--- /dev/null
+From 9133bc3f0564890218cbba6cc7e81ebc0841a6f1 Mon Sep 17 00:00:00 2001
+From: John Ripple <john.ripple@keysight.com>
+Date: Mon, 15 Sep 2025 11:45:43 -0600
+Subject: drm/bridge: ti-sn65dsi86: Add support for DisplayPort mode with HPD
+
+From: John Ripple <john.ripple@keysight.com>
+
+commit 9133bc3f0564890218cbba6cc7e81ebc0841a6f1 upstream.
+
+Add support for DisplayPort to the bridge, which entails the following:
+- Get and use an interrupt for HPD;
+- Properly clear all status bits in the interrupt handler;
+
+Signed-off-by: John Ripple <john.ripple@keysight.com>
+Reviewed-by: Douglas Anderson <dianders@chromium.org>
+Signed-off-by: Douglas Anderson <dianders@chromium.org>
+Link: https://lore.kernel.org/r/20250915174543.2564994-1-john.ripple@keysight.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/gpu/drm/bridge/ti-sn65dsi86.c | 112 ++++++++++++++++++++++++++++++++++
+ 1 file changed, 112 insertions(+)
+
+--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
++++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+@@ -106,10 +106,21 @@
+ #define SN_PWM_EN_INV_REG 0xA5
+ #define SN_PWM_INV_MASK BIT(0)
+ #define SN_PWM_EN_MASK BIT(1)
++
++#define SN_IRQ_EN_REG 0xE0
++#define IRQ_EN BIT(0)
++
++#define SN_IRQ_EVENTS_EN_REG 0xE6
++#define HPD_INSERTION_EN BIT(1)
++#define HPD_REMOVAL_EN BIT(2)
++
+ #define SN_AUX_CMD_STATUS_REG 0xF4
+ #define AUX_IRQ_STATUS_AUX_RPLY_TOUT BIT(3)
+ #define AUX_IRQ_STATUS_AUX_SHORT BIT(5)
+ #define AUX_IRQ_STATUS_NAT_I2C_FAIL BIT(6)
++#define SN_IRQ_STATUS_REG 0xF5
++#define HPD_REMOVAL_STATUS BIT(2)
++#define HPD_INSERTION_STATUS BIT(1)
+
+ #define MIN_DSI_CLK_FREQ_MHZ 40
+
+@@ -152,7 +163,9 @@
+ * @ln_assign: Value to program to the LN_ASSIGN register.
+ * @ln_polrs: Value for the 4-bit LN_POLRS field of SN_ENH_FRAME_REG.
+ * @comms_enabled: If true then communication over the aux channel is enabled.
++ * @hpd_enabled: If true then HPD events are enabled.
+ * @comms_mutex: Protects modification of comms_enabled.
++ * @hpd_mutex: Protects modification of hpd_enabled.
+ *
+ * @gchip: If we expose our GPIOs, this is used.
+ * @gchip_output: A cache of whether we've set GPIOs to output. This
+@@ -190,7 +203,9 @@ struct ti_sn65dsi86 {
+ u8 ln_assign;
+ u8 ln_polrs;
+ bool comms_enabled;
++ bool hpd_enabled;
+ struct mutex comms_mutex;
++ struct mutex hpd_mutex;
+
+ #if defined(CONFIG_OF_GPIO)
+ struct gpio_chip gchip;
+@@ -221,6 +236,23 @@ static const struct regmap_config ti_sn6
+ .max_register = 0xFF,
+ };
+
++static int ti_sn65dsi86_read_u8(struct ti_sn65dsi86 *pdata, unsigned int reg,
++ u8 *val)
++{
++ int ret;
++ unsigned int reg_val;
++
++ ret = regmap_read(pdata->regmap, reg, ®_val);
++ if (ret) {
++ dev_err(pdata->dev, "fail to read raw reg %#x: %d\n",
++ reg, ret);
++ return ret;
++ }
++ *val = (u8)reg_val;
++
++ return 0;
++}
++
+ static int __maybe_unused ti_sn65dsi86_read_u16(struct ti_sn65dsi86 *pdata,
+ unsigned int reg, u16 *val)
+ {
+@@ -379,6 +411,7 @@ static void ti_sn65dsi86_disable_comms(s
+ static int __maybe_unused ti_sn65dsi86_resume(struct device *dev)
+ {
+ struct ti_sn65dsi86 *pdata = dev_get_drvdata(dev);
++ const struct i2c_client *client = to_i2c_client(pdata->dev);
+ int ret;
+
+ ret = regulator_bulk_enable(SN_REGULATOR_SUPPLY_NUM, pdata->supplies);
+@@ -413,6 +446,13 @@ static int __maybe_unused ti_sn65dsi86_r
+ if (pdata->refclk)
+ ti_sn65dsi86_enable_comms(pdata, NULL);
+
++ if (client->irq) {
++ ret = regmap_update_bits(pdata->regmap, SN_IRQ_EN_REG, IRQ_EN,
++ IRQ_EN);
++ if (ret)
++ dev_err(pdata->dev, "Failed to enable IRQ events: %d\n", ret);
++ }
++
+ return ret;
+ }
+
+@@ -1211,6 +1251,8 @@ static void ti_sn65dsi86_debugfs_init(st
+ static void ti_sn_bridge_hpd_enable(struct drm_bridge *bridge)
+ {
+ struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
++ const struct i2c_client *client = to_i2c_client(pdata->dev);
++ int ret;
+
+ /*
+ * Device needs to be powered on before reading the HPD state
+@@ -1219,11 +1261,35 @@ static void ti_sn_bridge_hpd_enable(stru
+ */
+
+ pm_runtime_get_sync(pdata->dev);
++
++ mutex_lock(&pdata->hpd_mutex);
++ pdata->hpd_enabled = true;
++ mutex_unlock(&pdata->hpd_mutex);
++
++ if (client->irq) {
++ ret = regmap_set_bits(pdata->regmap, SN_IRQ_EVENTS_EN_REG,
++ HPD_REMOVAL_EN | HPD_INSERTION_EN);
++ if (ret)
++ dev_err(pdata->dev, "Failed to enable HPD events: %d\n", ret);
++ }
+ }
+
+ static void ti_sn_bridge_hpd_disable(struct drm_bridge *bridge)
+ {
+ struct ti_sn65dsi86 *pdata = bridge_to_ti_sn65dsi86(bridge);
++ const struct i2c_client *client = to_i2c_client(pdata->dev);
++ int ret;
++
++ if (client->irq) {
++ ret = regmap_clear_bits(pdata->regmap, SN_IRQ_EVENTS_EN_REG,
++ HPD_REMOVAL_EN | HPD_INSERTION_EN);
++ if (ret)
++ dev_err(pdata->dev, "Failed to disable HPD events: %d\n", ret);
++ }
++
++ mutex_lock(&pdata->hpd_mutex);
++ pdata->hpd_enabled = false;
++ mutex_unlock(&pdata->hpd_mutex);
+
+ pm_runtime_put_autosuspend(pdata->dev);
+ }
+@@ -1309,6 +1375,41 @@ static int ti_sn_bridge_parse_dsi_host(s
+ return 0;
+ }
+
++static irqreturn_t ti_sn_bridge_interrupt(int irq, void *private)
++{
++ struct ti_sn65dsi86 *pdata = private;
++ struct drm_device *dev = pdata->bridge.dev;
++ u8 status;
++ int ret;
++ bool hpd_event;
++
++ ret = ti_sn65dsi86_read_u8(pdata, SN_IRQ_STATUS_REG, &status);
++ if (ret) {
++ dev_err(pdata->dev, "Failed to read IRQ status: %d\n", ret);
++ return IRQ_NONE;
++ }
++
++ hpd_event = status & (HPD_REMOVAL_STATUS | HPD_INSERTION_STATUS);
++
++ dev_dbg(pdata->dev, "(SN_IRQ_STATUS_REG = %#x)\n", status);
++ if (!status)
++ return IRQ_NONE;
++
++ ret = regmap_write(pdata->regmap, SN_IRQ_STATUS_REG, status);
++ if (ret) {
++ dev_err(pdata->dev, "Failed to clear IRQ status: %d\n", ret);
++ return IRQ_NONE;
++ }
++
++ /* Only send the HPD event if we are bound with a device. */
++ mutex_lock(&pdata->hpd_mutex);
++ if (pdata->hpd_enabled && hpd_event)
++ drm_kms_helper_hotplug_event(dev);
++ mutex_unlock(&pdata->hpd_mutex);
++
++ return IRQ_HANDLED;
++}
++
+ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
+ const struct auxiliary_device_id *id)
+ {
+@@ -1933,6 +2034,7 @@ static int ti_sn65dsi86_probe(struct i2c
+ dev_set_drvdata(dev, pdata);
+ pdata->dev = dev;
+
++ mutex_init(&pdata->hpd_mutex);
+ mutex_init(&pdata->comms_mutex);
+
+ pdata->regmap = devm_regmap_init_i2c(client,
+@@ -1973,6 +2075,16 @@ static int ti_sn65dsi86_probe(struct i2c
+ if (strncmp(id_buf, "68ISD ", ARRAY_SIZE(id_buf)))
+ return dev_err_probe(dev, -EOPNOTSUPP, "unsupported device id\n");
+
++ if (client->irq) {
++ ret = devm_request_threaded_irq(pdata->dev, client->irq, NULL,
++ ti_sn_bridge_interrupt,
++ IRQF_ONESHOT,
++ dev_name(pdata->dev), pdata);
++
++ if (ret)
++ return dev_err_probe(dev, ret, "failed to request interrupt\n");
++ }
++
+ /*
+ * Break ourselves up into a collection of aux devices. The only real
+ * motiviation here is to solve the chicken-and-egg problem of probe
projects / thirdparty / kernel / stable-queue.git / commitdiff
