The Gateworks System Controller (GSC) is an I2C slave controller implemented with an MSP430 micro-controller whose firmware embeds the following features: - I/O expander (16 GPIO's) using PCA955x protocol - Real Time Clock using DS1672 protocol - User EEPROM using AT24 protocol - HWMON using custom protocol - Interrupt controller with tamper detect, user pushbotton - Watchdog controller capable of full board power-cycle - Power Control capable of full board power-cycle see http://trac.gateworks.com/wiki/gsc for more details Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> v4: - remove hwmon max reg check/define - fix powerdown function v3: - rename gsc->gateworks-gsc - remove uncecessary include for linux/mfd/core.h - upercase I2C in comments - remove i2c debug - remove uncecessary comments - don't use KBUILD_MODNAME for name - remove unnecessary v1/v2/v3 tracking - unregister hwmon i2c adapter on remove v2: - change license comment block style - remove COMPILE_TEST (Randy) - fixed whitespace issues - replaced a printk with dev_err --- MAINTAINERS | 8 ++ drivers/mfd/Kconfig | 10 ++ drivers/mfd/Makefile | 1 + drivers/mfd/gateworks-gsc.c | 294 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/mfd/gsc.h | 72 +++++++++++ 5 files changed, 385 insertions(+) create mode 100644 drivers/mfd/gateworks-gsc.c create mode 100644 include/linux/mfd/gsc.h diff --git a/MAINTAINERS b/MAINTAINERS index 56765f5..bb79b60 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6839,6 +6839,14 @@ F: tools/testing/selftests/futex/ F: tools/perf/bench/futex* F: Documentation/*futex* +GATEWORKS SYSTEM CONTROLLER (GSC) DRIVER +M: Tim Harvey <tharvey@xxxxxxxxxxxxx> +M: Robert Jones <rjones@xxxxxxxxxxxxx> +S: Maintained +F: Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml +F: drivers/mfd/gateworks-gsc.c +F: include/linux/mfd/gsc.h + GCC PLUGINS M: Kees Cook <keescook@xxxxxxxxxxxx> R: Emese Revfy <re.emese@xxxxxxxxx> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index 4209008..d84725a 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -407,6 +407,16 @@ config MFD_EXYNOS_LPASS Select this option to enable support for Samsung Exynos Low Power Audio Subsystem. +config MFD_GATEWORKS_GSC + tristate "Gateworks System Controller" + depends on (I2C && OF) + select MFD_CORE + select REGMAP_I2C + select REGMAP_IRQ + help + Enable support for the Gateworks System Controller found + on Gateworks Single Board Computers. + config MFD_MC13XXX tristate depends on (SPI_MASTER || I2C) diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile index aed99f0..c82b442 100644 --- a/drivers/mfd/Makefile +++ b/drivers/mfd/Makefile @@ -15,6 +15,7 @@ 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_EXYNOS_LPASS) += exynos-lpass.o +obj-$(CONFIG_MFD_GATEWORKS_GSC) += gateworks-gsc.o obj-$(CONFIG_HTC_PASIC3) += htc-pasic3.o obj-$(CONFIG_HTC_I2CPLD) += htc-i2cpld.o diff --git a/drivers/mfd/gateworks-gsc.c b/drivers/mfd/gateworks-gsc.c new file mode 100644 index 00000000..5eb7de5 --- /dev/null +++ b/drivers/mfd/gateworks-gsc.c @@ -0,0 +1,294 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * The Gateworks System Controller (GSC) is a multi-function + * device designed for use in Gateworks Single Board Computers. + * The control interface is I2C, with an interrupt. The device supports + * system functions such as pushbutton monitoring, multiple ADC's for + * voltage and temperature, fan controller, and watchdog monitor. + * + * Copyright (C) 2020 Gateworks Corporation + * + */ +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/mfd/gsc.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +/* + * The GSC suffers from an errata where occasionally during + * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable + * register access we place retries around register access. + */ +#define I2C_RETRIES 3 + +static int gsc_regmap_regwrite(void *context, unsigned int reg, + unsigned int val) +{ + struct i2c_client *client = context; + int retry, ret; + + for (retry = 0; retry < I2C_RETRIES; retry++) { + ret = i2c_smbus_write_byte_data(client, reg, val); + /* + * -EAGAIN returned when the i2c host controller is busy + * -EIO returned when i2c device is busy + */ + if (ret != -EAGAIN && ret != -EIO) + break; + } + + return 0; +} + +static int gsc_regmap_regread(void *context, unsigned int reg, + unsigned int *val) +{ + struct i2c_client *client = context; + int retry, ret; + + for (retry = 0; retry < I2C_RETRIES; retry++) { + ret = i2c_smbus_read_byte_data(client, reg); + /* + * -EAGAIN returned when the i2c host controller is busy + * -EIO returned when i2c device is busy + */ + if (ret != -EAGAIN && ret != -EIO) + break; + } + *val = ret & 0xff; + + return 0; +} + +static struct regmap_bus regmap_gsc = { + .reg_write = gsc_regmap_regwrite, + .reg_read = gsc_regmap_regread, +}; + +/* + * gsc_powerdown - API to use GSC to power down board for a specific time + * + * secs - number of seconds to remain powered off + */ +static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs) +{ + int ret; + unsigned char regs[4]; + + dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n", + secs); + regs[0] = secs & 0xff; + regs[1] = (secs >> 8) & 0xff; + regs[2] = (secs >> 16) & 0xff; + regs[3] = (secs >> 24) & 0xff; + ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4); + if (ret) + return ret; + regs[0] = 1 << GSC_CTRL_1_LATCH_SLEEP_ADD; + ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1, regs[0], regs[0]); + if (ret) + return ret; + regs[0] = (1 << GSC_CTRL_1_ACTIVATE_SLEEP) | + (1 << GSC_CTRL_1_SLEEP_ENABLE); + ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1, regs[0], regs[0]); + + return ret; +} + +static ssize_t gsc_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct gsc_dev *gsc = dev_get_drvdata(dev); + const char *name = attr->attr.name; + int rz = 0; + + if (strcasecmp(name, "fw_version") == 0) + rz = sprintf(buf, "%d\n", gsc->fwver); + else if (strcasecmp(name, "fw_crc") == 0) + rz = sprintf(buf, "0x%04x\n", gsc->fwcrc); + + return rz; +} + +static ssize_t gsc_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct gsc_dev *gsc = dev_get_drvdata(dev); + const char *name = attr->attr.name; + int ret; + + if (strcasecmp(name, "powerdown") == 0) { + long value; + + ret = kstrtol(buf, 0, &value); + if (ret == 0) + gsc_powerdown(gsc, value); + } else + dev_err(dev, "invalid name '%s\n", name); + + return count; +} + +static struct device_attribute attr_fwver = + __ATTR(fw_version, 0440, gsc_show, NULL); +static struct device_attribute attr_fwcrc = + __ATTR(fw_crc, 0440, gsc_show, NULL); +static struct device_attribute attr_pwrdown = + __ATTR(powerdown, 0220, NULL, gsc_store); + +static struct attribute *gsc_attrs[] = { + &attr_fwver.attr, + &attr_fwcrc.attr, + &attr_pwrdown.attr, + NULL, +}; + +static struct attribute_group attr_group = { + .attrs = gsc_attrs, +}; + +static const struct of_device_id gsc_of_match[] = { + { .compatible = "gw,gsc", }, + { } +}; + +static const struct regmap_config gsc_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .cache_type = REGCACHE_NONE, + .max_register = 0xf, +}; + +static const struct regmap_config gsc_regmap_hwmon_config = { + .reg_bits = 8, + .val_bits = 8, + .cache_type = REGCACHE_NONE, +}; + +static const struct regmap_irq gsc_irqs[] = { + REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)), + REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)), + REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)), + REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)), + REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)), + REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)), + REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)), + REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)), +}; + +static const struct regmap_irq_chip gsc_irq_chip = { + .name = "gateworks-gsc", + .irqs = gsc_irqs, + .num_irqs = ARRAY_SIZE(gsc_irqs), + .num_regs = 1, + .status_base = GSC_IRQ_STATUS, + .mask_base = GSC_IRQ_ENABLE, + .mask_invert = true, + .ack_base = GSC_IRQ_STATUS, + .ack_invert = true, +}; + +static int +gsc_probe(struct i2c_client *client, const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct gsc_dev *gsc; + int ret; + unsigned int reg; + + gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL); + if (!gsc) + return -ENOMEM; + + gsc->dev = &client->dev; + gsc->i2c = client; + gsc->irq = client->irq; + i2c_set_clientdata(client, gsc); + + gsc->regmap = devm_regmap_init(dev, ®map_gsc, client, + &gsc_regmap_config); + if (IS_ERR(gsc->regmap)) + return PTR_ERR(gsc->regmap); + + if (regmap_read(gsc->regmap, GSC_FW_VER, ®)) + return -EIO; + gsc->fwver = reg; + + regmap_read(gsc->regmap, GSC_FW_CRC, ®); + gsc->fwcrc = reg; + regmap_read(gsc->regmap, GSC_FW_CRC + 1, ®); + gsc->fwcrc |= reg << 8; + + gsc->i2c_hwmon = i2c_new_dummy_device(client->adapter, GSC_HWMON); + if (!gsc->i2c_hwmon) { + dev_err(dev, "Failed to allocate I2C device for HWMON\n"); + return -ENODEV; + } + i2c_set_clientdata(gsc->i2c_hwmon, gsc); + + gsc->regmap_hwmon = devm_regmap_init(dev, ®map_gsc, gsc->i2c_hwmon, + &gsc_regmap_hwmon_config); + if (IS_ERR(gsc->regmap_hwmon)) { + ret = PTR_ERR(gsc->regmap_hwmon); + dev_err(dev, "failed to allocate register map: %d\n", ret); + goto err_regmap; + } + + ret = devm_regmap_add_irq_chip(dev, gsc->regmap, gsc->irq, + IRQF_ONESHOT | IRQF_SHARED | + IRQF_TRIGGER_FALLING, 0, + &gsc_irq_chip, &gsc->irq_chip_data); + if (ret) + goto err_regmap; + + dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n", + gsc->fwver, gsc->fwcrc); + + ret = sysfs_create_group(&dev->kobj, &attr_group); + if (ret) + dev_err(dev, "failed to create sysfs attrs\n"); + + ret = of_platform_populate(dev->of_node, NULL, NULL, dev); + if (ret) + goto err_sysfs; + + return 0; + +err_sysfs: + sysfs_remove_group(&dev->kobj, &attr_group); +err_regmap: + i2c_unregister_device(gsc->i2c_hwmon); + + return ret; +} + +static int gsc_remove(struct i2c_client *client) +{ + struct gsc_dev *gsc = i2c_get_clientdata(client); + + sysfs_remove_group(&client->dev.kobj, &attr_group); + i2c_unregister_device(gsc->i2c_hwmon); + + return 0; +} + +static struct i2c_driver gsc_driver = { + .driver = { + .name = "gateworks-gsc", + .of_match_table = of_match_ptr(gsc_of_match), + }, + .probe = gsc_probe, + .remove = gsc_remove, +}; + +module_i2c_driver(gsc_driver); + +MODULE_AUTHOR("Tim Harvey <tharvey@xxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("I2C Core interface for GSC"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/mfd/gsc.h b/include/linux/mfd/gsc.h new file mode 100644 index 00000000..ed9e92d --- /dev/null +++ b/include/linux/mfd/gsc.h @@ -0,0 +1,72 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright (C) 2018 Gateworks Corporation + */ +#ifndef __LINUX_MFD_GSC_H_ +#define __LINUX_MFD_GSC_H_ + +/* Device Addresses */ +#define GSC_MISC 0x20 +#define GSC_UPDATE 0x21 +#define GSC_GPIO 0x23 +#define GSC_HWMON 0x29 +#define GSC_EEPROM0 0x50 +#define GSC_EEPROM1 0x51 +#define GSC_EEPROM2 0x52 +#define GSC_EEPROM3 0x53 +#define GSC_RTC 0x68 + +/* Register offsets */ +#define GSC_CTRL_0 0x00 +#define GSC_CTRL_1 0x01 +#define GSC_TIME 0x02 +#define GSC_TIME_ADD 0x06 +#define GSC_IRQ_STATUS 0x0A +#define GSC_IRQ_ENABLE 0x0B +#define GSC_FW_CRC 0x0C +#define GSC_FW_VER 0x0E +#define GSC_WP 0x0F + +/* Bit definitions */ +#define GSC_CTRL_0_PB_HARD_RESET 0 +#define GSC_CTRL_0_PB_CLEAR_SECURE_KEY 1 +#define GSC_CTRL_0_PB_SOFT_POWER_DOWN 2 +#define GSC_CTRL_0_PB_BOOT_ALTERNATE 3 +#define GSC_CTRL_0_PERFORM_CRC 4 +#define GSC_CTRL_0_TAMPER_DETECT 5 +#define GSC_CTRL_0_SWITCH_HOLD 6 + +#define GSC_CTRL_1_SLEEP_ENABLE 0 +#define GSC_CTRL_1_ACTIVATE_SLEEP 1 +#define GSC_CTRL_1_LATCH_SLEEP_ADD 2 +#define GSC_CTRL_1_SLEEP_NOWAKEPB 3 +#define GSC_CTRL_1_WDT_TIME 4 +#define GSC_CTRL_1_WDT_ENABLE 5 +#define GSC_CTRL_1_SWITCH_BOOT_ENABLE 6 +#define GSC_CTRL_1_SWITCH_BOOT_CLEAR 7 + +#define GSC_IRQ_PB 0 +#define GSC_IRQ_KEY_ERASED 1 +#define GSC_IRQ_EEPROM_WP 2 +#define GSC_IRQ_RESV 3 +#define GSC_IRQ_GPIO 4 +#define GSC_IRQ_TAMPER 5 +#define GSC_IRQ_WDT_TIMEOUT 6 +#define GSC_IRQ_SWITCH_HOLD 7 + +struct gsc_dev { + struct device *dev; + + struct i2c_client *i2c; /* 0x20: interrupt controller, WDT */ + struct i2c_client *i2c_hwmon; /* 0x29: hwmon, fan controller */ + + struct regmap *regmap; + struct regmap *regmap_hwmon; + struct regmap_irq_chip_data *irq_chip_data; + + int irq; + unsigned int fwver; + unsigned short fwcrc; +}; + +#endif /* __LINUX_MFD_GSC_H_ */ -- 2.7.4
