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/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");