[PATCH v6] Serial: silabs si4455 serial driver

["József Horváth" <info@ministro.hu>]

This is a serial port driver for
 Silicon Labs Si4455 Sub-GHz transciver.

The goal of this driver is to removing wires
 between central(linux) device and remote serial devices/sensors,
 but keeping the original user software.
 It represents regular serial interface for the user space.

Datasheet: https://www.silabs.com/documents/public/data-sheets/Si4455.pdf

changes v1:
 - fixed: drivers: serial: si4455: coding style
 - fixed: drivers: serial: si4455: error checking and order
 - fixed: drivers: serial: si4455: remove unnecessary compatibility
   strings from si4455_dt_ids
 - fixed: dt-bindings: rename sdn-gpios to shutdown-gpios

changes v2:
 - fixed: drivers: serial: si4455: coding style

changes v3:
 - fixed: drivers: serial: si4455: coding style
 - fixed: drivers: serial: si4455: replace device configuration procedure
   (SI4455_IOC_SEZC ioctl call) with request_firmware(...).
   The firmware name comes from dt (silabs,ez-config)
 - fixed: drivers: serial: si4455: replace transmit/receive channel
   select (SI4455_IOC_STXC/SI4455_IOC_SRXC ioctl calls)
   with sysfs entries (tx_channel, rx_channel).
   Initial values comes from dt (silabs,tx-channel and silabs,rx-channel)
 - fixed: drivers: serial: si4455: replace package size setting
   (SI4455_IOC_SSIZ ioctl call) with sysfs entry (package_size).
   Initial value comes from dt (silabs,package-size)
 - fixed: drivers: serial: si4455: replace getting last rssi
   (SI4455_IOC_GRSSI ioctl call) with sysfs entry (current_rssi)
 - fixed: drivers: serial: si4455: remove si4455_api.h
   and custom ioctl definitions
 - fixed: dt-bindings: silabs,si4455: more detailed description
 - added: dt-bindings: silabs,si4455: properties silabs,package-size,
   silabs,tx-channel, silabs,rx-channel, silabs,ez-config

changes v4:
 - fixed: dt-bindings: silabs,si4455: $id
   from http://devicetree.org/schemas/serial/silabs,si4455.yaml
   to http://devicetree.org/schemas/staging/serial/silabs,si4455.yaml

changes v5:
 - fixed: drivers: serial: si4455: coding style
 - fixed: drivers: serial: si4455: remove struct si4455_one,
   members moved to struct si4455_port
 - fixed: drivers: serial: si4455: fix line endings in dev_err and
   dev_dbg messages
 - fixed: drivers: serial: si4455: remove unnecessary else { ... }
 - fixed: drivers: serial: si4455: refactor si4455_do_work(...),
   xmit circular buffer handling and start tx moved to
   si4455_start_tx_xmit(...)
 - fixed: drivers: serial: si4455: refactor si4455_configure
 - fixed: drivers: serial: si4455: refactor interrupt handling,
   remove unnecessary wrapper
 - fixed: drivers: serial: si4455: modem line(si4455_get_mctrl)
   and tx buffer status(si4455_tx_empty) conditions and signaling
 - fixed: drivers: serial: si4455: remove unsafe int to pointer conversion
 - fixed: dt-bindings: silabs,si4455: $id
   from http://devicetree.org/schemas/staging/serial/silabs,si4455.yaml
   to http://devicetree.org/schemas/serial/silabs,si4455.yaml
 - fixed: dt-bindings: silabs,si4455: serial.yaml reference added

changes v6:
 - fixed: drivers: serial: si4455: illegal characters in
   MODULE_AUTHOR("...") Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Jozsef Horvath <info@ministro.hu>
---
 .../bindings/serial/silabs,si4455.yaml        |   98 ++
 MAINTAINERS                                   |    6 +
 drivers/tty/serial/Kconfig                    |    8 +
 drivers/tty/serial/Makefile                   |    1 +
 drivers/tty/serial/si4455.c                   | 1372 +++++++++++++++++
 5 files changed, 1485 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/silabs,si4455.yaml
 create mode 100644 drivers/tty/serial/si4455.c

diff --git a/Documentation/devicetree/bindings/serial/silabs,si4455.yaml b/Documentation/devicetree/bindings/serial/silabs,si4455.yaml
new file mode 100644
index 000000000000..ddff67e6a667
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/silabs,si4455.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/serial/silabs,si4455.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Silicon Labs Si4455 device tree bindings
+
+maintainers:
+  - József Horváth <info@ministro.hu>
+
+description:
+  This document is for describing the required device tree parameters for si4455 serial driver.
+  The si4455 driver tries to represent the Silicon Labs Si4455 sub-GHz transceiver device
+  like a serial port. The required parameters for proper operation are described below.
+  https://www.silabs.com/documents/public/data-sheets/Si4455.pdf
+
+allOf:
+  - $ref: "serial.yaml#"
+
+properties:
+  compatible:
+    const: silabs,si4455
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  spi-max-frequency:
+    description: maximum clock frequency on SPI port
+    maximum: 500000
+
+  shutdown-gpios:
+    description: gpio pin for SDN
+    maxItems: 1
+
+  silabs,package-size:
+    description:
+      Radio payload length, variable packet length is not supported by driver.
+      This value should equal with EZConfig payload length.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 64
+    minimum: 1
+
+  silabs,tx-channel:
+    description:
+      Radio transmit channel selection.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 255
+    minimum: 0
+
+  silabs,rx-channel:
+    description:
+      Radio receive channel selection.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 255
+    minimum: 0
+
+  silabs,ez-config:
+    description:
+      Radio configuration data file name.
+    $ref: /schemas/types.yaml#/definitions/string
+    items:
+      pattern: ^[0-9a-z\._\-]{1,255}$
+
+required:
+  - reg
+  - interrupts
+  - spi-max-frequency
+  - shutdown-gpios
+  - silabs,package-size
+  - silabs,tx-channel
+  - silabs,rx-channel
+  - silabs,ez-config
+
+additionalProperties: false
+
+examples:
+  - |
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      si4455_0: serial@0 {
+        compatible = "silabs,si4455";
+        reg = <0>;
+        interrupt-parent = <&gpio>;
+        interrupts = <7 2>;
+        shutdown-gpios = <&gpio 26 1>;
+        spi-max-frequency = <300000>;
+        silabs,package-size = <30>;
+        silabs,tx-channel = <1>;
+        silabs,rx-channel = <2>;
+        silabs,ez-config = "si4455_spi0_0.ez.bin";
+      };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index a008b70f3c16..ca6e32693a74 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15952,6 +15952,12 @@ M:	Jérôme Pouiller <jerome.pouiller@silabs.com>
 S:	Supported
 F:	drivers/staging/wfx/
 
+SILICON LABS SI4455 SERIAL DRIVER
+M:	Jozsef Horvath <info@ministro.hu>
+S:	Maintained
+F:	Documentation/devicetree/bindings/serial/silabs,si4455.yaml
+F:	drivers/tty/serial/si4455.c
+
 SILICON MOTION SM712 FRAME BUFFER DRIVER
 M:	Sudip Mukherjee <sudipm.mukherjee@gmail.com>
 M:	Teddy Wang <teddy.wang@siliconmotion.com>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 28f22e58639c..560aa311cd03 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1583,6 +1583,14 @@ config SERIAL_MILBEAUT_USIO_CONSOLE
 	  receives all kernel messages and warnings and which allows logins in
 	  single user mode).
 
+config SERIAL_SI4455
+	tristate "Si4455 support"
+	depends on SPI
+	select SERIAL_CORE
+	help
+	  This driver is for Silicon Labs's Si4455 Sub-GHz transciver.
+	  Say 'Y' here if you wish to use it as serial port.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index caf167f0c10a..f01ff43db1d6 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_MPS2_UART)	+= mps2-uart.o
 obj-$(CONFIG_SERIAL_OWL)	+= owl-uart.o
 obj-$(CONFIG_SERIAL_RDA)	+= rda-uart.o
 obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
+obj-$(CONFIG_SERIAL_SI4455)	+= si4455.o
 obj-$(CONFIG_SERIAL_SIFIVE)	+= sifive.o
 
 # GPIOLIB helpers for modem control lines
diff --git a/drivers/tty/serial/si4455.c b/drivers/tty/serial/si4455.c
new file mode 100644
index 000000000000..502d6cb88fa0
--- /dev/null
+++ b/drivers/tty/serial/si4455.c
@@ -0,0 +1,1372 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 József Horváth <info@ministro.hu>
+ *
+ */
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/spi/spi.h>
+#include <linux/uaccess.h>
+#include <linux/string.h>
+#include <linux/firmware.h>
+
+#define PORT_SI4455						1096
+#define SI4455_NAME						"Si4455"
+#define SI4455_MAJOR						432
+#define SI4455_MINOR						567
+#define SI4455_UART_NRMAX					1
+#define SI4455_FIFO_SIZE					64
+
+#define SI4455_CMD_ID_EZCONFIG_CHECK				0x19
+#define SI4455_CMD_ID_PART_INFO					0x01
+#define SI4455_CMD_REPLY_COUNT_PART_INFO			9
+#define SI4455_CMD_ID_GET_INT_STATUS				0x20
+#define SI4455_CMD_REPLY_COUNT_GET_INT_STATUS			8
+#define SI4455_CMD_ID_FIFO_INFO					0x15
+#define SI4455_CMD_ARG_COUNT_FIFO_INFO				2
+#define SI4455_CMD_REPLY_COUNT_FIFO_INFO			2
+#define SI4455_CMD_FIFO_INFO_ARG_TX_BIT				0x01
+#define SI4455_CMD_FIFO_INFO_ARG_RX_BIT				0x02
+#define SI4455_CMD_ID_READ_CMD_BUFF				0x44
+#define SI4455_CMD_ID_READ_RX_FIFO				0x77
+#define SI4455_CMD_ID_WRITE_TX_FIFO				0x66
+#define SI4455_CMD_ID_START_RX					0x32
+#define SI4455_CMD_ARG_COUNT_START_RX				8
+#define SI4455_CMD_START_RX_RXTIMEOUT_STATE_RX			8
+#define SI4455_CMD_START_RX_RXVALID_STATE_RX			8
+#define SI4455_CMD_START_RX_RXINVALID_STATE_RX			8
+#define SI4455_CMD_ID_START_TX					0x31
+#define SI4455_CMD_ARG_COUNT_START_TX				5
+#define SI4455_CMD_ID_CHANGE_STATE				0x34
+#define SI4455_CMD_ARG_COUNT_CHANGE_STATE			2
+#define SI4455_CMD_CHANGE_STATE_STATE_READY			3
+#define SI4455_CMD_GET_CHIP_STATUS_ERROR_PEND_MASK		0x08
+#define SI4455_CMD_GET_CHIP_STATUS_ERROR_PEND_BIT		0x08
+#define SI4455_CMD_GET_INT_STATUS_PACKET_SENT_PEND_BIT		0x20
+#define SI4455_CMD_GET_INT_STATUS_PACKET_RX_PEND_BIT		0x10
+#define SI4455_CMD_GET_INT_STATUS_CRC_ERROR_BIT			0x08
+#define SI4455_CMD_ID_GET_MODEM_STATUS				0x22
+#define SI4455_CMD_ARG_COUNT_GET_MODEM_STATUS			2
+#define SI4455_CMD_REPLY_COUNT_GET_MODEM_STATUS			8
+
+struct si4455_part_info {
+	u8 chip_rev;
+	u16 part;
+	u8 pbuild;
+	u16 id;
+	u8 customer;
+	u8 rom_id;
+	u8 bond;
+};
+
+struct si4455_int_status {
+	u8 int_pend;
+	u8 int_status;
+	u8 ph_pend;
+	u8 ph_status;
+	u8 modem_pend;
+	u8 modem_status;
+	u8 chip_pend;
+	u8 chip_status;
+};
+
+struct si4455_modem_status {
+	u8 modem_pend;
+	u8 modem_status;
+	u8 curr_rssi;
+	u8 latch_rssi;
+	u8 ant1_rssi;
+	u8 ant2_rssi;
+	u16 afc_freq_offset;
+};
+
+struct si4455_fifo_info {
+	u8 rx_fifo_count;
+	u8 tx_fifo_space;
+};
+
+struct si4455_port {
+	struct uart_port port;
+	struct work_struct tx_work;
+	struct mutex mutex; /* For syncing access to device */
+	struct gpio_desc *shdn_gpio;
+	struct si4455_part_info part_info;
+	struct si4455_modem_status modem_status;
+	u32 tx_channel;
+	u32 rx_channel;
+	u32 package_size;
+	u32 current_rssi;
+	int power_count;
+	bool connected;
+	bool configured;
+	bool tx_pending;
+	bool rx_pending;
+};
+
+static struct uart_driver si4455_uart = {
+	.owner			= THIS_MODULE,
+	.driver_name		= SI4455_NAME,
+#ifdef CONFIG_DEVFS_FS
+	.dev_name		= "ttySI%d",
+#else
+	.dev_name		= "ttySI",
+#endif
+	.major			= SI4455_MAJOR,
+	.minor			= SI4455_MINOR,
+	.nr			= SI4455_UART_NRMAX,
+};
+
+static int si4455_get_response(struct uart_port *port, int length, u8 *data)
+{
+	int ret;
+	u8 data_out[] = { SI4455_CMD_ID_READ_CMD_BUFF };
+	u8 *data_in;
+	struct spi_transfer xfer[2];
+	int timeout = 10000;
+
+	if (length > 0 && !data)
+		return -EINVAL;
+
+	data_in = kzalloc(1 + length, GFP_KERNEL);
+	if (!data_in)
+		return -ENOMEM;
+
+	memset(&xfer, 0x00, sizeof(xfer));
+	xfer[0].tx_buf = data_out;
+	xfer[0].len = sizeof(data_out);
+	xfer[1].rx_buf = data_in;
+	xfer[1].len = 1 + length;
+
+	while (--timeout > 0) {
+		data_out[0] = SI4455_CMD_ID_READ_CMD_BUFF;
+		ret = spi_sync_transfer(to_spi_device(port->dev), xfer,
+					ARRAY_SIZE(xfer));
+		if (ret) {
+			dev_err(port->dev, "%s: spi_sync_transfer error (%i)\n", __func__, ret);
+			break;
+		}
+
+		if (data_in[0] == 0xFF) {
+			if (length > 0 && data)
+				memcpy(data, &data_in[1], length);
+
+			break;
+		}
+		usleep_range(100, 200);
+	}
+	if (!ret && timeout == 0) {
+		dev_err(port->dev, "%s: timeout\n", __func__);
+		ret = -EIO;
+	}
+	kfree(data_in);
+	return ret;
+}
+
+static int si4455_poll_cts(struct uart_port *port)
+{
+	return si4455_get_response(port, 0, NULL);
+}
+
+static int si4455_send_command(struct uart_port *port, int length, u8 *data)
+{
+	int ret;
+
+	ret = si4455_poll_cts(port);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_poll_cts error (%i)\n", __func__, ret);
+		return ret;
+	}
+
+	ret = spi_write(to_spi_device(port->dev), data, length);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: spi_write error (%i)\n", __func__, ret);
+	}
+
+	return ret;
+}
+
+static int si4455_send_command_get_response(struct uart_port *port,
+					    int out_length, u8 *data_out,
+					    int in_length, u8 *data_in)
+{
+	int ret;
+
+	ret = si4455_send_command(port, out_length, data_out);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_send_command error (%i)\n", __func__, ret);
+		return ret;
+	}
+
+	return si4455_get_response(port, in_length, data_in);
+}
+
+static int si4455_read_data(struct uart_port *port, u8 command, int poll,
+			    int length, u8 *data)
+{
+	int ret = 0;
+	u8 data_out[] = { command };
+	struct spi_transfer xfer[] = {
+		{
+			.tx_buf = data_out,
+			.len = sizeof(data_out),
+		}, {
+			.rx_buf = data,
+			.len = length,
+		}
+	};
+
+	if (poll) {
+		ret = si4455_poll_cts(port);
+		if (ret)
+			return ret;
+	}
+
+	ret = spi_sync_transfer(to_spi_device(port->dev),
+				xfer,
+				ARRAY_SIZE(xfer));
+	if (ret) {
+		dev_err(port->dev,
+			"%s: spi_sync_transfer error (%i)\n", __func__, ret);
+	}
+
+	return ret;
+}
+
+static int si4455_write_data(struct uart_port *port, u8 command, int poll,
+			     int length, const u8 *data)
+{
+	int ret = 0;
+	u8 *data_out;
+
+	if (poll) {
+		ret = si4455_poll_cts(port);
+		if (ret)
+			return ret;
+	}
+
+	data_out = kzalloc(1 + length, GFP_KERNEL);
+	if (!data_out)
+		return -ENOMEM;
+
+	data_out[0] = command;
+	memcpy(&data_out[1], data, length);
+	ret = spi_write(to_spi_device(port->dev), data_out, 1 + length);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: spi_write error (%i)\n", __func__, ret);
+	}
+
+	kfree(data_out);
+
+	return ret;
+}
+
+static void si4455_set_power(struct si4455_port *priv, int on)
+{
+	if (!priv->shdn_gpio)
+		return;
+	if (on) {
+		gpiod_direction_output(priv->shdn_gpio, 0);
+		usleep_range(4000, 5000);
+		gpiod_set_value(priv->shdn_gpio, 1);
+		usleep_range(4000, 5000);
+	} else {
+		gpiod_direction_output(priv->shdn_gpio, 0);
+	}
+}
+
+static int si4455_s_power(struct device *dev, int on)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	dev_dbg(dev, "%s(on=%d)\n", __func__, on);
+	if (s->power_count == !on)
+		si4455_set_power(s, on);
+	s->power_count += on ? 1 : -1;
+	WARN_ON(s->power_count < 0);
+
+	return 0;
+}
+
+static int si4455_get_part_info(struct uart_port *port,
+				struct si4455_part_info *result)
+{
+	int ret;
+	u8 data_out[] = { SI4455_CMD_ID_PART_INFO };
+	u8 data_in[SI4455_CMD_REPLY_COUNT_PART_INFO];
+
+	ret = si4455_send_command_get_response(port, sizeof(data_out), data_out,
+					       sizeof(data_in), data_in);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_send_command_get_response error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	result->chip_rev = data_in[0];
+	memcpy(&result->part, &data_in[1], sizeof(result->part));
+	result->pbuild = data_in[3];
+	memcpy(&result->id, &data_in[4], sizeof(result->id));
+	result->customer = data_in[6];
+	result->rom_id = data_in[7];
+	result->bond = data_in[8];
+
+	return 0;
+}
+
+static int si4455_get_int_status(struct uart_port *port, u8 ph_clear,
+				 u8 modem_clear, u8 chip_clear,
+				 struct si4455_int_status *result)
+{
+	int ret;
+	u8 data_out[] = {
+		SI4455_CMD_ID_GET_INT_STATUS,
+		ph_clear,
+		modem_clear,
+		chip_clear
+	};
+	u8 data_in[SI4455_CMD_REPLY_COUNT_GET_INT_STATUS];
+
+	ret = si4455_send_command_get_response(port, sizeof(data_out), data_out,
+					       sizeof(data_in), data_in);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_send_command_get_response error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	result->int_pend       = data_in[0];
+	result->int_status     = data_in[1];
+	result->ph_pend        = data_in[2];
+	result->ph_status      = data_in[3];
+	result->modem_pend     = data_in[4];
+	result->modem_status   = data_in[5];
+	result->chip_pend      = data_in[6];
+	result->chip_status    = data_in[7];
+
+	return 0;
+}
+
+static int si4455_get_modem_status(struct uart_port *port, u8 modem_clear,
+				   struct si4455_modem_status *result)
+{
+	int ret;
+	u8 data_out[] = {
+		SI4455_CMD_ID_GET_MODEM_STATUS,
+		modem_clear,
+	};
+	u8 data_in[SI4455_CMD_REPLY_COUNT_GET_MODEM_STATUS];
+
+	ret = si4455_send_command_get_response(port, sizeof(data_out), data_out,
+					       sizeof(data_in), data_in);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_send_command_get_response error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	result->modem_pend      = data_in[0];
+	result->modem_status    = data_in[1];
+	result->curr_rssi       = data_in[2];
+	result->latch_rssi      = data_in[3];
+	result->ant1_rssi       = data_in[4];
+	result->ant2_rssi       = data_in[5];
+	memcpy(&result->afc_freq_offset, &data_in[6],
+	       sizeof(result->afc_freq_offset));
+
+	return 0;
+}
+
+static int si4455_fifo_info(struct uart_port *port, u8 fifo,
+			    struct si4455_fifo_info *result)
+{
+	int ret;
+	u8 data_out[SI4455_CMD_ARG_COUNT_FIFO_INFO] = {
+		SI4455_CMD_ID_FIFO_INFO, fifo
+	};
+	u8 data_in[SI4455_CMD_REPLY_COUNT_FIFO_INFO] = { 0 };
+
+	ret = si4455_send_command_get_response(port, sizeof(data_out), data_out,
+					       sizeof(data_in), data_in);
+	if (ret) {
+		dev_err(port->dev,
+			"%s: si4455_send_command_get_response error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	result->rx_fifo_count  = data_in[0];
+	result->tx_fifo_space  = data_in[1];
+
+	return 0;
+}
+
+static int si4455_read_rx_fifo(struct uart_port *port, int length, u8 *data)
+{
+	return si4455_read_data(port, SI4455_CMD_ID_READ_RX_FIFO, 0, length,
+				data);
+}
+
+static int si4455_write_tx_fifo(struct uart_port *port, int length, u8 *data)
+{
+	return si4455_write_data(port, SI4455_CMD_ID_WRITE_TX_FIFO, 0, length,
+				 data);
+}
+
+static int si4455_rx(struct uart_port *port, u32 channel, u8 condition,
+		     u16 length, u8 next_state1, u8 next_state2,
+		     u8 next_state3)
+{
+	u8 data_out[SI4455_CMD_ARG_COUNT_START_RX];
+
+	data_out[0] = SI4455_CMD_ID_START_RX;
+	data_out[1] = channel;
+	data_out[2] = condition;
+	data_out[3] = (u8)(length >> 8);
+	data_out[4] = (u8)(length);
+	data_out[5] = next_state1;
+	data_out[6] = next_state2;
+	data_out[7] = next_state3;
+
+	return si4455_send_command(port, SI4455_CMD_ARG_COUNT_START_RX,
+				   data_out);
+}
+
+static int si4455_tx(struct uart_port *port, u8 channel, u8 condition,
+		     u16 length)
+{
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+	u8 data_out[SI4455_CMD_ARG_COUNT_START_TX + 1];
+	u8 out_length = SI4455_CMD_ARG_COUNT_START_TX;
+
+	if (s->part_info.rom_id == 6)
+		out_length += 1;
+
+	data_out[0] = SI4455_CMD_ID_START_TX;
+	data_out[1] = channel;
+	data_out[2] = condition;
+	data_out[3] = (u8)(length >> 8);
+	data_out[4] = (u8)(length);
+	if (s->part_info.rom_id == 6)
+		data_out[5] = 0x44;
+
+	return si4455_send_command(port, out_length, data_out);
+}
+
+static int si4455_change_state(struct uart_port *port, u8 next_state1)
+{
+	u8 data_out[SI4455_CMD_ARG_COUNT_CHANGE_STATE];
+
+	data_out[0] = SI4455_CMD_ID_CHANGE_STATE;
+	data_out[1] = (u8)next_state1;
+
+	return si4455_send_command(port, SI4455_CMD_ARG_COUNT_CHANGE_STATE,
+				   data_out);
+}
+
+static int si4455_begin_tx(struct uart_port *port, u32 channel, int length,
+			   u8 *data)
+{
+	int ret = 0;
+	struct si4455_int_status int_status = { 0 };
+	struct si4455_fifo_info fifo_info = { 0 };
+
+	dev_dbg(port->dev, "%s(%u, %u)\n", __func__, channel, length);
+	if (length > SI4455_FIFO_SIZE || length < 0)
+		return -EINVAL;
+
+	ret = si4455_change_state(port, SI4455_CMD_CHANGE_STATE_STATE_READY);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_change_state error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_get_int_status(port, 0, 0, 0, &int_status);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_get_int_status error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_fifo_info(port, SI4455_CMD_FIFO_INFO_ARG_TX_BIT,
+			       &fifo_info);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_fifo_info error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_write_tx_fifo(port, (u16)length, data);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_write_tx_fifo error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_tx(port, channel, 0x30, length);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_tx error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int si4455_end_tx(struct uart_port *port)
+{
+	int ret = 0;
+	struct si4455_int_status int_status = { 0 };
+
+	ret = si4455_change_state(port, SI4455_CMD_CHANGE_STATE_STATE_READY);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_change_state error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_get_int_status(port, 0, 0, 0, &int_status);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_get_int_status error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int si4455_begin_rx(struct uart_port *port, u32 channel, u32 length)
+{
+	int ret = 0;
+	struct si4455_int_status int_status = { 0 };
+	struct si4455_fifo_info fifo_info = { 0 };
+
+	dev_dbg(port->dev, "%s(%u, %u)\n", __func__, channel, length);
+	ret = si4455_get_int_status(port, 0, 0, 0, &int_status);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_get_int_status error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_fifo_info(port, SI4455_CMD_FIFO_INFO_ARG_RX_BIT,
+			       &fifo_info);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_fifo_info error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	ret = si4455_rx(port, channel, 0x00, length,
+			SI4455_CMD_START_RX_RXTIMEOUT_STATE_RX,
+			SI4455_CMD_START_RX_RXVALID_STATE_RX,
+			SI4455_CMD_START_RX_RXINVALID_STATE_RX);
+	if (ret) {
+		dev_err(port->dev, "%s: si4455_rx error (%i)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int si4455_end_rx(struct uart_port *port, u32 length, u8 *data)
+{
+	return si4455_read_rx_fifo(port, length, data);
+}
+
+static int si4455_configure(struct uart_port *port, const u8 *configuration_data)
+{
+	int ret = 0;
+	u8 col;
+	u8 response;
+	u8 count;
+	u8 cmd;
+	struct si4455_int_status int_status = { 0 };
+	u8 radio_cmd[16];
+
+	/*
+	 * While cycle as far as the pointer points to a command
+	 */
+	while (*configuration_data != 0x00) {
+		/*
+		 * Commands structure in the array:
+		 * --------------------------------
+		 * LEN | <LEN length of data>
+		 */
+		count = *configuration_data++;
+		cmd = *configuration_data;
+		dev_dbg(port->dev, "%s: count (%u), cmd (%u)\n",
+			__func__, count, cmd);
+
+		if (count > 16 && count <= 128 && cmd == SI4455_CMD_ID_WRITE_TX_FIFO) {
+			/*
+			 * Load array to the device
+			 */
+			configuration_data++;
+			ret = si4455_write_data(port, SI4455_CMD_ID_WRITE_TX_FIFO,
+						1, count - 1, configuration_data);
+			if (ret) {
+				dev_err(port->dev, "%s: si4455_write_data error (%i)\n",
+					__func__, ret);
+				break;
+			}
+
+			/*
+			 * Point to the next command
+			 */
+			configuration_data += count - 1;
+
+			/*
+			 * Continue command interpreter
+			 */
+			continue;
+		} else if (count > 16) {
+			/*
+			 * Number of command bytes exceeds
+			 * maximal allowable length
+			 */
+			ret = -EINVAL;
+			break;
+		}
+
+		for (col = 0u; col < count; col++) {
+			radio_cmd[col] = *configuration_data;
+			configuration_data++;
+		}
+
+		dev_dbg(port->dev, "%s: radio_cmd[0] (%u)\n", __func__, radio_cmd[0]);
+		ret = si4455_send_command_get_response(port, count, radio_cmd,
+						       1, &response);
+		if (ret) {
+			dev_err(port->dev,
+				"%s: si4455_send_command_get_response error (%i)\n",
+				__func__, ret);
+			break;
+		}
+
+		/*
+		 * Check response byte of EZCONFIG_CHECK command
+		 */
+		if (radio_cmd[0] == SI4455_CMD_ID_EZCONFIG_CHECK) {
+			if (response) {
+				/*
+				 * Number of command bytes exceeds
+				 * maximal allowable length
+				 */
+				ret = -EIO;
+				dev_err(port->dev, "%s: EZConfig check error (%i)\n",
+					__func__, radio_cmd[0]);
+				break;
+			}
+		}
+
+		/*
+		 * Get and clear all interrupts.  An error has occurred...
+		 */
+		si4455_get_int_status(port, 0, 0, 0, &int_status);
+		if (int_status.chip_pend
+		    & SI4455_CMD_GET_CHIP_STATUS_ERROR_PEND_MASK) {
+			ret = -EIO;
+			dev_err(port->dev, "%s: chip error (%i)\n",
+				__func__, int_status.chip_pend);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int si4455_re_configure(struct uart_port *port, const struct firmware *configuration)
+{
+	int ret = 0;
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+
+	mutex_lock(&s->mutex);
+	s->configured = 0;
+	if (s->power_count > 0)
+		si4455_s_power(port->dev, 0);
+
+	si4455_s_power(port->dev, 1);
+	ret = si4455_configure(port, configuration->data);
+	if (ret == 0)
+		s->configured = 1;
+	mutex_unlock(&s->mutex);
+	return ret;
+}
+
+static int si4455_start_tx_xmit(struct uart_port *port)
+{
+	int ret;
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+	struct circ_buf *xmit = &port->state->xmit;
+	u32 tx_pending;
+	u32 tx_to_end;
+	u8 *data;
+
+	tx_pending = uart_circ_chars_pending(xmit);
+	if (tx_pending == 0 || tx_pending < s->package_size)
+		return 0;
+
+	if (s->package_size == 0) {
+		//TODO: variable packet length
+		dev_err(port->dev, "%s: variable packet length is not supported by the driver\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	tx_pending = s->package_size;
+	data = kzalloc(s->package_size, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	tx_to_end = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+	if (tx_to_end < tx_pending) {
+		memcpy(data, xmit->buf + xmit->tail, tx_to_end);
+		memcpy(data, xmit->buf, tx_pending - tx_to_end);
+	} else {
+		memcpy(data, xmit->buf + xmit->tail, tx_pending);
+	}
+
+	ret = si4455_begin_tx(port, s->tx_channel, tx_pending, data);
+	if (!ret) {
+		s->tx_pending = true;
+		uart_handle_cts_change(&s->port, 0);
+	}
+
+	kfree(data);
+
+	return ret;
+}
+
+static int si4455_do_work(struct uart_port *port)
+{
+	int ret = 0;
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+	struct circ_buf *xmit = &port->state->xmit;
+
+	mutex_lock(&s->mutex);
+	dev_dbg(port->dev, "%s(connected=%i, configured=%i, power_count=%i)\n",
+		__func__, s->connected, s->configured, s->power_count);
+	if (s->connected && s->configured && s->power_count > 0) {
+		if (!(uart_circ_empty(xmit) || uart_tx_stopped(port) || s->tx_pending))
+			ret = si4455_start_tx_xmit(port);
+
+		if (!ret && !s->tx_pending) {
+			if (s->package_size == 0) {
+				//TODO: variable packet length
+				dev_err(port->dev, "%s: variable packet length is not supported by the driver\n",
+					__func__);
+				ret = -EINVAL;
+			} else {
+				ret = si4455_begin_rx(port, s->rx_channel,
+						      s->package_size);
+			}
+		}
+	}
+	mutex_unlock(&s->mutex);
+	return ret;
+}
+
+static void si4455_handle_rx_pend(struct si4455_port *s)
+{
+	struct uart_port *port = &s->port;
+	u8 *data = NULL;
+	int sret = 0;
+	int i = 0;
+
+	if (s->package_size == 0) {
+		//TODO: variable packet length
+		dev_err(port->dev, "%s: variable packet length is not supported by the driver\n",
+			__func__);
+		return;
+	}
+
+	data = kzalloc(s->package_size, GFP_KERNEL);
+	sret = si4455_end_rx(port, s->package_size, data);
+	if (sret) {
+		dev_err(port->dev, "%s: si4455_end_rx error (%i)\n",
+			__func__, sret);
+	} else {
+		for (i = 0; i < s->package_size; i++) {
+			uart_insert_char(port, 0, 0, data[i], TTY_NORMAL);
+			port->icount.rx++;
+		}
+		tty_flip_buffer_push(&port->state->port);
+	}
+	kfree(data);
+}
+
+static void si4455_handle_tx_pend(struct si4455_port *s)
+{
+	struct uart_port *port = &s->port;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	if (s->tx_pending) {
+		if (s->package_size == 0) {
+			//TODO: variable packet length
+			dev_err(port->dev, "%s: variable packet length is not supported by the driver\n",
+				__func__);
+		} else {
+			port->icount.tx += s->package_size;
+			xmit->tail = (xmit->tail + s->package_size)
+				     & (UART_XMIT_SIZE - 1);
+		}
+		si4455_end_tx(port);
+		s->tx_pending = 0;
+		uart_handle_cts_change(&s->port, TIOCM_CTS);
+	}
+}
+
+static irqreturn_t si4455_ist(int irq, void *dev_id)
+{
+	struct si4455_port *s = (struct si4455_port *)dev_id;
+	struct uart_port *port = &s->port;
+	int ret;
+	struct si4455_int_status int_status = { 0 };
+	struct si4455_fifo_info fifo_info = { 0 };
+
+	if (!s->connected || !s->configured || s->power_count == 0)
+		return IRQ_NONE;
+
+	ret = si4455_get_int_status(port, 0, 0, 0, &int_status);
+	if (ret)
+		return IRQ_NONE;
+
+	mutex_lock(&s->mutex);
+	si4455_get_modem_status(port, 0, &s->modem_status);
+	if (int_status.chip_pend & SI4455_CMD_GET_CHIP_STATUS_ERROR_PEND_BIT) {
+		dev_err(port->dev, "%s: chip_status:CMD_ERROR_PEND\n", __func__);
+	} else if (int_status.ph_pend & SI4455_CMD_GET_INT_STATUS_PACKET_SENT_PEND_BIT) {
+		dev_dbg(port->dev, "%s: ph_status:PACKET_SENT_PEND\n", __func__);
+		si4455_handle_tx_pend(s);
+	} else if (int_status.ph_pend & SI4455_CMD_GET_INT_STATUS_PACKET_RX_PEND_BIT) {
+		dev_dbg(port->dev, "%s: ph_status:PACKET_RX_PEND\n", __func__);
+		s->current_rssi = s->modem_status.curr_rssi;
+		si4455_fifo_info(port, 0, &fifo_info);
+		si4455_handle_rx_pend(s);
+	} else if (int_status.ph_pend & SI4455_CMD_GET_INT_STATUS_CRC_ERROR_BIT) {
+		dev_dbg(port->dev, "%s: ph_status:CRC_ERROR_PEND\n", __func__);
+	}
+	mutex_unlock(&s->mutex);
+	si4455_do_work(port);
+	return IRQ_HANDLED;
+}
+
+static void si4455_tx_proc(struct work_struct *ws)
+{
+	struct si4455_port *s = container_of(ws, struct si4455_port, tx_work);
+
+	si4455_do_work(&s->port);
+}
+
+static unsigned int si4455_tx_empty(struct uart_port *port)
+{
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+	//TODO: variable packet length
+	return s->tx_pending ? 0 : TIOCSER_TEMT;
+}
+
+static unsigned int si4455_get_mctrl(struct uart_port *port)
+{
+	int ret;
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+
+	/*
+	 * there is no a continuous real "carrier" like on phone line,
+	 * but after configuration, the interface is ready to use the physical
+	 * transport channel
+	 */
+	ret = s->configured ? TIOCM_CAR | TIOCM_DSR : 0;
+	ret |= s->tx_pending ? 0 : TIOCM_CTS;
+
+	return ret;
+}
+
+static void si4455_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	dev_dbg(port->dev, "%s\n", __func__);
+}
+
+static void si4455_set_termios(struct uart_port *port, struct ktermios *termios,
+			       struct ktermios *old)
+{
+	dev_dbg(port->dev, "%s\n", __func__);
+	if ((termios->c_cflag & CSIZE) != CS8)
+		dev_err(port->dev, "%s: CSIZE must be CS8\n", __func__);
+}
+
+static int si4455_startup(struct uart_port *port)
+{
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+
+	dev_dbg(port->dev, "%s\n", __func__);
+	mutex_lock(&s->mutex);
+	s->connected = true;
+	mutex_unlock(&s->mutex);
+	return si4455_do_work(port);
+}
+
+static void si4455_shutdown(struct uart_port *port)
+{
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+
+	dev_dbg(port->dev, "%s\n", __func__);
+	mutex_lock(&s->mutex);
+	s->connected = false;
+	mutex_unlock(&s->mutex);
+}
+
+static const char *si4455_type(struct uart_port *port)
+{
+	struct si4455_port *s = dev_get_drvdata(port->dev);
+
+	if (port->type != PORT_SI4455)
+		return NULL;
+	if (s->part_info.rom_id == 3)
+		return "SI4455-B1A";
+	else if (s->part_info.rom_id == 6)
+		return "SI4455-C2A";
+
+	return "SI4455(UNKNOWN-REV)";
+}
+
+static void si4455_config_port(struct uart_port *port, int flags)
+{
+	dev_dbg(port->dev, "%s\n", __func__);
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_SI4455;
+}
+
+static int si4455_verify_port(struct uart_port *port, struct serial_struct *s)
+{
+	if (s->type != PORT_UNKNOWN && s->type != PORT_SI4455)
+		return -EINVAL;
+
+	if (s->irq != port->irq)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void si4455_start_tx(struct uart_port *port)
+{
+	struct si4455_port *s = container_of(port,
+					     struct si4455_port,
+					     port);
+
+	dev_dbg(port->dev, "%s\n", __func__);
+
+	schedule_work(&s->tx_work);
+}
+
+static void si4455_null_void(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+static const struct uart_ops si4455_ops = {
+	.tx_empty		= si4455_tx_empty,
+	.set_mctrl		= si4455_set_mctrl,/* required */
+	.get_mctrl		= si4455_get_mctrl,
+	.stop_tx		= si4455_null_void,
+	.start_tx		= si4455_start_tx,
+	.stop_rx		= si4455_null_void,
+	.startup		= si4455_startup,
+	.shutdown		= si4455_shutdown,
+	.set_termios		= si4455_set_termios,/* required */
+	.type			= si4455_type,
+	.release_port		= si4455_null_void,
+	.config_port		= si4455_config_port,
+	.verify_port		= si4455_verify_port,
+};
+
+static int __maybe_unused si4455_suspend(struct device *dev)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return uart_suspend_port(&si4455_uart, &s->port);
+}
+
+static int __maybe_unused si4455_resume(struct device *dev)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return uart_resume_port(&si4455_uart, &s->port);
+}
+
+static SIMPLE_DEV_PM_OPS(si4455_pm_ops, si4455_suspend, si4455_resume);
+
+static ssize_t package_size_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", s->package_size);
+}
+
+static ssize_t package_size_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > SI4455_FIFO_SIZE)
+		return -EINVAL;
+
+	s->package_size = val;
+	ret = si4455_do_work(&s->port);
+
+	return ret ? ret : count;
+}
+
+/*
+ * package_size: rw sysfs entry.
+ * Sets or returns the package size.
+ * The new value applied immediately.
+ * Variable package size (package_size == 0)
+ * currently not supported by driver.
+ */
+static DEVICE_ATTR_RW(package_size);
+
+static ssize_t rx_channel_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", s->rx_channel);
+}
+
+static ssize_t rx_channel_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	s->rx_channel = val;
+	ret = si4455_do_work(&s->port);
+
+	return ret ? ret : count;
+}
+
+/*
+ * rx_channel: rw sysfs entry.
+ * Sets or returns the receive channel index.
+ * The new value applied immediately.
+ */
+static DEVICE_ATTR_RW(rx_channel);
+
+static ssize_t tx_channel_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", s->tx_channel);
+}
+
+static ssize_t tx_channel_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	s->tx_channel = val;
+	ret = si4455_do_work(&s->port);
+
+	return ret ? ret : count;
+}
+
+/*
+ * tx_channel: rw sysfs entry.
+ * Sets or returns the transmit channel index.
+ * The new value will be used on next data transmit.
+ */
+static DEVICE_ATTR_RW(tx_channel);
+
+static ssize_t current_rssi_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", s->current_rssi);
+}
+
+/*
+ * current_rssi: ro sysfs entry.
+ * Returns the latest rssi value measured by chip.
+ */
+static DEVICE_ATTR_RO(current_rssi);
+
+static struct attribute *si4455_attributes[] = {
+	&dev_attr_package_size.attr,
+	&dev_attr_rx_channel.attr,
+	&dev_attr_tx_channel.attr,
+	&dev_attr_current_rssi.attr,
+	NULL
+};
+
+static const struct attribute_group si4455_attr_group = {
+	.attrs = si4455_attributes,
+};
+
+static int si4455_probe(struct device *dev,
+			int irq)
+{
+	int ret;
+	struct si4455_port *s;
+	const void *of_ptr;
+	char ez_fw_name[255] = { 0 };
+	const struct firmware *ez_fw = NULL;
+
+	/* Alloc port structure */
+	dev_dbg(dev, "%s\n", __func__);
+	s = devm_kzalloc(dev, sizeof(*s), GFP_KERNEL);
+	if (!s) {
+		dev_err(dev, "Error allocating port structure\n");
+		return -ENOMEM;
+	}
+
+	dev_set_drvdata(dev, s);
+	mutex_init(&s->mutex);
+
+	s->shdn_gpio = devm_gpiod_get(dev, "shutdown", GPIOD_OUT_HIGH);
+	if (IS_ERR(s->shdn_gpio)) {
+		dev_err(dev, "Unable to reguest shdn gpio\n");
+		ret = -EINVAL;
+		goto out_generic;
+	}
+
+	of_ptr = of_get_property(dev->of_node, "silabs,package-size", NULL);
+	if (IS_ERR_OR_NULL(of_ptr)) {
+		dev_err(dev, "dt silabs,package-size property not present\n");
+		ret = -EINVAL;
+		goto out_generic;
+	}
+	s->package_size = be32_to_cpup(of_ptr);
+	if (s->package_size > SI4455_FIFO_SIZE) {
+		dev_err(dev, "dt silabs,package-size property maximum is %i\n", SI4455_FIFO_SIZE);
+		ret = -EINVAL;
+		goto out_generic;
+	}
+
+	of_ptr = of_get_property(dev->of_node, "silabs,tx-channel", NULL);
+	if (IS_ERR_OR_NULL(of_ptr)) {
+		dev_err(dev, "dt silabs,tx-channel property not present\n");
+		ret = -EINVAL;
+		goto out_generic;
+	}
+	s->tx_channel = be32_to_cpup(of_ptr);
+
+	of_ptr = of_get_property(dev->of_node, "silabs,rx-channel", NULL);
+	if (IS_ERR_OR_NULL(of_ptr)) {
+		dev_err(dev, "dt silabs,rx-channel property not present\n");
+		ret = -EINVAL;
+		goto out_generic;
+	}
+	s->rx_channel = be32_to_cpup(of_ptr);
+
+	of_ptr = of_get_property(dev->of_node, "silabs,ez-config", NULL);
+	if (IS_ERR_OR_NULL(of_ptr)) {
+		dev_err(dev, "dt silabs,ez-config property not present\n");
+		ret = -EINVAL;
+		goto out_generic;
+	}
+	strncpy(ez_fw_name, of_ptr, sizeof(ez_fw_name) - 1);
+
+	/* Initialize port data */
+	s->port.dev		= dev;
+	s->port.line		= 0;
+	s->port.irq		= irq;
+	s->port.type		= PORT_SI4455;
+	s->port.fifosize	= SI4455_FIFO_SIZE;
+	s->port.flags		= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
+	s->port.iotype		= UPIO_PORT;
+	s->port.iobase		= 1;
+	s->port.ops		= &si4455_ops;
+
+	si4455_s_power(dev, 1);
+
+	//detect
+	ret = si4455_get_part_info(&s->port, &s->part_info);
+	dev_dbg(dev, "si4455_get_part_info() = %i\n", ret);
+	if (ret == 0) {
+		dev_dbg(dev, "partInfo.chip_rev = %u\n", s->part_info.chip_rev);
+		dev_dbg(dev, "partInfo.part = %u\n", s->part_info.part);
+		dev_dbg(dev, "partInfo.pbuild = %u\n", s->part_info.pbuild);
+		dev_dbg(dev, "partInfo.id = %u\n", s->part_info.id);
+		dev_dbg(dev, "partInfo.customer = %u\n", s->part_info.customer);
+		dev_dbg(dev, "partInfo.rom_id = %u\n", s->part_info.rom_id);
+		dev_dbg(dev, "partInfo.bond = %u\n", s->part_info.bond);
+		if (s->part_info.part != 0x5544) {
+			dev_err(dev, "unknown part(%u) error\n", s->part_info.part);
+			ret = -ENODEV;
+		}
+	}
+
+	if (ret)
+		goto out_generic;
+
+	ret = request_firmware(&ez_fw, ez_fw_name, dev);
+	if (ret) {
+		dev_err(dev, "firmware(%s) request error (%i)\n", ez_fw_name, ret);
+		ret = -EINVAL;
+		goto out_generic;
+	}
+
+	ret = si4455_re_configure(&s->port, ez_fw);
+	release_firmware(ez_fw);
+	if (ret) {
+		dev_err(dev, "device configuration error (%i)\n", ret);
+		ret = -EINVAL;
+		goto out_generic;
+	}
+
+	/* Initialize queue for start TX */
+	INIT_WORK(&s->tx_work, si4455_tx_proc);
+
+	/* Register port */
+	ret = uart_add_one_port(&si4455_uart, &s->port);
+	if (ret) {
+		s->port.dev = NULL;
+		goto out_uart;
+	}
+
+	ret = sysfs_create_group(&dev->kobj, &si4455_attr_group);
+	if (ret) {
+		dev_err(dev, "sysfs_create_group error (%i)\n", ret);
+		goto out_uart;
+	}
+	/* Setup interrupt */
+	ret = devm_request_threaded_irq(dev, irq, NULL, si4455_ist,
+					IRQF_ONESHOT | IRQF_SHARED,
+					dev_name(dev), s);
+
+	if (!ret)
+		return 0;
+
+	dev_err(dev, "Unable to reguest IRQ %i\n", irq);
+	sysfs_remove_group(&dev->kobj, &si4455_attr_group);
+
+out_uart:
+	uart_remove_one_port(&si4455_uart, &s->port);
+out_generic:
+	mutex_destroy(&s->mutex);
+	si4455_s_power(dev, 0);
+
+	return ret;
+}
+
+static int si4455_remove(struct device *dev)
+{
+	struct si4455_port *s = dev_get_drvdata(dev);
+
+	cancel_work_sync(&s->tx_work);
+	sysfs_remove_group(&dev->kobj, &si4455_attr_group);
+	uart_remove_one_port(&si4455_uart, &s->port);
+
+	mutex_destroy(&s->mutex);
+
+	return 0;
+}
+
+static const struct of_device_id __maybe_unused si4455_dt_ids[] = {
+	{ .compatible = "silabs,si4455" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, si4455_dt_ids);
+
+static int si4455_spi_probe(struct spi_device *spi)
+{
+	int ret;
+	const struct of_device_id *of_id;
+
+	/* Setup SPI bus */
+	spi->bits_per_word	= 8;
+	spi->mode		= SPI_MODE_0;
+	ret = spi_setup(spi);
+	if (ret)
+		return ret;
+
+	if (spi->dev.of_node) {
+		of_id = of_match_device(si4455_dt_ids, &spi->dev);
+		if (!of_id)
+			return -ENODEV;
+	}
+
+	return si4455_probe(&spi->dev, spi->irq);
+}
+
+static int si4455_spi_remove(struct spi_device *spi)
+{
+	return si4455_remove(&spi->dev);
+}
+
+static struct spi_driver si4455_spi_driver = {
+	.driver = {
+		.name		= SI4455_NAME,
+		.of_match_table	= of_match_ptr(si4455_dt_ids),
+		.pm		= &si4455_pm_ops,
+	},
+	.probe			= si4455_spi_probe,
+	.remove			= si4455_spi_remove,
+};
+
+static int __init si4455_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&si4455_uart);
+	if (ret)
+		return ret;
+
+	return spi_register_driver(&si4455_spi_driver);
+}
+module_init(si4455_uart_init);
+
+static void __exit si4455_uart_exit(void)
+{
+	spi_unregister_driver(&si4455_spi_driver);
+	uart_unregister_driver(&si4455_uart);
+}
+module_exit(si4455_uart_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jozsef Horvath <info@ministro.hu>");
+MODULE_DESCRIPTION("Si4455 serial driver");
-- 
2.17.1