Message-Id: <20220801044758.12679-2-samuel@sholland.org>
Date:   Sun, 31 Jul 2022 23:47:58 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Samuel Holland <samuel@...lland.org>, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...ts.linux.dev
Subject: [PATCH 2/2] regulator: sun20i: Add support for Allwinner D1 LDOs

D1 contains two pairs of LDOs. Since they have similar bindings, and
they always exist together, put them in a single driver.

The analog LDOs are relatively boring, with a single linear range. The
one quirk is that their bandgap reference must be calibrated for them to
produce the correct voltage.

The system LDOs have the complication that their voltage step is not an
integer, so a custom .list_voltage is needed to get the rounding right.

Signed-off-by: Samuel Holland <samuel@...lland.org>
---

 drivers/regulator/Kconfig            |   8 +
 drivers/regulator/Makefile           |   1 +
 drivers/regulator/sun20i-regulator.c | 244 +++++++++++++++++++++++++++
 3 files changed, 253 insertions(+)
 create mode 100644 drivers/regulator/sun20i-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index cbe0f96ca342..20a22f900bb2 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -1234,6 +1234,14 @@ config REGULATOR_STW481X_VMMC
 	  This driver supports the internal VMMC regulator in the STw481x
 	  PMIC chips.
 
+config REGULATOR_SUN20I
+	tristate "Allwinner D1 internal LDOs"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	depends on MFD_SYSCON && NVMEM
+	default ARCH_SUNXI
+	help
+	  This driver supports the internal LDOs in the Allwinner D1 SoC.
+
 config REGULATOR_SY7636A
 	tristate "Silergy SY7636A voltage regulator"
 	help
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 8d3ee8b6d41d..cb3ac9290fc3 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -145,6 +145,7 @@ obj-$(CONFIG_REGULATOR_STM32_VREFBUF) += stm32-vrefbuf.o
 obj-$(CONFIG_REGULATOR_STM32_PWR) += stm32-pwr.o
 obj-$(CONFIG_REGULATOR_STPMIC1) += stpmic1_regulator.o
 obj-$(CONFIG_REGULATOR_STW481X_VMMC) += stw481x-vmmc.o
+obj-$(CONFIG_REGULATOR_SUN20I) += sun20i-regulator.o
 obj-$(CONFIG_REGULATOR_SY7636A) += sy7636a-regulator.o
 obj-$(CONFIG_REGULATOR_SY8106A) += sy8106a-regulator.o
 obj-$(CONFIG_REGULATOR_SY8824X) += sy8824x.o
diff --git a/drivers/regulator/sun20i-regulator.c b/drivers/regulator/sun20i-regulator.c
new file mode 100644
index 000000000000..c4d075440249
--- /dev/null
+++ b/drivers/regulator/sun20i-regulator.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright (c) 2021-2022 Samuel Holland <samuel@...lland.org>
+//
+
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+
+#define SUN20I_POWER_REG		0x348
+
+#define SUN20I_SYS_LDO_CTRL_REG		0x150
+
+struct sun20i_regulator_data {
+	int				(*init)(struct device *dev,
+						struct regmap *regmap);
+	const struct regulator_desc	*descs;
+	unsigned int			ndescs;
+};
+
+static int sun20i_d1_analog_ldos_init(struct device *dev, struct regmap *regmap)
+{
+	u8 bg_trim;
+	int ret;
+
+	ret = nvmem_cell_read_u8(dev, "bg_trim", &bg_trim);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get bg_trim value\n");
+
+	/* The default value corresponds to 900 mV. */
+	if (!bg_trim)
+		bg_trim = 0x19;
+
+	return regmap_update_bits(regmap, SUN20I_POWER_REG,
+				  GENMASK(7, 0), bg_trim);
+}
+
+static const struct regulator_ops sun20i_d1_analog_ldo_ops = {
+	.list_voltage		= regulator_list_voltage_linear,
+	.map_voltage		= regulator_map_voltage_linear,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+	.enable			= regulator_enable_regmap,
+	.disable		= regulator_disable_regmap,
+	.is_enabled		= regulator_is_enabled_regmap,
+};
+
+static const struct regulator_desc sun20i_d1_analog_ldo_descs[] = {
+	{
+		.name		= "aldo",
+		.supply_name	= "vdd33",
+		.of_match	= "aldo",
+		.ops		= &sun20i_d1_analog_ldo_ops,
+		.type		= REGULATOR_VOLTAGE,
+		.owner		= THIS_MODULE,
+		.n_voltages	= BIT(3),
+		.min_uV		= 1650000,
+		.uV_step	= 50000,
+		.vsel_reg	= SUN20I_POWER_REG,
+		.vsel_mask	= GENMASK(14, 12),
+		.enable_reg	= SUN20I_POWER_REG,
+		.enable_mask	= BIT(31),
+	},
+	{
+		.name		= "hpldo",
+		.supply_name	= "hpldoin",
+		.of_match	= "hpldo",
+		.ops		= &sun20i_d1_analog_ldo_ops,
+		.type		= REGULATOR_VOLTAGE,
+		.owner		= THIS_MODULE,
+		.n_voltages	= BIT(3),
+		.min_uV		= 1650000,
+		.uV_step	= 50000,
+		.vsel_reg	= SUN20I_POWER_REG,
+		.vsel_mask	= GENMASK(10, 8),
+		.enable_reg	= SUN20I_POWER_REG,
+		.enable_mask	= BIT(30),
+	},
+};
+
+static const struct sun20i_regulator_data sun20i_d1_analog_ldos = {
+	.init	= sun20i_d1_analog_ldos_init,
+	.descs	= sun20i_d1_analog_ldo_descs,
+	.ndescs	= ARRAY_SIZE(sun20i_d1_analog_ldo_descs),
+};
+
+/* regulator_list_voltage_linear() modified for the non-integral uV_step. */
+static int sun20i_d1_system_ldo_list_voltage(struct regulator_dev *rdev,
+					     unsigned int selector)
+{
+	const struct regulator_desc *desc = rdev->desc;
+	unsigned int uV;
+
+	if (selector >= desc->n_voltages)
+		return -EINVAL;
+
+	uV = desc->min_uV + (desc->uV_step * selector);
+
+	/* Produce correctly-rounded absolute voltages. */
+	return uV + ((selector + 1 + (desc->min_uV % 4)) / 3);
+}
+
+static const struct regulator_ops sun20i_d1_system_ldo_ops = {
+	.list_voltage		= sun20i_d1_system_ldo_list_voltage,
+	.map_voltage		= regulator_map_voltage_ascend,
+	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
+	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
+};
+
+static const struct regulator_desc sun20i_d1_system_ldo_descs[] = {
+	{
+		.name		= "ldoa",
+		.supply_name	= "ldo-in",
+		.of_match	= "ldoa",
+		.ops		= &sun20i_d1_system_ldo_ops,
+		.type		= REGULATOR_VOLTAGE,
+		.owner		= THIS_MODULE,
+		.n_voltages	= BIT(5),
+		.min_uV		= 1600000,
+		.uV_step	= 13333, /* repeating */
+		.vsel_reg	= SUN20I_SYS_LDO_CTRL_REG,
+		.vsel_mask	= GENMASK(7, 0),
+	},
+	{
+		.name		= "ldob",
+		.supply_name	= "ldo-in",
+		.of_match	= "ldob",
+		.ops		= &sun20i_d1_system_ldo_ops,
+		.type		= REGULATOR_VOLTAGE,
+		.owner		= THIS_MODULE,
+		.n_voltages	= BIT(6),
+		.min_uV		= 1166666,
+		.uV_step	= 13333, /* repeating */
+		.vsel_reg	= SUN20I_SYS_LDO_CTRL_REG,
+		.vsel_mask	= GENMASK(15, 8),
+	},
+};
+
+static const struct sun20i_regulator_data sun20i_d1_system_ldos = {
+	.descs	= sun20i_d1_system_ldo_descs,
+	.ndescs	= ARRAY_SIZE(sun20i_d1_system_ldo_descs),
+};
+
+static const struct of_device_id sun20i_regulator_of_match[] = {
+	{
+		.compatible = "allwinner,sun20i-d1-analog-ldos",
+		.data = &sun20i_d1_analog_ldos,
+	},
+	{
+		.compatible = "allwinner,sun20i-d1-system-ldos",
+		.data = &sun20i_d1_system_ldos,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sun20i_regulator_of_match);
+
+static struct regmap *sun20i_regulator_get_regmap(struct device *dev)
+{
+	struct platform_device *syscon_pdev;
+	struct device_node *syscon_node;
+	struct regmap *regmap;
+
+	/*
+	 * First try the syscon interface. The system control device is not
+	 * compatible with "syscon", so fall back to getting the regmap from
+	 * its platform device. This is ugly, but required for devicetree
+	 * backward compatibility.
+	 */
+	regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
+	if (!IS_ERR(regmap))
+		return regmap;
+
+	syscon_node = of_parse_phandle(dev->of_node, "syscon", 0);
+	if (!syscon_node)
+		return ERR_PTR(-ENODEV);
+
+	syscon_pdev = of_find_device_by_node(syscon_node);
+	of_node_put(syscon_node);
+	if (!syscon_pdev)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	regmap = dev_get_regmap(&syscon_pdev->dev, NULL);
+	platform_device_put(syscon_pdev);
+	if (!regmap)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return regmap;
+}
+
+static int sun20i_regulator_probe(struct platform_device *pdev)
+{
+	const struct sun20i_regulator_data *data;
+	struct device *dev = &pdev->dev;
+	struct regulator_config config;
+	struct regmap *regmap;
+	int ret;
+
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return -EINVAL;
+
+	regmap = sun20i_regulator_get_regmap(dev);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to get regmap\n");
+
+	if (data->init) {
+		ret = data->init(dev, regmap);
+		if (ret)
+			return ret;
+	}
+
+	config = (struct regulator_config) {
+		.dev	= dev,
+		.regmap	= regmap,
+	};
+
+	for (unsigned int i = 0; i < data->ndescs; ++i) {
+		const struct regulator_desc *desc = &data->descs[i];
+		struct regulator_dev *rdev;
+
+		rdev = devm_regulator_register(dev, desc, &config);
+		if (IS_ERR(rdev))
+			return PTR_ERR(rdev);
+	}
+
+	return 0;
+}
+
+static struct platform_driver sun20i_regulator_driver = {
+	.probe	= sun20i_regulator_probe,
+	.driver	= {
+		.name		= "sun20i-regulator",
+		.of_match_table	= sun20i_regulator_of_match,
+	},
+};
+module_platform_driver(sun20i_regulator_driver);
+
+MODULE_AUTHOR("Samuel Holland <samuel@...lland.org>");
+MODULE_DESCRIPTION("Allwinner D1 internal LDO driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1

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