qcom-coincell.c (3721B)
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");