1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
3 * Copyright (c) 2015, Sony Mobile Communications Inc.
4 */
5
6#include <linux/kernel.h>
7#include <linux/module.h>
8#include <linux/slab.h>
9#include <linux/of.h>
10#include <linux/regmap.h>
11#include <linux/platform_device.h>
12
13struct qcom_coincell {
14	struct device	*dev;
15	struct regmap	*regmap;
16	u32		base_addr;
17};
18
19#define QCOM_COINCELL_REG_RSET		0x44
20#define QCOM_COINCELL_REG_VSET		0x45
21#define QCOM_COINCELL_REG_ENABLE	0x46
22
23#define QCOM_COINCELL_ENABLE		BIT(7)
24
25static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 };
26static const int qcom_vset_map[] = { 2500, 3200, 3100, 3000 };
27/* NOTE: for pm8921 and others, voltage of 2500 is 16 (10000b), not 0 */
28
29/* if enable==0, rset and vset are ignored */
30static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset,
31				     int vset, bool enable)
32{
33	int i, j, rc;
34
35	/* if disabling, just do that and skip other operations */
36	if (!enable)
37		return regmap_write(chgr->regmap,
38			  chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0);
39
40	/* find index for current-limiting resistor */
41	for (i = 0; i < ARRAY_SIZE(qcom_rset_map); i++)
42		if (rset == qcom_rset_map[i])
43			break;
44
45	if (i >= ARRAY_SIZE(qcom_rset_map)) {
46		dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset);
47		return -EINVAL;
48	}
49
50	/* find index for charge voltage */
51	for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++)
52		if (vset == qcom_vset_map[j])
53			break;
54
55	if (j >= ARRAY_SIZE(qcom_vset_map)) {
56		dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset);
57		return -EINVAL;
58	}
59
60	rc = regmap_write(chgr->regmap,
61			  chgr->base_addr + QCOM_COINCELL_REG_RSET, i);
62	if (rc) {
63		/*
64		 * This is mainly to flag a bad base_addr (reg) from dts.
65		 * Other failures writing to the registers should be
66		 * extremely rare, or indicative of problems that
67		 * should be reported elsewhere (eg. spmi failure).
68		 */
69		dev_err(chgr->dev, "could not write to RSET register\n");
70		return rc;
71	}
72
73	rc = regmap_write(chgr->regmap,
74		chgr->base_addr + QCOM_COINCELL_REG_VSET, j);
75	if (rc)
76		return rc;
77
78	/* set 'enable' register */
79	return regmap_write(chgr->regmap,
80			    chgr->base_addr + QCOM_COINCELL_REG_ENABLE,
81			    QCOM_COINCELL_ENABLE);
82}
83
84static int qcom_coincell_probe(struct platform_device *pdev)
85{
86	struct device_node *node = pdev->dev.of_node;
87	struct qcom_coincell chgr;
88	u32 rset = 0;
89	u32 vset = 0;
90	bool enable;
91	int rc;
92
93	chgr.dev = &pdev->dev;
94
95	chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL);
96	if (!chgr.regmap) {
97		dev_err(chgr.dev, "Unable to get regmap\n");
98		return -EINVAL;
99	}
100
101	rc = of_property_read_u32(node, "reg", &chgr.base_addr);
102	if (rc)
103		return rc;
104
105	enable = !of_property_read_bool(node, "qcom,charger-disable");
106
107	if (enable) {
108		rc = of_property_read_u32(node, "qcom,rset-ohms", &rset);
109		if (rc) {
110			dev_err(chgr.dev,
111				"can't find 'qcom,rset-ohms' in DT block");
112			return rc;
113		}
114
115		rc = of_property_read_u32(node, "qcom,vset-millivolts", &vset);
116		if (rc) {
117			dev_err(chgr.dev,
118			    "can't find 'qcom,vset-millivolts' in DT block");
119			return rc;
120		}
121	}
122
123	return qcom_coincell_chgr_config(&chgr, rset, vset, enable);
124}
125
126static const struct of_device_id qcom_coincell_match_table[] = {
127	{ .compatible = "qcom,pm8941-coincell", },
128	{}
129};
130
131MODULE_DEVICE_TABLE(of, qcom_coincell_match_table);
132
133static struct platform_driver qcom_coincell_driver = {
134	.driver	= {
135		.name		= "qcom-spmi-coincell",
136		.of_match_table	= qcom_coincell_match_table,
137	},
138	.probe		= qcom_coincell_probe,
139};
140
141module_platform_driver(qcom_coincell_driver);
142
143MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver");
144MODULE_LICENSE("GPL v2");
145