From: Peter Vasil <peter.vasil@xxxxxxxxx>
Nokia Tahvo/Betty ASIC is a companion chip for mobile devices. One of
its outputs is a Vcore adjustable voltage regulator.
Register control code has been written based on original Nokia kernel
sources for N810 display driver.
Driver expects a regmap device as parent, usually retu-mfd driver bound
to the Tahvo ASIC.
---
drivers/regulator/Kconfig | 8 ++
drivers/regulator/Makefile | 1 +
drivers/regulator/tahvo-vcore-regulator.c | 104 ++++++++++++++++++++++
3 files changed, 113 insertions(+)
create mode 100644 drivers/regulator/tahvo-vcore-regulator.c
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 6be9b1c8a615..16c684c742cf 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -1404,6 +1404,14 @@ config REGULATOR_WM8994
This driver provides support for the voltage regulators on the
WM8994 CODEC.
+config REGULATOR_TAHVO_VCORE
+ tristate "Tahvo/Betty Vcore regulator support"
+ depends on MFD_RETU
+ help
+ This driver supports Vcore voltage control on Nokia's Tahvo/Betty
+ ASIC chip. The regulator controls framebuffer supply voltage in
+ Nokia internet tablets (for sure at least N810).
+
config REGULATOR_QCOM_LABIBB
tristate "QCOM LAB/IBB regulator support"
depends on SPMI || COMPILE_TEST
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index b07d2a22df0b..ed64d2cf8a42 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -170,5 +170,6 @@ obj-$(CONFIG_REGULATOR_WM831X) += wm831x-ldo.o
obj-$(CONFIG_REGULATOR_WM8350) += wm8350-regulator.o
obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
obj-$(CONFIG_REGULATOR_WM8994) += wm8994-regulator.o
+obj-$(CONFIG_REGULATOR_TAHVO_VCORE) += tahvo-vcore-regulator.o
ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG
diff --git a/drivers/regulator/tahvo-vcore-regulator.c b/drivers/regulator/tahvo-vcore-regulator.c
new file mode 100644
index 000000000000..a7c92aa7a148
--- /dev/null
+++ b/drivers/regulator/tahvo-vcore-regulator.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright (C) 2004, 2005 Nokia Corporation
+//
+// Based on original 2.6 kernel driver for Nokia N8x0 LCD panel.
+// Rewritten in 2021 by Peter Vasil <petervasil@xxxxxxxxx>.
+//
+// Driver for Nokia Betty/Tahvo Vcore regulator
+// The only known voltages are currently 1.005V==0x0f and 1.475V==0x00 with mask 0x0f
+// Whether the sequence is actually linear is only a guess.
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+#define TAHVO_REG_VCORE 0x07
+
+// Values in this table are simply interpolated from the only known min/max.
+static const unsigned int tahvo_vcore_voltages[] = {
+ 1475000, 1443667, 1412333, 1381000, 1349667, 1318333, 1287000, 1255667,
+ 1224333, 1193000, 1161667, 1130333, 1099000, 1067667, 1036333, 1005000,
+};
+
+static const struct regulator_ops tahvo_vcore_regulator_voltage_ops = {
+ .list_voltage = regulator_list_voltage_table,
+ .map_voltage = regulator_map_voltage_iterate,
+ .get_voltage_sel = regulator_get_voltage_sel_regmap,
+ .set_voltage_sel = regulator_set_voltage_sel_regmap,
+};
+
+static const struct regulator_desc vcore_regulator = {
+ .name = "vcore",
+ .ops = &tahvo_vcore_regulator_voltage_ops,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+ .volt_table = tahvo_vcore_voltages,
+ .n_voltages = ARRAY_SIZE(tahvo_vcore_voltages),
+ .vsel_reg = TAHVO_REG_VCORE,
+ .vsel_mask = 0x0f,
+};
+
+static const struct regmap_config tahvo_vcore_regmap_config = {
+ .reg_bits = 8,
+ .reg_stride = 1,
+ .val_bits = 16,
+};
+
+static int tahvo_vcore_regulator_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct regulator_init_data *init_data;
+ struct regulator_config cfg = {};
+ struct regulator_dev *rdev;
+
+ init_data = of_get_regulator_init_data(dev, dev->of_node,
+ &vcore_regulator);
+ if (!init_data) {
+ dev_err(dev, "Failed to init regulator data!\n");
+ return -EINVAL;
+ }
+
+ cfg.dev = dev;
+ cfg.init_data = init_data;
+ cfg.of_node = dev->of_node;
+
+ cfg.regmap = dev_get_regmap(dev->parent, NULL);
+ if (!cfg.regmap) {
+ dev_err(dev, "failed to locate regmap\n");
+ return -ENODEV;
+ }
+
+ rdev = devm_regulator_register(dev, &vcore_regulator, &cfg);
+ if (IS_ERR(rdev)) {
+ dev_err(dev, "Failed to register regulator: %ld\n",
+ PTR_ERR(rdev));
+ return PTR_ERR(rdev);
+ }
+ platform_set_drvdata(pdev, rdev);
+
+ return 0;
+}
+
+static const struct of_device_id regulator_tahvo_vcore_of_match[] = {
+ { .compatible = "nokia,tahvo-vcore-regulator", },
+ {},
+};
+
+static struct platform_driver tahvo_vcore_regulator_driver = {
+ .probe = tahvo_vcore_regulator_probe,
+ .driver = {
+ .name = "tahvo-vcore-regulator",
+ .of_match_table = of_match_ptr(regulator_tahvo_vcore_of_match),
+ },
+};
+module_platform_driver(tahvo_vcore_regulator_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Peter Vasil <petervasil@xxxxxxxxx>");
+MODULE_DESCRIPTION("Tahvo/Betty Vcore voltage regulator");
--
2.25.1
