[PATCH v3 2/5] platform/x86: int3472: tps68470: fix clock consumer registration for Dell Latitude 5285

[Thierry Chatard <tchatard@gmail.com>]

The BIOS on the Dell Latitude 5285 leaves GNVS field C0TP at zero.
With C0TP=0 the ACPI _DEP method on INT3479 (OV5670, front camera)
resolves to PCI0 instead of the INT3472 (TPS68470 PMIC) device.

Because for_each_acpi_consumer_dev() walks the _DEP reverse-mapping,
INT3479 is invisible to it: the clock consumer lookup entry for the
front camera is never registered with the tps68470-clk driver, and
the OV5670 sensor driver cannot acquire its MCLK.

Fix this without touching ACPI tables by adding optional static clock
consumer fields to struct int3472_tps68470_board_data:

  unsigned int n_clk_consumers;
  const struct tps68470_clk_consumer *clk_consumers;

When board data is present and n_clk_consumers is non-zero, probe uses
the static list instead of for_each_acpi_consumer_dev() to populate
tps68470-clk platform data.  Platforms that do not set these fields
continue to use the existing ACPI traversal path unchanged.

The board_data lookup is moved before the clock-pdata allocation so
that it is available for both the static and dynamic paths.

Signed-off-by: Thierry Chatard <tchatard@gmail.com>
---
 drivers/platform/x86/intel/int3472/tps68470.c | 29 ++++++++++++++++---
 drivers/platform/x86/intel/int3472/tps68470.h | 10 +++++++
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/intel/int3472/tps68470.c b/drivers/platform/x86/intel/int3472/tps68470.c
index a496075c0..3364ef428 100644
--- a/drivers/platform/x86/intel/int3472/tps68470.c
+++ b/drivers/platform/x86/intel/int3472/tps68470.c
@@ -155,9 +155,31 @@ static int skl_int3472_tps68470_probe(struct i2c_client *client)
 	if (!adev)
 		return -ENODEV;
 
-	n_consumers = skl_int3472_fill_clk_pdata(&client->dev, &clk_pdata);
-	if (n_consumers < 0)
-		return n_consumers;
+	/*
+	 * Look up board data before building clock platform data.  On platforms
+	 * where a sensor's ACPI _DEP does not list the INT3472 device,
+	 * for_each_acpi_consumer_dev() misses that sensor and its clock consumer
+	 * entry is never registered.  Board data can supply a static consumer
+	 * list to use instead, bypassing the broken _DEP traversal.
+	 */
+	board_data = int3472_tps68470_get_board_data(dev_name(&client->dev));
+
+	if (board_data && board_data->n_clk_consumers) {
+		clk_pdata = devm_kzalloc(&client->dev,
+					 struct_size(clk_pdata, consumers,
+						     board_data->n_clk_consumers),
+					 GFP_KERNEL);
+		if (!clk_pdata)
+			return -ENOMEM;
+		clk_pdata->n_consumers = board_data->n_clk_consumers;
+		for (i = 0; i < (int)board_data->n_clk_consumers; i++)
+			clk_pdata->consumers[i] = board_data->clk_consumers[i];
+		n_consumers = board_data->n_clk_consumers;
+	} else {
+		n_consumers = skl_int3472_fill_clk_pdata(&client->dev, &clk_pdata);
+		if (n_consumers < 0)
+			return n_consumers;
+	}
 
 	regmap = devm_regmap_init_i2c(client, &tps68470_regmap_config);
 	if (IS_ERR(regmap)) {
@@ -176,7 +198,6 @@ static int skl_int3472_tps68470_probe(struct i2c_client *client)
 	device_type = skl_int3472_tps68470_calc_type(adev);
 	switch (device_type) {
 	case DESIGNED_FOR_WINDOWS:
-		board_data = int3472_tps68470_get_board_data(dev_name(&client->dev));
 		if (!board_data)
 			return dev_err_probe(&client->dev, -ENODEV, "No board-data found for this model\n");
 
diff --git a/drivers/platform/x86/intel/int3472/tps68470.h b/drivers/platform/x86/intel/int3472/tps68470.h
index 35915e701..4aefb728e 100644
--- a/drivers/platform/x86/intel/int3472/tps68470.h
+++ b/drivers/platform/x86/intel/int3472/tps68470.h
@@ -12,11 +12,21 @@
 #define _INTEL_SKL_INT3472_TPS68470_H
 
 struct gpiod_lookup_table;
+struct tps68470_clk_consumer;
 struct tps68470_regulator_platform_data;
 
 struct int3472_tps68470_board_data {
 	const char *dev_name;
 	const struct tps68470_regulator_platform_data *tps68470_regulator_pdata;
+	/*
+	 * Static clock consumers.  When n_clk_consumers is non-zero these are
+	 * used in place of for_each_acpi_consumer_dev() to build the tps68470-clk
+	 * platform data.  Needed on platforms where a sensor's ACPI _DEP does not
+	 * list the INT3472 device, causing that sensor to be missed by the ACPI
+	 * dependency traversal.
+	 */
+	unsigned int n_clk_consumers;
+	const struct tps68470_clk_consumer *clk_consumers;
 	unsigned int n_gpiod_lookups;
 	struct gpiod_lookup_table *tps68470_gpio_lookup_tables[];
 };
-- 
2.51.0