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