181) {
+ dev_warn(&data->client->dev, "Detected: TMDS181\n");
+ *chip = tmds181;
+ }
+ return 0;
+ }
+
+ if (memcmp(buffer, tmds181_id_dp159, sizeof(buffer)) == 0) {
+ if (*chip != dp159) {
+ dev_warn(&data->client->dev, "Detected: DP159\n");
+ *chip = dp159;
+ }
+ return 0;
+ }
+
+ dev_err(&data->client->dev, "Unknown ID: %*pE\n", (int)sizeof(buffer),
buffer);
+
+ return -ENODEV;
+}
+
+static bool tmds181_regmap_is_volatile(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ /* IBERT result and status registers, not used yet */
+ case TMDS181_REG_EYESCAN_15:
+ case TMDS181_REG_EYESCAN_17 ... TMDS181_REG_EYESCAN_1F:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config tmds181_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .cache_type = REGCACHE_RBTREE,
+ .max_register = TMDS181_REG_AUX,
+ .volatile_reg = tmds181_regmap_is_volatile,
+};
+
+static int tmds181_probe(struct i2c_client *client)
+{
+ struct tmds181_data *data;
+ struct gpio_desc *oe_gpio;
+ enum tmds181_chip chip;
+ int ret;
+ u32 param;
+ u8 val;
+
+ /* Check if the adapter supports the needed features */
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -EIO;
+
+ data = devm_drm_bridge_alloc(&client->dev, struct tmds181_data, bridge,
+ &tmds181_bridge_funcs);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ data->client = client;
+ i2c_set_clientdata(client, data);
+ data->regmap = devm_regmap_init_i2c(client, &tmds181_regmap_config);
+ if (IS_ERR(data->regmap))
+ return PTR_ERR(data->regmap);
+
+ /* The "OE" pin acts as a reset */
+ oe_gpio = devm_gpiod_get_optional(&client->dev, "oe", GPIOD_OUT_LOW);
+ if (IS_ERR(oe_gpio)) {
+ ret = PTR_ERR(oe_gpio);
+ if (ret != -EPROBE_DEFER)
+ dev_err(&client->dev, "failed to acquire 'oe' gpio\n");
+ return ret;
+ }
+ if (oe_gpio) {
+ /* Need at least 100us reset pulse */
+ usleep_range(100, 200);
+ gpiod_set_value_cansleep(oe_gpio, 1);
+ }
+
+ /* Reading the ID also provides enough time for the reset */
+ chip = (enum tmds181_chip)of_device_get_match_data(&client->dev);
+ ret = tmds181_check_id(data, &chip);
+ if (ret)
+ return ret;
+
+ /*
+ * We take care of power control, so disable the chips PM functions, and
+ * allow the DDC to run at 400kHz
+ */
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRL9,
+ TMDS181_CTRL9_SIG_EN | TMDS181_CTRL9_PD_EN |
+ TMDS181_CTRL9_HPD_AUTO_PWRDWN_DISABLE |
+ TMDS181_CTRL9_I2C_DR_CTL,
+ TMDS181_CTRL9_PD_EN |
+ TMDS181_CTRL9_HPD_AUTO_PWRDWN_DISABLE |
+ TMDS181_CTRL9_I2C_DR_CTL);
+
+ /* Apply configuration changes */
+ if (of_property_read_bool(client->dev.of_node, "ti,source-mode"))
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_MODE_SINK, 0);
+ if (of_property_read_bool(client->dev.of_node, "ti,sink-mode"))
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_MODE_SINK,
TMDS181_CTRLA_MODE_SINK);
+
+ /*
+ * Using the automatic modes of the chip uses considerable power as it
+ * will keep the PLL running at all times. So instead, define our own
+ * threshold for the pixel rate. This also allows to use a sane default
+ * of 200MHz pixel rate for the redriver-retimer crossover point, as the
+ * modes below 3k don't show any benefit from the retimer.
+ */
+ data->retimer_threshold_khz = 200000;
+ if (!of_property_read_u32(client->dev.of_node,
+ "ti,retimer-threshold-hz", ¶m))
+ data->retimer_threshold_khz = param / 1000;
+
+ /* Default to low-power redriver mode */
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_DEV_FUNC_MODE, 0x00);
+
+ if (of_property_read_bool(client->dev.of_node, "ti,adaptive-equalizer"))
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_EQ_EN |
TMDS181_CTRLA_EQ_ADA_EN,
+ TMDS181_CTRLA_EQ_EN |
TMDS181_CTRLA_EQ_ADA_EN);
+ if (of_property_read_bool(client->dev.of_node, "ti,disable-equalizer"))
+ regmap_update_bits(data->regmap, TMDS181_REG_CTRLA,
+ TMDS181_CTRLA_EQ_EN |
TMDS181_CTRLA_EQ_ADA_EN,
+ 0);
+
+ switch (chip) {
+ case dp159:
+ val = 0;
+ if (!of_property_read_u32(client->dev.of_node,
+ "ti,slew-rate", ¶m)) {
+ if (param > 3) {
+ dev_err(&client->dev, "invalid slew-rate\n");
+ return -EINVAL;
+ }
+ /* Implement 0 = slow, 3 = fast slew rate */
+ val = FIELD_PREP(TMDS181_CTRLB_SLEW_CTL, (3 - param));
+ }
+ if (of_property_read_bool(client->dev.of_node, "ti,dvi-mode"))
+ val |= TMDS181_CTRLB_HDMI_SEL_DVI;
+ break;
+ default:
+ val = TMDS181_CTRLB_DDC_DR_SEL;
+ break;
+ }
+
+ /* Default to low-speed termination */
+ val |= FIELD_PREP(TMDS181_CTRLB_TX_TERM_CTL,
TMDS181_CTRLB_TX_TERM_150_300_OHMS);
+
+ ret = regmap_write(data->regmap, TMDS181_REG_CTRLB, val);
+ if (ret < 0) {
+ dev_err(&client->dev, "regmap_write(B) failed\n");
+ return ret;
+ }
+
+ /* Find next bridge in chain */
+ data->next_bridge = devm_drm_of_get_bridge(&client->dev,
client->dev.of_node, 1, 0);
+ if (IS_ERR(data->next_bridge))
+ return dev_err_probe(&client->dev, PTR_ERR(data->next_bridge),
+ "Failed to find next bridge\n");
+
+ /* Register the bridge. */
+ data->bridge.of_node = client->dev.of_node;
+
+ return devm_drm_bridge_add(&client->dev, &data->bridge);
+}
+
+static const struct i2c_device_id tmds181_id[] = {
+ { "tmds181", tmds181 },
+ { "sn65dp159", dp159 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, tmds181_id);
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id tmds181_of_match[] = {
+ { .compatible = "ti,tmds181", .data = (void *)tmds181 },
+ { .compatible = "ti,sn65dp159", .data = (void *)dp159 },
+ {}
+};
+MODULE_DEVICE_TABLE(of, tmds181_of_match);
+#endif
+
+static struct i2c_driver tmds181_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "tmds181",
+ .of_match_table = of_match_ptr(tmds181_of_match),
+ },
+ .probe = tmds181_probe,
+ .id_table = tmds181_id,
+};
+
+module_i2c_driver(tmds181_driver);
--
2.43.0
Met vriendelijke groet / kind regards,
Mike Looijmans
System Expert
TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands
T: +31 (0) 499 33 69 69
E: mike.looijm...@topic.nl
W: www.topic.nl
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