1// SPDX-License-Identifier: GPL-2.0-only
  2//
  3// Copyright (c) 2021-2022 Samuel Holland <samuel@sholland.org>
  4//
  5
  6#include <linux/mfd/syscon.h>
  7#include <linux/module.h>
  8#include <linux/of.h>
  9#include <linux/of_device.h>
 10#include <linux/platform_device.h>
 11#include <linux/regmap.h>
 12#include <linux/regulator/driver.h>
 13
 14#define SUN20I_SYS_LDO_CTRL_REG		0x150
 15
 16struct sun20i_regulator_data {
 17	const struct regulator_desc	*descs;
 18	unsigned int			ndescs;
 19};
 20
 21/* regulator_list_voltage_linear() modified for the non-integral uV_step. */
 22static int sun20i_d1_system_ldo_list_voltage(struct regulator_dev *rdev,
 23					     unsigned int selector)
 24{
 25	const struct regulator_desc *desc = rdev->desc;
 26	unsigned int fraction, uV;
 27
 28	if (selector >= desc->n_voltages)
 29		return -EINVAL;
 30
 31	uV = desc->min_uV + (desc->uV_step * selector);
 32	fraction = selector + (desc->min_uV % 4);
 33
 34	if (uV > 1606667)
 35		uV += 6667;
 36	else
 37		fraction++;
 38
 39	/* Produce correctly-rounded absolute voltages. */
 40	return uV + (fraction / 3);
 41}
 42
 43static const struct regulator_ops sun20i_d1_system_ldo_ops = {
 44	.list_voltage		= sun20i_d1_system_ldo_list_voltage,
 45	.map_voltage		= regulator_map_voltage_ascend,
 46	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
 47	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
 48};
 49
 50static const struct regulator_desc sun20i_d1_system_ldo_descs[] = {
 51	{
 52		.name		= "ldoa",
 53		.supply_name	= "ldo-in",
 54		.of_match	= "ldoa",
 55		.ops		= &sun20i_d1_system_ldo_ops,
 56		.type		= REGULATOR_VOLTAGE,
 57		.owner		= THIS_MODULE,
 58		.n_voltages	= 32,
 59		.min_uV		= 1593333,
 60		.uV_step	= 13333, /* repeating */
 61		.vsel_reg	= SUN20I_SYS_LDO_CTRL_REG,
 62		.vsel_mask	= GENMASK(7, 0),
 63	},
 64	{
 65		.name		= "ldob",
 66		.supply_name	= "ldo-in",
 67		.of_match	= "ldob",
 68		.ops		= &sun20i_d1_system_ldo_ops,
 69		.type		= REGULATOR_VOLTAGE,
 70		.owner		= THIS_MODULE,
 71		.n_voltages	= 64,
 72		.min_uV		= 1166666,
 73		.uV_step	= 13333, /* repeating */
 74		.vsel_reg	= SUN20I_SYS_LDO_CTRL_REG,
 75		.vsel_mask	= GENMASK(15, 8),
 76	},
 77};
 78
 79static const struct sun20i_regulator_data sun20i_d1_system_ldos = {
 80	.descs	= sun20i_d1_system_ldo_descs,
 81	.ndescs	= ARRAY_SIZE(sun20i_d1_system_ldo_descs),
 82};
 83
 84static struct regmap *sun20i_regulator_get_regmap(struct device *dev)
 85{
 86	struct regmap *regmap;
 87
 88	/*
 89	 * First try the syscon interface. The system control device is not
 90	 * compatible with "syscon", so fall back to getting the regmap from
 91	 * its platform device. This is ugly, but required for devicetree
 92	 * backward compatibility.
 93	 */
 94	regmap = syscon_node_to_regmap(dev->parent->of_node);
 95	if (!IS_ERR(regmap))
 96		return regmap;
 97
 98	regmap = dev_get_regmap(dev->parent, NULL);
 99	if (regmap)
100		return regmap;
101
102	return ERR_PTR(-EPROBE_DEFER);
103}
104
105static int sun20i_regulator_probe(struct platform_device *pdev)
106{
107	const struct sun20i_regulator_data *data;
108	struct device *dev = &pdev->dev;
109	struct regulator_config config;
110	struct regmap *regmap;
111
112	data = of_device_get_match_data(dev);
113	if (!data)
114		return -EINVAL;
115
116	regmap = sun20i_regulator_get_regmap(dev);
117	if (IS_ERR(regmap))
118		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to get regmap\n");
119
120	config = (struct regulator_config) {
121		.dev	= dev,
122		.regmap	= regmap,
123	};
124
125	for (unsigned int i = 0; i < data->ndescs; ++i) {
126		const struct regulator_desc *desc = &data->descs[i];
127		struct regulator_dev *rdev;
128
129		rdev = devm_regulator_register(dev, desc, &config);
130		if (IS_ERR(rdev))
131			return PTR_ERR(rdev);
132	}
133
134	return 0;
135}
136
137static const struct of_device_id sun20i_regulator_of_match[] = {
138	{
139		.compatible = "allwinner,sun20i-d1-system-ldos",
140		.data = &sun20i_d1_system_ldos,
141	},
142	{ },
143};
144MODULE_DEVICE_TABLE(of, sun20i_regulator_of_match);
145
146static struct platform_driver sun20i_regulator_driver = {
147	.probe	= sun20i_regulator_probe,
148	.driver	= {
149		.name		= "sun20i-regulator",
150		.of_match_table	= sun20i_regulator_of_match,
151	},
152};
153module_platform_driver(sun20i_regulator_driver);
154
155MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
156MODULE_DESCRIPTION("Allwinner D1 internal LDO driver");
157MODULE_LICENSE("GPL");