421 lines
10 KiB
C
421 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Driver for SBS compliant Smart Battery System Managers
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*
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* The device communicates via i2c at address 0x0a and multiplexes access to up
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* to four smart batteries at address 0x0b.
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*
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* Via sysfs interface the online state and charge type are presented.
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*
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* Datasheet SBSM: http://sbs-forum.org/specs/sbsm100b.pdf
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* Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf
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*
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* Karl-Heinz Schneider <karl-heinz@schneider-inet.de>
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*/
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#include <linux/gpio/driver.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/i2c-mux.h>
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#include <linux/power_supply.h>
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#include <linux/property.h>
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#define SBSM_MAX_BATS 4
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#define SBSM_RETRY_CNT 3
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/* registers addresses */
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#define SBSM_CMD_BATSYSSTATE 0x01
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#define SBSM_CMD_BATSYSSTATECONT 0x02
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#define SBSM_CMD_BATSYSINFO 0x04
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#define SBSM_CMD_LTC 0x3c
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#define SBSM_MASK_BAT_SUPPORTED GENMASK(3, 0)
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#define SBSM_MASK_CHARGE_BAT GENMASK(7, 4)
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#define SBSM_BIT_AC_PRESENT BIT(0)
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#define SBSM_BIT_TURBO BIT(7)
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#define SBSM_SMB_BAT_OFFSET 11
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struct sbsm_data {
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struct i2c_client *client;
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struct i2c_mux_core *muxc;
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struct power_supply *psy;
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u8 cur_chan; /* currently selected channel */
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struct gpio_chip chip;
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bool is_ltc1760; /* special capabilities */
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unsigned int supported_bats;
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unsigned int last_state;
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unsigned int last_state_cont;
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};
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static enum power_supply_property sbsm_props[] = {
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POWER_SUPPLY_PROP_ONLINE,
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POWER_SUPPLY_PROP_CHARGE_TYPE,
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};
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static int sbsm_read_word(struct i2c_client *client, u8 address)
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{
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int reg, retries;
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for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
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reg = i2c_smbus_read_word_data(client, address);
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if (reg >= 0)
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break;
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}
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if (reg < 0) {
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dev_err(&client->dev, "failed to read register 0x%02x\n",
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address);
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}
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return reg;
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}
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static int sbsm_write_word(struct i2c_client *client, u8 address, u16 word)
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{
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int ret, retries;
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for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
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ret = i2c_smbus_write_word_data(client, address, word);
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if (ret >= 0)
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break;
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}
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if (ret < 0)
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dev_err(&client->dev, "failed to write to register 0x%02x\n",
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address);
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return ret;
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}
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static int sbsm_get_property(struct power_supply *psy,
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enum power_supply_property psp,
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union power_supply_propval *val)
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{
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struct sbsm_data *data = power_supply_get_drvdata(psy);
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int regval = 0;
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switch (psp) {
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case POWER_SUPPLY_PROP_ONLINE:
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regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATECONT);
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if (regval < 0)
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return regval;
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val->intval = !!(regval & SBSM_BIT_AC_PRESENT);
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break;
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case POWER_SUPPLY_PROP_CHARGE_TYPE:
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regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
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if (regval < 0)
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return regval;
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if ((regval & SBSM_MASK_CHARGE_BAT) == 0) {
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val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
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return 0;
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}
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val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
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if (data->is_ltc1760) {
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/* charge mode fast if turbo is active */
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regval = sbsm_read_word(data->client, SBSM_CMD_LTC);
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if (regval < 0)
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return regval;
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else if (regval & SBSM_BIT_TURBO)
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val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
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}
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static int sbsm_prop_is_writeable(struct power_supply *psy,
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enum power_supply_property psp)
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{
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struct sbsm_data *data = power_supply_get_drvdata(psy);
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return (psp == POWER_SUPPLY_PROP_CHARGE_TYPE) && data->is_ltc1760;
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}
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static int sbsm_set_property(struct power_supply *psy,
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enum power_supply_property psp,
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const union power_supply_propval *val)
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{
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struct sbsm_data *data = power_supply_get_drvdata(psy);
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int ret = -EINVAL;
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u16 regval;
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switch (psp) {
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case POWER_SUPPLY_PROP_CHARGE_TYPE:
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/* write 1 to TURBO if type fast is given */
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if (!data->is_ltc1760)
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break;
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regval = val->intval ==
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POWER_SUPPLY_CHARGE_TYPE_FAST ? SBSM_BIT_TURBO : 0;
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ret = sbsm_write_word(data->client, SBSM_CMD_LTC, regval);
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break;
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default:
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break;
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}
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return ret;
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}
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/*
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* Switch to battery
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* Parameter chan is directly the content of SMB_BAT* nibble
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*/
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static int sbsm_select(struct i2c_mux_core *muxc, u32 chan)
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{
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struct sbsm_data *data = i2c_mux_priv(muxc);
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struct device *dev = &data->client->dev;
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int ret = 0;
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u16 reg;
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if (data->cur_chan == chan)
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return ret;
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/* chan goes from 1 ... 4 */
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reg = BIT(SBSM_SMB_BAT_OFFSET + chan);
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ret = sbsm_write_word(data->client, SBSM_CMD_BATSYSSTATE, reg);
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if (ret)
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dev_err(dev, "Failed to select channel %i\n", chan);
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else
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data->cur_chan = chan;
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return ret;
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}
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static int sbsm_gpio_get_value(struct gpio_chip *gc, unsigned int off)
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{
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struct sbsm_data *data = gpiochip_get_data(gc);
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int ret;
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ret = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
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if (ret < 0)
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return ret;
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return ret & BIT(off);
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}
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/*
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* This needs to be defined or the GPIO lib fails to register the pin.
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* But the 'gpio' is always an input.
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*/
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static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
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{
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return 0;
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}
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static int sbsm_do_alert(struct device *dev, void *d)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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if (!client || client->addr != 0x0b)
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return 0;
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device_lock(dev);
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if (client->dev.driver) {
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driver = to_i2c_driver(client->dev.driver);
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if (driver->alert)
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driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, 0);
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else
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dev_warn(&client->dev, "no driver alert()!\n");
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} else {
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dev_dbg(&client->dev, "alert with no driver\n");
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}
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device_unlock(dev);
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return -EBUSY;
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}
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static void sbsm_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
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unsigned int d)
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{
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struct sbsm_data *sbsm = i2c_get_clientdata(client);
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int ret, i, irq_bat = 0, state = 0;
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ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATE);
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if (ret >= 0) {
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irq_bat = ret ^ sbsm->last_state;
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sbsm->last_state = ret;
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state = ret;
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}
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ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATECONT);
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if ((ret >= 0) &&
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((ret ^ sbsm->last_state_cont) & SBSM_BIT_AC_PRESENT)) {
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irq_bat |= sbsm->supported_bats & state;
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power_supply_changed(sbsm->psy);
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}
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sbsm->last_state_cont = ret;
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for (i = 0; i < SBSM_MAX_BATS; i++) {
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if (irq_bat & BIT(i)) {
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device_for_each_child(&sbsm->muxc->adapter[i]->dev,
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NULL, sbsm_do_alert);
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}
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}
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}
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static int sbsm_gpio_setup(struct sbsm_data *data)
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{
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struct gpio_chip *gc = &data->chip;
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struct i2c_client *client = data->client;
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struct device *dev = &client->dev;
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int ret;
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if (!device_property_present(dev, "gpio-controller"))
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return 0;
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ret = sbsm_read_word(client, SBSM_CMD_BATSYSSTATE);
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if (ret < 0)
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return ret;
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data->last_state = ret;
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ret = sbsm_read_word(client, SBSM_CMD_BATSYSSTATECONT);
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if (ret < 0)
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return ret;
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data->last_state_cont = ret;
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gc->get = sbsm_gpio_get_value;
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gc->direction_input = sbsm_gpio_direction_input;
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gc->can_sleep = true;
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gc->base = -1;
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gc->ngpio = SBSM_MAX_BATS;
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gc->label = client->name;
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gc->parent = dev;
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gc->owner = THIS_MODULE;
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ret = devm_gpiochip_add_data(dev, gc, data);
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if (ret)
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return dev_err_probe(dev, ret, "devm_gpiochip_add_data failed\n");
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return ret;
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}
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static const struct power_supply_desc sbsm_default_psy_desc = {
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.type = POWER_SUPPLY_TYPE_MAINS,
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.properties = sbsm_props,
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.num_properties = ARRAY_SIZE(sbsm_props),
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.get_property = &sbsm_get_property,
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.set_property = &sbsm_set_property,
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.property_is_writeable = &sbsm_prop_is_writeable,
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};
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static void sbsm_del_mux_adapter(void *data)
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{
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struct sbsm_data *sbsm = data;
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i2c_mux_del_adapters(sbsm->muxc);
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}
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static int sbsm_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = client->adapter;
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struct sbsm_data *data;
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struct device *dev = &client->dev;
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struct power_supply_desc *psy_desc;
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struct power_supply_config psy_cfg = {};
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int ret = 0, i;
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/* Device listens only at address 0x0a */
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if (client->addr != 0x0a)
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return -EINVAL;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
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return -EPFNOSUPPORT;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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i2c_set_clientdata(client, data);
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data->client = client;
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data->is_ltc1760 = !!strstr(id->name, "ltc1760");
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ret = sbsm_read_word(client, SBSM_CMD_BATSYSINFO);
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if (ret < 0)
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return ret;
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data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED;
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data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0,
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I2C_MUX_LOCKED, &sbsm_select, NULL);
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if (!data->muxc)
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return dev_err_probe(dev, -ENOMEM, "failed to alloc i2c mux\n");
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data->muxc->priv = data;
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ret = devm_add_action_or_reset(dev, sbsm_del_mux_adapter, data);
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if (ret)
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return ret;
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/* register muxed i2c channels. One for each supported battery */
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for (i = 0; i < SBSM_MAX_BATS; ++i) {
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if (data->supported_bats & BIT(i)) {
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ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0);
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if (ret)
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break;
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}
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}
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if (ret)
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return dev_err_probe(dev, ret, "failed to register i2c mux channel %d\n", i + 1);
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psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc, sizeof(*psy_desc), GFP_KERNEL);
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if (!psy_desc)
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return -ENOMEM;
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psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s", dev_name(&client->dev));
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if (!psy_desc->name)
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return -ENOMEM;
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ret = sbsm_gpio_setup(data);
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if (ret < 0)
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return ret;
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psy_cfg.drv_data = data;
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psy_cfg.of_node = dev->of_node;
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data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg);
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if (IS_ERR(data->psy))
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return dev_err_probe(dev, PTR_ERR(data->psy),
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"failed to register power supply %s\n", psy_desc->name);
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return 0;
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}
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static const struct i2c_device_id sbsm_ids[] = {
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{ "sbs-manager", 0 },
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{ "ltc1760", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, sbsm_ids);
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#ifdef CONFIG_OF
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static const struct of_device_id sbsm_dt_ids[] = {
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{ .compatible = "sbs,sbs-manager" },
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{ .compatible = "lltc,ltc1760" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, sbsm_dt_ids);
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#endif
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static struct i2c_driver sbsm_driver = {
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.driver = {
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.name = "sbsm",
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.of_match_table = of_match_ptr(sbsm_dt_ids),
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},
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.probe = sbsm_probe,
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.alert = sbsm_alert,
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.id_table = sbsm_ids
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};
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module_i2c_driver(sbsm_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");
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MODULE_DESCRIPTION("SBSM Smart Battery System Manager");
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