1 /* Copyright (c) 2013, The Linux Foundation. All rights reserved. 2 * Copyright (c) 2015, Sony Mobile Communications Inc. 3 * 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. 7 * 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. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <linux/of.h> 18 #include <linux/regmap.h> 19 #include <linux/of_device.h> 20 #include <linux/platform_device.h> 21 22 struct qcom_coincell { 23 struct device *dev; 24 struct regmap *regmap; 25 u32 base_addr; 26 }; 27 28 #define QCOM_COINCELL_REG_RSET 0x44 29 #define QCOM_COINCELL_REG_VSET 0x45 30 #define QCOM_COINCELL_REG_ENABLE 0x46 31 32 #define QCOM_COINCELL_ENABLE BIT(7) 33 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 */ 37 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) 41 { 42 int i, j, rc; 43 44 /* if disabling, just do that and skip other operations */ 45 if (!enable) 46 return regmap_write(chgr->regmap, 47 chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0); 48 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]) 52 break; 53 54 if (i >= ARRAY_SIZE(qcom_rset_map)) { 55 dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset); 56 return -EINVAL; 57 } 58 59 /* find index for charge voltage */ 60 for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++) 61 if (vset == qcom_vset_map[j]) 62 break; 63 64 if (j >= ARRAY_SIZE(qcom_vset_map)) { 65 dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset); 66 return -EINVAL; 67 } 68 69 rc = regmap_write(chgr->regmap, 70 chgr->base_addr + QCOM_COINCELL_REG_RSET, i); 71 if (rc) { 72 /* 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). 77 */ 78 dev_err(chgr->dev, "could not write to RSET register\n"); 79 return rc; 80 } 81 82 rc = regmap_write(chgr->regmap, 83 chgr->base_addr + QCOM_COINCELL_REG_VSET, j); 84 if (rc) 85 return rc; 86 87 /* set 'enable' register */ 88 return regmap_write(chgr->regmap, 89 chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 90 QCOM_COINCELL_ENABLE); 91 } 92 93 static int qcom_coincell_probe(struct platform_device *pdev) 94 { 95 struct device_node *node = pdev->dev.of_node; 96 struct qcom_coincell chgr; 97 u32 rset, vset; 98 bool enable; 99 int rc; 100 101 chgr.dev = &pdev->dev; 102 103 chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL); 104 if (!chgr.regmap) { 105 dev_err(chgr.dev, "Unable to get regmap\n"); 106 return -EINVAL; 107 } 108 109 rc = of_property_read_u32(node, "reg", &chgr.base_addr); 110 if (rc) 111 return rc; 112 113 enable = !of_property_read_bool(node, "qcom,charger-disable"); 114 115 if (enable) { 116 rc = of_property_read_u32(node, "qcom,rset-ohms", &rset); 117 if (rc) { 118 dev_err(chgr.dev, 119 "can't find 'qcom,rset-ohms' in DT block"); 120 return rc; 121 } 122 123 rc = of_property_read_u32(node, "qcom,vset-millivolts", &vset); 124 if (rc) { 125 dev_err(chgr.dev, 126 "can't find 'qcom,vset-millivolts' in DT block"); 127 return rc; 128 } 129 } 130 131 return qcom_coincell_chgr_config(&chgr, rset, vset, enable); 132 } 133 134 static const struct of_device_id qcom_coincell_match_table[] = { 135 { .compatible = "qcom,pm8941-coincell", }, 136 {} 137 }; 138 139 MODULE_DEVICE_TABLE(of, qcom_coincell_match_table); 140 141 static struct platform_driver qcom_coincell_driver = { 142 .driver = { 143 .name = "qcom-spmi-coincell", 144 .of_match_table = qcom_coincell_match_table, 145 }, 146 .probe = qcom_coincell_probe, 147 }; 148 149 module_platform_driver(qcom_coincell_driver); 150 151 MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver"); 152 MODULE_LICENSE("GPL v2"); 153