[PATCH v6 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 | 113 +++++++++++-------
 drivers/platform/x86/intel/int3472/tps68470.h |  10 ++
 2 files changed, 79 insertions(+), 44 deletions(-)

diff --git a/drivers/platform/x86/intel/int3472/tps68470.c b/drivers/platform/x86/intel/int3472/tps68470.c
index a496075c0..92da2ba80 100644
--- a/drivers/platform/x86/intel/int3472/tps68470.c
+++ b/drivers/platform/x86/intel/int3472/tps68470.c
@@ -147,17 +147,41 @@ static int skl_int3472_tps68470_probe(struct i2c_client *client)
 	struct tps68470_clk_platform_data *clk_pdata;
 	struct mfd_cell *cells;
 	struct regmap *regmap;
+	struct gpiod_lookup_table * const *tables;
 	int n_consumers;
 	int device_type;
 	int ret;
-	int i;
+	unsigned int i;
 
 	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 < 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)) {
@@ -176,52 +200,53 @@ 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");
-
-		cells = kzalloc_objs(*cells, TPS68470_WIN_MFD_CELL_COUNT);
-		if (!cells)
-			return -ENOMEM;
-
-		/*
-		 * The order of the cells matters here! The clk must be first
-		 * because the regulator depends on it. The gpios must be last,
-		 * acpi_gpiochip_add() calls acpi_dev_clear_dependencies() and
-		 * the clk + regulators must be ready when this happens.
-		 */
-		cells[0].name = "tps68470-clk";
-		cells[0].platform_data = clk_pdata;
-		cells[0].pdata_size = struct_size(clk_pdata, consumers, n_consumers);
-		cells[1].name = "tps68470-regulator";
-		cells[1].platform_data = (void *)board_data->tps68470_regulator_pdata;
-		cells[1].pdata_size = sizeof(struct tps68470_regulator_platform_data);
-		cells[2].name = "tps68470-gpio";
-
-		for (i = 0; i < board_data->n_gpiod_lookups; i++)
-			gpiod_add_lookup_table(board_data->tps68470_gpio_lookup_tables[i]);
-
-		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
-					   cells, TPS68470_WIN_MFD_CELL_COUNT,
-					   NULL, 0, NULL);
-		kfree(cells);
-
-		if (ret) {
-			for (i = 0; i < board_data->n_gpiod_lookups; i++)
-				gpiod_remove_lookup_table(board_data->tps68470_gpio_lookup_tables[i]);
-		}
-
 		break;
 	case DESIGNED_FOR_CHROMEOS:
-		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
-					   tps68470_cros, ARRAY_SIZE(tps68470_cros),
-					   NULL, 0, NULL);
-		break;
+		return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+					    tps68470_cros,
+					    ARRAY_SIZE(tps68470_cros),
+					    NULL, 0, NULL);
 	default:
 		dev_err(&client->dev, "Failed to add MFD devices\n");
 		return device_type;
 	}
 
+	if (!board_data)
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "No board-data found for this model\n");
+
+	cells = kzalloc_objs(*cells, TPS68470_WIN_MFD_CELL_COUNT);
+	if (!cells)
+		return -ENOMEM;
+
+	/*
+	 * The order of the cells matters here! The clk must be first
+	 * because the regulator depends on it. The gpios must be last,
+	 * acpi_gpiochip_add() calls acpi_dev_clear_dependencies() and
+	 * the clk + regulators must be ready when this happens.
+	 */
+	cells[0].name = "tps68470-clk";
+	cells[0].platform_data = clk_pdata;
+	cells[0].pdata_size = struct_size(clk_pdata, consumers, n_consumers);
+	cells[1].name = "tps68470-regulator";
+	cells[1].platform_data = (void *)board_data->tps68470_regulator_pdata;
+	cells[1].pdata_size = sizeof(struct tps68470_regulator_platform_data);
+	cells[2].name = "tps68470-gpio";
+
+	tables = board_data->tps68470_gpio_lookup_tables;
+	for (i = 0; i < board_data->n_gpiod_lookups; i++)
+		gpiod_add_lookup_table(tables[i]);
+
+	ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+				   cells, TPS68470_WIN_MFD_CELL_COUNT,
+				   NULL, 0, NULL);
+	kfree(cells);
+
+	if (ret) {
+		for (i = 0; i < board_data->n_gpiod_lookups; i++)
+			gpiod_remove_lookup_table(tables[i]);
+	}
+
 	/*
 	 * No acpi_dev_clear_dependencies() here, since the acpi_gpiochip_add()
 	 * for the GPIO cell already does this.
@@ -233,7 +258,7 @@ static int skl_int3472_tps68470_probe(struct i2c_client *client)
 static void skl_int3472_tps68470_remove(struct i2c_client *client)
 {
 	const struct int3472_tps68470_board_data *board_data;
-	int i;
+	unsigned int i;
 
 	board_data = int3472_tps68470_get_board_data(dev_name(&client->dev));
 	if (board_data) {
diff --git a/drivers/platform/x86/intel/int3472/tps68470.h b/drivers/platform/x86/intel/int3472/tps68470.h
index 35915e701..1d3d67459 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