ARM: qcom: Add coincell charger driver
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@sonymobile.com>
Reviewed-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/qcom-coincell.c b/drivers/misc/qcom-coincell.c
new file mode 100644
index 0000000..7b4a2da
--- /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");