[PATCH v6 7/8] power: bq27xxx_battery: Add power_supply_battery_info support

[Liam Breck <liam@networkimprov.net>]

From: Matt Ranostay <matt@ranostay.consulting>

Previously there was no way to set chip registers in the event that the
defaults didn't match the battery in question.

BQ27xxx driver now calls power_supply_get_battery_info, checks the inputs,
and writes battery data to non-volatile memory.

Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Signed-off-by: Liam Breck <kernel@networkimprov.net>
---
 drivers/power/supply/bq27xxx_battery.c | 302 ++++++++++++++++++++++++++++++++-
 1 file changed, 301 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index 7475a5f..70d0142 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -37,6 +37,7 @@
  * http://www.ti.com/product/bq27621-g1
  */
 
+#include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -452,6 +453,59 @@ static struct {
 static DEFINE_MUTEX(bq27xxx_list_lock);
 static LIST_HEAD(bq27xxx_battery_devices);
 
+#define BQ27XXX_TERM_V_MIN	2800
+#define BQ27XXX_TERM_V_MAX	3700
+
+#define BQ27XXX_BLOCK_DATA_CLASS	0x3E
+#define BQ27XXX_DATA_BLOCK		0x3F
+#define BQ27XXX_BLOCK_DATA		0x40
+#define BQ27XXX_BLOCK_DATA_CHECKSUM	0x60
+#define BQ27XXX_BLOCK_DATA_CONTROL	0x61
+#define BQ27XXX_SET_CFGUPDATE		0x13
+#define BQ27XXX_SOFT_RESET		0x42
+#define BQ27XXX_SUBCLASS_STATE_NVM	82
+
+struct bq27xxx_dm_buf {
+	u8 a[32];
+};
+
+struct bq27xxx_dm_reg {
+	unsigned int subclass_id;
+	unsigned int offset;
+	unsigned int bytes;
+	char *name;
+};
+
+#define BQ27XXX_DM_SUPPORTED(r) ( \
+	   r->subclass_id == BQ27XXX_SUBCLASS_STATE_NVM \
+	&& r->offset <= 30 \
+	&& r->bytes == 2 \
+)
+
+enum bq27xxx_dm_reg_id {
+	BQ27XXX_DM_DESIGN_CAPACITY = 0,
+	BQ27XXX_DM_DESIGN_ENERGY,
+	BQ27XXX_DM_TERMINATE_VOLTAGE,
+	BQ27XXX_DM_END,
+};
+
+static struct bq27xxx_dm_reg bq27425_dm_regs[] = {
+	[BQ27XXX_DM_DESIGN_CAPACITY] =
+		{ BQ27XXX_SUBCLASS_STATE_NVM, 12, 2, "design-capacity" },
+	[BQ27XXX_DM_DESIGN_ENERGY] =
+		{ BQ27XXX_SUBCLASS_STATE_NVM, 14, 2, "design-energy" },
+	[BQ27XXX_DM_TERMINATE_VOLTAGE] =
+		{ BQ27XXX_SUBCLASS_STATE_NVM, 18, 2, "terminate-voltage" },
+};
+
+static struct bq27xxx_dm_reg *bq27xxx_dm_regs[] = {
+	[BQ27425] = bq27425_dm_regs,
+};
+
+static unsigned int bq27xxx_unseal_keys[] = {
+	[BQ27425] = 0x04143672,
+};
+
 static int poll_interval_param_set(const char *val, const struct kernel_param *kp)
 {
 	struct bq27xxx_device_info *di;
@@ -496,6 +550,183 @@ static inline int bq27xxx_read(struct bq27xxx_device_info *di, int reg_index,
 	return di->bus.read(di, di->regs[reg_index], single);
 }
 
+static int bq27xxx_battery_set_seal_state(struct bq27xxx_device_info *di,
+					  bool state)
+{
+	unsigned int key = bq27xxx_unseal_keys[di->chip];
+	int ret;
+
+	if (state)
+		return di->bus.write(di, BQ27XXX_REG_CTRL, 0x20, false);
+
+	ret = di->bus.write(di, BQ27XXX_REG_CTRL, (key >> 16) & 0xffff, false);
+	if (ret < 0)
+		return ret;
+
+	return di->bus.write(di, BQ27XXX_REG_CTRL, key & 0xffff, false);
+}
+
+static int bq27xxx_battery_read_dm_block(struct bq27xxx_device_info *di,
+					 int subclass,
+					 struct bq27xxx_dm_buf *buf)
+{
+	int ret;
+
+	ret = di->bus.write(di, BQ27XXX_REG_CTRL, 0, false);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_BLOCK_DATA_CONTROL, 0, true);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_BLOCK_DATA_CLASS, subclass, true);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_DATA_BLOCK, 0, true);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(1000, 1500);
+
+	return di->bus.read_bulk(di, BQ27XXX_BLOCK_DATA, buf->a, sizeof buf->a);
+}
+
+static int bq27xxx_battery_print_config(struct bq27xxx_device_info *di)
+{
+	struct bq27xxx_dm_buf buf;
+	struct bq27xxx_dm_reg *reg = bq27xxx_dm_regs[di->chip];
+	int ret, i;
+
+	ret = bq27xxx_battery_read_dm_block(di, BQ27XXX_SUBCLASS_STATE_NVM,
+					    &buf);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < BQ27XXX_DM_END; i++, reg++) {
+		int val;
+
+		if (!BQ27XXX_DM_SUPPORTED(reg)) {
+			dev_warn(di->dev, "unsupported config register %s\n", reg->name);
+			continue;
+		}
+
+		val = be16_to_cpup((u16 *) &buf.a[reg->offset]);
+
+		dev_info(di->dev, "config register %s set at %d\n", reg->name, val);
+	}
+
+	return 0;
+}
+
+static bool bq27xxx_battery_update_dm_block(struct bq27xxx_device_info *di,
+					    struct bq27xxx_dm_buf *buf,
+					    enum bq27xxx_dm_reg_id reg_id,
+					    unsigned int val)
+{
+	struct bq27xxx_dm_reg *reg = &bq27xxx_dm_regs[di->chip][reg_id];
+	u16 *prev;
+
+	if (!BQ27XXX_DM_SUPPORTED(reg))
+		return false;
+
+	prev = (u16 *) &buf->a[reg->offset];
+
+	if (be16_to_cpup(prev) == val)
+		return false;
+
+	*prev = cpu_to_be16(val);
+
+	return true;
+}
+
+static u8 bq27xxx_battery_checksum(struct bq27xxx_dm_buf *buf)
+{
+	u16 sum = 0;
+	int i;
+
+	for (i = 0; i < sizeof buf->a; i++) {
+		sum += buf->a[i];
+		sum &= 0xff;
+	}
+
+	return 0xff - sum;
+}
+
+static int bq27xxx_battery_write_dm_block(struct bq27xxx_device_info *di,
+					  int subclass,
+					  struct bq27xxx_dm_buf *buf)
+{
+	int ret;
+
+	ret = di->bus.write(di, BQ27XXX_REG_CTRL, BQ27XXX_SET_CFGUPDATE, false);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_BLOCK_DATA_CONTROL, 0, true);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_BLOCK_DATA_CLASS, subclass, true);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write(di, BQ27XXX_DATA_BLOCK, 0, true);
+	if (ret < 0)
+		return ret;
+
+	ret = di->bus.write_bulk(di, BQ27XXX_BLOCK_DATA, buf->a, sizeof buf->a);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(1000, 1500);
+
+	ret = di->bus.write(di, BQ27XXX_BLOCK_DATA_CHECKSUM,
+			    bq27xxx_battery_checksum(buf), true);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(1000, 1500);
+
+	return di->bus.write(di, BQ27XXX_REG_CTRL, BQ27XXX_SOFT_RESET, false);
+}
+
+static int bq27xxx_battery_set_config(struct bq27xxx_device_info *di,
+				      struct power_supply_battery_info *info)
+{
+	struct bq27xxx_dm_buf buf;
+	int ret;
+
+	ret = bq27xxx_battery_read_dm_block(di, BQ27XXX_SUBCLASS_STATE_NVM,
+					    &buf);
+	if (ret < 0)
+		return ret;
+
+	if (info->charge_full_design_uah != -EINVAL
+	 && info->energy_full_design_uwh != -EINVAL) {
+		ret |= bq27xxx_battery_update_dm_block(di, &buf,
+					BQ27XXX_DM_DESIGN_CAPACITY,
+					info->charge_full_design_uah / 1000);
+		ret |= bq27xxx_battery_update_dm_block(di, &buf,
+					BQ27XXX_DM_DESIGN_ENERGY,
+					info->energy_full_design_uwh / 1000);
+	}
+
+	if (info->voltage_min_design_uv != -EINVAL)
+		ret |= bq27xxx_battery_update_dm_block(di, &buf,
+					BQ27XXX_DM_TERMINATE_VOLTAGE,
+					info->voltage_min_design_uv / 1000);
+
+	if (ret) {
+		dev_info(di->dev, "updating NVM settings\n");
+		return bq27xxx_battery_write_dm_block(di, BQ27XXX_SUBCLASS_STATE_NVM,
+						      &buf);
+	}
+
+	return 0;
+}
+
 /*
  * Return the battery State-of-Charge
  * Or < 0 if something fails.
@@ -757,6 +988,64 @@ static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
 	return POWER_SUPPLY_HEALTH_GOOD;
 }
 
+void bq27xxx_battery_settings(struct bq27xxx_device_info *di)
+{
+	struct power_supply_battery_info info = {};
+
+	/* functions don't exist for writing data so abort */
+	if (!di->bus.write || !di->bus.write_bulk)
+		return;
+
+	/* no settings to be set for this chipset so abort */
+	if (!bq27xxx_dm_regs[di->chip])
+		return;
+
+	bq27xxx_battery_set_seal_state(di, false);
+
+	if (power_supply_get_battery_info(di->bat, &info) < 0)
+		goto out;
+
+	if (info.energy_full_design_uwh != info.charge_full_design_uah) {
+		if (info.energy_full_design_uwh == -EINVAL)
+			dev_warn(di->dev,
+				"missing battery:energy-full-design-microwatt-hours\n");
+		else if (info.charge_full_design_uah == -EINVAL)
+			dev_warn(di->dev,
+				"missing battery:charge-full-design-microamp-hours\n");
+	}
+
+	if (info.energy_full_design_uwh > 0x7fff * 1000) {
+		dev_err(di->dev, "invalid battery:energy-full-design-microwatt-hours %d\n",
+			info.energy_full_design_uwh);
+		info.energy_full_design_uwh = -EINVAL;
+	}
+
+	if (info.charge_full_design_uah > 0x7fff * 1000) {
+		dev_err(di->dev, "invalid battery:charge-full-design-microamp-hours %d\n",
+			info.charge_full_design_uah);
+		info.charge_full_design_uah = -EINVAL;
+	}
+
+	if ((info.voltage_min_design_uv < BQ27XXX_TERM_V_MIN * 1000
+	  || info.voltage_min_design_uv > BQ27XXX_TERM_V_MAX * 1000)
+	  && info.voltage_min_design_uv != -EINVAL) {
+		dev_err(di->dev, "invalid battery:voltage-min-design-microvolt %d\n",
+			info.voltage_min_design_uv);
+		info.voltage_min_design_uv = -EINVAL;
+	}
+
+	if ((info.energy_full_design_uwh == -EINVAL
+	  || info.charge_full_design_uah == -EINVAL)
+	  && info.voltage_min_design_uv  == -EINVAL)
+		goto out;
+
+	bq27xxx_battery_set_config(di, &info);
+
+out:
+	bq27xxx_battery_print_config(di);
+	bq27xxx_battery_set_seal_state(di, true);
+}
+
 void bq27xxx_battery_update(struct bq27xxx_device_info *di)
 {
 	struct bq27xxx_reg_cache cache = {0, };
@@ -1006,6 +1295,13 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 		ret = bq27xxx_simple_value(di->charge_design_full, val);
 		break;
+	/*
+	 * TODO: Implement these to make registers set from
+	 * power_supply_battery_info visible in sysfs.
+	 */
+	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		return -EINVAL;
 	case POWER_SUPPLY_PROP_CYCLE_COUNT:
 		ret = bq27xxx_simple_value(di->cache.cycle_count, val);
 		break;
@@ -1039,7 +1335,10 @@ static void bq27xxx_external_power_changed(struct power_supply *psy)
 int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
 {
 	struct power_supply_desc *psy_desc;
-	struct power_supply_config psy_cfg = { .drv_data = di, };
+	struct power_supply_config psy_cfg = {
+		.of_node = di->dev->of_node,
+		.drv_data = di,
+	};
 
 	INIT_DELAYED_WORK(&di->work, bq27xxx_battery_poll);
 	mutex_init(&di->lock);
@@ -1064,6 +1363,7 @@ int bq27xxx_battery_setup(struct bq27xxx_device_info *di)
 
 	dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 
+	bq27xxx_battery_settings(di);
 	bq27xxx_battery_update(di);
 
 	mutex_lock(&bq27xxx_list_lock);
-- 
2.9.3