Modern Qualcomm SoCs have a REFGEN (reference voltage generator)
regulator, providing reference voltage to on-chip IP, like PHYs.

Add a driver to support toggling that regulator.

Signed-off-by: Konrad Dybcio <konrad.dyb...@linaro.org>
---
 drivers/regulator/Kconfig                 |  10 ++
 drivers/regulator/Makefile                |   1 +
 drivers/regulator/qcom-refgen-regulator.c | 154 ++++++++++++++++++++++++++++++
 3 files changed, 165 insertions(+)

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 2c2405024ace..ea5549d62825 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -978,6 +978,16 @@ config REGULATOR_PWM
          This driver supports PWM controlled voltage regulators. PWM
          duty cycle can increase or decrease the voltage.
 
+config REGULATOR_QCOM_REFGEN
+       tristate "Qualcomm REFGEN regulator driver"
+       depends on REGMAP
+       help
+         This driver supports the MMIO-mapped reference voltage regulator,
+         used internally by some PHYs on many Qualcomm SoCs.
+
+         Say M here if you want to include support for this regulator as
+         a module. The module will be named "qcom-refgen-regulator".
+
 config REGULATOR_QCOM_RPM
        tristate "Qualcomm RPM regulator driver"
        depends on MFD_QCOM_RPM
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index ebfa75379c20..a044ad20e202 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -107,6 +107,7 @@ obj-$(CONFIG_REGULATOR_MT6380)      += mt6380-regulator.o
 obj-$(CONFIG_REGULATOR_MT6397) += mt6397-regulator.o
 obj-$(CONFIG_REGULATOR_MTK_DVFSRC) += mtk-dvfsrc-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_LABIBB) += qcom-labibb-regulator.o
+obj-$(CONFIG_REGULATOR_QCOM_REFGEN) += qcom-refgen-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
diff --git a/drivers/regulator/qcom-refgen-regulator.c 
b/drivers/regulator/qcom-refgen-regulator.c
new file mode 100644
index 000000000000..4c442fa3f552
--- /dev/null
+++ b/drivers/regulator/qcom-refgen-regulator.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2017, 2019-2020, The Linux Foundation. All rights reserved.
+// Copyright (c) 2023, Linaro Limited
+
+#include <linux/bitfield.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 REFGEN_REG_BIAS_EN             0x08
+#define REFGEN_BIAS_EN_MASK            GENMASK(2, 0)
+ #define REFGEN_BIAS_EN_ENABLE         0x7
+ #define REFGEN_BIAS_EN_DISABLE                0x6
+
+#define REFGEN_REG_BG_CTRL             0x14
+#define REFGEN_BG_CTRL_MASK            GENMASK(2, 1)
+ #define REFGEN_BG_CTRL_ENABLE         0x3
+ #define REFGEN_BG_CTRL_DISABLE                0x2
+
+#define REFGEN_REG_PWRDWN_CTRL5                0x80
+#define REFGEN_PWRDWN_CTRL5_MASK       BIT(0)
+ #define REFGEN_PWRDWN_CTRL5_ENABLE    0x1
+
+static int qcom_sdm845_refgen_enable(struct regulator_dev *rdev)
+{
+       regmap_update_bits(rdev->regmap, REFGEN_REG_BG_CTRL, 
REFGEN_BG_CTRL_MASK,
+                          FIELD_PREP(REFGEN_BG_CTRL_MASK, 
REFGEN_BG_CTRL_ENABLE));
+
+       regmap_write(rdev->regmap, REFGEN_REG_BIAS_EN,
+                    FIELD_PREP(REFGEN_BIAS_EN_MASK, REFGEN_BIAS_EN_ENABLE));
+
+       return 0;
+}
+
+static int qcom_sdm845_refgen_disable(struct regulator_dev *rdev)
+{
+       regmap_write(rdev->regmap, REFGEN_REG_BIAS_EN,
+                    FIELD_PREP(REFGEN_BIAS_EN_MASK, REFGEN_BIAS_EN_DISABLE));
+
+       regmap_update_bits(rdev->regmap, REFGEN_REG_BG_CTRL, 
REFGEN_BG_CTRL_MASK,
+                          FIELD_PREP(REFGEN_BG_CTRL_MASK, 
REFGEN_BG_CTRL_DISABLE));
+
+       return 0;
+}
+
+static int qcom_sdm845_refgen_is_enabled(struct regulator_dev *rdev)
+{
+       u32 val;
+
+       regmap_read(rdev->regmap, REFGEN_REG_BG_CTRL, &val);
+       if (FIELD_GET(REFGEN_BG_CTRL_MASK, val) != REFGEN_BG_CTRL_ENABLE)
+               return 0;
+
+       regmap_read(rdev->regmap, REFGEN_REG_BIAS_EN, &val);
+       if (FIELD_GET(REFGEN_BIAS_EN_MASK, val) != REFGEN_BIAS_EN_ENABLE)
+               return 0;
+
+       return 1;
+}
+
+static struct regulator_desc sdm845_refgen_desc = {
+       .enable_time = 5,
+       .name = "refgen",
+       .owner = THIS_MODULE,
+       .type = REGULATOR_VOLTAGE,
+       .ops = &(struct regulator_ops) {
+               .enable         = qcom_sdm845_refgen_enable,
+               .disable        = qcom_sdm845_refgen_disable,
+               .is_enabled     = qcom_sdm845_refgen_is_enabled,
+       },
+};
+
+static struct regulator_desc sm8250_refgen_desc = {
+       .enable_reg = REFGEN_REG_PWRDWN_CTRL5,
+       .enable_mask = REFGEN_PWRDWN_CTRL5_MASK,
+       .enable_val = REFGEN_PWRDWN_CTRL5_ENABLE,
+       .disable_val = 0,
+       .enable_time = 5,
+       .name = "refgen",
+       .owner = THIS_MODULE,
+       .type = REGULATOR_VOLTAGE,
+       .ops = &(struct regulator_ops) {
+               .enable         = regulator_enable_regmap,
+               .disable        = regulator_disable_regmap,
+               .is_enabled     = regulator_is_enabled_regmap,
+       },
+};
+
+static const struct regmap_config qcom_refgen_regmap_config = {
+       .reg_bits = 32,
+       .reg_stride = 4,
+       .val_bits = 32,
+       .fast_io = true,
+};
+
+static int qcom_refgen_probe(struct platform_device *pdev)
+{
+       struct regulator_init_data *init_data;
+       struct regulator_config config = {};
+       const struct regulator_desc *rdesc;
+       struct device *dev = &pdev->dev;
+       struct regulator_dev *rdev;
+       struct regmap *regmap;
+       void __iomem *base;
+
+       rdesc = of_device_get_match_data(dev);
+       if (!rdesc)
+               return -ENODATA;
+
+       base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+
+       regmap = devm_regmap_init_mmio(dev, base, &qcom_refgen_regmap_config);
+       if (IS_ERR(regmap))
+               return PTR_ERR(regmap);
+
+       init_data = of_get_regulator_init_data(dev, dev->of_node, rdesc);
+       if (!init_data)
+               return -ENOMEM;
+
+       config.dev = dev;
+       config.init_data = init_data;
+       config.of_node = dev->of_node;
+       config.regmap = regmap;
+
+       rdev = devm_regulator_register(dev, rdesc, &config);
+       if (IS_ERR(rdev))
+               return PTR_ERR(rdev);
+
+       return 0;
+}
+
+static const struct of_device_id qcom_refgen_match_table[] = {
+       { .compatible = "qcom,sdm845-refgen-regulator", .data = 
&sdm845_refgen_desc },
+       { .compatible = "qcom,sm8250-refgen-regulator", .data = 
&sm8250_refgen_desc },
+       { }
+};
+
+static struct platform_driver qcom_refgen_driver = {
+       .probe = qcom_refgen_probe,
+       .driver = {
+               .name = "qcom-refgen-regulator",
+               .of_match_table = qcom_refgen_match_table,
+       },
+};
+module_platform_driver(qcom_refgen_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Qualcomm REFGEN regulator driver");

-- 
2.41.0

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