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SubjectRe: [PATCH 1/2] power: Add support for the Toby Churchill SBS battery monitor driver.
From
Date
Hi,

On 15/03/17 22:52, Sebastian Reichel wrote:
> Hi,
>
> On Thu, Feb 23, 2017 at 06:38:11PM +0100, Enric Balletbo i Serra wrote:
>> 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.
>
> Sorry for the delay. I'm mostly fine with the driver. You can find a
> few notes below.
>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.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);
>
> spi_write_then_read(spi, &i, 1, &buf[i], 1)
> if (err)
> complain
>

Hmm, how odd, it works with

err = spi_write(
if (err)
complain
err = spi_read(
if (err)
complain

But not with
err = spi_write_then_read(
if (err)
complain

I'm wondering what's the difference. I need to debug a bit this thing before
send v2.


>> + }
>> +
>> + 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;
>
> dev_dbg? So it happens regularly?
>

Right, should be dev_err, also I think I'll move the print_hex_dump here and
just print the dump if it fails (and replace for print_hex_dump_debug)

>> + }
>> +
>> + /* 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);
>
> looks like the driver would benefit from regmap.
>
>> + 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),
>
> Either put xmega16d4_battery_of_match inside of #ifdef CONFIG_OF
> or drop of_match_ptr. Otherwise there will be an unused warning
> for the CONFIG_OF=n case.
>

Ok

>> + },
>> + .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@collabora.com>");
>> +MODULE_DESCRIPTION("xmega16d4 battery monitor driver");
>
> Otherwise the driver looks fine. I'm a bit worried about the name,
> though. xmega16d4 is just a microcontroller. This driver is more
> about its firmware. I think something like "toby-churchill-battery-monitor"
> would be better.
>

It's not a problem rename the driver, I'm thinking in tcl-sbs-battery if it's
fine, a bit shorted that the one you proposed.

> -- Sebastian
>
Thanks,
Enric

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