LXR linux/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/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");
 146