Date:   Thu, 23 Feb 2017 18:38:11 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Sebastian Reichel <sre@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH 1/2] power: Add support for the Toby Churchill SBS battery monitor driver.

Some of the Toby Churchill devices come with a smart battery and one
AVR XMEGA Microcontroller monitor its state. This patch adds the driver
for this battery monitor.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
---
 drivers/power/supply/Kconfig             |  10 +
 drivers/power/supply/Makefile            |   2 +
 drivers/power/supply/xmega16d4_battery.c | 353 +++++++++++++++++++++++++++++++
 3 files changed, 365 insertions(+)
 create mode 100644 drivers/power/supply/xmega16d4_battery.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 76806a0..f95f8d5 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -511,4 +511,14 @@ config AXP20X_POWER
 	  This driver provides support for the power supply features of
 	  AXP20x PMIC.
 
+config BATTERY_XMEGA16D4
+	tristate "XMEGA16D4 Battery Gauge Driver"
+	depends on SPI
+	help
+	  Say Y here to include support for XMEGA16D4 Battery Gauge. The
+	  driver reports the charge count, and measures the voltage and
+	  the current.
+
+	  This adds support for XMEGA16D4 battery.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 36c599d..abae887 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -72,3 +72,5 @@ obj-$(CONFIG_CHARGER_TPS65090)	+= tps65090-charger.o
 obj-$(CONFIG_CHARGER_TPS65217)	+= tps65217_charger.o
 obj-$(CONFIG_AXP288_FUEL_GAUGE) += axp288_fuel_gauge.o
 obj-$(CONFIG_AXP288_CHARGER)	+= axp288_charger.o
+obj-$(CONFIG_BATTERY_XMEGA16D4)	+= xmega16d4_battery.o
+
diff --git a/drivers/power/supply/xmega16d4_battery.c b/drivers/power/supply/xmega16d4_battery.c
new file mode 100644
index 0000000..8c6b11a
--- /dev/null
+++ b/drivers/power/supply/xmega16d4_battery.c
@@ -0,0 +1,353 @@
+/*
+ * Battery monitor driver for SL50 Toby Churchill SBS Batteries
+ *
+ * Copyright (c) 2017, Collabora Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/spi/spi.h>
+#include <linux/workqueue.h>
+
+#define SBS_MEMORY_MAP_SIZE		128
+/* Charging voltage, 2 bytes */
+#define SBS_CHARGING_VOLTAGE		0x0a
+/* Design voltage, 2 bytes */
+#define SBS_DESIGN_VOLTAGE		0x0c
+/* Fast charging current, 2 bytes */
+#define SBS_FAST_CHARGING_CURRENT	0x0e
+/* Max T, Low T, 2 bytes */
+#define SBS_MAX_LOW_TEMPERATURE		0x10
+/* Pack capacity, 2 bytes */
+#define SBS_PACK_CAPACITY		0x12
+/* Serial number, 2 bytes */
+#define SBS_SERIAL_NUMBER		0x18
+/* Manufacturer name, 16 bytes */
+#define SBS_MANUFACTURER_NAME		0x20
+/* Model name, 16 bytes */
+#define SBS_MODEL_NAME			0x30
+/* Device chemistry, 5 bytes */
+#define SBS_DEVICE_CHEMISTRY		0x40
+/* Cycle count, 2 bytes */
+#define SBS_CYCLE_COUNT			0x50
+/* Voltage now, 2 bytes */
+#define SBS_VOLTAGE_NOW			0x70
+/* Current now, 2 bytes */
+#define SBS_CURRENT_NOW			0x72
+/* Battery Status, 2 bytes */
+#define SBS_BATTERY_STATUS		0x74
+# define BATTERY_STATUS_CHARGING	0
+# define BATTERY_STATUS_DISCHARGING	BIT(6)
+# define BATTERY_STATUS_FULLY_CHARGED	BIT(5)
+/* State of charge in percentage, 1 byte */
+#define SBS_STATE_OF_CHARGE		0x76
+
+/* MM SIZE + START(u16) + CHECKSUM(u16) */
+#define SPI_MSG_LENGTH		(SBS_MEMORY_MAP_SIZE + 4)
+#define SPI_MSG_DATA_BP		2
+/* MSB checksum byte position */
+#define SPI_MSG_CSUM_BP		(2 + SBS_MEMORY_MAP_SIZE)
+#define SPI_MSG_START_TOKEN	0xb00b
+
+struct xmega16d4_battery_data {
+	struct spi_device *spi;
+	struct power_supply *bat;
+
+	struct mutex		work_lock; /* protect work data */
+	struct delayed_work	bat_work;
+
+	u8 map[SBS_MEMORY_MAP_SIZE];
+
+	char model_name[16];
+	char manufacturer_name[16];
+	char serial_number[5];
+
+	int technology;
+	int voltage_uV;			/* units of uV */
+	int current_uA;			/* units of uA */
+	int rated_capacity;		/* units of µAh */
+	int cycle_count;
+	int rem_capacity;		/* percentage */
+	int life_sec;			/* units of seconds */
+	int status;			/* state of charge */
+};
+
+#define MAX_KEYLENGTH 256
+struct battery_property_map {
+	int value;
+	char const *key;
+};
+
+static struct battery_property_map map_technology[] = {
+	{ POWER_SUPPLY_TECHNOLOGY_NiMH, "NiMH" },
+	{ POWER_SUPPLY_TECHNOLOGY_LION, "LION" },
+	{ POWER_SUPPLY_TECHNOLOGY_LIPO, "LIPO" },
+	{ POWER_SUPPLY_TECHNOLOGY_LiFe, "LiFe" },
+	{ POWER_SUPPLY_TECHNOLOGY_NiCd, "NiCd" },
+	{ POWER_SUPPLY_TECHNOLOGY_LiMn, "LiMn" },
+	{ -1,				NULL   },
+};
+
+static int map_get_value(struct battery_property_map *map, const char *key,
+			 int def_val)
+{
+	char buf[MAX_KEYLENGTH];
+	int cr;
+
+	strncpy(buf, key, MAX_KEYLENGTH);
+	buf[MAX_KEYLENGTH - 1] = '\0';
+
+	cr = strnlen(buf, MAX_KEYLENGTH) - 1;
+	if (buf[cr] == '\n')
+		buf[cr] = '\0';
+
+	while (map->key) {
+		if (strncasecmp(map->key, buf, MAX_KEYLENGTH) == 0)
+			return map->value;
+		map++;
+	}
+
+	return def_val;
+}
+
+static int xmega16d4_battery_read_status(struct xmega16d4_battery_data *data)
+{
+	int i;
+	int csum = 0;
+	u8 buf[SBS_MEMORY_MAP_SIZE], technology[5];
+	unsigned int uval;
+	int sval;
+	struct spi_device *spi = data->spi;
+
+	for (i = 0; i < SBS_MEMORY_MAP_SIZE; i++) {
+		spi_write(spi, &i, 1);
+		spi_read(spi, &buf[i], 1);
+	}
+
+	print_hex_dump(KERN_DEBUG, ": ", DUMP_PREFIX_OFFSET, 16, 1,
+		       buf, SBS_MEMORY_MAP_SIZE, false);
+
+	/* Calculate the data checksum */
+	for (i = 0; i < SBS_MEMORY_MAP_SIZE - 2; i++)
+		csum += buf[i];
+
+	/* Verify the checksum */
+	uval = (buf[SBS_MEMORY_MAP_SIZE - 2] << 8) |
+		buf[SBS_MEMORY_MAP_SIZE - 1];
+	if (csum != uval) {
+		dev_dbg(&spi->dev,
+			"message received with invalid checksum (%d != %d)\n",
+			csum, uval);
+		return -ENOMSG;
+	}
+
+	/* Update memory map with the new data */
+	memcpy(data->map, buf, SBS_MEMORY_MAP_SIZE);
+
+	strncpy(data->model_name, &data->map[SBS_MODEL_NAME], 16);
+
+	strncpy(data->manufacturer_name, &data->map[SBS_MANUFACTURER_NAME],
+		16);
+
+	strncpy(technology, &data->map[SBS_DEVICE_CHEMISTRY], 5);
+
+	uval = (u16)((data->map[SBS_SERIAL_NUMBER + 1] << 8) |
+		data->map[SBS_SERIAL_NUMBER]);
+	snprintf(data->serial_number, ARRAY_SIZE(data->serial_number), "%04d",
+		 uval);
+
+	data->technology = map_get_value(map_technology, technology,
+					 POWER_SUPPLY_TECHNOLOGY_UNKNOWN);
+
+	data->voltage_uV = (u16)((data->map[SBS_VOLTAGE_NOW + 1] << 8) |
+			    data->map[SBS_VOLTAGE_NOW]);
+	data->voltage_uV *= 1000;	/* convert from mV to uV */
+
+	sval = (s16)((data->map[SBS_CURRENT_NOW + 1] << 8) |
+		data->map[SBS_CURRENT_NOW]);
+	data->current_uA = sval;
+	data->current_uA *= 1000;	/* convert from mA to uA */
+
+	data->rated_capacity = (u16)((data->map[SBS_PACK_CAPACITY + 1] << 8) |
+				data->map[SBS_PACK_CAPACITY]);
+	data->rated_capacity *= 1000;	/* convert from mAh to uAh */
+
+	uval = (u16)((data->map[SBS_BATTERY_STATUS + 1] << 8) |
+		data->map[SBS_BATTERY_STATUS]);
+	if (uval == BATTERY_STATUS_CHARGING)
+		data->status = POWER_SUPPLY_STATUS_CHARGING;
+	else if (uval == BATTERY_STATUS_DISCHARGING)
+		data->status = POWER_SUPPLY_STATUS_DISCHARGING;
+	else if (uval == BATTERY_STATUS_FULLY_CHARGED)
+		data->status = POWER_SUPPLY_STATUS_FULL;
+	else
+		data->status = POWER_SUPPLY_STATUS_UNKNOWN;
+
+	data->cycle_count = (u16)((data->map[SBS_CYCLE_COUNT + 1] << 8) |
+			     data->map[SBS_CYCLE_COUNT]);
+
+	data->rem_capacity = data->map[SBS_STATE_OF_CHARGE];
+
+	uval = (data->rem_capacity * (data->rated_capacity / 1000)) / 100;
+	if (data->current_uA)
+		data->life_sec = (3600l * uval) / (data->current_uA / 1000);
+
+	return 0;
+}
+
+static void xmega16d4_battery_work(struct work_struct *work)
+{
+	struct xmega16d4_battery_data *data = container_of(work,
+		struct xmega16d4_battery_data, bat_work.work);
+
+	/* Update values */
+	mutex_lock(&data->work_lock);
+	xmega16d4_battery_read_status(data);
+	mutex_unlock(&data->work_lock);
+
+	schedule_delayed_work(&data->bat_work, HZ * 60);
+}
+
+static int xmega16d4_battery_get_property(struct power_supply *psy,
+					  enum power_supply_property psp,
+					  union power_supply_propval *val)
+{
+	struct xmega16d4_battery_data *data = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = data->status;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = data->voltage_uV;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		val->intval = data->current_uA;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		val->intval = data->rated_capacity;
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+		val->intval = data->life_sec;
+		break;
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = data->rem_capacity;
+		break;
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = data->technology;
+		break;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = data->model_name;
+		break;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = data->manufacturer_name;
+		break;
+	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+		val->strval = data->serial_number;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static enum power_supply_property xmega16d4_battery_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	/* Properties of type `const char *' */
+	POWER_SUPPLY_PROP_MODEL_NAME,
+	POWER_SUPPLY_PROP_MANUFACTURER,
+	POWER_SUPPLY_PROP_SERIAL_NUMBER,
+};
+
+static const struct power_supply_desc xmega16d4_battery_desc = {
+	.name			= "battery-monitor",
+	.type			= POWER_SUPPLY_TYPE_BATTERY,
+	.properties		= xmega16d4_battery_props,
+	.num_properties		= ARRAY_SIZE(xmega16d4_battery_props),
+	.get_property		= xmega16d4_battery_get_property,
+};
+
+static int xmega16d4_battery_probe(struct spi_device *spi)
+{
+	struct xmega16d4_battery_data *data;
+	struct power_supply_config psy_cfg = {};
+
+	data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->spi = spi;
+	psy_cfg.of_node = spi->dev.of_node;
+	psy_cfg.drv_data = data;
+
+	mutex_init(&data->work_lock);
+
+	INIT_DELAYED_WORK(&data->bat_work, xmega16d4_battery_work);
+
+	spi_set_drvdata(spi, data);
+
+	/* Get initial status */
+	if (xmega16d4_battery_read_status(data))
+		return -ENODEV;
+
+	data->bat = devm_power_supply_register(&spi->dev,
+					       &xmega16d4_battery_desc,
+					       &psy_cfg);
+	if (IS_ERR(data->bat))
+		return PTR_ERR(data->bat);
+
+	schedule_delayed_work(&data->bat_work, 0);
+
+	return 0;
+}
+
+static int xmega16d4_battery_remove(struct spi_device *spi)
+{
+	struct xmega16d4_battery_data *data = spi_get_drvdata(spi);
+
+	cancel_delayed_work_sync(&data->bat_work);
+
+	return 0;
+}
+
+static const struct of_device_id xmega16d4_battery_of_match[] = {
+	{ .compatible = "tcl,xmega16d4-battery", },
+	{ /* sentinel */ },
+};
+
+static struct spi_driver xmega16d4_battery_driver = {
+	.driver = {
+		.name		= "xmega16d4-battery",
+		.owner		= THIS_MODULE,
+		.of_match_table = of_match_ptr(xmega16d4_battery_of_match),
+	},
+	.probe	= xmega16d4_battery_probe,
+	.remove	= xmega16d4_battery_remove,
+};
+module_spi_driver(xmega16d4_battery_driver);
+
+MODULE_ALIAS("spi:xmega16d4-battery");
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Enric Balletbo Serra <enric.balletbo@...labora.com>");
+MODULE_DESCRIPTION("xmega16d4 battery monitor driver");
-- 
2.9.3

Powered by blists - more mailing lists