1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2017, 2020-2021, The Linux Foundation. All rights reserved.
  4 */
  5
  6#include <linux/device.h>
  7#include <linux/module.h>
  8#include <linux/of.h>
  9#include <linux/of_platform.h>
 10#include <linux/nvmem-provider.h>
 11#include <linux/regmap.h>
 12
 13#define SDAM_MEM_START			0x40
 14#define REGISTER_MAP_ID			0x40
 15#define REGISTER_MAP_VERSION		0x41
 16#define SDAM_SIZE			0x44
 17#define SDAM_PBS_TRIG_SET		0xE5
 18#define SDAM_PBS_TRIG_CLR		0xE6
 19
 20struct sdam_chip {
 21	struct regmap			*regmap;
 22	struct nvmem_config		sdam_config;
 23	unsigned int			base;
 24	unsigned int			size;
 25};
 26
 27/* read only register offsets */
 28static const u8 sdam_ro_map[] = {
 29	REGISTER_MAP_ID,
 30	REGISTER_MAP_VERSION,
 31	SDAM_SIZE
 32};
 33
 34static bool sdam_is_valid(struct sdam_chip *sdam, unsigned int offset,
 35				size_t len)
 36{
 37	unsigned int sdam_mem_end = SDAM_MEM_START + sdam->size - 1;
 38
 39	if (!len)
 40		return false;
 41
 42	if (offset >= SDAM_MEM_START && offset <= sdam_mem_end
 43				&& (offset + len - 1) <= sdam_mem_end)
 44		return true;
 45	else if ((offset == SDAM_PBS_TRIG_SET || offset == SDAM_PBS_TRIG_CLR)
 46				&& (len == 1))
 47		return true;
 48
 49	return false;
 50}
 51
 52static bool sdam_is_ro(unsigned int offset, size_t len)
 53{
 54	int i;
 55
 56	for (i = 0; i < ARRAY_SIZE(sdam_ro_map); i++)
 57		if (offset <= sdam_ro_map[i] && (offset + len) > sdam_ro_map[i])
 58			return true;
 59
 60	return false;
 61}
 62
 63static int sdam_read(void *priv, unsigned int offset, void *val,
 64				size_t bytes)
 65{
 66	struct sdam_chip *sdam = priv;
 67	struct device *dev = sdam->sdam_config.dev;
 68	int rc;
 69
 70	if (!sdam_is_valid(sdam, offset, bytes)) {
 71		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
 72			offset, bytes);
 73		return -EINVAL;
 74	}
 75
 76	rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
 77	if (rc < 0)
 78		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
 79						offset, bytes, rc);
 80
 81	return rc;
 82}
 83
 84static int sdam_write(void *priv, unsigned int offset, void *val,
 85				size_t bytes)
 86{
 87	struct sdam_chip *sdam = priv;
 88	struct device *dev = sdam->sdam_config.dev;
 89	int rc;
 90
 91	if (!sdam_is_valid(sdam, offset, bytes)) {
 92		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
 93			offset, bytes);
 94		return -EINVAL;
 95	}
 96
 97	if (sdam_is_ro(offset, bytes)) {
 98		dev_err(dev, "Invalid write offset %#x len=%zd\n",
 99			offset, bytes);
100		return -EINVAL;
101	}
102
103	rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
104	if (rc < 0)
105		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
106						offset, bytes, rc);
107
108	return rc;
109}
110
111static int sdam_probe(struct platform_device *pdev)
112{
113	struct sdam_chip *sdam;
114	struct nvmem_device *nvmem;
115	unsigned int val;
116	int rc;
117
118	sdam = devm_kzalloc(&pdev->dev, sizeof(*sdam), GFP_KERNEL);
119	if (!sdam)
120		return -ENOMEM;
121
122	sdam->regmap = dev_get_regmap(pdev->dev.parent, NULL);
123	if (!sdam->regmap) {
124		dev_err(&pdev->dev, "Failed to get regmap handle\n");
125		return -ENXIO;
126	}
127
128	rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam->base);
129	if (rc < 0) {
130		dev_err(&pdev->dev, "Failed to get SDAM base, rc=%d\n", rc);
131		return -EINVAL;
132	}
133
134	rc = regmap_read(sdam->regmap, sdam->base + SDAM_SIZE, &val);
135	if (rc < 0) {
136		dev_err(&pdev->dev, "Failed to read SDAM_SIZE rc=%d\n", rc);
137		return -EINVAL;
138	}
139	sdam->size = val * 32;
140
141	sdam->sdam_config.dev = &pdev->dev;
142	sdam->sdam_config.name = "spmi_sdam";
143	sdam->sdam_config.id = NVMEM_DEVID_AUTO;
144	sdam->sdam_config.owner = THIS_MODULE;
145	sdam->sdam_config.stride = 1;
146	sdam->sdam_config.word_size = 1;
147	sdam->sdam_config.reg_read = sdam_read;
148	sdam->sdam_config.reg_write = sdam_write;
149	sdam->sdam_config.priv = sdam;
150
151	nvmem = devm_nvmem_register(&pdev->dev, &sdam->sdam_config);
152	if (IS_ERR(nvmem)) {
153		dev_err(&pdev->dev,
154			"Failed to register SDAM nvmem device rc=%ld\n",
155			PTR_ERR(nvmem));
156		return -ENXIO;
157	}
158	dev_dbg(&pdev->dev,
159		"SDAM base=%#x size=%u registered successfully\n",
160		sdam->base, sdam->size);
161
162	return 0;
163}
164
165static const struct of_device_id sdam_match_table[] = {
166	{ .compatible = "qcom,spmi-sdam" },
167	{},
168};
169MODULE_DEVICE_TABLE(of, sdam_match_table);
170
171static struct platform_driver sdam_driver = {
172	.driver = {
173		.name = "qcom,spmi-sdam",
174		.of_match_table = sdam_match_table,
175	},
176	.probe		= sdam_probe,
177};
178
179static int __init sdam_init(void)
180{
181	return platform_driver_register(&sdam_driver);
182}
183subsys_initcall(sdam_init);
184
185static void __exit sdam_exit(void)
186{
187	return platform_driver_unregister(&sdam_driver);
188}
189module_exit(sdam_exit);
190
191MODULE_DESCRIPTION("QCOM SPMI SDAM driver");
192MODULE_LICENSE("GPL v2");