On Sat, 9 Jan 2021 19:02:16 +0100 Jonathan Neuschäfer <j.neuschae...@gmx.net> wrote:
> The Netronix embedded controller is a microcontroller found in some > e-book readers designed by the original design manufacturer Netronix, > Inc. It contains RTC, battery monitoring, system power management, and > PWM functionality. > > This driver implements register access and version detection. > > Third-party hardware documentation is available at: > > > https://github.com/neuschaefer/linux/wiki/Netronix-MSP430-embedded-controller > > The EC supports interrupts, but the driver doesn't make use of them so > far. > > Signed-off-by: Jonathan Neuschäfer <j.neuschae...@gmx.net> > Acked-for-MFD-by: Lee Jones <lee.jo...@linaro.org> > --- > v7: > - Add #define for version number (suggested by Lee Jones). > > v6: > - https://lore.kernel.org/lkml/20201208011000.3060239-4-j.neuschae...@gmx.net/ > - Add Lee Jones' ACK > > v5: > - no changes > > v4: > - https://lore.kernel.org/lkml/20201122222739.1455132-4-j.neuschae...@gmx.net/ > - include asm/unaligned.h after linux/* > - Use put_unaligned_be16 instead of open-coded big-endian packing > - Clarify that 0x90=0xff00 causes an error in downstream kernel too > - Add commas after non-sentinel positions > - ntxec.h: declare structs device and regmap > - Replace WARN_ON usage and add comments to explain errors > - Replace dev_alert with dev_warn when the result isn't handled > - Change subdevice registration error message to dev_err > - Declare ntxec_reg8 as returning __be16 > - Restructure version detection code > - Spell out ODM > > v3: > - https://lore.kernel.org/lkml/20200924192455.2484005-4-j.neuschae...@gmx.net/ > - Add (EC) to CONFIG_MFD_NTXEC prompt > - Relicense as GPLv2 or later > - Add email address to copyright line > - remove empty lines in ntxec_poweroff and ntxec_restart functions > - Split long lines > - Remove 'Install ... handler' comments > - Make naming of struct i2c_client parameter consistent > - Remove struct ntxec_info > - Rework 'depends on' lines in Kconfig, hard-depend on I2C, select REGMAP_I2C > and > MFD_CORE > - Register subdevices via mfd_cells > - Move 8-bit register conversion to ntxec.h > > v2: > - https://lore.kernel.org/lkml/20200905133230.1014581-4-j.neuschae...@gmx.net/ > - Add a description of the device to the patch text > - Unify spelling as 'Netronix embedded controller'. > 'Netronix' is the proper name of the manufacturer, but 'embedded controller' > is just a label that I have assigned to the device. > - Switch to regmap, avoid regmap use in poweroff and reboot handlers. > Inspired by cf84dc0bb40f4 ("mfd: rn5t618: Make restart handler atomic safe") > - Use a list of known-working firmware versions instead of checking for a > known-incompatible version > - Prefix registers with NTXEC_REG_ > - Define register values as constants > - Various style cleanups as suggested by Lee Jones > - Don't align = signs in struct initializers [Uwe Kleine-König] > - Don't use dev_dbg for an error message > - Explain sleep in poweroff handler > - Remove (struct ntxec).client > - Switch to .probe_new in i2c driver > - Add .remove callback > - Make CONFIG_MFD_NTXEC a tristate option > --- > drivers/mfd/Kconfig | 11 ++ > drivers/mfd/Makefile | 1 + > drivers/mfd/ntxec.c | 216 ++++++++++++++++++++++++++++++++++++++ > include/linux/mfd/ntxec.h | 37 +++++++ > 4 files changed, 265 insertions(+) > create mode 100644 drivers/mfd/ntxec.c > create mode 100644 include/linux/mfd/ntxec.h > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index bdfce7b156216..4280bcd47ec7d 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -976,6 +976,17 @@ config MFD_VIPERBOARD > You need to select the mfd cell drivers separately. > The drivers do not support all features the board exposes. > > +config MFD_NTXEC > + tristate "Netronix embedded controller (EC)" > + depends on OF || COMPILE_TEST > + depends on I2C > + select REGMAP_I2C > + select MFD_CORE > + help > + Say yes here if you want to support the embedded controller found in > + certain e-book readers designed by the original design manufacturer > + Netronix. > + > config MFD_RETU > tristate "Nokia Retu and Tahvo multi-function device" > select MFD_CORE > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile > index 14fdb188af022..948a3bf8e3e57 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -219,6 +219,7 @@ obj-$(CONFIG_MFD_INTEL_PMC_BXT) += intel_pmc_bxt.o > obj-$(CONFIG_MFD_INTEL_PMT) += intel_pmt.o > obj-$(CONFIG_MFD_PALMAS) += palmas.o > obj-$(CONFIG_MFD_VIPERBOARD) += viperboard.o > +obj-$(CONFIG_MFD_NTXEC) += ntxec.o > obj-$(CONFIG_MFD_RC5T583) += rc5t583.o rc5t583-irq.o > obj-$(CONFIG_MFD_RK808) += rk808.o > obj-$(CONFIG_MFD_RN5T618) += rn5t618.o > diff --git a/drivers/mfd/ntxec.c b/drivers/mfd/ntxec.c > new file mode 100644 > index 0000000000000..22ed2ef0669cb > --- /dev/null > +++ b/drivers/mfd/ntxec.c > @@ -0,0 +1,216 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * The Netronix embedded controller is a microcontroller found in some > + * e-book readers designed by the original design manufacturer Netronix, Inc. > + * It contains RTC, battery monitoring, system power management, and PWM > + * functionality. > + * > + * This driver implements register access, version detection, and system > + * power-off/reset. > + * > + * Copyright 2020 Jonathan Neuschäfer <j.neuschae...@gmx.net> > + */ > + > +#include <linux/delay.h> > +#include <linux/errno.h> > +#include <linux/i2c.h> > +#include <linux/mfd/core.h> > +#include <linux/mfd/ntxec.h> > +#include <linux/module.h> > +#include <linux/pm.h> > +#include <linux/reboot.h> > +#include <linux/regmap.h> > +#include <linux/types.h> > +#include <asm/unaligned.h> > + > +#define NTXEC_REG_VERSION 0x00 > +#define NTXEC_REG_POWEROFF 0x50 > +#define NTXEC_REG_POWERKEEP 0x70 > +#define NTXEC_REG_RESET 0x90 > + > +#define NTXEC_POWEROFF_VALUE 0x0100 > +#define NTXEC_POWERKEEP_VALUE 0x0800 > +#define NTXEC_RESET_VALUE 0xff00 > + > +static struct i2c_client *poweroff_restart_client; > + > +static void ntxec_poweroff(void) > +{ > + int res; > + u8 buf[3] = { NTXEC_REG_POWEROFF }; > + struct i2c_msg msgs[] = { > + { > + .addr = poweroff_restart_client->addr, > + .flags = 0, > + .len = sizeof(buf), > + .buf = buf, > + }, > + }; > + > + put_unaligned_be16(NTXEC_POWEROFF_VALUE, buf + 1); > + > + res = i2c_transfer(poweroff_restart_client->adapter, msgs, > ARRAY_SIZE(msgs)); > + if (res < 0) > + dev_warn(&poweroff_restart_client->dev, > + "Failed to power off (err = %d)\n", res); > + > + /* > + * The time from the register write until the host CPU is powered off > + * has been observed to be about 2.5 to 3 seconds. Sleep long enough to > + * safely avoid returning from the poweroff handler. > + */ > + msleep(5000); > +} > + > +static int ntxec_restart(struct notifier_block *nb, > + unsigned long action, void *data) > +{ > + int res; > + u8 buf[3] = { NTXEC_REG_RESET }; > + /* > + * NOTE: The lower half of the reset value is not sent, because sending > + * it causes an I2C error. (The reset handler in the downstream driver > + * does send the full two-byte value, but doesn't check the result). > + */ > + struct i2c_msg msgs[] = { > + { > + .addr = poweroff_restart_client->addr, > + .flags = 0, > + .len = sizeof(buf) - 1, > + .buf = buf, > + }, > + }; > + > + put_unaligned_be16(NTXEC_RESET_VALUE, buf + 1); > + > + res = i2c_transfer(poweroff_restart_client->adapter, msgs, > ARRAY_SIZE(msgs)); > + if (res < 0) > + dev_warn(&poweroff_restart_client->dev, > + "Failed to restart (err = %d)\n", res); > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block ntxec_restart_handler = { > + .notifier_call = ntxec_restart, > + .priority = 128, > +}; > + > +static const struct regmap_config regmap_config = { > + .name = "ntxec", > + .reg_bits = 8, > + .val_bits = 16, > + .cache_type = REGCACHE_NONE, > + .val_format_endian = REGMAP_ENDIAN_BIG, > +}; > + > +static const struct mfd_cell ntxec_subdevices[] = { > + { .name = "ntxec-rtc" }, > + { .name = "ntxec-pwm" }, > +}; > + > +static int ntxec_probe(struct i2c_client *client) > +{ > + struct ntxec *ec; > + unsigned int version; > + int res; > + > + ec = devm_kmalloc(&client->dev, sizeof(*ec), GFP_KERNEL); > + if (!ec) > + return -ENOMEM; > + > + ec->dev = &client->dev; > + > + ec->regmap = devm_regmap_init_i2c(client, ®map_config); > + if (IS_ERR(ec->regmap)) { > + dev_err(ec->dev, "Failed to set up regmap for device\n"); > + return res; > + } > + > + /* Determine the firmware version */ > + res = regmap_read(ec->regmap, NTXEC_REG_VERSION, &version); > + if (res < 0) { > + dev_err(ec->dev, "Failed to read firmware version number\n"); > + return res; > + } > + > + /* Bail out if we encounter an unknown firmware version */ > + switch (version) { > + case NTXEC_VERSION_KOBO_AURA: > + break; > + default: > + dev_err(ec->dev, > + "Netronix embedded controller version %04x is not > supported.\n", > + version); > + return -ENODEV; > + } > + > + dev_info(ec->dev, > + "Netronix embedded controller version %04x detected.\n", > version); > + > + if (of_device_is_system_power_controller(ec->dev->of_node)) { > + /* > + * Set the 'powerkeep' bit. This is necessary on some boards > + * in order to keep the system running. > + */ > + res = regmap_write(ec->regmap, NTXEC_REG_POWERKEEP, > + NTXEC_POWERKEEP_VALUE); > + if (res < 0) > + return res; > + > + if (poweroff_restart_client) > + /* > + * Another instance of the driver already took > + * poweroff/restart duties. > + */ > + dev_err(ec->dev, "poweroff_restart_client already > assigned\n"); > + else > + poweroff_restart_client = client; > + > + if (pm_power_off) > + /* Another driver already registered a poweroff > handler. */ > + dev_err(ec->dev, "pm_power_off already assigned\n"); > + else > + pm_power_off = ntxec_poweroff; > + > + res = register_restart_handler(&ntxec_restart_handler); > + if (res) > + dev_err(ec->dev, > + "Failed to register restart handler: %d\n", > res); > + } > + > + i2c_set_clientdata(client, ec); > + > + res = devm_mfd_add_devices(ec->dev, PLATFORM_DEVID_NONE, > ntxec_subdevices, > + ARRAY_SIZE(ntxec_subdevices), NULL, 0, NULL); > + if (res) > + dev_err(ec->dev, "Failed to add subdevices: %d\n", res); > + > + return res; > +} > + > +static int ntxec_remove(struct i2c_client *client) > +{ > + if (client == poweroff_restart_client) { > + poweroff_restart_client = NULL; > + pm_power_off = NULL; > + unregister_restart_handler(&ntxec_restart_handler); > + } > + > + return 0; > +} > + > +static const struct of_device_id of_ntxec_match_table[] = { > + { .compatible = "netronix,ntxec", }, > + {} > +}; > + MODULE_DEVICE_TABLE? > +static struct i2c_driver ntxec_driver = { > + .driver = { > + .name = "ntxec", > + .of_match_table = of_ntxec_match_table, > + }, > + .probe_new = ntxec_probe, > + .remove = ntxec_remove, > +}; > +module_i2c_driver(ntxec_driver); MODULE_LICENSE()? modpost moans about that here. Regards, Andreas
