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
14 struct 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
26 static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 };
27 static 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 */
qcom_coincell_chgr_config(struct qcom_coincell * chgr,int rset,int vset,bool enable)31 static 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
qcom_coincell_probe(struct platform_device * pdev)85 static 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
127 static const struct of_device_id qcom_coincell_match_table[] = {
128 { .compatible = "qcom,pm8941-coincell", },
129 {}
130 };
131
132 MODULE_DEVICE_TABLE(of, qcom_coincell_match_table);
133
134 static 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
142 module_platform_driver(qcom_coincell_driver);
143
144 MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver");
145 MODULE_LICENSE("GPL v2");
146