GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / misc / qcom-coincell.c
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 */
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
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");