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");