linux-stable/drivers/mfd/ntxec.c
Uwe Kleine-König ed5c2f5fd1 i2c: Make remove callback return void
The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-16 12:46:26 +02:00

269 lines
6.6 KiB
C

// 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.neuschaefer@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 int regmap_ignore_write(void *context,
unsigned int reg, unsigned int val)
{
struct regmap *regmap = context;
regmap_write(regmap, reg, val);
return 0;
}
static int regmap_wrap_read(void *context, unsigned int reg,
unsigned int *val)
{
struct regmap *regmap = context;
return regmap_read(regmap, reg, val);
}
/*
* Some firmware versions do not ack written data, add a wrapper. It
* is used to stack another regmap on top.
*/
static const struct regmap_config regmap_config_noack = {
.name = "ntxec_noack",
.reg_bits = 8,
.val_bits = 16,
.cache_type = REGCACHE_NONE,
.reg_write = regmap_ignore_write,
.reg_read = regmap_wrap_read
};
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_subdev[] = {
{ .name = "ntxec-rtc" },
{ .name = "ntxec-pwm" },
};
static const struct mfd_cell ntxec_subdev_pwm[] = {
{ .name = "ntxec-pwm" },
};
static int ntxec_probe(struct i2c_client *client)
{
struct ntxec *ec;
unsigned int version;
int res;
const struct mfd_cell *subdevs;
size_t n_subdevs;
ec = devm_kmalloc(&client->dev, sizeof(*ec), GFP_KERNEL);
if (!ec)
return -ENOMEM;
ec->dev = &client->dev;
ec->regmap = devm_regmap_init_i2c(client, &regmap_config);
if (IS_ERR(ec->regmap)) {
dev_err(ec->dev, "Failed to set up regmap for device\n");
return PTR_ERR(ec->regmap);
}
/* 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:
subdevs = ntxec_subdev;
n_subdevs = ARRAY_SIZE(ntxec_subdev);
break;
case NTXEC_VERSION_TOLINO_SHINE2:
subdevs = ntxec_subdev_pwm;
n_subdevs = ARRAY_SIZE(ntxec_subdev_pwm);
/* Another regmap stacked on top of the other */
ec->regmap = devm_regmap_init(ec->dev, NULL,
ec->regmap,
&regmap_config_noack);
if (IS_ERR(ec->regmap))
return PTR_ERR(ec->regmap);
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,
subdevs, n_subdevs, NULL, 0, NULL);
if (res)
dev_err(ec->dev, "Failed to add subdevices: %d\n", res);
return res;
}
static void 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);
}
}
static const struct of_device_id of_ntxec_match_table[] = {
{ .compatible = "netronix,ntxec", },
{}
};
MODULE_DEVICE_TABLE(of, of_ntxec_match_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_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
MODULE_DESCRIPTION("Core driver for Netronix EC");
MODULE_LICENSE("GPL");