On Sun, 21 Jun 2020 00:42:15 +0200 Jonathan Neuschäfer <j.neuschae...@gmx.net> wrote:
> 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. > > Known problems: > - The reboot handler is installed in such a way that it directly calls > into the i2c subsystem to send the reboot command to the EC. This > means that the reboot handler may sleep, which is not allowed. > see https://patchwork.ozlabs.org/project/linux-i2c/patch/20190415213432.8972-3-cont...@stefanchrist.eu/ for a fix of such problems. > Signed-off-by: Jonathan Neuschäfer <j.neuschae...@gmx.net> > --- > drivers/mfd/Kconfig | 7 ++ > drivers/mfd/Makefile | 1 + > drivers/mfd/ntxec.c | 188 ++++++++++++++++++++++++++++++++++++++ > include/linux/mfd/ntxec.h | 30 ++++++ > 4 files changed, 226 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 a37d7d1713820..78410b928648e 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 > + bool "Netronix Embedded Controller" > + depends on I2C && OF > + help > + Say yes here if you want to support the embedded controller of > + 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 9367a92f795a6..19d9391ed6f32 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -218,6 +218,7 @@ 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..82adea34ea746 > --- /dev/null > +++ b/drivers/mfd/ntxec.c > @@ -0,0 +1,188 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright 2020 Jonathan Neuschäfer > +// > +// MFD driver for the usually MSP430-based embedded controller used in > certain > +// Netronix ebook reader board designs > + > +#include <asm/unaligned.h> > +#include <linux/delay.h> > +#include <linux/errno.h> > +#include <linux/i2c.h> > +#include <linux/mfd/ntxec.h> > +#include <linux/of_platform.h> > +#include <linux/pm.h> > +#include <linux/reboot.h> > +#include <linux/types.h> > + > + > +#define NTXEC_VERSION 0x00 > +#define NTXEC_POWEROFF 0x50 > +#define NTXEC_POWERKEEP 0x70 > +#define NTXEC_RESET 0x90 > + > + > +/* Register access */ > + > +int ntxec_read16(struct ntxec *ec, u8 addr) > +{ > + u8 request[1] = { addr }; > + u8 response[2]; > + int res; > + > + struct i2c_msg msgs[] = { > + { > + .addr = ec->client->addr, > + .flags = ec->client->flags, > + .len = sizeof(request), > + .buf = request > + }, { > + .addr = ec->client->addr, > + .flags = ec->client->flags | I2C_M_RD, > + .len = sizeof(response), > + .buf = response > + } > + }; > + > + res = i2c_transfer(ec->client->adapter, msgs, ARRAY_SIZE(msgs)); > + if (res < 0) > + return res; > + if (res != ARRAY_SIZE(msgs)) > + return -EIO; > + > + return get_unaligned_be16(response); > +} > +EXPORT_SYMBOL(ntxec_read16); > + > +int ntxec_write16(struct ntxec *ec, u8 addr, u16 value) > +{ > + u8 request[3] = { addr, }; > + int res; > + > + put_unaligned_be16(value, request + 1); > + > + res = i2c_transfer_buffer_flags(ec->client, request, sizeof(request), > + ec->client->flags); > + if (res < 0) > + return res; > + > + return 0; > +} > +EXPORT_SYMBOL(ntxec_write16); > + > +int ntxec_read8(struct ntxec *ec, u8 addr) > +{ > + int res = ntxec_read16(ec, addr); > + > + if (res < 0) > + return res; > + > + return (res >> 8) & 0xff; > +} > +EXPORT_SYMBOL(ntxec_read8); > + > +int ntxec_write8(struct ntxec *ec, u8 addr, u8 value) > +{ > + return ntxec_write16(ec, addr, value << 8); > +} > +EXPORT_SYMBOL(ntxec_write8); > + do we really need both 16bit and 8bit accessors? If not, then simply use regmap_i2c_init and set val_bits accordingly. Maybe just doing the << 8 in the constants? > + > +/* Reboot/poweroff handling */ > + > +static struct ntxec *poweroff_restart_instance; > + > +static void ntxec_poweroff(void) > +{ > + ntxec_write8(poweroff_restart_instance, NTXEC_POWEROFF, 0x01); > + msleep(5000); > +} > + > +static int ntxec_restart(struct notifier_block *nb, > + unsigned long action, void *data) > +{ > + /* FIXME: The I2C driver sleeps, but restart handlers may not sleep */ > + ntxec_write8(poweroff_restart_instance, NTXEC_RESET, 0xff); > + /* TODO: delay? */ > + return NOTIFY_DONE; > +} > + > +static struct notifier_block ntxec_restart_handler = { > + .notifier_call = ntxec_restart, > + .priority = 128 > +}; > + > + > +/* Driver setup */ > + > +static int ntxec_probe(struct i2c_client *client, > + const struct i2c_device_id *ids) > +{ > + struct ntxec *ec; > + int res; > + > + ec = devm_kmalloc(&client->dev, sizeof(*ec), GFP_KERNEL); > + if (!ec) > + return -ENOMEM; > + > + ec->dev = &client->dev; > + ec->client = client; > + > + /* Determine the firmware version */ > + res = ntxec_read16(ec, NTXEC_VERSION); > + if (res < 0) { > + dev_dbg(ec->dev, "Failed to read firmware version number\n"); > + return res; > + } > + ec->version = res; > + > + dev_info(ec->dev, > + "Netronix embedded controller version %04x detected.\n", > + ec->version); > + > + /* For now, we don't support the new register layout. */ > + if (ntxec_has_new_layout(ec)) > + return -EOPNOTSUPP; > + > + 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 = ntxec_write8(ec, NTXEC_POWERKEEP, 0x08); > + if (res < 0) > + return res; > + > + /* Install poweroff handler */ > + WARN_ON(poweroff_restart_instance); > + poweroff_restart_instance = ec; > + if (pm_power_off != NULL) > + /* TODO: Refactor among all poweroff drivers */ > + dev_err(ec->dev, "pm_power_off already assigned\n"); > + else > + pm_power_off = ntxec_poweroff; > + common pattern, across drivers, so I think doing something else would be a separate cleanup issue. Regards, Andreas
