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/of_device.h>
12#include <linux/platform_device.h>
13
14struct qcom_coincell {
15	struct device	*dev;
16	struct regmap	*regmap;
17	u32		base_addr;
18};
19
20#define QCOM_COINCELL_REG_RSET		0x44
21#define QCOM_COINCELL_REG_VSET		0x45
22#define QCOM_COINCELL_REG_ENABLE	0x46
23
24#define QCOM_COINCELL_ENABLE		BIT(7)
25
26static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 };
27static const int qcom_vset_map[] = { 2500, 3200, 3100, 3000 };
28/* NOTE: for pm8921 and others, voltage of 2500 is 16 (10000b), not 0 */
29
30/* if enable==0, rset and vset are ignored */
31static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset,
32				     int vset, bool enable)
33{
34	int i, j, rc;
35
36	/* if disabling, just do that and skip other operations */
37	if (!enable)
38		return regmap_write(chgr->regmap,
39			  chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0);
40
41	/* find index for current-limiting resistor */
42	for (i = 0; i < ARRAY_SIZE(qcom_rset_map); i++)
43		if (rset == qcom_rset_map[i])
44			break;
45
46	if (i >= ARRAY_SIZE(qcom_rset_map)) {
47		dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset);
48		return -EINVAL;
49	}
50
51	/* find index for charge voltage */
52	for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++)
53		if (vset == qcom_vset_map[j])
54			break;
55
56	if (j >= ARRAY_SIZE(qcom_vset_map)) {
57		dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset);
58		return -EINVAL;
59	}
60
61	rc = regmap_write(chgr->regmap,
62			  chgr->base_addr + QCOM_COINCELL_REG_RSET, i);
63	if (rc) {
64		/*
65		 * This is mainly to flag a bad base_addr (reg) from dts.
66		 * Other failures writing to the registers should be
67		 * extremely rare, or indicative of problems that
68		 * should be reported elsewhere (eg. spmi failure).
69		 */
70		dev_err(chgr->dev, "could not write to RSET register\n");
71		return rc;
72	}
73
74	rc = regmap_write(chgr->regmap,
75		chgr->base_addr + QCOM_COINCELL_REG_VSET, j);
76	if (rc)
77		return rc;
78
79	/* set 'enable' register */
80	return regmap_write(chgr->regmap,
81			    chgr->base_addr + QCOM_COINCELL_REG_ENABLE,
82			    QCOM_COINCELL_ENABLE);
83}
84
85static int qcom_coincell_probe(struct platform_device *pdev)
86{
87	struct device_node *node = pdev->dev.of_node;
88	struct qcom_coincell chgr;
89	u32 rset = 0;
90	u32 vset = 0;
91	bool enable;
92	int rc;
93
94	chgr.dev = &pdev->dev;
95
96	chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL);
97	if (!chgr.regmap) {
98		dev_err(chgr.dev, "Unable to get regmap\n");
99		return -EINVAL;
100	}
101
102	rc = of_property_read_u32(node, "reg", &chgr.base_addr);
103	if (rc)
104		return rc;
105
106	enable = !of_property_read_bool(node, "qcom,charger-disable");
107
108	if (enable) {
109		rc = of_property_read_u32(node, "qcom,rset-ohms", &rset);
110		if (rc) {
111			dev_err(chgr.dev,
112				"can't find 'qcom,rset-ohms' in DT block");
113			return rc;
114		}
115
116		rc = of_property_read_u32(node, "qcom,vset-millivolts", &vset);
117		if (rc) {
118			dev_err(chgr.dev,
119			    "can't find 'qcom,vset-millivolts' in DT block");
120			return rc;
121		}
122	}
123
124	return qcom_coincell_chgr_config(&chgr, rset, vset, enable);
125}
126
127static const struct of_device_id qcom_coincell_match_table[] = {
128	{ .compatible = "qcom,pm8941-coincell", },
129	{}
130};
131
132MODULE_DEVICE_TABLE(of, qcom_coincell_match_table);
133
134static struct platform_driver qcom_coincell_driver = {
135	.driver	= {
136		.name		= "qcom-spmi-coincell",
137		.of_match_table	= qcom_coincell_match_table,
138	},
139	.probe		= qcom_coincell_probe,
140};
141
142module_platform_driver(qcom_coincell_driver);
143
144MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver");
145MODULE_LICENSE("GPL v2");
146