On Sat, 05 Sep 2020, Jonathan Neuschäfer wrote: > The Netronix embedded controller is a microcontroller found in some > e-book readers designed by the ODM 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.neuschaefer@xxxxxxx> > --- > > v2: > - 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 | 7 ++ > drivers/mfd/Makefile | 1 + > drivers/mfd/ntxec.c | 217 ++++++++++++++++++++++++++++++++++++++ > include/linux/mfd/ntxec.h | 24 +++++ > 4 files changed, 249 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 33df0837ab415..bab999081f32d 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -978,6 +978,13 @@ 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" Nit: "Embedded Controller (EC)" > + depends on I2C && OF depends on (I2C && OF) || COMPILE_TEST > + help > + Say yes here if you want to support the embedded controller found in > + certain e-book readers designed by the ODM 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 a60e5f835283e..236a8acd917a0 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -217,6 +217,7 @@ obj-$(CONFIG_MFD_INTEL_MSIC) += intel_msic.o > obj-$(CONFIG_MFD_INTEL_PMC_BXT) += intel_pmc_bxt.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..49cc4fa35b9fe > --- /dev/null > +++ b/drivers/mfd/ntxec.c > @@ -0,0 +1,217 @@ > +// SPDX-License-Identifier: GPL-2.0-only Why 2 only? > +/* > + * The Netronix embedded controller is a microcontroller found in some > + * e-book readers designed by the ODM 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 Email? > + */ > + > +#include <asm/unaligned.h> > +#include <linux/delay.h> > +#include <linux/errno.h> > +#include <linux/i2c.h> > +#include <linux/mfd/ntxec.h> > +#include <linux/module.h> > +#include <linux/of_platform.h> > +#include <linux/pm.h> > +#include <linux/reboot.h> > +#include <linux/regmap.h> > +#include <linux/types.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; > + Remove this line please. > + u8 buf[] = { > + NTXEC_REG_POWEROFF, > + (NTXEC_POWEROFF_VALUE >> 8) & 0xff, > + NTXEC_POWEROFF_VALUE & 0xff, > + }; > + And this one. > + struct i2c_msg msgs[] = { > + { > + .addr = poweroff_restart_client->addr, > + .flags = 0, > + .len = sizeof(buf), > + .buf = buf > + } > + }; > + > + res = i2c_transfer(poweroff_restart_client->adapter, msgs, ARRAY_SIZE(msgs)); > + And this one. > + if (res < 0) > + dev_alert(&poweroff_restart_client->dev, "Failed to power off (err = %d)\n", res); This looks way over 80 chars. Did you run checkpatch.pl? > + /* > + * 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; > + > + /* > + * NOTE: The lower half of the reset value is not sent, because sending > + * it causes an error > + */ > + u8 buf[] = { > + NTXEC_REG_RESET, > + (NTXEC_RESET_VALUE >> 8) & 0xff, > + }; > + > + struct i2c_msg msgs[] = { > + { > + .addr = poweroff_restart_client->addr, > + .flags = 0, > + .len = sizeof(buf), > + .buf = buf > + } > + }; > + > + res = i2c_transfer(poweroff_restart_client->adapter, msgs, ARRAY_SIZE(msgs)); > + > + if (res < 0) > + dev_alert(&poweroff_restart_client->dev, "Failed to restart (err = %d)\n", res); > + > + return NOTIFY_DONE; > +} All as above for this function. > +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 ntxec_info ntxec_known_versions[] = { > + { 0xd726 }, /* found in Kobo Aura */ > +}; > + > +static const struct ntxec_info *ntxec_lookup_info(u16 version) > +{ > + int i; > + > + for (i = 0; i < ARRAY_SIZE(ntxec_known_versions); i++) { > + const struct ntxec_info *info = &ntxec_known_versions[i]; > + > + if (info->version == version) > + return info; > + } > + > + return NULL; > +} Wait, what? This is over-engineered. Just have a look-up table (switch) of supported devices. > +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; > + } > + dev_info(ec->dev, > + "Netronix embedded controller version %04x detected.\n", > + version); > + > + /* Bail out if we encounter an unknown firmware version */ > + ec->info = ntxec_lookup_info(version); > + if (!ec->info) > + return -EOPNOTSUPP; #define EOPNOTSUPP 95 /* Operation not supported on transport endpoint */ I think you want: #define ENODEV 19 /* No such device */ > + 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; > + > + /* Install poweroff handler */ Don't think this comment is required. > + WARN_ON(poweroff_restart_client); > + poweroff_restart_client = client; > + if (pm_power_off) > + dev_err(ec->dev, "pm_power_off already assigned\n"); > + else > + pm_power_off = ntxec_poweroff; > + > + /* Install board reset handler */ Nor this. > + 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); > + > + return devm_of_platform_populate(ec->dev); > +} > + > +static int ntxec_remove(struct i2c_client *i2c) Why do you call it 'client' in .probe, but 'i2c' in .remove? > +{ > + if (i2c == 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", }, > + {} > +}; > + > +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); > diff --git a/include/linux/mfd/ntxec.h b/include/linux/mfd/ntxec.h > new file mode 100644 > index 0000000000000..65e389af79da6 > --- /dev/null > +++ b/include/linux/mfd/ntxec.h > @@ -0,0 +1,24 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright 2020 Jonathan Neuschäfer > + * > + * Register access and version information for the Netronix embedded > + * controller. > + */ > + > +#ifndef NTXEC_H > +#define NTXEC_H > + > +#include <linux/types.h> > + > +struct ntxec_info { > + u16 version; > +}; > + > +struct ntxec { > + struct device *dev; > + struct regmap *regmap; > + const struct ntxec_info *info; What is this used for? > +}; > + > +#endif -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
