diff options
Diffstat (limited to 'drivers/misc/qcom-coincell.c')
| -rw-r--r-- | drivers/misc/qcom-coincell.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/drivers/misc/qcom-coincell.c b/drivers/misc/qcom-coincell.c new file mode 100644 index 000000000000..7b4a2da487a5 --- /dev/null +++ b/drivers/misc/qcom-coincell.c @@ -0,0 +1,152 @@ +/* Copyright (c) 2013, The Linux Foundation. All rights reserved. + * Copyright (c) 2015, Sony Mobile Communications Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/regmap.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> + +struct qcom_coincell { + struct device *dev; + struct regmap *regmap; + u32 base_addr; +}; + +#define QCOM_COINCELL_REG_RSET 0x44 +#define QCOM_COINCELL_REG_VSET 0x45 +#define QCOM_COINCELL_REG_ENABLE 0x46 + +#define QCOM_COINCELL_ENABLE BIT(7) + +static const int qcom_rset_map[] = { 2100, 1700, 1200, 800 }; +static const int qcom_vset_map[] = { 2500, 3200, 3100, 3000 }; +/* NOTE: for pm8921 and others, voltage of 2500 is 16 (10000b), not 0 */ + +/* if enable==0, rset and vset are ignored */ +static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset, + int vset, bool enable) +{ + int i, j, rc; + + /* if disabling, just do that and skip other operations */ + if (!enable) + return regmap_write(chgr->regmap, + chgr->base_addr + QCOM_COINCELL_REG_ENABLE, 0); + + /* find index for current-limiting resistor */ + for (i = 0; i < ARRAY_SIZE(qcom_rset_map); i++) + if (rset == qcom_rset_map[i]) + break; + + if (i >= ARRAY_SIZE(qcom_rset_map)) { + dev_err(chgr->dev, "invalid rset-ohms value %d\n", rset); + return -EINVAL; + } + + /* find index for charge voltage */ + for (j = 0; j < ARRAY_SIZE(qcom_vset_map); j++) + if (vset == qcom_vset_map[j]) + break; + + if (j >= ARRAY_SIZE(qcom_vset_map)) { + dev_err(chgr->dev, "invalid vset-millivolts value %d\n", vset); + return -EINVAL; + } + + rc = regmap_write(chgr->regmap, + chgr->base_addr + QCOM_COINCELL_REG_RSET, i); + if (rc) { + /* + * This is mainly to flag a bad base_addr (reg) from dts. + * Other failures writing to the registers should be + * extremely rare, or indicative of problems that + * should be reported elsewhere (eg. spmi failure). + */ + dev_err(chgr->dev, "could not write to RSET register\n"); + return rc; + } + + rc = regmap_write(chgr->regmap, + chgr->base_addr + QCOM_COINCELL_REG_VSET, j); + if (rc) + return rc; + + /* set 'enable' register */ + return regmap_write(chgr->regmap, + chgr->base_addr + QCOM_COINCELL_REG_ENABLE, + QCOM_COINCELL_ENABLE); +} + +static int qcom_coincell_probe(struct platform_device *pdev) +{ + struct device_node *node = pdev->dev.of_node; + struct qcom_coincell chgr; + u32 rset, vset; + bool enable; + int rc; + + chgr.dev = &pdev->dev; + + chgr.regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (!chgr.regmap) { + dev_err(chgr.dev, "Unable to get regmap\n"); + return -EINVAL; + } + + rc = of_property_read_u32(node, "reg", &chgr.base_addr); + if (rc) + return rc; + + enable = !of_property_read_bool(node, "qcom,charger-disable"); + + if (enable) { + rc = of_property_read_u32(node, "qcom,rset-ohms", &rset); + if (rc) { + dev_err(chgr.dev, + "can't find 'qcom,rset-ohms' in DT block"); + return rc; + } + + rc = of_property_read_u32(node, "qcom,vset-millivolts", &vset); + if (rc) { + dev_err(chgr.dev, + "can't find 'qcom,vset-millivolts' in DT block"); + return rc; + } + } + + return qcom_coincell_chgr_config(&chgr, rset, vset, enable); +} + +static const struct of_device_id qcom_coincell_match_table[] = { + { .compatible = "qcom,pm8941-coincell", }, + {} +}; + +MODULE_DEVICE_TABLE(of, qcom_coincell_match_table); + +static struct platform_driver qcom_coincell_driver = { + .driver = { + .name = "qcom-spmi-coincell", + .of_match_table = qcom_coincell_match_table, + }, + .probe = qcom_coincell_probe, +}; + +module_platform_driver(qcom_coincell_driver); + +MODULE_DESCRIPTION("Qualcomm PMIC coincell charger driver"); +MODULE_LICENSE("GPL v2"); |