diff mbox series

[v2,8/9] platform/x86: int3472: Add handshake pin support

Message ID 20250402202510.432888-9-hdegoede@redhat.com
State New
Headers show
Series platform/x86: int3472: Add handshake pin support | expand

Commit Message

Hans de Goede April 2, 2025, 8:25 p.m. UTC 
New Intel Meteor Lake based laptops with IPU6 cameras have a new type 0x12
pin defined in the INT3472 sensor companion device which describes
the sensor's GPIOs.

This pin is primarily used on designs with a Lattice FPGA chip which is
capable of running the sensor independently of the main CPU for features
like presence detection. This pin needs to be driven high to make the FPGA
run the power-on sequence of the sensor. After driving the pin high
the FPGA "firmware" needs 25ms to comlpete the power-on sequence.

Add support for this modelling the handshake pin as a GPIO driven "dvdd"
regulator with a 25 ms enable time. This model was chosen because:

1. Sensor chips don't have a handshake pin, so we need to abstract this
   in some way which does not require modification to the sensor drivers,
   sensor drivers using the bulk-regulator API to get avdd + vddio + dvdd
   is normal. So this will work to get the right value set to the handshake
   pin without requiring sensor driver modifications.

2. Sensors typically wait only a small time for the sensor to power-on
   after de-asserting reset. Not the 25ms the Lattice chip requires.
   Using the regulator framework's enable_time allows hiding the need for
   this delay from the sensor drivers.

Link: https://lore.kernel.org/platform-driver-x86/59f672c3-6d87-4ec7-9b7f-f44fe2cce934@redhat.com/
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2341731
Tested-by: Alan Stern <stern@rowland.harvard.edu> # Dell Latitude 7450, ov02e10
Tested-by: Duane <duanek@chorus.net> # HP Spectre x360 16t-aa000, ov08x40
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 .../platform/x86/intel/int3472/clk_and_regulator.c |  1 +
 drivers/platform/x86/intel/int3472/common.h        |  1 +
 drivers/platform/x86/intel/int3472/discrete.c      | 14 ++++++++++++++
 3 files changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
index e4bb93892104..04cc52d28f16 100644
--- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
+++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
@@ -224,6 +224,7 @@  int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
 	}
 
 	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
+	init_data.constraints.enable_time = enable_time;
 	init_data.consumer_supplies = regulator->supply_map;
 	init_data.num_consumer_supplies = j;
 
diff --git a/drivers/platform/x86/intel/int3472/common.h b/drivers/platform/x86/intel/int3472/common.h
index cd94346270c5..c7b8f0224320 100644
--- a/drivers/platform/x86/intel/int3472/common.h
+++ b/drivers/platform/x86/intel/int3472/common.h
@@ -22,6 +22,7 @@ 
 #define INT3472_GPIO_TYPE_POWER_ENABLE				0x0b
 #define INT3472_GPIO_TYPE_CLK_ENABLE				0x0c
 #define INT3472_GPIO_TYPE_PRIVACY_LED				0x0d
+#define INT3472_GPIO_TYPE_HANDSHAKE				0x12
 
 #define INT3472_PDEV_MAX_NAME_LEN				23
 #define INT3472_MAX_SENSOR_GPIOS				3
diff --git a/drivers/platform/x86/intel/int3472/discrete.c b/drivers/platform/x86/intel/int3472/discrete.c
index a2db4fae0e6d..4dddba4e1fde 100644
--- a/drivers/platform/x86/intel/int3472/discrete.c
+++ b/drivers/platform/x86/intel/int3472/discrete.c
@@ -191,6 +191,10 @@  static void int3472_get_con_id_and_polarity(struct acpi_device *adev, u8 *type,
 		*con_id = "avdd";
 		*gpio_flags = GPIO_ACTIVE_HIGH;
 		break;
+	case INT3472_GPIO_TYPE_HANDSHAKE:
+		*con_id = "dvdd";
+		*gpio_flags = GPIO_ACTIVE_HIGH;
+		break;
 	default:
 		*con_id = "unknown";
 		*gpio_flags = GPIO_ACTIVE_HIGH;
@@ -290,6 +294,7 @@  static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
 	case INT3472_GPIO_TYPE_CLK_ENABLE:
 	case INT3472_GPIO_TYPE_PRIVACY_LED:
 	case INT3472_GPIO_TYPE_POWER_ENABLE:
+	case INT3472_GPIO_TYPE_HANDSHAKE:
 		gpio = skl_int3472_gpiod_get_from_temp_lookup(int3472, agpio, con_id, gpio_flags);
 		if (IS_ERR(gpio)) {
 			ret = PTR_ERR(gpio);
@@ -318,6 +323,15 @@  static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
 			if (ret)
 				err_msg = "Failed to map regulator to sensor\n";
 
+			break;
+		case INT3472_GPIO_TYPE_HANDSHAKE:
+			/* Setups using a handshake pin need 25 ms enable delay */
+			ret = skl_int3472_register_regulator(int3472, gpio,
+							     25 * USEC_PER_MSEC,
+							     con_id, NULL);
+			if (ret)
+				err_msg = "Failed to map regulator to sensor\n";
+
 			break;
 		default: /* Never reached */
 			ret = -EINVAL;