touch: retry + hard-reset when FT5426 boots into wedged 0xff state

After a long bench session of taps + power cycles, the FT5426 on this
unit started returning dev_mode=0xff on every read. The polling loop
interpreted that as 15 simultaneous touches forever (td_status bits
0..3 all set), wedged `was_down=true` permanently, and no tap or
long-press ever fired — the screen looked dead.

Two layers of defence in touch_init:
  1. retry the dev_mode read up to 10 × 30 ms in case the chip is just
     slow to come up after PC_RST_TP_N is released.
  2. if still stuck, pulse PC_RST_TP_N via a new
     display_touch_reset_pulse() helper (drop reset for 20 ms then
     release + 50 ms settle), then retry the read another 10 × 30 ms.

Plus a polling-loop sanity check: an FT5x06 supports max 5 simultaneous
points, so a TD_STATUS lower-nibble value > 5 is bogus and the poll
cycle is skipped. That keeps a wedged chip from producing phantom
"15 touches" reports if it slips into 0xff during runtime.

If both attempts still report 0xff, we log loudly and let the polling
task run — it harmlessly drops cycles via the >5 sanity check. Wake
still works via POST /state from Scrypted; this only disables touch
gestures on a hardware-stuck boot.

1 files changed, 16 insertions, 0 deletions

diff --git a/main/display.c b/main/display.c
index a704891..8c5ffb2 100644
--- a/main/display.c
+++ b/main/display.c
@@ -218,6 +218,22 @@ static esp_err_t touch_release_reset(void)
         PC_LED_EN | PC_RST_TP_N | PC_RST_LCD_N | PC_RST_BRIDGE_N);
 }
 
+// Hard-reset the touch IC: drop PC_RST_TP_N for ~20 ms, then release.
+// touch_init() calls this if its dev_mode read keeps returning 0xff —
+// usually unwedges a stuck FT5426 without needing a power cycle.
+esp_err_t display_touch_reset_pulse(void)
+{
+    if (!s_panel_mcu) return ESP_ERR_INVALID_STATE;
+    // Hold touch in reset (clear PC_RST_TP_N), keep everything else as-is.
+    esp_err_t err = mcu_write_u8(REG_PORTC,
+        PC_LED_EN | PC_RST_LCD_N | PC_RST_BRIDGE_N);
+    if (err != ESP_OK) return err;
+    vTaskDelay(pdMS_TO_TICKS(20));
+    err = touch_release_reset();
+    vTaskDelay(pdMS_TO_TICKS(50));
+    return err;
+}
+
 // ============================================================================
 // TC358762 bridge configuration (DSI Generic Long Write packets)
 // Sequence mirrors Linux drivers/gpu/drm/bridge/tc358762.c tc358762_init().