ACPI / PMIC: Add support for executing PMIC MIPI sequence elements

DSI LCD panels describe an initialization sequence in the Video BIOS
Tables using so called MIPI sequences. One possible element in these
sequences is a PMIC specific element of 15 bytes.

Although this is not really an ACPI opregion, the ACPI opregion code is the
closest thing we have. We need to have support for these PMIC specific MIPI
sequence elements somwhere. Since we already instantiate a special platform
device for Intel PMICs for the ACPI PMIC OpRegion handler to bind to,
with PMIC specific implementations of the OpRegion, the handling of MIPI
sequence PMIC elements fits very well in the ACPI PMIC OpRegion code.

This commit adds a new intel_soc_pmic_exec_mipi_pmic_seq_element()
function, which is to be backed by a PMIC specific
exec_mipi_pmic_seq_element callback. This function will be called by the
i915 code to execture MIPI sequence PMIC elements.
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190107111556.4510-2-hdegoede@redhat.com

drivers/acpi/pmic/intel_pmic.c

@@ -15,6 +15,7 @@
 
 #include <linux/export.h>
 #include <linux/acpi.h>
+#include <linux/mfd/intel_soc_pmic.h>
 #include <linux/regmap.h>
 #include <acpi/acpi_lpat.h>
 #include "intel_pmic.h"
@@ -36,6 +37,8 @@ struct intel_pmic_opregion {
 	struct intel_pmic_regs_handler_ctx ctx;
 };
 
+static struct intel_pmic_opregion *intel_pmic_opregion;
+
 static int pmic_get_reg_bit(int address, struct pmic_table *table,
 			    int count, int *reg, int *bit)
 {
@@ -304,6 +307,7 @@ int intel_pmic_install_opregion_handler(struct device *dev, acpi_handle handle,
 	}
 
 	opregion->data = d;
+	intel_pmic_opregion = opregion;
 	return 0;
 
 out_remove_thermal_handler:
@@ -319,3 +323,51 @@ int intel_pmic_install_opregion_handler(struct device *dev, acpi_handle handle,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(intel_pmic_install_opregion_handler);
+
+/**
+ * intel_soc_pmic_exec_mipi_pmic_seq_element - Execute PMIC MIPI sequence
+ * @i2c_address:  I2C client address for the PMIC
+ * @reg_address:  PMIC register address
+ * @value:        New value for the register bits to change
+ * @mask:         Mask indicating which register bits to change
+ *
+ * DSI LCD panels describe an initialization sequence in the i915 VBT (Video
+ * BIOS Tables) using so called MIPI sequences. One possible element in these
+ * sequences is a PMIC specific element of 15 bytes.
+ *
+ * This function executes these PMIC specific elements sending the embedded
+ * commands to the PMIC.
+ *
+ * Return 0 on success, < 0 on failure.
+ */
+int intel_soc_pmic_exec_mipi_pmic_seq_element(u16 i2c_address, u32 reg_address,
+					      u32 value, u32 mask)
+{
+	struct intel_pmic_opregion_data *d;
+	int ret;
+
+	if (!intel_pmic_opregion) {
+		pr_warn("%s: No PMIC registered\n", __func__);
+		return -ENXIO;
+	}
+
+	d = intel_pmic_opregion->data;
+
+	mutex_lock(&intel_pmic_opregion->lock);
+
+	if (d->exec_mipi_pmic_seq_element) {
+		ret = d->exec_mipi_pmic_seq_element(intel_pmic_opregion->regmap,
+						    i2c_address, reg_address,
+						    value, mask);
+	} else {
+		pr_warn("%s: Not implemented\n", __func__);
+		pr_warn("%s: i2c-addr: 0x%x reg-addr 0x%x value 0x%x mask 0x%x\n",
+			__func__, i2c_address, reg_address, value, mask);
+		ret = -EOPNOTSUPP;
+	}
+
+	mutex_unlock(&intel_pmic_opregion->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_soc_pmic_exec_mipi_pmic_seq_element);

drivers/acpi/pmic/intel_pmic.h

@@ -15,6 +15,8 @@ struct intel_pmic_opregion_data {
 	int (*update_aux)(struct regmap *r, int reg, int raw_temp);
 	int (*get_policy)(struct regmap *r, int reg, int bit, u64 *value);
 	int (*update_policy)(struct regmap *r, int reg, int bit, int enable);
+	int (*exec_mipi_pmic_seq_element)(struct regmap *r, u16 i2c_address,
+					  u32 reg_address, u32 value, u32 mask);
 	struct pmic_table *power_table;
 	int power_table_count;
 	struct pmic_table *thermal_table;

include/linux/mfd/intel_soc_pmic.h

@@ -26,4 +26,7 @@ struct intel_soc_pmic {
 	struct device *dev;
 };
 
+int intel_soc_pmic_exec_mipi_pmic_seq_element(u16 i2c_address, u32 reg_address,
+					      u32 value, u32 mask);
+
 #endif	/* __INTEL_SOC_PMIC_H__ */