This driver is used to configure the coincell charger found in
Qualcomm PMICs.
The driver allows configuring the current-limiting resistor for
the charger, as well as the voltage to apply to the coincell
(or capacitor) when charging.
Signed-off-by: Tim Bird <tim.bird@xxxxxxxxxxxxxx>
---
drivers/misc/Kconfig | 11 ++++
drivers/misc/Makefile | 1 +
drivers/misc/qcom-coincell.c | 154 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 166 insertions(+)
create mode 100644 drivers/misc/qcom-coincell.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 42c3852..0909869 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -271,6 +271,17 @@ config HP_ILO
To compile this driver as a module, choose M here: the
module will be called hpilo.
+config QCOM_COINCELL
+ tristate "Qualcomm coincell charger support"
+ depends on OF
+ select REGMAP
+ help
+ This driver supports the coincell block found inside of
+ Qualcomm PMICs. The coincell charger provides a means to
+ charge a coincell battery or backup capacitor which is used
+ to maintain PMIC register and RTC state in the absence of
+ external power.
+
config SGI_GRU
tristate "SGI GRU driver"
depends on X86_UV && SMP
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index d056fb7..537d7f3 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_LKDTM) += lkdtm.o
obj-$(CONFIG_TIFM_CORE) += tifm_core.o
obj-$(CONFIG_TIFM_7XX1) += tifm_7xx1.o
obj-$(CONFIG_PHANTOM) += phantom.o
+obj-$(CONFIG_QCOM_COINCELL) += qcom-coincell.o
obj-$(CONFIG_SENSORS_BH1780) += bh1780gli.o
obj-$(CONFIG_SENSORS_BH1770) += bh1770glc.o
obj-$(CONFIG_SENSORS_APDS990X) += apds990x.o
diff --git a/drivers/misc/qcom-coincell.c b/drivers/misc/qcom-coincell.c
new file mode 100644
index 0000000..9c019e4
--- /dev/null
+++ b/drivers/misc/qcom-coincell.c
@@ -0,0 +1,154 @@
+/* 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 */
+
+static int qcom_coincell_chgr_config(struct qcom_coincell *chgr, int rset,
+ int vset, int enable)
+{
+ int i, rc;
+ unsigned int value;
+
+ /* select 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;
+ }
+
+ rc = regmap_write(chgr->regmap,
+ chgr->base_addr + QCOM_COINCELL_REG_RSET, i);
+ if (rc)
+ dev_err(chgr->dev, "could not write to RSET register\n");
+ return rc;
+
+ /* select charge voltage */
+ for (i = 0; i < ARRAY_SIZE(qcom_vset_map); i++)
+ if (vset == qcom_vset_map[i])
+ break;
+
+ if (i >= 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_VSET, i);
+ if (rc)
+ dev_err(chgr->dev, "could not write to VSET register\n");
+ return rc;
+
+ /* set 'enable' register */
+ value = enable ? QCOM_COINCELL_ENABLE : 0;
+ rc = regmap_write(chgr->regmap,
+ chgr->base_addr + QCOM_COINCELL_REG_ENABLE, value);
+ if (rc)
+ dev_err(chgr->dev, "could not write to ENABLE register\n");
+
+ return rc;
+}
+
+static int qcom_coincell_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct qcom_coincell *chgr;
+ u32 rset, vset, enable;
+ int rc;
+
+ if (!node) {
+ dev_err(&pdev->dev, "%s: device node missing\n", __func__);
+ return -ENODEV;
+ }
+
+ chgr = devm_kzalloc(&pdev->dev, sizeof(*chgr), GFP_KERNEL);
+ if (!chgr)
+ return -ENOMEM;
+
+ 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;
+
+ 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;
+ }
+
+ rc = of_property_read_u32(node, "qcom,charge-enable", &enable);
+ if (rc)
+ enable = 0;
+
+ rc = qcom_coincell_chgr_config(chgr, rset, vset, enable);
+
+ return rc;
+}
+
+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,pm8941-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");
--
1.8.2.2
--
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