platform/chrome: cros_ec_lpc: Add a new quirk for ACPI id

Framework Laptops' ACPI exposes the EC with id "PNP0C09". But
"PNP0C09" is part of the ACPI standard; there are lots of computers
with EC chips with this id, and most of them don't support the cros_ec
protocol.

The driver could find the ACPI device by having "PNP0C09" in the
acpi_match_table, but this would match devices which don't support the
cros_ec protocol. Instead, add a new quirk "CROS_EC_LPC_QUIRK_ACPI_ID"
which allows the id to be specified. This quirk is applied after the
DMI check shows that the device is supported.

Tested-by: Dustin L. Howett <dustin@howett.net>
Signed-off-by: Ben Walsh <ben@jubnut.com>
Link: https://lore.kernel.org/r/20240605063351.14836-4-ben@jubnut.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 7bf13c1d2c670ee96a8857cff92edf5d079be326..fa6606da802a05e98c8076bbf3b9128fe15b464b 100644 (file)
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -39,6 +39,11 @@ static bool cros_ec_lpc_acpi_device_found;
  * be used as the base port for EC mapped memory.
  */
 #define CROS_EC_LPC_QUIRK_REMAP_MEMORY              BIT(0)
+/*
+ * Indicates that lpc_driver_data.quirk_acpi_id should be used to find
+ * the ACPI device.
+ */
+#define CROS_EC_LPC_QUIRK_ACPI_ID                   BIT(1)
 
 /**
  * struct lpc_driver_data - driver data attached to a DMI device ID to indicate
@@ -46,10 +51,12 @@ static bool cros_ec_lpc_acpi_device_found;
  * @quirks: a bitfield composed of quirks from CROS_EC_LPC_QUIRK_*
  * @quirk_mmio_memory_base: The first I/O port addressing EC mapped memory (used
  *                          when quirk ...REMAP_MEMORY is set.)
+ * @quirk_acpi_id: An ACPI HID to be used to find the ACPI device.
  */
 struct lpc_driver_data {
        u32 quirks;
        u16 quirk_mmio_memory_base;
+       const char *quirk_acpi_id;
 };
 
 /**
@@ -418,6 +425,26 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
                pm_system_wakeup();
 }
 
+static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
+                                           void *context, void **retval)
+{
+       *(struct acpi_device **)context = acpi_fetch_acpi_dev(handle);
+       return AE_CTRL_TERMINATE;
+}
+
+static struct acpi_device *cros_ec_lpc_get_device(const char *id)
+{
+       struct acpi_device *adev = NULL;
+       acpi_status status = acpi_get_devices(id, cros_ec_lpc_parse_device,
+                                             &adev, NULL);
+       if (ACPI_FAILURE(status)) {
+               pr_warn(DRV_NAME ": Looking for %s failed\n", id);
+               return NULL;
+       }
+
+       return adev;
+}
+
 static int cros_ec_lpc_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
@@ -445,6 +472,16 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 
                if (quirks & CROS_EC_LPC_QUIRK_REMAP_MEMORY)
                        ec_lpc->mmio_memory_base = driver_data->quirk_mmio_memory_base;
+
+               if (quirks & CROS_EC_LPC_QUIRK_ACPI_ID) {
+                       adev = cros_ec_lpc_get_device(driver_data->quirk_acpi_id);
+                       if (!adev) {
+                               dev_err(dev, "failed to get ACPI device '%s'",
+                                       driver_data->quirk_acpi_id);
+                               return -ENODEV;
+                       }
+                       ACPI_COMPANION_SET(dev, adev);
+               }
        }
 
        /*
@@ -709,23 +746,12 @@ static struct platform_device cros_ec_lpc_device = {
        .name = DRV_NAME
 };
 
-static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
-                                           void *context, void **retval)
-{
-       *(bool *)context = true;
-       return AE_CTRL_TERMINATE;
-}
-
 static int __init cros_ec_lpc_init(void)
 {
        int ret;
-       acpi_status status;
        const struct dmi_system_id *dmi_match;
 
-       status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
-                                 &cros_ec_lpc_acpi_device_found, NULL);
-       if (ACPI_FAILURE(status))
-               pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);
+       cros_ec_lpc_acpi_device_found = !!cros_ec_lpc_get_device(ACPI_DRV_NAME);
 
        dmi_match = dmi_first_match(cros_ec_lpc_dmi_table);