mfd: intel_soc_pmic_chtwc: Add cht_wc_model data to struct intel_soc_pmic

Tablet / laptop designs using an Intel Cherry Trail x86 main SoC with
an Intel Whiskey Cove PMIC do not use a single standard setup for
the charger, fuel-gauge and other chips surrounding the PMIC /
charging+data USB port.

Unlike what is normal on x86 this diversity in designs is not handled
by the ACPI tables. On 2 of the 3 known designs there are no standard
(PNP0C0A) ACPI battery devices and on the 3th design the ACPI battery
device does not work under Linux due to it requiring non-standard
and undocumented ACPI behavior.

So to make things work under Linux we use native charger and fuel-gauge
drivers on these devices, re-using the native drivers used on ARM boards
with the same charger / fuel-gauge ICs.

This requires various MFD-cell drivers for the CHT-WC PMIC cells to
know which model they are exactly running on so that they can e.g.
instantiate an I2C-client for the right model charger-IC (the charger
is connected to an I2C-controller which is part of the PMIC).

Rather then duplicating DMI-id matching to check which model we are
running on in each MFD-cell driver, add a check for this to the
shared drivers/mfd/intel_soc_pmic_chtwc.c code by using a
DMI table for all 3 known models:

1. The GPD Win and GPD Pocket mini-laptops, these are really 2 models
but the Pocket re-uses the GPD Win's design in a different housing:

The WC PMIC is connected to a TI BQ24292i charger, paired with
a Maxim MAX17047 fuelgauge + a FUSB302 USB Type-C Controller +
a PI3USB30532 USB switch, for a fully functional Type-C port.

2. The Xiaomi Mi Pad 2:

The WC PMIC is connected to a TI BQ25890 charger, paired with
a TI BQ27520 fuelgauge, using the TI BQ25890 for BC1.2 charger type
detection, for a USB-2 only Type-C port without PD.

3. The Lenovo Yoga Book YB1-X90 / Lenovo Yoga Book YB1-X91 series:

The WC PMIC is connected to a TI BQ25892 charger, paired with
a TI BQ27542 fuelgauge, using the WC PMIC for BC1.2 charger type
detection and using the BQ25892's Mediatek Pump Express+ (1.0)
support to enable charging with up to 12V through a micro-USB port.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/mfd/intel_soc_pmic_chtwc.c

@@ -10,6 +10,7 @@
 
 #include <linux/acpi.h>
 #include <linux/delay.h>
+#include <linux/dmi.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -134,9 +135,44 @@ static const struct regmap_irq_chip cht_wc_regmap_irq_chip = {
 	.num_regs = 1,
 };
 
+static const struct dmi_system_id cht_wc_model_dmi_ids[] = {
+	{
+		/* GPD win / GPD pocket mini laptops */
+		.driver_data = (void *)(long)INTEL_CHT_WC_GPD_WIN_POCKET,
+		/*
+		 * This DMI match may not seem unique, but it is. In the 67000+
+		 * DMI decode dumps from linux-hardware.org only 116 have
+		 * board_vendor set to "AMI Corporation" and of those 116 only
+		 * the GPD win's and pocket's board_name is "Default string".
+		 */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_BOARD_VENDOR, "AMI Corporation"),
+			DMI_EXACT_MATCH(DMI_BOARD_NAME, "Default string"),
+			DMI_EXACT_MATCH(DMI_BOARD_SERIAL, "Default string"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Default string"),
+		},
+	}, {
+		/* Xiaomi Mi Pad 2 */
+		.driver_data = (void *)(long)INTEL_CHT_WC_XIAOMI_MIPAD2,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Xiaomi Inc"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Mipad2"),
+		},
+	}, {
+		/* Lenovo Yoga Book X90F / X91F / X91L */
+		.driver_data = (void *)(long)INTEL_CHT_WC_LENOVO_YOGABOOK1,
+		.matches = {
+			/* Non exact match to match all versions */
+			DMI_MATCH(DMI_PRODUCT_NAME, "Lenovo YB1-X9"),
+		},
+	},
+	{ }
+};
+
 static int cht_wc_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
+	const struct dmi_system_id *id;
 	struct intel_soc_pmic *pmic;
 	acpi_status status;
 	unsigned long long hrv;
@@ -160,6 +196,10 @@ static int cht_wc_probe(struct i2c_client *client)
 	if (!pmic)
 		return -ENOMEM;
 
+	id = dmi_first_match(cht_wc_model_dmi_ids);
+	if (id)
+		pmic->cht_wc_model = (long)id->driver_data;
+
 	pmic->irq = client->irq;
 	pmic->dev = dev;
 	i2c_set_clientdata(client, pmic);

include/linux/mfd/intel_soc_pmic.h

@@ -13,6 +13,13 @@
 
 #include <linux/regmap.h>
 
+enum intel_cht_wc_models {
+	INTEL_CHT_WC_UNKNOWN,
+	INTEL_CHT_WC_GPD_WIN_POCKET,
+	INTEL_CHT_WC_XIAOMI_MIPAD2,
+	INTEL_CHT_WC_LENOVO_YOGABOOK1,
+};
+
 /**
  * struct intel_soc_pmic - Intel SoC PMIC data
  * @irq: Master interrupt number of the parent PMIC device
@@ -39,6 +46,7 @@ struct intel_soc_pmic {
 	struct regmap_irq_chip_data *irq_chip_data_crit;
 	struct device *dev;
 	struct intel_scu_ipc_dev *scu;
+	enum intel_cht_wc_models cht_wc_model;
 };
 
 int intel_soc_pmic_exec_mipi_pmic_seq_element(u16 i2c_address, u32 reg_address,