From: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
To: linux-kernel@vger.kernel.org
Cc: "Alexandre Belloni" <alexandre.belloni@bootlin.com>,
"Heiko Stuebner" <heiko@sntech.de>,
linux-pwm@vger.kernel.org,
"Linus Walleij" <linus.walleij@linaro.org>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Fabio Estevam" <festevam@gmail.com>,
linux-rtc@vger.kernel.org, "Arnd Bergmann" <arnd@arndb.de>,
"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
"Sam Ravnborg" <sam@ravnborg.org>,
"Daniel Palmer" <daniel@0x0f.com>,
"Andreas Kemnade" <andreas@kemnade.info>,
"NXP Linux Team" <linux-imx@nxp.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
devicetree@vger.kernel.org,
"Stephan Gerhold" <stephan@gerhold.net>,
allen <allen.chen@ite.com.tw>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
"Lubomir Rintel" <lkundrak@v3.sk>,
"Rob Herring" <robh+dt@kernel.org>,
"Lee Jones" <lee.jones@linaro.org>,
linux-arm-kernel@lists.infradead.org,
"Alessandro Zummo" <a.zummo@towertech.it>,
"Mark Brown" <broonie@kernel.org>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Heiko Stuebner" <heiko.stuebner@theobroma-systems.com>,
"Josua Mayer" <josua.mayer@jm0.eu>,
"Shawn Guo" <shawnguo@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH v2 03/10] mfd: Add base driver for Netronix embedded controller
Date: Sat, 5 Sep 2020 15:32:23 +0200 [thread overview]
Message-ID: <20200905133230.1014581-4-j.neuschaefer@gmx.net> (raw)
In-Reply-To: <20200905133230.1014581-1-j.neuschaefer@gmx.net>
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@gmx.net>
---
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"
+ depends on I2C && OF
+ 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
+/*
+ * 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
+ */
+
+#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;
+
+ u8 buf[] = {
+ NTXEC_REG_POWEROFF,
+ (NTXEC_POWEROFF_VALUE >> 8) & 0xff,
+ NTXEC_POWEROFF_VALUE & 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 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;
+
+ /*
+ * 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;
+}
+
+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;
+}
+
+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;
+
+ 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 */
+ 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 */
+ 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)
+{
+ 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;
+};
+
+#endif
--
2.28.0
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next prev parent reply other threads:[~2020-09-05 13:36 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-05 13:32 [PATCH v2 00/10] Netronix embedded controller driver for Kobo and Tolino ebook readers Jonathan Neuschäfer
2020-09-05 13:32 ` [PATCH v2 01/10] dt-bindings: Add vendor prefix for Netronix, Inc Jonathan Neuschäfer
2020-09-15 0:43 ` Rob Herring
2020-09-05 13:32 ` [PATCH v2 02/10] dt-bindings: mfd: Add binding for Netronix's embedded controller Jonathan Neuschäfer
2020-09-15 0:50 ` Rob Herring
2020-09-17 11:12 ` Jonathan Neuschäfer
2020-09-05 13:32 ` Jonathan Neuschäfer [this message]
2020-09-08 13:29 ` [PATCH v2 03/10] mfd: Add base driver for Netronix " Lee Jones
2020-09-10 12:04 ` Jonathan Neuschäfer
2020-09-05 13:32 ` [PATCH v2 04/10] dt-bindings: pwm: Add bindings for PWM function in Netronix EC Jonathan Neuschäfer
2020-09-15 0:54 ` Rob Herring
2020-09-15 6:23 ` Andreas Kemnade
2020-09-15 14:31 ` Rob Herring
2020-09-17 11:58 ` Jonathan Neuschäfer
2020-09-05 13:32 ` [PATCH v2 05/10] pwm: ntxec: Add driver " Jonathan Neuschäfer
[not found] ` <CAHp75VdUHoOyM3bObzhdfiqpne0AmSK_UakteTZxnjqJVrNV9A@mail.gmail.com>
2020-09-08 8:14 ` Lee Jones
2020-09-08 8:47 ` Andy Shevchenko
2020-09-08 9:35 ` Lee Jones
2020-09-10 19:13 ` Jonathan Neuschäfer
2020-09-10 19:09 ` Jonathan Neuschäfer
2020-09-05 13:32 ` [PATCH v2 06/10] dt-bindings: rtc: Add bindings for Netronix embedded controller RTC Jonathan Neuschäfer
2020-09-05 13:32 ` [PATCH v2 07/10] rtc: Introduce RTC_TIMESTAMP_END_2255 Jonathan Neuschäfer
2020-09-08 9:39 ` Alexandre Belloni
2020-09-10 19:21 ` Jonathan Neuschäfer
2020-09-05 14:45 ` [PATCH v2 08/10] rtc: New driver for RTC in Netronix embedded controller Jonathan Neuschäfer
[not found] ` <CAHp75Vca+Tp0v_Q4RBuUNSo_5aq_u6mBGeXecHULC1Avgm5=Xg@mail.gmail.com>
2020-09-10 19:42 ` Jonathan Neuschäfer
2020-09-05 14:45 ` [PATCH v2 09/10] MAINTAINERS: Add entry for " Jonathan Neuschäfer
2020-09-05 14:45 ` [PATCH v2 10/10] ARM: dts: imx50-kobo-aura: Add " Jonathan Neuschäfer
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