[PATCH] HID: intel-thc-hid: intel-quickspi: reset touch IC on system resume

[d3z-the-dev]

On the Surface Pro 10 (Meteor Lake) the touchscreen stops working after a
suspend/resume cycle and only recovers after a reboot. The driver logs
"GET_DEVICE_INFO: recv failed: -11" on resume.

The touch IC loses power during system suspend (s2idle) on this platform,
the same way it does across hibernation. quickspi_resume() only restores
the THC port, interrupts and DMA and sends a HIDSPI_ON command, assuming
the touch IC kept its power and state. When it has actually lost power the
HIDSPI_ON command is never acknowledged and the descriptor read fails,
leaving the touchscreen dead until the module is reloaded.

quickspi_restore() already handles this for hibernation by running
reset_tic() and reconfiguring the THC SPI/LTR settings. Make
quickspi_resume() do the same: quiesce interrupts, re-select the THC port,
reconfigure the SPI input/output addresses and read/write parameters, run
reset_tic() to re-enumerate the device and restore the LTR configuration.

Tested on a Surface Pro 10 across multiple s2idle suspend/resume cycles.

Link: https://github.com/linux-surface/linux-surface/issues/1799

Signed-off-by: d3z-the-dev <d3z.the.dev@xxxxxxxxx>
---
 .../intel-quickspi/pci-quickspi.c             | 38 +++++++++++++++++--
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/intel-thc-hid/intel-quickspi/pci-quickspi.c b/drivers/hid/intel-thc-hid/intel-quickspi/pci-quickspi.c
index f669235f1883..d59278a3e5c1 100644
--- a/drivers/hid/intel-thc-hid/intel-quickspi/pci-quickspi.c
+++ b/drivers/hid/intel-thc-hid/intel-quickspi/pci-quickspi.c
@@ -780,24 +780,54 @@ static int quickspi_resume(struct device *device)
 	if (!qsdev)
 		return -ENODEV;
 
+	ret = thc_interrupt_quiesce(qsdev->thc_hw, true);
+	if (ret)
+		return ret;
+
 	ret = thc_port_select(qsdev->thc_hw, THC_PORT_TYPE_SPI);
 	if (ret)
 		return ret;
 
+	thc_spi_input_output_address_config(qsdev->thc_hw,
+					    qsdev->input_report_hdr_addr,
+					    qsdev->input_report_bdy_addr,
+					    qsdev->output_report_addr);
+
+	ret = thc_spi_read_config(qsdev->thc_hw, qsdev->spi_freq_val,
+				  qsdev->spi_read_io_mode,
+				  qsdev->spi_read_opcode,
+				  qsdev->spi_packet_size);
+	if (ret)
+		return ret;
+
+	ret = thc_spi_write_config(qsdev->thc_hw, qsdev->spi_freq_val,
+				   qsdev->spi_write_io_mode,
+				   qsdev->spi_write_opcode,
+				   qsdev->spi_packet_size,
+				   qsdev->performance_limit);
+	if (ret)
+		return ret;
+
 	thc_interrupt_config(qsdev->thc_hw);
 
 	thc_interrupt_enable(qsdev->thc_hw, true);
 
-	ret = thc_dma_configure(qsdev->thc_hw);
+	/* The TIC may lose power across system suspend, reset it to recover */
+	ret = reset_tic(qsdev);
 	if (ret)
 		return ret;
 
-	ret = thc_interrupt_quiesce(qsdev->thc_hw, false);
+	ret = thc_dma_configure(qsdev->thc_hw);
 	if (ret)
 		return ret;
 
-	if (!device_may_wakeup(qsdev->dev))
-		return quickspi_set_power(qsdev, HIDSPI_ON);
+	thc_ltr_config(qsdev->thc_hw,
+		       qsdev->active_ltr_val,
+		       qsdev->low_power_ltr_val);
+
+	thc_change_ltr_mode(qsdev->thc_hw, THC_LTR_MODE_ACTIVE);
+
+	qsdev->state = QUICKSPI_ENABLED;
 
 	return 0;
 }
-- 
2.54.0