Re: [PATCH v4 7/8] platform/x86: Add intel_skl_int3472 driver

+INTEL SKYLAKE INT3472 ACPI DEVICE DRIVER
+M:	Daniel Scally <djrscally@gmail.com>
+S:	Maintained
+F:	drivers/platform/x86/intel-int3472/intel_skl_int3472_*

+	help
+	  This driver adds support for the INT3472 ACPI devices found on some
+	  Intel SkyLake devices.

+	  hardware devices depending on the platform. On machines
+	  designed for Chrome OS, it maps to a TPS68470 camera PMIC. On
+	  machines designed for Windows, it maps to either a TP68470
+	  camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs
+	  and power gates.
+
+	  If your device was designed for Chrome OS, this driver will provide
+	  an ACPI OpRegion, which must be available before any of the devices
+	  using it are probed. For this reason, you should select Y if your
+	  device was designed for ChromeOS. For the same reason the
+	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
+
+	  Say Y or M here if you have a SkyLake device designed for use
+	  with Windows or ChromeOS. Say N here if you are not sure.
+
+	  The module will be named "intel-skl-int3472"

+/*
+ * The regulators have to have .ops to be valid, but the only ops we actually
+ * support are .enable and .disable which are handled via .ena_gpiod. Pass an
+ * empty struct to clear the check without lying about capabilities.
+ */
+static const struct regulator_ops int3472_gpio_regulator_ops;

+static int skl_int3472_clk_prepare(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value(clk->ena_gpio, 1);
+	gpiod_set_value(clk->led_gpio, 1);
+
+	return 0;
+}
+
+static void skl_int3472_clk_unprepare(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value(clk->ena_gpio, 0);
+	gpiod_set_value(clk->led_gpio, 0);
+}
+
+static int skl_int3472_clk_enable(struct clk_hw *hw)
+{
+	/*
+	 * We're just turning a GPIO on to enable the clock, which operation
+	 * has the potential to sleep. Given .enable() cannot sleep, but
+	 * .prepare() can, we toggle the GPIO in .prepare() instead. Thus,
+	 * nothing to do here.
+	 */

+static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
+{
+	union acpi_object *obj;
+	unsigned int freq;
+
+	obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
+	if (IS_ERR(obj))
+		return 0; /* report rate as 0 on error */
+
+	if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
+		dev_err(int3472->dev, "The buffer is too small\n");

+	}
+
+	freq = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
+
+out_free_buff:
+	kfree(obj);
+	return freq;
+}

+int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
+{
+	struct clk_init_data init = {
+		.ops = &skl_int3472_clock_ops,
+		.flags = CLK_GET_RATE_NOCACHE,
+	};

+	init.name = kasprintf(GFP_KERNEL, "%s-clk",
+			      acpi_dev_name(int3472->adev));
+	if (!init.name)
+		return -ENOMEM;
+
+	int3472->clock.frequency = skl_int3472_get_clk_frequency(int3472);
+
+	int3472->clock.clk_hw.init = &init;
+	int3472->clock.clk = clk_register(&int3472->adev->dev,
+					  &int3472->clock.clk_hw);
+	if (IS_ERR(int3472->clock.clk)) {
+		ret = PTR_ERR(int3472->clock.clk);
+		goto out_free_init_name;
+	}
+
+	int3472->clock.cl = clkdev_create(int3472->clock.clk, NULL,
+					  int3472->sensor_name);
+	if (!int3472->clock.cl) {
+		ret = -ENOMEM;
+		goto err_unregister_clk;
+	}

+err_unregister_clk:
+	clk_unregister(int3472->clock.clk);
+out_free_init_name:
+	kfree(init.name);
+
+	return ret;
+}

+int skl_int3472_fill_cldb(struct acpi_device *adev, struct int3472_cldb *cldb)
+{
+	union acpi_object *obj;

+	obj = skl_int3472_get_acpi_buffer(adev, "CLDB");
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	if (obj->buffer.length > sizeof(*cldb)) {
+		acpi_handle_err(adev->handle, "The CLDB buffer is too large\n");
+		ret = -EINVAL;
+		goto out_free_obj;
+	}
+
+	memcpy(cldb, obj->buffer.pointer, obj->buffer.length);

+out_free_obj:
+	kfree(obj);
+	return ret;
+}

+static const struct int3472_sensor_config *
+skl_int3472_get_sensor_module_config(struct int3472_discrete_device *int3472)
+{
+	const struct int3472_sensor_config *ret;
+	union acpi_object *obj;
+	unsigned int i;
+
+	obj = acpi_evaluate_dsm_typed(int3472->sensor->handle,
+				      &cio2_sensor_module_guid, 0x00,
+				      0x01, NULL, ACPI_TYPE_STRING);
+
+	if (!obj) {
+		dev_err(int3472->dev,
+			"Failed to get sensor module string from _DSM\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	if (obj->string.type != ACPI_TYPE_STRING) {
+		dev_err(int3472->dev,
+			"Sensor _DSM returned a non-string value\n");
+		ret = ERR_PTR(-EINVAL);
+		goto out_free_obj;
+	}

+	ret = ERR_PTR(-EINVAL);
+	for (i = 0; i < ARRAY_SIZE(int3472_sensor_configs); i++) {
+		if (!strcmp(int3472_sensor_configs[i].sensor_module_name,
+			    obj->string.pointer)) {
+			ret = &int3472_sensor_configs[i];
+			break;
+		}
+	}

+out_free_obj:
+	ACPI_FREE(obj);
+	return ret;

+ * * -EINVAL	- If the resource is not a GPIO IO resource
+ * * -ENODEV	- If the resource has no corresponding _DSM entry
+ * * -Other	- Errors propagated from one of the sub-functions.

+	/*
+	 * n_gpios + 2 because the index of this _DSM function is 1-based and
+	 * the first function is just a count.
+	 */
+	obj = acpi_evaluate_dsm_typed(int3472->adev->handle,
+				      &int3472_gpio_guid, 0x00,
+				      int3472->n_gpios + 2,
+				      NULL, ACPI_TYPE_INTEGER);

+	if (int3472->clock.ena_gpio) {
+		ret = skl_int3472_register_clock(int3472);
+		if (ret)
+			goto out_free_res_list;
+	} else {

+		if (int3472->clock.led_gpio)
+			dev_warn(int3472->dev,
+				 "No clk GPIO. The privacy LED won't work\n");
+	}

+	ret = skl_int3472_fill_cldb(adev, &cldb);
+	if (!ret && cldb.control_logic_type != 2) {
+		dev_err(&client->dev, "Unsupported control logic type %u\n",
+			cldb.control_logic_type);
+		return -EINVAL;
+	}