[RFC net-next 07/15] net: lora: Add Semtech SX1276

Andreas Färber
2018-07-01T11:12:30Z

Semtech SX1276/77/78/79 and SX1272/73 are LoRa transceivers with a SPI
interface. They also offer a non-LoRa mode (not exposed here).

Signed-off-by: Andreas Färber <afaerber@suse.de>
---
drivers/net/lora/Kconfig | 11 +
drivers/net/lora/Makefile | 3 +
drivers/net/lora/sx1276.c | 608 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 622 insertions(+)
create mode 100644 drivers/net/lora/sx1276.c

diff --git a/drivers/net/lora/Kconfig b/drivers/net/lora/Kconfig
index 40969b148a50..0436f6b09a1c 100644
--- a/drivers/net/lora/Kconfig
+++ b/drivers/net/lora/Kconfig
@@ -15,4 +15,15 @@ config LORA_DEV
# Alphabetically sorted.
#

+if LORA_DEV
+
+config LORA_SX1276
+ tristate "Semtech SX127x SPI driver"
+ default y
+ depends on SPI
+ help
+ Semtech SX1272/1276/1278
+
+endif
+
endmenu
diff --git a/drivers/net/lora/Makefile b/drivers/net/lora/Makefile
index 8f9d25ea4e70..8845542dba50 100644
--- a/drivers/net/lora/Makefile
+++ b/drivers/net/lora/Makefile
@@ -8,3 +8,6 @@ lora-dev-y := dev.o
#
# Alphabetically sorted.
#
+
+obj-$(CONFIG_LORA_SX1276) += lora-sx1276.o
+lora-sx1276-y := sx1276.o
diff --git a/drivers/net/lora/sx1276.c b/drivers/net/lora/sx1276.c
new file mode 100644
index 000000000000..d6732111247a
--- /dev/null
+++ b/drivers/net/lora/sx1276.c
@@ -0,0 +1,608 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Semtech SX1272/SX1276 LoRa transceiver
+ *
+ * Copyright (c) 2016-2018 Andreas Färber
+ */
+
+#include <linux/delay.h>
+#include <linux/lora.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/lora/dev.h>
+#include <linux/spi/spi.h>
+
+#define REG_FIFO 0x00
+#define REG_OPMODE 0x01
+#define REG_FRF_MSB 0x06
+#define REG_FRF_MID 0x07
+#define REG_FRF_LSB 0x08
+#define REG_PA_CONFIG 0x09
+#define LORA_REG_FIFO_ADDR_PTR 0x0d
+#define LORA_REG_FIFO_TX_BASE_ADDR 0x0e
+#define LORA_REG_IRQ_FLAGS_MASK 0x11
+#define LORA_REG_IRQ_FLAGS 0x12
+#define LORA_REG_PAYLOAD_LENGTH 0x22
+#define LORA_REG_SYNC_WORD 0x39
+#define REG_DIO_MAPPING1 0x40
+#define REG_DIO_MAPPING2 0x41
+#define REG_VERSION 0x42
+#define REG_PA_DAC 0x4d
+
+#define REG_OPMODE_LONG_RANGE_MODE BIT(7)
+#define REG_OPMODE_LOW_FREQUENCY_MODE_ON BIT(3)
+#define REG_OPMODE_MODE_MASK GENMASK(2, 0)
+#define REG_OPMODE_MODE_SLEEP (0x0 << 0)
+#define REG_OPMODE_MODE_STDBY (0x1 << 0)
+#define REG_OPMODE_MODE_TX (0x3 << 0)
+#define REG_OPMODE_MODE_RXCONTINUOUS (0x5 << 0)
+#define REG_OPMODE_MODE_RXSINGLE (0x6 << 0)
+
+#define REG_PA_CONFIG_PA_SELECT BIT(7)
+
+#define LORA_REG_IRQ_FLAGS_TX_DONE BIT(3)
+
+#define REG_DIO_MAPPING1_DIO0_MASK GENMASK(7, 6)
+
+struct sx1276_priv {
+ struct lora_priv lora;
+ struct spi_device *spi;
+
+ size_t fifosize;
+ int dio_gpio[6];
+
+ struct mutex spi_lock;
+
+ struct sk_buff *tx_skb;
+ int tx_len;
+
+ struct workqueue_struct *wq;
+ struct work_struct tx_work;
+};
+
+static int sx1276_read_single(struct spi_device *spi, u8 reg, u8 *val)
+{
+ u8 addr = reg & 0x7f;
+ return spi_write_then_read(spi, &addr, 1, val, 1);
+}
+
+static int sx1276_write_single(struct spi_device *spi, u8 reg, u8 val)
+{
+ u8 buf[2];
+
+ buf[0] = reg | BIT(7);
+ buf[1] = val;
+ return spi_write(spi, buf, 2);
+}
+
+static int sx1276_write_burst(struct spi_device *spi, u8 reg, size_t len, void *val)
+{
+ u8 buf = reg | BIT(7);
+ struct spi_transfer xfers[2] = {
+ [0] = {
+ .tx_buf = &buf,
+ .len = 1,
+ },
+ [1] = {
+ .tx_buf = val,
+ .len = len,
+ },
+ };
+
+ return spi_sync_transfer(spi, xfers, 2);
+}
+
+static int sx1276_write_fifo(struct spi_device *spi, size_t len, void *val)
+{
+ return sx1276_write_burst(spi, REG_FIFO, len, val);
+}
+
+static netdev_tx_t sx1276_loradev_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+ struct sx1276_priv *priv = netdev_priv(netdev);
+
+ netdev_dbg(netdev, "%s\n", __func__);
+
+ if (priv->tx_skb || priv->tx_len) {
+ netdev_warn(netdev, "TX busy\n");
+ return NETDEV_TX_BUSY;
+ }
+
+ if (skb->protocol != htons(ETH_P_LORA)) {
+ kfree_skb(skb);
+ netdev->stats.tx_dropped++;
+ return NETDEV_TX_OK;
+ }
+
+ netif_stop_queue(netdev);
+ priv->tx_skb = skb;
+ queue_work(priv->wq, &priv->tx_work);
+
+ return NETDEV_TX_OK;
+}
+
+static int sx1276_tx(struct spi_device *spi, void *data, int data_len)
+{
+ u8 addr, val;
+ int ret;
+
+ dev_dbg(&spi->dev, "%s\n", __func__);
+
+ ret = sx1276_read_single(spi, REG_OPMODE, &val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegOpMode (%d)\n", ret);
+ return ret;
+ }
+ dev_dbg(&spi->dev, "RegOpMode = 0x%02x\n", val);
+ if (!(val & REG_OPMODE_LONG_RANGE_MODE))
+ dev_err(&spi->dev, "LongRange Mode not active!\n");
+ if ((val & REG_OPMODE_MODE_MASK) == REG_OPMODE_MODE_SLEEP)
+ dev_err(&spi->dev, "Cannot access FIFO in Sleep Mode!\n");
+
+ ret = sx1276_read_single(spi, LORA_REG_FIFO_TX_BASE_ADDR, &addr);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegFifoTxBaseAddr (%d)\n", ret);
+ return ret;
+ }
+ dev_dbg(&spi->dev, "RegFifoTxBaseAddr = 0x%02x\n", addr);
+
+ ret = sx1276_write_single(spi, LORA_REG_FIFO_ADDR_PTR, addr);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegFifoAddrPtr (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_write_single(spi, LORA_REG_PAYLOAD_LENGTH, data_len);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegPayloadLength (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_write_fifo(spi, data_len, data);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write into FIFO (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, LORA_REG_IRQ_FLAGS, &val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegIrqFlags (%d)\n", ret);
+ return ret;
+ }
+ dev_dbg(&spi->dev, "RegIrqFlags = 0x%02x\n", val);
+
+ ret = sx1276_write_single(spi, LORA_REG_IRQ_FLAGS, LORA_REG_IRQ_FLAGS_TX_DONE);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegIrqFlags (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, LORA_REG_IRQ_FLAGS_MASK, &val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegIrqFlagsMask (%d)\n", ret);
+ return ret;
+ }
+ dev_dbg(&spi->dev, "RegIrqFlagsMask = 0x%02x\n", val);
+
+ val &= ~LORA_REG_IRQ_FLAGS_TX_DONE;
+ ret = sx1276_write_single(spi, LORA_REG_IRQ_FLAGS_MASK, val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegIrqFlagsMask (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, REG_DIO_MAPPING1, &val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegDioMapping1 (%d)\n", ret);
+ return ret;
+ }
+
+ val &= ~REG_DIO_MAPPING1_DIO0_MASK;
+ val |= 0x1 << 6;
+ ret = sx1276_write_single(spi, REG_DIO_MAPPING1, val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegDioMapping1 (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, REG_OPMODE, &val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to read RegOpMode (%d)\n", ret);
+ return ret;
+ }
+
+ val &= ~REG_OPMODE_MODE_MASK;
+ val |= REG_OPMODE_MODE_TX;
+ ret = sx1276_write_single(spi, REG_OPMODE, val);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to write RegOpMode (%d)\n", ret);
+ return ret;
+ }
+
+ dev_dbg(&spi->dev, "%s: done\n", __func__);
+
+ return 0;
+}
+
+static void sx1276_tx_work_handler(struct work_struct *ws)
+{
+ struct sx1276_priv *priv = container_of(ws, struct sx1276_priv, tx_work);
+ struct spi_device *spi = priv->spi;
+ struct net_device *netdev = spi_get_drvdata(spi);
+
+ netdev_dbg(netdev, "%s\n", __func__);
+
+ mutex_lock(&priv->spi_lock);
+
+ if (priv->tx_skb) {
+ sx1276_tx(spi, priv->tx_skb->data, priv->tx_skb->data_len);
+ priv->tx_len = 1 + priv->tx_skb->data_len;
+ if (!(netdev->flags & IFF_ECHO) ||
+ priv->tx_skb->pkt_type != PACKET_LOOPBACK ||
+ priv->tx_skb->protocol != htons(ETH_P_LORA))
+ kfree_skb(priv->tx_skb);
+ priv->tx_skb = NULL;
+ }
+
+ mutex_unlock(&priv->spi_lock);
+}
+
+static irqreturn_t sx1276_dio_interrupt(int irq, void *dev_id)
+{
+ struct net_device *netdev = dev_id;
+ struct sx1276_priv *priv = netdev_priv(netdev);
+ struct spi_device *spi = priv->spi;
+ u8 val;
+ int ret;
+
+ netdev_dbg(netdev, "%s\n", __func__);
+
+ mutex_lock(&priv->spi_lock);
+
+ ret = sx1276_read_single(spi, LORA_REG_IRQ_FLAGS, &val);
+ if (ret) {
+ netdev_warn(netdev, "Failed to read RegIrqFlags (%d)\n", ret);
+ val = 0;
+ }
+
+ if (val & LORA_REG_IRQ_FLAGS_TX_DONE) {
+ netdev_info(netdev, "TX done.\n");
+ netdev->stats.tx_packets++;
+ netdev->stats.tx_bytes += priv->tx_len - 1;
+ priv->tx_len = 0;
+ netif_wake_queue(netdev);
+
+ ret = sx1276_write_single(spi, LORA_REG_IRQ_FLAGS, LORA_REG_IRQ_FLAGS_TX_DONE);
+ if (ret)
+ netdev_warn(netdev, "Failed to write RegIrqFlags (%d)\n", ret);
+ }
+
+ mutex_unlock(&priv->spi_lock);
+
+ return IRQ_HANDLED;
+}
+
+static int sx1276_loradev_open(struct net_device *netdev)
+{
+ struct sx1276_priv *priv = netdev_priv(netdev);
+ struct spi_device *spi = to_spi_device(netdev->dev.parent);
+ u8 val;
+ int ret, irq;
+
+ netdev_dbg(netdev, "%s\n", __func__);
+
+ ret = open_loradev(netdev);
+ if (ret)
+ return ret;
+
+ mutex_lock(&priv->spi_lock);
+
+ ret = sx1276_read_single(spi, REG_OPMODE, &val);
+ if (ret) {
+ netdev_err(netdev, "Failed to read RegOpMode (%d)\n", ret);
+ goto err_opmode;
+ }
+
+ val &= ~REG_OPMODE_MODE_MASK;
+ val |= REG_OPMODE_MODE_STDBY;
+ ret = sx1276_write_single(spi, REG_OPMODE, val);
+ if (ret) {
+ netdev_err(netdev, "Failed to write RegOpMode (%d)\n", ret);
+ goto err_opmode;
+ }
+
+ priv->tx_skb = NULL;
+ priv->tx_len = 0;
+
+ priv->wq = alloc_workqueue("sx1276_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM, 0);
+ INIT_WORK(&priv->tx_work, sx1276_tx_work_handler);
+
+ if (gpio_is_valid(priv->dio_gpio[0])) {
+ irq = gpio_to_irq(priv->dio_gpio[0]);
+ if (irq <= 0)
+ netdev_warn(netdev, "Failed to obtain interrupt for DIO0 (%d)\n", irq);
+ else {
+ netdev_info(netdev, "Succeeded in obtaining interrupt for DIO0: %d\n", irq);
+ ret = request_threaded_irq(irq, NULL, sx1276_dio_interrupt, IRQF_ONESHOT | IRQF_TRIGGER_RISING, netdev->name, netdev);
+ if (ret) {
+ netdev_err(netdev, "Failed to request interrupt for DIO0 (%d)\n", ret);
+ goto err_irq;
+ }
+ }
+ }
+
+ netif_wake_queue(netdev);
+
+ mutex_unlock(&priv->spi_lock);
+
+ return 0;
+
+err_irq:
+ destroy_workqueue(priv->wq);
+ priv->wq = NULL;
+err_opmode:
+ close_loradev(netdev);
+ mutex_unlock(&priv->spi_lock);
+ return ret;
+}
+
+static int sx1276_loradev_stop(struct net_device *netdev)
+{
+ struct sx1276_priv *priv = netdev_priv(netdev);
+ struct spi_device *spi = to_spi_device(netdev->dev.parent);
+ u8 val;
+ int ret, irq;
+
+ netdev_dbg(netdev, "%s\n", __func__);
+
+ close_loradev(netdev);
+
+ mutex_lock(&priv->spi_lock);
+
+ ret = sx1276_write_single(spi, LORA_REG_IRQ_FLAGS_MASK, 0xff);
+ if (ret) {
+ netdev_err(netdev, "Failed to write RegIrqFlagsMask (%d)\n", ret);
+ goto err_irqmask;
+ }
+
+ ret = sx1276_read_single(spi, REG_OPMODE, &val);
+ if (ret) {
+ netdev_err(netdev, "Failed to read RegOpMode (%d)\n", ret);
+ goto err_opmode;
+ }
+
+ val &= ~REG_OPMODE_MODE_MASK;
+ val |= REG_OPMODE_MODE_SLEEP;
+ ret = sx1276_write_single(spi, REG_OPMODE, val);
+ if (ret) {
+ netdev_err(netdev, "Failed to write RegOpMode (%d)\n", ret);
+ goto err_opmode;
+ }
+
+ if (gpio_is_valid(priv->dio_gpio[0])) {
+ irq = gpio_to_irq(priv->dio_gpio[0]);
+ if (irq > 0) {
+ netdev_dbg(netdev, "Freeing IRQ %d\n", irq);
+ free_irq(irq, netdev);
+ }
+ }
+
+ destroy_workqueue(priv->wq);
+ priv->wq = NULL;
+
+ if (priv->tx_skb || priv->tx_len)
+ netdev->stats.tx_errors++;
+ if (priv->tx_skb)
+ dev_kfree_skb(priv->tx_skb);
+ priv->tx_skb = NULL;
+ priv->tx_len = 0;
+
+ mutex_unlock(&priv->spi_lock);
+
+ return 0;
+
+err_opmode:
+err_irqmask:
+ mutex_unlock(&priv->spi_lock);
+ return ret;
+}
+
+static const struct net_device_ops sx1276_netdev_ops = {
+ .ndo_open = sx1276_loradev_open,
+ .ndo_stop = sx1276_loradev_stop,
+ .ndo_start_xmit = sx1276_loradev_start_xmit,
+};
+
+static int sx1276_probe(struct spi_device *spi)
+{
+ struct net_device *netdev;
+ struct sx1276_priv *priv;
+ int rst, dio[6], ret, model, i;
+ u32 freq_xosc, freq_band;
+ unsigned long long freq_rf;
+ u8 val;
+
+ rst = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0);
+ if (rst == -ENOENT)
+ dev_warn(&spi->dev, "no reset GPIO available, ignoring");
+
+ for (i = 0; i < 6; i++) {
+ dio[i] = of_get_named_gpio(spi->dev.of_node, "dio-gpios", i);
+ if (dio[i] == -ENOENT)
+ dev_dbg(&spi->dev, "DIO%d not available, ignoring", i);
+ else {
+ ret = gpio_direction_input(dio[i]);
+ if (ret)
+ dev_err(&spi->dev, "couldn't set DIO%d to input", i);
+ }
+ }
+
+ if (gpio_is_valid(rst)) {
+ gpio_set_value(rst, 1);
+ udelay(100);
+ gpio_set_value(rst, 0);
+ msleep(5);
+ }
+
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ ret = sx1276_read_single(spi, REG_VERSION, &val);
+ if (ret) {
+ dev_err(&spi->dev, "version read failed");
+ return ret;
+ }
+
+ if (val == 0x22)
+ model = 1272;
+ else {
+ if (gpio_is_valid(rst)) {
+ gpio_set_value(rst, 0);
+ udelay(100);
+ gpio_set_value(rst, 1);
+ msleep(5);
+ }
+
+ ret = sx1276_read_single(spi, REG_VERSION, &val);
+ if (ret) {
+ dev_err(&spi->dev, "version read failed");
+ return ret;
+ }
+
+ if (val == 0x12)
+ model = 1276;
+ else {
+ dev_err(&spi->dev, "transceiver not recognized (RegVersion = 0x%02x)", (unsigned)val);
+ return -EINVAL;
+ }
+ }
+
+ ret = of_property_read_u32(spi->dev.of_node, "clock-frequency", &freq_xosc);
+ if (ret) {
+ dev_err(&spi->dev, "failed reading clock-frequency");
+ return ret;
+ }
+
+ ret = of_property_read_u32(spi->dev.of_node, "radio-frequency", &freq_band);
+ if (ret) {
+ dev_err(&spi->dev, "failed reading radio-frequency");
+ return ret;
+ }
+
+ val = REG_OPMODE_LONG_RANGE_MODE | REG_OPMODE_MODE_SLEEP;
+ if (freq_band < 525000000)
+ val |= REG_OPMODE_LOW_FREQUENCY_MODE_ON;
+ ret = sx1276_write_single(spi, REG_OPMODE, val);
+ if (ret) {
+ dev_err(&spi->dev, "failed writing opmode");
+ return ret;
+ }
+
+ freq_rf = freq_band;
+ freq_rf *= (1 << 19);
+ freq_rf /= freq_xosc;
+ dev_dbg(&spi->dev, "Frf = %llu", freq_rf);
+
+ ret = sx1276_write_single(spi, REG_FRF_MSB, freq_rf >> 16);
+ if (!ret)
+ ret = sx1276_write_single(spi, REG_FRF_MID, freq_rf >> 8);
+ if (!ret)
+ ret = sx1276_write_single(spi, REG_FRF_LSB, freq_rf);
+ if (ret) {
+ dev_err(&spi->dev, "failed writing frequency (%d)", ret);
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, REG_PA_CONFIG, &val);
+ if (ret) {
+ dev_err(&spi->dev, "failed reading RegPaConfig\n");
+ return ret;
+ }
+ if (true)
+ val |= REG_PA_CONFIG_PA_SELECT;
+ val &= ~GENMASK(3, 0);
+ val |= (23 - 3) - 5;
+ ret = sx1276_write_single(spi, REG_PA_CONFIG, val);
+ if (ret) {
+ dev_err(&spi->dev, "failed writing RegPaConfig\n");
+ return ret;
+ }
+
+ ret = sx1276_read_single(spi, REG_PA_DAC, &val);
+ if (ret) {
+ dev_err(&spi->dev, "failed reading RegPaDac\n");
+ return ret;
+ }
+ val &= ~GENMASK(2, 0);
+ val |= 0x7;
+ ret = sx1276_write_single(spi, REG_PA_DAC, val);
+ if (ret) {
+ dev_err(&spi->dev, "failed writing RegPaDac\n");
+ return ret;
+ }
+
+ netdev = alloc_loradev(sizeof(struct sx1276_priv));
+ if (!netdev)
+ return -ENOMEM;
+
+ netdev->netdev_ops = &sx1276_netdev_ops;
+ netdev->flags |= IFF_ECHO;
+
+ priv = netdev_priv(netdev);
+ priv->spi = spi;
+ mutex_init(&priv->spi_lock);
+ for (i = 0; i < 6; i++)
+ priv->dio_gpio[i] = dio[i];
+
+ spi_set_drvdata(spi, netdev);
+ SET_NETDEV_DEV(netdev, &spi->dev);
+
+ ret = register_loradev(netdev);
+ if (ret) {
+ free_loradev(netdev);
+ return ret;
+ }
+
+ dev_info(&spi->dev, "SX1276 module probed (SX%d)", model);
+
+ return 0;
+}
+
+static int sx1276_remove(struct spi_device *spi)
+{
+ struct net_device *netdev = spi_get_drvdata(spi);
+
+ unregister_loradev(netdev);
+ free_loradev(netdev);
+
+ dev_info(&spi->dev, "SX1276 module removed");
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id sx1276_dt_ids[] = {
+ { .compatible = "semtech,sx1272" },
+ { .compatible = "semtech,sx1276" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sx1276_dt_ids);
+#endif
+
+static struct spi_driver sx1276_spi_driver = {
+ .driver = {
+ .name = "sx1276",
+ .of_match_table = of_match_ptr(sx1276_dt_ids),
+ },
+ .probe = sx1276_probe,
+ .remove = sx1276_remove,
+};
+
+module_spi_driver(sx1276_spi_driver);
+
+MODULE_DESCRIPTION("SX1276 SPI driver");
+MODULE_AUTHOR("Andreas Färber <afaerber@suse.de>");
+MODULE_LICENSE("GPL");
--
2.16.4