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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");