/*
* Driver for SBS compliant Smart Battery System Managers
*
* The device communicates via i2c at address 0x0a and multiplexes access to up
* to four smart batteries at address 0x0b.
*
* Via sysfs interface the online state and charge type are presented.
*
* Datasheet SBSM: http://sbs-forum.org/specs/sbsm100b.pdf
* Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf
*
* Karl-Heinz Schneider <karl-heinz@schneider-inet.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/gpio.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/power_supply.h>
#include <linux/property.h>
#define SBSM_MAX_BATS 4
#define SBSM_RETRY_CNT 3
/* registers addresses */
#define SBSM_CMD_BATSYSSTATE 0x01
#define SBSM_CMD_BATSYSSTATECONT 0x02
#define SBSM_CMD_BATSYSINFO 0x04
#define SBSM_CMD_LTC 0x3c
#define SBSM_MASK_BAT_SUPPORTED GENMASK(3, 0)
#define SBSM_MASK_CHARGE_BAT GENMASK(7, 4)
#define SBSM_BIT_AC_PRESENT BIT(0)
#define SBSM_BIT_TURBO BIT(7)
#define SBSM_SMB_BAT_OFFSET 11
struct sbsm_data {
struct i2c_client *client;
struct i2c_mux_core *muxc;
struct power_supply *psy;
u8 cur_chan; /* currently selected channel */
struct gpio_chip chip;
bool is_ltc1760; /* special capabilities */
unsigned int supported_bats;
unsigned int last_state;
unsigned int last_state_cont;
};
static enum power_supply_property sbsm_props[] = {
POWER_SUPPLY_PROP_ONLINE,
POWER_SUPPLY_PROP_CHARGE_TYPE,
};
static int sbsm_read_word(struct i2c_client *client, u8 address)
{
int reg, retries;
for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
reg = i2c_smbus_read_word_data(client, address);
if (reg >= 0)
break;
}
if (reg < 0) {
dev_err(&client->dev, "failed to read register 0x%02x\n",
address);
}
return reg;
}
static int sbsm_write_word(struct i2c_client *client, u8 address, u16 word)
{
int ret, retries;
for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
ret = i2c_smbus_write_word_data(client, address, word);
if (ret >= 0)
break;
}
if (ret < 0)
dev_err(&client->dev, "failed to write to register 0x%02x\n",
address);
return ret;
}
static int sbsm_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct sbsm_data *data = power_supply_get_drvdata(psy);
int regval = 0;
switch (psp) {
case POWER_SUPPLY_PROP_ONLINE:
regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATECONT);
if (regval < 0)
return regval;
val->intval = !!(regval & SBSM_BIT_AC_PRESENT);
break;
case POWER_SUPPLY_PROP_CHARGE_TYPE:
regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
if (regval < 0)
return regval;
if ((regval & SBSM_MASK_CHARGE_BAT) == 0) {
val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
return 0;
}
val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
if (data->is_ltc1760) {
/* charge mode fast if turbo is active */
regval = sbsm_read_word(data->client, SBSM_CMD_LTC);
if (regval < 0)
return regval;
else if (regval & SBSM_BIT_TURBO)
val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
}
break;
default:
return -EINVAL;
}
return 0;
}
static int sbsm_prop_is_writeable(struct power_supply *psy,
enum power_supply_property psp)
{
struct sbsm_data *data = power_supply_get_drvdata(psy);
return (psp == POWER_SUPPLY_PROP_CHARGE_TYPE) && data->is_ltc1760;
}
static int sbsm_set_property(struct power_supply *psy,
enum power_supply_property psp,
const union power_supply_propval *val)
{
struct sbsm_data *data = power_supply_get_drvdata(psy);
int ret = -EINVAL;
u16 regval;
switch (psp) {
case POWER_SUPPLY_PROP_CHARGE_TYPE:
/* write 1 to TURBO if type fast is given */
if (!data->is_ltc1760)
break;
regval = val->intval ==
POWER_SUPPLY_CHARGE_TYPE_FAST ? SBSM_BIT_TURBO : 0;
ret = sbsm_write_word(data->client, SBSM_CMD_LTC, regval);
break;
default:
break;
}
return ret;
}
/*
* Switch to battery
* Parameter chan is directly the content of SMB_BAT* nibble
*/
static int sbsm_select(struct i2c_mux_core *muxc, u32 chan)
{
struct sbsm_data *data = i2c_mux_priv(muxc);
struct device *dev = &data->client->dev;
int ret = 0;
u16 reg;
if (data->cur_chan == chan)
return ret;
/* chan goes from 1 ... 4 */
reg = BIT(SBSM_SMB_BAT_OFFSET + chan);
ret = sbsm_write_word(data->client, SBSM_CMD_BATSYSSTATE, reg);
if (ret)
dev_err(dev, "Failed to select channel %i\n", chan);
else
data->cur_chan = chan;
return ret;
}
static int sbsm_gpio_get_value(struct gpio_chip *gc, unsigned int off)
{
struct sbsm_data *data = gpiochip_get_data(gc);
int ret;
ret = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
if (ret < 0)
return ret;
return ret & BIT(off);
}
/*
* This needs to be defined or the GPIO lib fails to register the pin.
* But the 'gpio' is always an input.
*/
static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
{
return 0;
}
static int sbsm_do_alert(struct device *dev, void *d)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
if (!client || client->addr != 0x0b)
return 0;
device_lock(dev);
if (client->dev.driver) {
driver = to_i2c_driver(client->dev.driver);
if (driver->alert)
driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, 0);
else
dev_warn(&client->dev, "no driver alert()!\n");
} else {
dev_dbg(&client->dev, "alert with no driver\n");
}
device_unlock(dev);
return -EBUSY;
}
static void sbsm_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
unsigned int d)
{
struct sbsm_data *sbsm = i2c_get_clientdata(client);
int ret, i, irq_bat = 0, state = 0;
ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATE);
if (ret >= 0) {
irq_bat = ret ^ sbsm->last_state;
sbsm->last_state = ret;
state = ret;
}
ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATECONT);
if ((ret >= 0) &&
((ret ^ sbsm->last_state_cont) & SBSM_BIT_AC_PRESENT)) {
irq_bat |= sbsm->supported_bats & state;
power_supply_changed(sbsm->psy);
}
sbsm->last_state_cont = ret;
for (i = 0; i < SBSM_MAX_BATS; i++) {
if (irq_bat & BIT(i)) {
device_for_each_child(&sbsm->muxc->adapter[i]->dev,
NULL, sbsm_do_alert);
}
}
}
static int sbsm_gpio_setup(struct sbsm_data *data)
{
struct gpio_chip *gc = &data->chip;
struct i2c_client *client = data->client;
struct device *dev = &client->dev;
int ret;
if (!device_property_present(dev, "gpio-controller"))
return 0;
ret = sbsm_read_word(client, SBSM_CMD_BATSYSSTATE);
if (ret < 0)
return ret;
data->last_state = ret;
ret = sbsm_read_word(client, SBSM_CMD_BATSYSSTATECONT);
if (ret < 0)
return ret;
data->last_state_cont = ret;
gc->get = sbsm_gpio_get_value;
gc->direction_input = sbsm_gpio_direction_input;
gc->can_sleep = true;
gc->base = -1;
gc->ngpio = SBSM_MAX_BATS;
gc->label = client->name;
gc->parent = dev;
gc->owner = THIS_MODULE;
ret = devm_gpiochip_add_data(dev, gc, data);
if (ret) {
dev_err(dev, "devm_gpiochip_add_data failed: %d\n", ret);
return ret;
}
return ret;
}
static const struct power_supply_desc sbsm_default_psy_desc = {
.type = POWER_SUPPLY_TYPE_MAINS,
.properties = sbsm_props,
.num_properties = ARRAY_SIZE(sbsm_props),
.get_property = &sbsm_get_property,
.set_property = &sbsm_set_property,
.property_is_writeable = &sbsm_prop_is_writeable,
};
static int sbsm_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
struct sbsm_data *data;
struct device *dev = &client->dev;
struct power_supply_desc *psy_desc;
struct power_supply_config psy_cfg = {};
int ret = 0, i;
/* Device listens only at address 0x0a */
if (client->addr != 0x0a)
return -EINVAL;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -EPFNOSUPPORT;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
data->client = client;
data->is_ltc1760 = !!strstr(id->name, "ltc1760");
ret = sbsm_read_word(client, SBSM_CMD_BATSYSINFO);
if (ret < 0)
return ret;
data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED;
data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0,
I2C_MUX_LOCKED, &sbsm_select, NULL);
if (!data->muxc) {
dev_err(dev, "failed to alloc i2c mux\n");
ret = -ENOMEM;
goto err_mux_alloc;
}
data->muxc->priv = data;
/* register muxed i2c channels. One for each supported battery */
for (i = 0; i < SBSM_MAX_BATS; ++i) {
if (data->supported_bats & BIT(i)) {
ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0);
if (ret)
break;
}
}
if (ret) {
dev_err(dev, "failed to register i2c mux channel %d\n", i + 1);
goto err_mux_register;
}
psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc,
sizeof(struct power_supply_desc),
GFP_KERNEL);
if (!psy_desc) {
ret = -ENOMEM;
goto err_psy;
}
psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s",
dev_name(&client->dev));
if (!psy_desc->name) {
ret = -ENOMEM;
goto err_psy;
}
ret = sbsm_gpio_setup(data);
if (ret < 0)
goto err_psy;
psy_cfg.drv_data = data;
psy_cfg.of_node = dev->of_node;
data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg);
if (IS_ERR(data->psy)) {
ret = PTR_ERR(data->psy);
dev_err(dev, "failed to register power supply %s\n",
psy_desc->name);
goto err_psy;
}
return 0;
err_psy:
err_mux_register:
i2c_mux_del_adapters(data->muxc);
err_mux_alloc:
return ret;
}
static int sbsm_remove(struct i2c_client *client)
{
struct sbsm_data *data = i2c_get_clientdata(client);
i2c_mux_del_adapters(data->muxc);
return 0;
}
static const struct i2c_device_id sbsm_ids[] = {
{ "sbs-manager", 0 },
{ "ltc1760", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, sbsm_ids);
#ifdef CONFIG_OF
static const struct of_device_id sbsm_dt_ids[] = {
{ .compatible = "sbs,sbs-manager" },
{ .compatible = "lltc,ltc1760" },
{ }
};
MODULE_DEVICE_TABLE(of, sbsm_dt_ids);
#endif
static struct i2c_driver sbsm_driver = {
.driver = {
.name = "sbsm",
.of_match_table = of_match_ptr(sbsm_dt_ids),
},
.probe = sbsm_probe,
.remove = sbsm_remove,
.alert = sbsm_alert,
.id_table = sbsm_ids
};
module_i2c_driver(sbsm_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");
MODULE_DESCRIPTION("SBSM Smart Battery System Manager");
