lora_sx127/lora_sx127.c

/*-
 * Copyright (c) 2017 Jian-Hong, Pan <starnight@g.ncu.edu.tw>
 * Copyright (c) 2024 Fabian Montero <fabian@posixlycorrect.com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 *    redistribution must be conditioned upon including a substantially
 *    similar Disclaimer requirement for further binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGES.
 *
 */

#define SX127X_LEGACY_KERNEL

#define DEBUG

#include <linux/module.h>
#include <linux/timer.h>
#include <linux/device.h>
#include <linux/acpi.h>
#include <linux/of_device.h>
#include <linux/spinlock.h>
#include <linux/spi/spi.h>
#include <linux/regmap.h>
#include <net/mac802154.h>

static unsigned tx_poll_div = 10;
module_param(tx_poll_div, uint, 0000);
MODULE_PARM_DESC(tx_poll_div, "Number of RX poll cycles to perform before attempting a single TX op");

/* SX127X Registers addresses */
#define SX127X_REG_FIFO				0x00
#define SX127X_REG_OP_MODE			0x01
#define SX127X_REG_FRF_MSB			0x06
#define SX127X_REG_FRF_MID			0x07
#define SX127X_REG_FRF_LSB			0x08
#define SX127X_REG_PA_CONFIG			0x09
#define SX127X_REG_PA_RAMP			0x0A
#define SX127X_REG_OCP				0x0B
#define SX127X_REG_LNA				0x0C
#define SX127X_REG_FIFO_ADDR_PTR		0x0D
#define SX127X_REG_FIFO_TX_BASE_ADDR		0x0E
#define SX127X_REG_FIFO_RX_BASE_ADDR		0x0F
#define SX127X_REG_FIFO_RX_CURRENT_ADDR		0x10
#define SX127X_REG_IRQ_FLAGS_MASK		0x11
#define SX127X_REG_IRQ_FLAGS			0x12
#define SX127X_REG_RX_NB_BYTES			0x13
#define SX127X_REG_RX_HEADER_CNT_VALUE_MSB	0x14
#define SX127X_REG_RX_HEADER_CNT_VALUE_LSB	0x15
#define SX127X_REG_RX_PACKET_CNT_VALUE_MSB	0x16
#define SX127X_REG_RX_PACKET_CNT_VALUE_LSB	0x17
#define SX127X_REG_MODEM_STAT			0x18
#define SX127X_REG_PKT_SNR_VALUE		0x19
#define SX127X_REG_PKT_RSSI_VALUE		0x1A
#define SX127X_REG_RSSI_VALUE			0x1B
#define SX127X_REG_HOP_CHANNEL			0x1C
#define SX127X_REG_MODEM_CONFIG1		0x1D
#define SX127X_REG_MODEM_CONFIG2		0x1E
#define SX127X_REG_SYMB_TIMEOUT_LSB		0x1F
#define SX127X_REG_PREAMBLE_MSB			0x20
#define SX127X_REG_PREAMBLE_LSB			0x21
#define SX127X_REG_PAYLOAD_LENGTH		0x22
#define SX127X_REG_MAX_PAYLOAD_LENGTH		0x23
#define SX127X_REG_HOP_PERIOD			0x24
#define SX127X_REG_FIFO_RX_BYTE_ADDR		0x25
#define SX127X_REG_MODEM_CONFIG3		0x26
#define SX127X_REG_FEI_MSB			0x28
#define SX127X_REG_FEI_MID			0x29
#define SX127X_REG_FEI_LSB			0x2A
#define SX127X_REG_RSSI_WIDEBAND		0x2C
#define SX127X_REG_DETECT_OPTIMIZE		0x31
#define SX127X_REG_INVERT_IRQ			0x33
#define SX127X_REG_DETECTION_THRESHOLD		0x37
#define SX127X_REG_SYNC_WORD			0x39
#define SX127X_REG_VERSION			0x42
#define SX127X_REG_TCXO				0x4B
#define SX127X_REG_PA_DAC			0x4D
#define SX127X_REG_FORMER_TEMP			0x5B
#define SX127X_REG_AGC_REF			0x61
#define SX127X_REG_AGC_THRESH1			0x62
#define SX127X_REG_AGC_THRESH2			0x63
#define SX127X_REG_AGC_THRESH3			0x64
#define SX127X_REG_PLL				0x70
#define SX127X_MAX_REG				SX127X_REG_PLL

/* SX127X's operating states in LoRa mode */
#define SX127X_MODE_MASK			0x07
#define SX127X_SLEEP_MODE			0x00
#define SX127X_STANDBY_MODE			0x01
#define SX127X_FSTX_MODE			0x02
#define SX127X_TX_MODE				0x03
#define SX127X_FSRX_MODE			0x04
#define SX127X_RXCONTINUOUS_MODE		0x05
#define SX127X_RXSINGLE_MODE			0x06
#define SX127X_CAD_MODE				0x07
#define SX127X_LORA_MODE			0x80

/* SX127X_REG_OCP flags */
#define SX127X_FLAG_OCPON			0x20

/* SX127X's IRQ flags in LoRa mode */
#define SX127X_FLAG_RXTIMEOUT			0x80
#define	SX127X_FLAG_RXDONE			0x40
#define SX127X_FLAG_PAYLOADCRCERROR		0x20
#define SX127X_FLAG_VALIDHEADER			0x10
#define SX127X_FLAG_TXDONE			0x08
#define SX127X_FLAG_CADDONE			0x04
#define SX127X_FLAG_FHSSCHANGECHANNEL		0x02
#define SX127X_FLAG_CADDETECTED			0x01

/* SX127X's IRQ flags' mask for output pins in LoRa mode */
#define SX127X_FLAGMASK_RXTIMEOUT		0x80
#define	SX127X_FLAGMASK_RXDONE			0x40
#define SX127X_FLAGMASK_PAYLOADCRCERROR		0x20
#define SX127X_FLAGMASK_VALIDHEADER		0x10
#define SX127X_FLAGMASK_TXDONE			0x08
#define SX127X_FLAGMASK_CADDONE			0x04
#define SX127X_FLAGMASK_FHSSCHANGECHANNEL	0x02
#define SX127X_FLAGMASK_CADDETECTED		0x01

#define SX127X_MODEM_CONFIG1_HEADER_MODE_MASK		0x01
#define SX127X_MODEM_CONFIG1_HEADER_MODE_EXPLICIT	0x00
#define SX127X_MODEM_CONFIG1_HEADER_MODE_IMPLICIT	0x01

/* SX127X's RX/TX FIFO base address */
#define SX127X_FIFO_RX_BASE_ADDRESS		0x00
#define SX127X_FIFO_TX_BASE_ADDRESS		0x80

#define POLL_JIFFIES (msecs_to_jiffies(10))

struct sx127x {
	struct regmap        *regmap;
	struct ieee802154_hw *ieee;
	struct spi_device    *spi;

	spinlock_t            lock;
	bool                  busy;
	struct sk_buff       *tx_skb;
	size_t                delayed_tx_length;
	unsigned              tx_wait;

	struct timer_list     poll_timer;
	struct work_struct    poll_work;
	struct work_struct    tx_work;

	u32                   oscillator_freq;
};

static int sx127x_reg_read(struct sx127x *hw, unsigned int address, u8 *data)
{
	int ret = regmap_raw_read(hw->regmap, address, data, 1);
	if (ret < 0)
		dev_err(&hw->spi->dev, "regmap_raw_read(0x%x) failed: %d\n", address, ret);

	return ret;
}

static int sx127x_reg_write(struct sx127x *hw, unsigned int address, u8 data)
{
	int ret = regmap_raw_write(hw->regmap, address, &data, 1);
	if (ret < 0)
		dev_err(&hw->spi->dev, "regmap_raw_write(0x%x) failed: %d\n", address, ret);

	return ret;
}

static int sx127x_mode(struct sx127x *hw, unsigned int mode)
{
	return sx127x_reg_write(hw, SX127X_REG_OP_MODE, SX127X_LORA_MODE | mode);
}

static int sx127x_set_frequency(struct sx127x *hw, unsigned long frequency)
{
	u8 msb_mid_lsb[3];
	int i;
	u64 frf;

	frf = (((u64) frequency) << 19) / hw->oscillator_freq;
	for (i = sizeof msb_mid_lsb - 1; i >= 0; --i) {
		msb_mid_lsb[i] = (frf & 0xff);
		frf >>= 8;
	}

	return regmap_raw_write(hw->regmap, SX127X_REG_FRF_MSB, msb_mid_lsb, sizeof msb_mid_lsb);
}

static int sx127x_get_frequency(struct sx127x *hw, unsigned long *frequency)
{
	u8 msb_mid_lsb[3];
	int i, ret;
	u64 frt;

	ret = regmap_raw_read(hw->regmap, SX127X_REG_FRF_MSB, msb_mid_lsb, sizeof msb_mid_lsb);
	if (ret < 0)
		return ret;

	frt = 0;
	for (i = 0; i < sizeof msb_mid_lsb; ++i)
		frt = (frt << 8) | msb_mid_lsb[i];

	*frequency = (frt * hw->oscillator_freq) >> 19;
	return 0;
}

static int sx127x_set_ocp(struct sx127x *hw, u8 current_ma)
{
	u8 ocp_trim;

	/* P. 109
	 *
	 * Trimming of OCP current:
	 * Imax = 45+5*OcpTrim [mA] if OcpTrim <= 15 (120 mA) /
	 * Imax = -30+10*OcpTrim [mA] if 15 < OcpTrim <= 27 (130 to
	 * 240 mA)
	 * Imax = 240mA for higher settings
	 * Default Imax = 100mA
	 */
	if (current_ma <= 45)
		ocp_trim = 0;
	else if (current_ma <= 120)
		ocp_trim = (current_ma - 45) / 5;
	else if (current_ma <= 240)
		ocp_trim = (current_ma + 30) / 10;
	else
		ocp_trim = 28;

	return sx127x_reg_write(hw, SX127X_REG_OCP, SX127X_FLAG_OCPON | ocp_trim);
}

static int sx127x_set_tx_power(struct sx127x *hw, int level)
{
	int ret;

	// PA BOOST
	if (level > 17) {
		if (level > 20)
			level = 20;

		// subtract 3 from level, so 18 - 20 maps to 15 - 17
		level -= 3;
	
		// High Power +20 dBm Operation (Semtech SX1276/77/78/79 5.4.3.)
		ret = sx127x_reg_write(hw, SX127X_REG_PA_DAC, 0x87);
		if (ret < 0)
			return ret;

		ret = sx127x_set_ocp(hw, 140);
		if (ret < 0)
			return ret;
	} else {
		if (level < 2)
			level = 2;

		// Default value PA_HF/LF or +17dBm
		ret = sx127x_reg_write(hw, SX127X_REG_PA_DAC, 0x84);
		if (ret < 0)
			return ret;

		ret = sx127x_set_ocp(hw, 100);
		if (ret < 0)
			return ret;
	}

	// PA_CONFIG
#define PA_BOOST 0x80
	return sx127x_reg_write(hw, SX127X_REG_PA_CONFIG, PA_BOOST | (level - 2));
}

static int sx127x_init(struct sx127x *hw, u8 *major, u8 *minor)
{
	u8 modem_config1, lna, version;
	int ret;

	ret = sx127x_reg_read(hw, SX127X_REG_VERSION, &version);
	if (ret < 0)
		return ret;

	if (version != 0x12) {
		dev_err(&hw->spi->dev, "%s: bad version 0x%02x\n", __func__, version);
		return -ENODEV;
	}

	*major = (version >> 4) & 0xf;
	*minor = (version >> 0) & 0xf;

	ret = sx127x_mode(hw, SX127X_SLEEP_MODE);
	if (ret < 0) {
		dev_err(&hw->spi->dev, "%s: sx127x_mode() failed: %d\n", __func__, ret);
		return ret;
	}

	ret = sx127x_reg_write(hw, SX127X_REG_FIFO_RX_BASE_ADDR, SX127X_FIFO_RX_BASE_ADDRESS);
	if (ret < 0)
		return ret;

	ret = sx127x_reg_write(hw, SX127X_REG_FIFO_TX_BASE_ADDR, SX127X_FIFO_TX_BASE_ADDRESS);
	if (ret < 0)
		return ret;

	ret = sx127x_reg_read(hw, SX127X_REG_LNA, &lna);
	if (ret < 0)
		return ret;

	lna |= 0x3; // ???, pero lo hace el sketch
	ret = sx127x_reg_write(hw, SX127X_REG_LNA, lna);
	if (ret < 0)
		return ret;

	ret = sx127x_reg_read(hw, SX127X_REG_MODEM_CONFIG1, &modem_config1);
	if (ret < 0)
		return ret;

	modem_config1 &= ~SX127X_MODEM_CONFIG1_HEADER_MODE_MASK;
	modem_config1 |= SX127X_MODEM_CONFIG1_HEADER_MODE_EXPLICIT;

	ret = sx127x_reg_write(hw, SX127X_REG_MODEM_CONFIG1, modem_config1);
	if (ret < 0)
		return ret;

	ret = sx127x_reg_write(hw, SX127X_REG_MODEM_CONFIG3, 0x4);
	if (ret < 0)
		return ret;

	return 0;
}

static void sx127x_tx_work(struct work_struct *work)
{
	u8 mode;
	int ret = 0;
	bool set_busy = false;
	size_t i, size;
	const u8 *buffer;
	struct sx127x *hw = container_of(work, struct sx127x, tx_work);
	struct sk_buff *tx_skb;
	unsigned long spin_irq;

	spin_lock_irqsave(&hw->lock, spin_irq);

	tx_skb = hw->tx_skb;
	if (!hw->busy && !hw->delayed_tx_length) {
		hw->busy = true;
		set_busy = true;
	}

	spin_unlock_irqrestore(&hw->lock, spin_irq);

	if (!set_busy) {
		ret = -EBUSY;
		goto exit_busy;
	} else if (!tx_skb) {
		ret = -EINVAL;
		goto exit_busy;
	}

	size = tx_skb->len;
	buffer = tx_skb->data;

	if (!size || size > 128) {
		ret = -EINVAL;
		goto exit_busy;
	}

	ret = sx127x_reg_read(hw, SX127X_REG_OP_MODE, &mode);
	if (ret < 0)
		goto exit_busy;

	if ((mode & SX127X_MODE_MASK) == SX127X_TX_MODE) {
		ret = -EBUSY;
		goto exit_busy;
	}

	// reset FIFO address and payload length
	ret = sx127x_reg_write(hw, SX127X_REG_FIFO_TX_BASE_ADDR, SX127X_FIFO_TX_BASE_ADDRESS);
	if (ret < 0)
		goto exit_busy;

	ret = sx127x_reg_write(hw, SX127X_REG_FIFO_ADDR_PTR, SX127X_FIFO_TX_BASE_ADDRESS);
	if (ret < 0)
		goto exit_busy;

	// write data
	for (i = 0; i < size; i++) {
		ret = sx127x_reg_write(hw, SX127X_REG_FIFO, buffer[i]);
		if (ret < 0)
			goto exit_busy;
	}

	ret = sx127x_reg_write(hw, SX127X_REG_PAYLOAD_LENGTH, (u8) size);
	if (ret < 0)
		goto exit_busy;

	hw->delayed_tx_length = size;

exit_busy:
	spin_lock_irqsave(&hw->lock, spin_irq);
	if (set_busy)
		hw->busy = false;

	if (ret && tx_skb)
		hw->tx_skb = NULL;
	spin_unlock_irqrestore(&hw->lock, spin_irq);

	if (ret && tx_skb) {
#ifdef SX127X_LEGACY_KERNEL
		ieee802154_xmit_complete(hw->ieee, tx_skb, false);
#else
		ieee802154_xmit_error(hw->ieee, tx_skb, ret);
#endif
	}

	(void) ret;
}

static void sx127x_poll_work(struct work_struct *work)
{
	u8 ack_flags, lqi, mode, read_flags, rx_base, *rx_data, rx_length = 0;
	bool do_rx = false, was_busy = false;
	unsigned long spin_irq;
	struct sx127x *hw = container_of(work, struct sx127x, poll_work);
	struct sk_buff *rx_skb = NULL, *tx_skb = NULL;

	spin_lock_irqsave(&hw->lock, spin_irq);
	if (!hw->busy)
		hw->busy = true;
	else
		was_busy = true;

	tx_skb = hw->tx_skb;
	spin_unlock_irqrestore(&hw->lock, spin_irq);

	if (was_busy)
		return;

	if (sx127x_reg_read(hw, SX127X_REG_IRQ_FLAGS, &read_flags) < 0)
		goto exit_busy;

	ack_flags = 0;

	if (read_flags & SX127X_FLAG_TXDONE)
		ack_flags |= SX127X_FLAG_TXDONE;
	else
		tx_skb = NULL;

	if (read_flags & SX127X_FLAG_RXDONE) {
		do_rx = true;
		ack_flags |= SX127X_FLAG_RXDONE;

		if (read_flags & SX127X_FLAG_VALIDHEADER)
			ack_flags |= SX127X_FLAG_VALIDHEADER;
		else
			do_rx = false;

		if (read_flags & SX127X_FLAG_PAYLOADCRCERROR) {
			do_rx = false;
			ack_flags |= SX127X_FLAG_PAYLOADCRCERROR;
		}
	}

	if (do_rx) {
		if (sx127x_reg_read(hw, SX127X_REG_FIFO_RX_CURRENT_ADDR, &rx_base) < 0
		 || sx127x_reg_read(hw, SX127X_REG_RX_NB_BYTES, &rx_length) < 0)
			goto exit_busy;

		if (sx127x_reg_write(hw, SX127X_REG_FIFO_ADDR_PTR, rx_base) < 0)
			goto exit_busy;

		if (rx_length <= IEEE802154_MTU) {
			rx_skb = dev_alloc_skb(IEEE802154_MTU);
			if (!rx_skb)
				goto exit_busy;

			rx_data = skb_put(rx_skb, rx_length);

			while (rx_length--)
				if (sx127x_reg_read(hw, SX127X_REG_FIFO, rx_data++) < 0)
					goto exit_busy;
		} else
			dev_err(&hw->spi->dev, "%s: rx_length overflow: %u > IEEE802154_MTU\n", __func__, rx_length);

		if (sx127x_reg_write(hw, SX127X_REG_FIFO_RX_BASE_ADDR, SX127X_FIFO_RX_BASE_ADDRESS) < 0)
			goto exit_busy;
	}

	if (sx127x_reg_write(hw, SX127X_REG_IRQ_FLAGS, ack_flags) < 0)
		goto exit_busy;

	if (sx127x_reg_read(hw, SX127X_REG_OP_MODE, &mode) < 0)
		goto exit_busy;

	if ((mode & SX127X_MODE_MASK) != SX127X_TX_MODE) {
		if (++hw->tx_wait >= tx_poll_div)
			hw->tx_wait = 0;

		if (hw->delayed_tx_length && hw->tx_wait == 0) {
			sx127x_mode(hw, SX127X_TX_MODE);
			hw->delayed_tx_length = 0;
		} else if ((mode & SX127X_MODE_MASK) != SX127X_RXCONTINUOUS_MODE)
			sx127x_mode(hw, SX127X_RXCONTINUOUS_MODE);
	}

	if (rx_skb) {
		lqi = 69; //TODO
		ieee802154_rx_irqsafe(hw->ieee, rx_skb, lqi);
		rx_skb = NULL; // rx_skb ownership transferred to the mac802154 layer
	}

exit_busy:
	if (rx_skb)
		kfree_skb(rx_skb);

	spin_lock_irqsave(&hw->lock, spin_irq);
	hw->busy = false;
	if (tx_skb)
		hw->tx_skb = NULL;
	spin_unlock_irqrestore(&hw->lock, spin_irq);

	if (tx_skb)
		ieee802154_xmit_complete(hw->ieee, tx_skb, false);
}

static void sx127x_poll_timer(struct timer_list *timer)
{
	struct sx127x *hw = container_of(timer, struct sx127x, poll_timer);
	schedule_work(&hw->poll_work);
	mod_timer(&hw->poll_timer, jiffies + POLL_JIFFIES);
}

static int sx127x_802154_xmit_async(struct ieee802154_hw *ieee, struct sk_buff *skb)
{
	int ret = 0;
	struct sx127x *hw = ieee->priv;
	unsigned long spin_irq;

	spin_lock_irqsave(&hw->lock, spin_irq);
	if (!hw->tx_skb)
		hw->tx_skb = skb;
	else
		ret = -EBUSY;
	spin_unlock_irqrestore(&hw->lock, spin_irq);

	if (!ret)
		schedule_work(&hw->tx_work);

	return ret;
}

static int sx127x_802154_ed(struct ieee802154_hw *ieee, u8 *level)
{
	struct sx127x *hw = ieee->priv;
	(void) hw;
	return -ENOSYS;
}

static int sx127x_802154_set_channel(struct ieee802154_hw *ieee, u8 page, u8 channel)
{
	struct sx127x *hw = ieee->priv;
	(void) hw;
	return -ENOSYS;
}

static int sx127x_802154_set_txpower(struct ieee802154_hw *ieee, s32 mbm)
{
	struct sx127x *hw = ieee->priv;
	(void) hw;
	return -ENOSYS;
}

static int sx127x_802154_start(struct ieee802154_hw *ieee)
{
	int ret;
	struct sx127x *hw = ieee->priv;

	ret = sx127x_mode(hw, SX127X_STANDBY_MODE);
	if (ret < 0) {
		dev_err(&hw->spi->dev, "%s: sx127x_mode() failed: %d\n", __func__, ret);
		return ret;
	}

	mod_timer(&hw->poll_timer, jiffies + POLL_JIFFIES);
	return 0;
}

static void sx127x_802154_stop(struct ieee802154_hw *ieee)
{
	struct sx127x *hw = ieee->priv;

	del_timer_sync(&hw->poll_timer);
	cancel_work_sync(&hw->poll_work);

	(void) sx127x_mode(hw, SX127X_SLEEP_MODE);
}

static int sx127x_802154_set_promiscuous_mode(struct ieee802154_hw *ieee, const bool on)
{
	return 0;
}

static const struct ieee802154_ops sx127x_802154_ops = {
	.owner                = THIS_MODULE,
	.xmit_async           = sx127x_802154_xmit_async,
	.ed                   = sx127x_802154_ed,
	.set_channel          = sx127x_802154_set_channel,
	.set_txpower          = sx127x_802154_set_txpower,
	.start                = sx127x_802154_start,
	.stop                 = sx127x_802154_stop,
	.set_promiscuous_mode = sx127x_802154_set_promiscuous_mode,
};

static bool sx127x_reg_volatile(struct device *dev, unsigned int reg)
{
	return true;
}

static const struct regmap_config sx127x_regmap_config = {
	.reg_bits        = 8,
	.val_bits        = 8,
	.max_register    = SX127X_MAX_REG,
	.read_flag_mask	 = 0x00,
	.write_flag_mask = 0x80,
	.volatile_reg    = sx127x_reg_volatile,
};

/* in mbm */
static const s32 sx127x_tx_powers[] = {
	-200, -100, 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100,
	1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300};

static int sx127x_spi_probe(struct spi_device *spi)
{
	u8 major, minor;
	int ret = 0;
	struct sx127x *hw;
	unsigned long frequency;
	struct ieee802154_hw *ieee;
	struct device_node *of_node;

	dev_dbg(&spi->dev, "%s hello\n", __func__);

	ieee = ieee802154_alloc_hw(sizeof *hw, &sx127x_802154_ops);
	if (!ieee) {
		dev_err(&spi->dev, "ieee802154_alloc_hw(): out of memory\n");
		return -ENOMEM;
	}

	hw = ieee->priv;
	hw->spi = spi;
	hw->ieee = ieee;
	hw->busy = false;
	hw->tx_wait = 0;
	hw->delayed_tx_length = 0;
	spin_lock_init(&hw->lock);

	INIT_WORK(&hw->tx_work, sx127x_tx_work);
	INIT_WORK(&hw->poll_work, sx127x_poll_work);
	timer_setup(&hw->poll_timer, sx127x_poll_timer, 0);

	hw->regmap = devm_regmap_init_spi(spi, &sx127x_regmap_config);
	if (IS_ERR(hw->regmap)) {
		dev_err(&spi->dev, "%s: devm_regmap_init_spi() failed: %d\n", __func__, ret);
		return PTR_ERR(hw->regmap);
	}

	of_node = regmap_get_device(hw->regmap)->of_node;
	if (of_property_read_u32(of_node, "clock-frequency", &hw->oscillator_freq)) {
		dev_err(&spi->dev, "%s: 'clock-frequency' missing from DT node\n", __func__);
		return -EINVAL;
	}

	ieee->parent = &spi->dev;
	spi_set_drvdata(spi, hw);

	//TODO: pin de reset

	ieee802154_random_extended_addr(&ieee->phy->perm_extended_addr);

	ieee->flags = IEEE802154_HW_TX_OMIT_CKSUM
			| IEEE802154_HW_RX_OMIT_CKSUM
			| IEEE802154_HW_PROMISCUOUS;

	ieee->phy->flags = WPAN_PHY_FLAG_TXPOWER;
	ieee->phy->transmit_power = sx127x_tx_powers[12];
	ieee->phy->supported.tx_powers = sx127x_tx_powers;
	ieee->phy->supported.tx_powers_size = ARRAY_SIZE(sx127x_tx_powers);

	/* SX1278 phy channel 11 as default */
	ieee->phy->current_channel = 11;
	/* Define channels could be used. */
	ieee->phy->supported.channels[0] = 1 << 11; /*TODO: sx1278_ieee_channel_mask(hw);*/

	ret = sx127x_init(hw, &major, &minor);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_init() failed: %d\n", __func__, ret);
		goto fail_init;
	}

	dev_info(&spi->dev, "IEEE 802.15.4 over LoRa SX127x compatible device v%u.%u\n", major, minor);

	// Valor viene del sketch
	ret = sx127x_set_frequency(hw, 434000000);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_set_frequency() failed: %d\n", __func__, ret);
		goto fail_init;
	}
 
	ret = sx127x_get_frequency(hw, &frequency);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_get_frequency() failed: %d\n", __func__, ret);
		goto fail_init;
	}
 
	dev_dbg(&spi->dev, "%s: frequency sanity test: %lu Hz\n", __func__, frequency);

	ret = sx127x_set_tx_power(hw, 17); // 17 dBm
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_set_tx_power() failed: %d\n", __func__, ret);
		goto fail_init;
	}

	ret = ieee802154_register_hw(ieee);
	if (ret < 0)
		dev_err(&spi->dev, "ieee802154_register_hw() failed: %d\n", ret);

	return ret;
	/*u8 buffer[] = { 0x36, 0x39 }; // 69?
	ret = sx127x_mode(hw, SX127X_STANDBY_MODE);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_mode() failed: %d\n", __func__, ret);
		goto fail_begin;
	}

	ret = sx127x_begin_packet(hw);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_begin_packet() failed: %d\n", __func__, ret);
		goto fail_begin;
	}

	ret = sx127x_write_buffer(hw, buffer, sizeof buffer);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_send() failed: %d\n", __func__, ret);
		goto fail_begin;
	}

	ret = sx127x_end_packet(hw, 0);
	if (ret < 0) {
		dev_err(&spi->dev, "%s: sx127x_end_packet() failed: %d\n", __func__, ret);
		goto fail_begin;
	}*/

fail_init:
	ieee802154_free_hw(ieee);
	return ret;
}

#ifdef SX127X_LEGACY_KERNEL
static int sx127x_spi_remove(struct spi_device *spi)
#else
static void sx127x_spi_remove(struct spi_device *spi)
#endif
{
	struct sx127x *hw = spi_get_drvdata(spi);

	dev_dbg(&hw->spi->dev, "%s bye\n", __func__);

	ieee802154_unregister_hw(hw->ieee);
	ieee802154_free_hw(hw->ieee);

#ifdef SX127X_LEGACY_KERNEL
	return 0;
#endif
}

static const struct of_device_id sx127x_of_ids[] = {
	{ .compatible = "semtech,sx1276" },
	{ .compatible = "semtech,sx1277" },
	{ .compatible = "semtech,sx1278" },
	{ .compatible = "semtech,sx1279" },
	{},
};
MODULE_DEVICE_TABLE(of, sx127x_of_ids);

static const struct spi_device_id sx127x_spi_ids[] = {
	{ .name = "sx1276" },
	{ .name = "sx1277" },
	{ .name = "sx1278" },
	{ .name = "sx1279" },
	{},
};
MODULE_DEVICE_TABLE(spi, sx127x_spi_ids);

static struct spi_driver sx127x_spi_driver = {
	.driver = {
		.name           = "sx127x",
		.owner          = THIS_MODULE,
		.of_match_table = of_match_ptr(sx127x_of_ids),
	},
	.probe    = sx127x_spi_probe,
	.remove   = sx127x_spi_remove,
	.id_table = sx127x_spi_ids,
};

module_spi_driver(sx127x_spi_driver);

MODULE_AUTHOR("Jian-Hong Pan, <starnight@g.ncu.edu.tw>");
MODULE_AUTHOR("Fabian Montero <fabian@posixlycorrect.com>");
MODULE_DESCRIPTION("Semtech SX127x LoRa PHY driver with IEEE 802.15.4 MAC interface");
MODULE_LICENSE("GPL");