Turris Omnia MCU driver

Add support for GPIOs connected to the MCU on the Turris Omnia board.

This includes:
- front button pin
- enable pins for USB regulators
- MiniPCIe / mSATA card presence pins in MiniPCIe port 0
- LED output pins from WAN ethernet PHY, LAN switch and MiniPCIe ports
- on board revisions 32+ also various peripheral resets and another voltage regulator enable pin

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +4 -0

+		return mcu->features & gpio->feat;
+
+	return true;
+}

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +5 -0

+static int omnia_gpio_init_valid_mask(struct gpio_chip *gc,
+				      unsigned long *valid_mask,
+				      unsigned int ngpios)
+{
+	struct omnia_mcu *mcu = gpiochip_get_data(gc);

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +4 -0

+	}
+
+	return 0;
+}

+}

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +31 -0

+static void omnia_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct omnia_mcu *mcu = gpiochip_get_data(gc);
+	struct device *dev = &mcu->client->dev;
+	u8 cmd[1 + CMD_INT_ARG_LEN];
+	u32 rising, falling;
+	int err;
+
+	/* nothing to do if MCU firmware does not support new interrupt API */
+	if (!(mcu->features & FEAT_NEW_INT_API))
+		return;
+
+	cmd[0] = CMD_SET_INT_MASK;
+
+	rising = mcu->rising & mcu->mask;
+	falling = mcu->falling & mcu->mask;
+
+	/* interleave the rising and falling bytes into the command arguments */
+	omnia_mask_interleave(&cmd[1], rising, falling);
+
+	dev_dbg(dev, "set int mask %8ph\n", &cmd[1]);
+
+	err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
+	if (err) {
+		dev_err(dev, "Cannot set mask: %d\n", err);
+		goto unlock;
+	}
+
+	/*
+	 * Remember which GPIOs have both rising and falling interrupts enabled.

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +5 -0

+static void omnia_irq_init_valid_mask(struct gpio_chip *gc,
+				      unsigned long *valid_mask,
+				      unsigned int ngpios)
+{
+	struct omnia_mcu *mcu = gpiochip_get_data(gc);

(quoted diff) +2 -0

+	}
+}

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +13 -0

+		/*
+		 * The button_release_emul_work has to be initialized before the
+		 * thread is requested, and on driver remove it needs to be
+		 * canceled before the thread is freed. Therefore we can't use
+		 * devm_delayed_work_autocancel() directly, because the order
+		 *   devm_delayed_work_autocancel();
+		 *   devm_request_threaded_irq();
+		 * would cause improper release order:
+		 *   free_irq();
+		 *   cancel_delayed_work_sync();
+		 * Instead we first initialize the work above, and only now
+		 * after IRQ is requested we add the work devm action.
+		 */

drivers/platform/cznic/turris-omnia-mcu.h +7 -0

+/* Returns 0 on success */
+static inline int omnia_cmd_read_bits(const struct i2c_client *client, u8 cmd,
+				      u32 bits, u32 *dst)
+{
+	__le32 reply;
+	int err;
+

drivers/platform/cznic/turris-omnia-mcu.h +14 -0

+}
+
+static inline int omnia_cmd_read_bit(const struct i2c_client *client, u8 cmd,
+				     u32 bit)
+{
+	u32 reply;
+	int err;
+
+	err = omnia_cmd_read_bits(client, cmd, bit, &reply);
+	if (err)
+		return err;
+
+	return !!reply;
+}

}

On Mon, Oct 23, 2023 at 04:31:26PM +0200, Marek Behún wrote:

Quoted 5 lines

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +5 -0

+static void omnia_irq_bus_lock(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct omnia_mcu *mcu = gpiochip_get_data(gc);
+

drivers/platform/cznic/turris-omnia-mcu-gpio.c line 540

Quoted 5 lines

drivers/platform/cznic/turris-omnia-mcu-gpio.c new file +5 -0

+	/* nothing to do if MCU firmware does not support new interrupt API */
+	if (!(mcu->features & FEAT_NEW_INT_API))
+		return;
+
+	mutex_lock(&mcu->lock);

I'm wondering if sparse complains on unbalanced locking. If so, the function needs an annotation.

Add support for true board poweroff (MCU can disable all unnecessary voltage regulators) and wakeup at a specified time, implemented via a RTC driver so that the rtcwake utility can be used to configure it.

(quoted diff) +2 -0

+		return 0;
+}

drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c new file +10 -0

+static int omnia_power_off(struct sys_off_data *data)
+
+	struct omnia_mcu *mcu = data->cb_data;
+	__be32 tmp;
+	u8 cmd[9];
+	u16 arg;
+	int err;
+
+	if (mcu->front_button_poweron)
+		arg = CMD_POWER_OFF_POWERON_BUTTON;

drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c new file +7 -0

+	err = omnia_cmd_write(mcu->client, cmd, sizeof(cmd));
+	if (err)
+		dev_err(&mcu->client->dev,
+			"Unable to send the poweroff command: %d\n", err);
+
+	return NOTIFY_DONE;
+}

(quoted diff) +1 -0

+	 */

On Mon, Oct 23, 2023 at 04:31:27PM +0200, Marek Behún wrote:

drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c line 125

Quoted 3 lines

drivers/platform/cznic/turris-omnia-mcu-sys-off-wakeup.c new file +3 -0

+	tmp = cpu_to_be32(get_unaligned_le32(&cmd[1]));
+	put_unaligned_le32(crc32_be(0xffffffff, (void *)&tmp, sizeof(tmp)),
+			   &cmd[5]);

Hmm... Why crc32_le*() can't be used?

Add support for the watchdog mechanism provided by the MCU.

Signed-off-by Marek Behún <[email protected]>

---
  drivers/platform/cznic/Kconfig                |   2 +
  drivers/platform/cznic/Makefile               |   1 +
  .../platform/cznic/turris-omnia-mcu-base.c    |   4 +
  .../cznic/turris-omnia-mcu-watchdog.c         | 122 ++++++++++++++++++
  drivers/platform/cznic/turris-omnia-mcu.h     |  24 ++++
  5 files changed, 153 insertions(+)

create mode 100644 drivers/platform/cznic/turris-omnia-mcu-watchdog.c

drivers/platform/cznic/Kconfig +2 -0

index 0a752aa654fa..e2649cdecc38 100644
@@ -20,6 +20,7 @@ config TURRIS_OMNIA_MCU
  	select GPIOLIB
  	select GPIOLIB_IRQCHIP
  	select RTC_CLASS
+	select WATCHDOG_CORE
  	help
  	  Say Y here to add support for the features implemented by the
  	  microcontroller on the CZ.NIC's Turris Omnia SOHO router.

@@ -27,6 +28,7 @@ config TURRIS_OMNIA_MCU
  	  - board poweroff into true low power mode (with voltage regulators
  	    disabled) and the ability to configure wake up from this mode (via
  	    rtcwake)
+	  - MCU watchdog
  	  - GPIO pins
  	    - to get front button press events (the front button can be
  	      configured either to generate press events to the CPU or to change

drivers/platform/cznic/Makefile +1 -0

index 6f1470d1f673..a43997a12d74 100644
@@ -4,3 +4,4 @@ obj-$(CONFIG_TURRIS_OMNIA_MCU)	+= turris-omnia-mcu.o
  turris-omnia-mcu-objs		:= turris-omnia-mcu-base.o
  turris-omnia-mcu-objs		+= turris-omnia-mcu-gpio.o
  turris-omnia-mcu-objs		+= turris-omnia-mcu-sys-off-wakeup.o
+turris-omnia-mcu-objs		+= turris-omnia-mcu-watchdog.o

drivers/platform/cznic/turris-omnia-mcu-base.c +4 -0

index 942061a0ee66..521397bfc022 100644
@@ -243,6 +243,10 @@ static int omnia_mcu_probe(struct i2c_client *client)
  	if (err)
  		return err;
 
+	err = omnia_mcu_register_watchdog(mcu);
+	if (err)
+		return err;
+
  	return omnia_mcu_register_gpiochip(mcu);
  }
 

drivers/platform/cznic/turris-omnia-mcu-watchdog.c new file +82 -0

new file mode 100644
index 000000000000..6685166bc4c7
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CZ.NIC's Turris Omnia MCU watchdog driver
+ *
+ * 2023 by Marek Behún <[email protected]>
+ */
+
+#include <linux/moduleparam.h>
+#include <linux/turris-omnia-mcu-interface.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#include "turris-omnia-mcu.h"
+
+#define WATCHDOG_TIMEOUT		120
+
+static unsigned int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+			   __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int omnia_wdt_start(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, CMD_SET_WATCHDOG_STATE, 1);
+}
+
+static int omnia_wdt_stop(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, CMD_SET_WATCHDOG_STATE, 0);
+}
+
+static int omnia_wdt_ping(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u8(mcu->client, CMD_SET_WATCHDOG_STATE, 1);
+}
+
+static int omnia_wdt_set_timeout(struct watchdog_device *wdt,
+				 unsigned int timeout)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+
+	return omnia_cmd_write_u16(mcu->client, CMD_SET_WDT_TIMEOUT,
+				   timeout * 10);
+}
+
+static unsigned int omnia_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+	struct omnia_mcu *mcu = watchdog_get_drvdata(wdt);
+	int ret;
+
+	ret = omnia_cmd_read_u16(mcu->client, CMD_GET_WDT_TIMELEFT);
+	if (ret < 0) {
+		dev_err(&mcu->client->dev, "Cannot get watchdog timeleft: %d\n",
+			ret);
+		return 0;
+	}
+
+	return ret / 10;
+}
+
+static const struct watchdog_info omnia_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Turris Omnia MCU Watchdog",
+};
+
+static const struct watchdog_ops omnia_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= omnia_wdt_start,
+	.stop		= omnia_wdt_stop,
+	.ping		= omnia_wdt_ping,
+	.set_timeout	= omnia_wdt_set_timeout,
+	.get_timeleft	= omnia_wdt_get_timeleft,

drivers/platform/cznic/turris-omnia-mcu-watchdog.c new file +30 -0

+	mcu->wdt.info = &omnia_wdt_info;
+	mcu->wdt.ops = &omnia_wdt_ops;
+	mcu->wdt.parent = dev;
+	mcu->wdt.min_timeout = 1;
+	mcu->wdt.max_timeout = 6553; /* 65535 deciseconds */
+
+	mcu->wdt.timeout = WATCHDOG_TIMEOUT;
+	watchdog_init_timeout(&mcu->wdt, timeout, dev);
+
+	watchdog_set_drvdata(&mcu->wdt, mcu);
+
+	omnia_wdt_set_timeout(&mcu->wdt, mcu->wdt.timeout);
+
+	ret = omnia_cmd_read_u8(mcu->client, CMD_GET_WATCHDOG_STATE);
+	if (ret < 0)
+		return dev_err_probe(dev, ret,
+				     "Cannot get MCU watchdog state\n");
+
+	if (ret)
+		set_bit(WDOG_HW_RUNNING, &mcu->wdt.status);
+
+	watchdog_set_nowayout(&mcu->wdt, nowayout);
+	watchdog_stop_on_reboot(&mcu->wdt);
+	ret = devm_watchdog_register_device(dev, &mcu->wdt);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Cannot register MCU watchdog\n");
+
+	return 0;
+}

drivers/platform/cznic/turris-omnia-mcu.h +1 -0

index c6a8036e0534..db2d18d6eea8 100644
@@ -14,6 +14,7 @@
  #include <linux/mutex.h>
  #include <linux/rtc.h>
  #include <linux/types.h>
+#include <linux/watchdog.h>
  #include <linux/workqueue.h>
  #include <asm/byteorder.h>
  #include <asm/unaligned.h>

drivers/platform/cznic/turris-omnia-mcu.h +20 -0

  };
 
  static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,

@@ -48,6 +52,25 @@ static inline int omnia_cmd_write(const struct i2c_client *client, void *cmd,
  	return ret < 0 ? ret : 0;
  }
 
+static inline int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd,
+				     u8 val)
+{
+	u8 buf[2] = { cmd, val };
+
+	return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
+static inline int omnia_cmd_write_u16(const struct i2c_client *client, u8 cmd,
+				      u16 val)
+{
+	u8 buf[3];
+
+	buf[0] = cmd;
+	put_unaligned_le16(val, &buf[1]);
+
+	return omnia_cmd_write(client, buf, sizeof(buf));
+}
+
  static inline int omnia_cmd_write_u32(const struct i2c_client *client, u8 cmd,
  				      u32 val)
  {

@@ -140,5 +163,6 @@ extern const struct attribute_group omnia_mcu_poweroff_group;
 
  int omnia_mcu_register_gpiochip(struct omnia_mcu *mcu);
  int omnia_mcu_register_sys_off_and_wakeup(struct omnia_mcu *mcu);
+int omnia_mcu_register_watchdog(struct omnia_mcu *mcu);
 
  #endif /* __TURRIS_OMNIA_MCU_H */

Quoted 3 lines · Marek Behún

Add support for the watchdog mechanism provided by the MCU.

Signed-off-by Marek Behún <[email protected]>

Any reason for keeping this out of drivers/watchdog ?

drivers/platform/cznic/turris-omnia-mcu-watchdog.c line 92

Quoted 3 lines

drivers/platform/cznic/turris-omnia-mcu-watchdog.c new file +3 -0

+	if (!(mcu->features & FEAT_WDT_PING))
+		return 0;
+  

Why check this here and not in the calling code ?

drivers/platform/cznic/turris-omnia-mcu.h struct omnia_mcu { · line 42

Quoted 7 lines

drivers/platform/cznic/turris-omnia-mcu.h +3 -0

@@ -36,6 +37,9 @@ struct omnia_mcu {
  	struct rtc_device *rtcdev;
  	u32 rtc_alarm;
  	bool front_button_poweron;
+
+	/* MCU watchdog */
+	struct watchdog_device wdt;  

This should be internal to the watchdog driver.

Quoted 5 lines · Guenter Roeck

Quoted 1 line · Marek Behún

Add support for the watchdog mechanism provided by the MCU.

Any reason for keeping this out of drivers/watchdog ?

Because this whole thing is compiled as one driver, turris-omnia-mcu.ko. The whole driver is specific for one device, the Turris Omnia router. Splitting it into separate modules would be unnecessary, the driver is meant to provide all the Turris Omnia MCU functionality.

I've seen this done in various platform drivers.

Moreover, all of the functionality lives at one I2C address, so only one I2C client is used.

Quoted 11 lines · Marek Behún

Quoted 5 lines · Guenter Roeck

Quoted 1 line · Marek Behún

Add support for the watchdog mechanism provided by the MCU.

Any reason for keeping this out of drivers/watchdog ?

Because this whole thing is compiled as one driver, turris-omnia-mcu.ko. The whole driver is specific for one device, the Turris Omnia router. Splitting it into separate modules would be unnecessary, the driver is meant to provide all the Turris Omnia MCU functionality.

Quoted 4 lines

I've seen this done in various platform drivers.

Moreover, all of the functionality lives at one I2C address, so only one I2C client is used.

That all sounds a bit like drivers/mfd...