1 /* Copyright (c) 2013, The Linux Foundation. All rights reserved.
2 * Copyright (c) 2015, Sony Mobile Communications Inc.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 and
6 * only version 2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
18 #include <linux/regmap.h>
19 #include <linux/of_device.h>
20 #include <linux/platform_device.h>
22 struct qcom_coincell {
24 struct regmap *regmap;
28 #define QCOM_COINCELL_REG_RSET 0x44
29 #define QCOM_COINCELL_REG_VSET 0x45
30 #define QCOM_COINCELL_REG_ENABLE 0x46
32 #define QCOM_COINCELL_ENABLE BIT(7)
34 static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 };
35 static const int qcom_vset_map[] = { 2500, 3200, 3100, 3000 };
36 /* NOTE: for pm8921 and others, voltage of 2500 is 16 (10000b), not 0 */
38 /* if enable==0, rset and vset are ignored */
39 static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset,
40 int vset, bool enable)
44 /* if disabling, just do that and skip other operations */
46 return regmap_write(chgr->regmap,
47 chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0);
49 /* find index for current-limiting resistor */
50 for (i = 0; i < ARRAY_SIZE(qcom_rset_map); i++)
51 if (rset == qcom_rset_map[i])
54 if (i >= ARRAY_SIZE(qcom_rset_map)) {
55 dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset);
59 /* find index for charge voltage */
60 for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++)
61 if (vset == qcom_vset_map[j])
64 if (j >= ARRAY_SIZE(qcom_vset_map)) {
65 dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset);
69 rc = regmap_write(chgr->regmap,
70 chgr->base_addr + QCOM_COINCELL_REG_RSET, i);
73 * This is mainly to flag a bad base_addr (reg) from dts.
74 * Other failures writing to the registers should be
75 * extremely rare, or indicative of problems that
76 * should be reported elsewhere (eg. spmi failure).
78 dev_err(chgr->dev, "could not write to RSET register\n");
82 rc = regmap_write(chgr->regmap,
83 chgr->base_addr + QCOM_COINCELL_REG_VSET, j);
87 /* set 'enable' register */
88 return regmap_write(chgr->regmap,
89 chgr->base_addr + QCOM_COINCELL_REG_ENABLE,
90 QCOM_COINCELL_ENABLE);
93 static int qcom_coincell_probe(struct platform_device *pdev)
95 struct device_node *node = pdev->dev.of_node;
96 struct qcom_coincell chgr;
101 chgr.dev = &pdev->dev;
103 chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL);
105 dev_err(chgr.dev, "Unable to get regmap\n");
109 rc = of_property_read_u32(node, "reg", &chgr.base_addr);
113 enable = !of_property_read_bool(node, "qcom,charger-disable");
116 rc = of_property_read_u32(node, "qcom,rset-ohms", &rset);
119 "can't find 'qcom,rset-ohms' in DT block");
123 rc = of_property_read_u32(node, "qcom,vset-millivolts", &vset);
126 "can't find 'qcom,vset-millivolts' in DT block");
131 return qcom_coincell_chgr_config(&chgr, rset, vset, enable);
134 static const struct of_device_id qcom_coincell_match_table[] = {
135 { .compatible = "qcom,pm8941-coincell", },
139 MODULE_DEVICE_TABLE(of, qcom_coincell_match_table);
141 static struct platform_driver qcom_coincell_driver = {
143 .name = "qcom-spmi-coincell",
144 .of_match_table = qcom_coincell_match_table,
146 .probe = qcom_coincell_probe,
149 module_platform_driver(qcom_coincell_driver);
151 MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver");
152 MODULE_LICENSE("GPL v2");