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 13 struct 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 25 static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 }; 26 static 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 */ 30 static 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 84 static 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 } 125 126 static const struct of_device_id qcom_coincell_match_table[] = { 127 { .compatible = "qcom,pm8941-coincell", }, 128 {} 129 }; 130 131 MODULE_DEVICE_TABLE(of, qcom_coincell_match_table); 132 133 static 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 }; 140 141 module_platform_driver(qcom_coincell_driver); 142 143 MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver"); 144 MODULE_LICENSE("GPL v2"); 145