This driver supports STMicroelectronics STM32 VREFBUF (voltage
reference buffer) which can be used as voltage reference for
internal ADCs, DACs and also for external components through
dedicated Vref+ pin. Ported from Linux v5.11-rc1.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
arch/arm/dts/stm32mp151.dtsi | 4 +
drivers/regulator/Kconfig | 9 ++
drivers/regulator/Makefile | 1 +
drivers/regulator/helpers.c | 25 ++++
drivers/regulator/stm32-vrefbuf.c | 220 ++++++++++++++++++++++++++++++
include/regulator.h | 5 +
6 files changed, 264 insertions(+)
create mode 100644 drivers/regulator/stm32-vrefbuf.c
diff --git a/arch/arm/dts/stm32mp151.dtsi b/arch/arm/dts/stm32mp151.dtsi
index ca11492de564..b82227fa206e 100644
--- a/arch/arm/dts/stm32mp151.dtsi
+++ b/arch/arm/dts/stm32mp151.dtsi
@@ -62,3 +62,7 @@
&bsec {
barebox,provide-mac-address = <ðernet0 0x39>;
};
+
+&vrefbuf {
+ regulator-name = "vref";
+};
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 1ce057180a01..9be81832f23d 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -28,6 +28,15 @@ config REGULATOR_STM32_PWR
This driver supports internal regulators (1V1, 1V8, 3V3) in the
STMicroelectronics STM32 chips.
+config REGULATOR_STM32_VREFBUF
+ tristate "STMicroelectronics STM32 VREFBUF"
+ depends on ARCH_STM32MP || COMPILE_TEST
+ help
+ This driver supports STMicroelectronics STM32 VREFBUF (voltage
+ reference buffer) which can be used as voltage reference for
+ internal ADCs, DACs and also for external components through
+ dedicated Vref+ pin.
+
config REGULATOR_STPMIC1
tristate "STMicroelectronics STPMIC1 PMIC Regulators"
depends on MFD_STPMIC1
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 4d0bba6c52dd..67859bb79ee4 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_REGULATOR_PFUZE) += pfuze.o
obj-$(CONFIG_REGULATOR_STPMIC1) += stpmic1_regulator.o
obj-$(CONFIG_REGULATOR_ANATOP) += anatop-regulator.o
obj-$(CONFIG_REGULATOR_STM32_PWR) += stm32-pwr.o
+obj-$(CONFIG_REGULATOR_STM32_VREFBUF) += stm32-vrefbuf.o
diff --git a/drivers/regulator/helpers.c b/drivers/regulator/helpers.c
index c4877cecf7e9..e741944ce7cf 100644
--- a/drivers/regulator/helpers.c
+++ b/drivers/regulator/helpers.c
@@ -369,4 +369,29 @@ int regulator_map_voltage_iterate(struct regulator_dev *rdev,
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_iterate);
+/**
+ * regulator_list_voltage_table - List voltages with table based mapping
+ *
+ * @rdev: Regulator device
+ * @selector: Selector to convert into a voltage
+ *
+ * Regulators with table based mapping between voltages and
+ * selectors can set volt_table in the regulator descriptor
+ * and then use this function as their list_voltage() operation.
+ */
+int regulator_list_voltage_table(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ if (!rdev->desc->volt_table) {
+ BUG_ON(!rdev->desc->volt_table);
+ return -EINVAL;
+ }
+ if (selector >= rdev->desc->n_voltages)
+ return -EINVAL;
+ if (selector < rdev->desc->linear_min_sel)
+ return 0;
+
+ return rdev->desc->volt_table[selector];
+}
+EXPORT_SYMBOL_GPL(regulator_list_voltage_table);
diff --git a/drivers/regulator/stm32-vrefbuf.c b/drivers/regulator/stm32-vrefbuf.c
new file mode 100644
index 000000000000..3956b1f64f6e
--- /dev/null
+++ b/drivers/regulator/stm32-vrefbuf.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) STMicroelectronics 2017
+ *
+ * Author: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
+ */
+
+#include <common.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <of.h>
+#include <regulator.h>
+
+/* STM32 VREFBUF registers */
+#define STM32_VREFBUF_CSR 0x00
+
+/* STM32 VREFBUF CSR bitfields */
+#define STM32_VRS GENMASK(6, 4)
+#define STM32_VRR BIT(3)
+#define STM32_HIZ BIT(1)
+#define STM32_ENVR BIT(0)
+
+#define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10
+
+#define readl_relaxed readl
+#define writel_relaxed writel
+
+struct stm32_vrefbuf {
+ void __iomem *base;
+ struct clk *clk;
+ struct device_d *dev;
+ struct regulator_dev rdev;
+};
+
+struct stm32_vrefbuf_desc {
+ struct regulator_desc desc;
+ const char *supply_name;
+};
+
+static inline struct stm32_vrefbuf *to_stm32_vrefbuf(struct regulator_dev *rdev)
+{
+ return container_of(rdev, struct stm32_vrefbuf, rdev);
+}
+
+static const unsigned int stm32_vrefbuf_voltages[] = {
+ /* Matches resp. VRS = 000b, 001b, 010b, 011b */
+ 2500000, 2048000, 1800000, 1500000,
+};
+
+static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
+{
+ struct stm32_vrefbuf *priv = to_stm32_vrefbuf(rdev);
+ u32 val;
+ int ret;
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ val = (val & ~STM32_HIZ) | STM32_ENVR;
+ writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
+
+ /*
+ * Vrefbuf startup time depends on external capacitor: wait here for
+ * VRR to be set. That means output has reached expected value.
+ * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
+ * arbitrary timeout.
+ */
+ ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
+ val & STM32_VRR, 10000);
+ if (ret) {
+ dev_err(priv->dev, "stm32 vrefbuf timed out!\n");
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ val = (val & ~STM32_ENVR) | STM32_HIZ;
+ writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
+ }
+
+ return ret;
+}
+
+static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
+{
+ struct stm32_vrefbuf *priv = to_stm32_vrefbuf(rdev);
+ u32 val;
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ val &= ~STM32_ENVR;
+ writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
+
+ return 0;
+}
+
+static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
+{
+ struct stm32_vrefbuf *priv = to_stm32_vrefbuf(rdev);
+ int ret;
+
+ ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
+
+ return ret;
+}
+
+static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
+ unsigned sel)
+{
+ struct stm32_vrefbuf *priv = to_stm32_vrefbuf(rdev);
+ u32 val;
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
+ writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
+
+ return 0;
+}
+
+static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct stm32_vrefbuf *priv = to_stm32_vrefbuf(rdev);
+ u32 val;
+ int ret;
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ ret = FIELD_GET(STM32_VRS, val);
+
+ return ret;
+}
+
+static const struct regulator_ops stm32_vrefbuf_volt_ops = {
+ .enable = stm32_vrefbuf_enable,
+ .disable = stm32_vrefbuf_disable,
+ .is_enabled = stm32_vrefbuf_is_enabled,
+ .get_voltage_sel = stm32_vrefbuf_get_voltage_sel,
+ .set_voltage_sel = stm32_vrefbuf_set_voltage_sel,
+ .list_voltage = regulator_list_voltage_table,
+};
+
+static const struct stm32_vrefbuf_desc stm32_vrefbuf_regu = {
+ .desc = {
+ .volt_table = stm32_vrefbuf_voltages,
+ .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages),
+ .ops = &stm32_vrefbuf_volt_ops,
+ .off_on_delay = 1000,
+ },
+ .supply_name = "vdda",
+};
+
+static int stm32_vrefbuf_probe(struct device_d *dev)
+{
+ struct stm32_vrefbuf *priv;
+ struct regulator_dev *rdev;
+ struct regulator *supply;
+ int ret;
+
+ supply = regulator_get(dev, stm32_vrefbuf_regu.supply_name);
+ if (IS_ERR(supply))
+ return PTR_ERR(supply);
+
+ priv = xzalloc(sizeof(*priv));
+ priv->dev = dev;
+
+ priv->base = dev_request_mem_region(dev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->clk = clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return PTR_ERR(priv->clk);
+
+ ret = clk_enable(priv->clk);
+ if (ret) {
+ dev_err(dev, "clk enable failed with error %d\n", ret);
+ return ret;
+ }
+
+ rdev = &priv->rdev;
+
+ rdev->dev = dev;
+ rdev->desc = &stm32_vrefbuf_regu.desc;
+
+ ret = of_regulator_register(rdev, dev->device_node);
+ if (ret) {
+ ret = PTR_ERR(rdev);
+ dev_err(dev, "register failed with error %d\n", ret);
+ goto err_clk_dis;
+ }
+
+ regulator_enable(supply);
+
+ dev->priv = priv;
+
+ return 0;
+
+err_clk_dis:
+ clk_disable(priv->clk);
+
+ return ret;
+}
+
+static void stm32_vrefbuf_remove(struct device_d *dev)
+{
+ struct stm32_vrefbuf *priv = dev->priv;
+
+ clk_disable(priv->clk);
+};
+
+static const struct of_device_id __maybe_unused stm32_vrefbuf_of_match[] = {
+ { .compatible = "st,stm32-vrefbuf", },
+ {},
+};
+
+static struct driver_d stm32_vrefbuf_driver = {
+ .probe = stm32_vrefbuf_probe,
+ .name = "stm32-vrefbuf",
+ .remove = stm32_vrefbuf_remove,
+ .of_compatible = stm32_vrefbuf_of_match,
+};
+device_platform_driver(stm32_vrefbuf_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@xxxxxx>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 VREFBUF driver");
+MODULE_ALIAS("platform:stm32-vrefbuf");
diff --git a/include/regulator.h b/include/regulator.h
index 83a8813265ff..bbe8dd91d84b 100644
--- a/include/regulator.h
+++ b/include/regulator.h
@@ -51,6 +51,7 @@ struct regulator_bulk_data {
* @disable_val: Disabling value for control when using regmap enable/disable ops
* @enable_is_inverted: A flag to indicate set enable_mask bits to disable
* when using regulator_enable_regmap and friends APIs.
+ * @volt_table: Voltage mapping table (if table based mapping)
* @fixed_uV: Fixed voltage of rails.
* @off_on_delay: guard time (in uS), before re-enabling a regulator
*/
@@ -75,6 +76,7 @@ struct regulator_desc {
const struct regulator_linear_range *linear_ranges;
int n_linear_ranges;
+ const unsigned int *volt_table;
int fixed_uV;
unsigned int off_on_delay;
};
@@ -190,6 +192,9 @@ int regulator_get_voltage(struct regulator *regulator);
*/
int regulator_desc_list_voltage_linear_range(const struct regulator_desc *desc,
unsigned int selector);
+
+int regulator_list_voltage_table(struct regulator_dev *rdev,
+ unsigned int selector);
#else
static inline struct regulator *regulator_get(struct device_d *dev, const char *id)
--
2.30.0
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