This driver provides access to the EC RAM of said embedded controller attached to the I2C bus as well as optionally supporting its slightly weird power-off/restart protocol.

A particular implementation of the EC firmware can be identified by a model byte. If this driver identifies the Dell Ariel platform, it registers the appropriate cells.

Signed-off-by: Lubomir Rintel lkundrak@v3.sk

--- Changes since v3: - Clarify that the power-off function is provided by this driver while LEDS_ARIEL is necessary to drive the leds in Kconfig help text - s/kb3930_power_off/kb3930_pm_power_off/, s/global_kb3930/kb3930_power_off/ - Don't fail with -EEXIST with more than one instance - s/ret < 0/ret/ for devm_mfd_add_devices() return value - Drop a \n between struct i2c_driver and module_i2c_driver()

Changes since v2: - Sort the includes - s/EC_MODEL_ID/EC_MODEL/ - Add a couple of clarifying comments - Use #defines for values used in poweroff routine - Remove priority from a restart notifier block - s/priv/ddata/ - s/ec_ram/ram_regmap/ for the regmap name - Fix the error handling when getting off gpios was not successful - Remove a useless dev_info at the end of probe() - Use i2c probe_new() callback, drop i2c_device_id - Modify the logic in checking the model ID

drivers/mfd/Kconfig | 11 ++ drivers/mfd/Makefile | 1 + drivers/mfd/ene-kb3930.c | 211 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 223 insertions(+) create mode 100644 drivers/mfd/ene-kb3930.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index a37d7d1713820..7569f1d1703e3 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -398,6 +398,17 @@ config MFD_DLN2 etc. must be enabled in order to use the functionality of the device.

+config MFD_ENE_KB3930 + tristate "ENE KB3930 Embedded Controller support" + depends on I2C + depends on MACH_MMP3_DT || COMPILE_TEST + select MFD_CORE + help + This adds support for the power-off functionality and access to + the registers that control LEDS and USB port power on ENE KB3930 + Embedded Controller. To use the LED functionality LEDS_ARIEL must + be enabled. + config MFD_EXYNOS_LPASS tristate "Samsung Exynos SoC Low Power Audio Subsystem" depends on ARCH_EXYNOS || COMPILE_TEST diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile index 9367a92f795a6..11085a6968398 100644 --- a/drivers/mfd/Makefile +++ b/drivers/mfd/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_BCM2835) += bcm2835-pm.o obj-$(CONFIG_MFD_BCM590XX) += bcm590xx.o obj-$(CONFIG_MFD_BD9571MWV) += bd9571mwv.o obj-$(CONFIG_MFD_CROS_EC_DEV) += cros_ec_dev.o +obj-$(CONFIG_MFD_ENE_KB3930) += ene-kb3930.o obj-$(CONFIG_MFD_EXYNOS_LPASS) += exynos-lpass.o obj-$(CONFIG_MFD_GATEWORKS_GSC) += gateworks-gsc.o

diff --git a/drivers/mfd/ene-kb3930.c b/drivers/mfd/ene-kb3930.c new file mode 100644 index 0000000000000..75eced148ce53 --- /dev/null +++ b/drivers/mfd/ene-kb3930.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later +/* + * ENE KB3930 Embedded Controller Driver + * + * Copyright (C) 2020 Lubomir Rintel + */ + +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/mfd/core.h> +#include <linux/module.h> +#include <linux/reboot.h> +#include <linux/regmap.h> + +/* I2C registers that are multiplexing access to the EC RAM. */ +enum { + EC_DATA_IN = 0x00, + EC_RAM_OUT = 0x80, + EC_RAM_IN = 0x81, +}; + +/* EC RAM registers. */ +enum { + EC_MODEL = 0x30, + EC_VERSION_MAJ = 0x31, + EC_VERSION_MIN = 0x32, +}; + +struct kb3930 { + struct i2c_client *client; + struct regmap *ram_regmap; + struct gpio_descs *off_gpios; +}; + +struct kb3930 *kb3930_power_off; + +#define EC_GPIO_WAVE 0 +#define EC_GPIO_OFF_MODE 1 + +#define EC_OFF_MODE_REBOOT 0 +#define EC_OFF_MODE_POWER 1 + +static void kb3930_off(struct kb3930 *ddata, int off_mode) +{ + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_OFF_MODE], + off_mode); + + /* + * The EC initiates a shutdown when it detects a 10 MHz wave, inspecting the + * other GPIO pin to decide whether it's supposed to turn the power off or + * reset the board. + */ + while (1) { + mdelay(50); + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 0); + mdelay(50); + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 1); + } +} + +static int kb3930_restart(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + kb3930_off(kb3930_power_off, EC_OFF_MODE_REBOOT); + return NOTIFY_DONE; +} + +static void kb3930_pm_power_off(void) +{ + kb3930_off(kb3930_power_off, EC_OFF_MODE_POWER); +} + +static struct notifier_block kb3930_restart_nb = { + .notifier_call = kb3930_restart, +}; + +static const struct mfd_cell ariel_ec_cells[] = { + { .name = "dell-wyse-ariel-led", }, + { .name = "dell-wyse-ariel-power", }, +}; + +static int kb3930_ec_ram_reg_write(void *context, unsigned int reg, + unsigned int val) +{ + struct kb3930 *ddata = context; + + return i2c_smbus_write_word_data(ddata->client, EC_RAM_OUT, + (val << 8) | reg); +} + +static int kb3930_ec_ram_reg_read(void *context, unsigned int reg, + unsigned int *val) +{ + struct kb3930 *ddata = context; + int ret; + + ret = i2c_smbus_write_word_data(ddata->client, EC_RAM_IN, reg); + if (ret < 0) + return ret; + + ret = i2c_smbus_read_word_data(ddata->client, EC_DATA_IN); + if (ret < 0) + return ret; + + *val = ret >> 8; + return 0; +} + +static const struct regmap_config kb3930_ram_regmap_config = { + .name = "ec_ram", + .reg_bits = 8, + .val_bits = 8, + .reg_stride = 1, + .max_register = 0xff, + .reg_write = kb3930_ec_ram_reg_write, + .reg_read = kb3930_ec_ram_reg_read, + .fast_io = false, +}; + +static int kb3930_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct device_node *np = dev->of_node; + struct kb3930 *ddata; + unsigned int model; + int ret; + + ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) + return -ENOMEM; + + kb3930_power_off = ddata; + ddata->client = client; + i2c_set_clientdata(client, ddata); + + ddata->ram_regmap = devm_regmap_init(dev, NULL, ddata, + &kb3930_ram_regmap_config); + if (IS_ERR(ddata->ram_regmap)) + return PTR_ERR(ddata->ram_regmap); + + ret = regmap_read(ddata->ram_regmap, EC_MODEL, &model); + if (ret < 0) + return ret; + + /* Currently we only support the cells present on Dell Ariel model. */ + if (model != 'J') { + dev_err(dev, "unknown board model: %02x\n", model); + return -ENODEV; + } + + /* These are the cells valid for model == 'J' only. */ + ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, + ariel_ec_cells, + ARRAY_SIZE(ariel_ec_cells), + NULL, 0, NULL); + if (ret) + return ret; + + if (of_property_read_bool(np, "system-power-controller")) { + ddata->off_gpios = + devm_gpiod_get_array_optional(dev, "off", GPIOD_IN); + if (IS_ERR(ddata->off_gpios)) + return PTR_ERR(ddata->off_gpios); + if (ddata->off_gpios->ndescs < 2) { + dev_err(dev, "invalid off-gpios property\n"); + return -EINVAL; + } + } + if (ddata->off_gpios) { + register_restart_handler(&kb3930_restart_nb); + if (pm_power_off == NULL) + pm_power_off = kb3930_pm_power_off; + } + + return 0; +} + +static int kb3930_remove(struct i2c_client *client) +{ + struct kb3930 *ddata = i2c_get_clientdata(client); + + if (ddata->off_gpios) { + if (pm_power_off == kb3930_pm_power_off) + pm_power_off = NULL; + unregister_restart_handler(&kb3930_restart_nb); + } + kb3930_power_off = NULL; + + return 0; +} + +static const struct of_device_id kb3930_dt_ids[] = { + { .compatible = "ene,kb3930" }, + { } +}; +MODULE_DEVICE_TABLE(of, kb3930_dt_ids); + +static struct i2c_driver kb3930_driver = { + .probe_new = kb3930_probe, + .remove = kb3930_remove, + .driver = { + .name = "ene-kb3930", + .of_match_table = of_match_ptr(kb3930_dt_ids), + }, +}; +module_i2c_driver(kb3930_driver); + +MODULE_AUTHOR("Lubomir Rintel lkundrak@v3.sk"); +MODULE_DESCRIPTION("ENE KB3930 Embedded Controller Driver"); +MODULE_LICENSE("Dual BSD/GPL");