[RFC net-next 15/15] net: lora: Add Semtech SX1301

Andreas Färber
2018-07-01T11:08:04Z

The Semtech SX1301 was the first multi-channel LoRa "concentrator".
It uses a SPI interface to the host as well as a dual SPI interface to
its radios. These two have been implemented as spi_controller, so that
the Device Tree can specify whether the respective module uses two
SX1257, two SX1255 or a combination of these or some unforeseen chipset.

This implementation is the most recent - initialization is not yet
complete, it will need to load firmware into the two on-chip MCUs.

Unfortunately there is no full datasheet with register descriptions,
only a BSD-licensed userspace HAL implementation using spidev devices.
Therefore some register names are unknown.

Cc: Ben Whitten <ben.whitten@lairdtech.com>
Cc: Steve deRosier <derosier@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Röder <michael.roeder@avnet.eu>
Cc: Ken Yu (禹凯) <ken.yu@rakwireless.com>
Cc: linux-spi@vger.kernel.org
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
drivers/net/lora/Kconfig | 7 +
drivers/net/lora/Makefile | 3 +
drivers/net/lora/sx1301.c | 446 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 456 insertions(+)
create mode 100644 drivers/net/lora/sx1301.c

diff --git a/drivers/net/lora/Kconfig b/drivers/net/lora/Kconfig
index 68c7480d7812..950450e353b4 100644
--- a/drivers/net/lora/Kconfig
+++ b/drivers/net/lora/Kconfig
@@ -45,6 +45,13 @@ config LORA_SX1276
help
Semtech SX1272/1276/1278

+config LORA_SX1301
+ tristate "Semtech SX1301 SPI driver"
+ default y
+ depends on SPI
+ help
+ Semtech SX1301
+
config LORA_USI
tristate "USI WM-SG-SM-42 driver"
default y
diff --git a/drivers/net/lora/Makefile b/drivers/net/lora/Makefile
index 44c578bde7d5..1cc1e3aa189b 100644
--- a/drivers/net/lora/Makefile
+++ b/drivers/net/lora/Makefile
@@ -22,6 +22,9 @@ lora-sx1257-y := sx1257.o
obj-$(CONFIG_LORA_SX1276) += lora-sx1276.o
lora-sx1276-y := sx1276.o

+obj-$(CONFIG_LORA_SX1301) += lora-sx1301.o
+lora-sx1301-y := sx1301.o
+
obj-$(CONFIG_LORA_USI) += lora-usi.o
lora-usi-y := usi.o

diff --git a/drivers/net/lora/sx1301.c b/drivers/net/lora/sx1301.c
new file mode 100644
index 000000000000..5c936c1116d1
--- /dev/null
+++ b/drivers/net/lora/sx1301.c
@@ -0,0 +1,446 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Semtech SX1301 LoRa concentrator
+ *
+ * Copyright (c) 2018 Andreas Färber
+ *
+ * Based on SX1301 HAL code:
+ * Copyright (c) 2013 Semtech-Cycleo
+ */
+
+#include <linux/bitops.h>
+#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_PAGE_RESET 0
+#define REG_VERSION 1
+#define REG_2_SPI_RADIO_A_DATA 33
+#define REG_2_SPI_RADIO_A_DATA_READBACK 34
+#define REG_2_SPI_RADIO_A_ADDR 35
+#define REG_2_SPI_RADIO_A_CS 37
+#define REG_2_SPI_RADIO_B_DATA 38
+#define REG_2_SPI_RADIO_B_DATA_READBACK 39
+#define REG_2_SPI_RADIO_B_ADDR 40
+#define REG_2_SPI_RADIO_B_CS 42
+
+#define REG_PAGE_RESET_SOFT_RESET BIT(7)
+
+#define REG_16_GLOBAL_EN BIT(3)
+
+#define REG_17_CLK32M_EN BIT(0)
+
+#define REG_2_43_RADIO_A_EN BIT(0)
+#define REG_2_43_RADIO_B_EN BIT(1)
+#define REG_2_43_RADIO_RST BIT(2)
+
+struct spi_sx1301 {
+ struct spi_device *parent;
+ u8 page;
+ u8 regs;
+};
+
+struct sx1301_priv {
+ struct lora_priv lora;
+ struct gpio_desc *rst_gpio;
+ u8 cur_page;
+ struct spi_controller *radio_a_ctrl, *radio_b_ctrl;
+};
+
+static int sx1301_read(struct spi_device *spi, u8 reg, u8 *val)
+{
+ u8 addr = reg & 0x7f;
+ return spi_write_then_read(spi, &addr, 1, val, 1);
+}
+
+static int sx1301_write(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 sx1301_page_switch(struct spi_device *spi, u8 page)
+{
+ struct sx1301_priv *priv = spi_get_drvdata(spi);
+ int ret;
+
+ if (priv->cur_page == page)
+ return 0;
+
+ dev_dbg(&spi->dev, "switching to page %u\n", (unsigned)page);
+ ret = sx1301_write(spi, REG_PAGE_RESET, page & 0x3);
+ if (ret) {
+ dev_err(&spi->dev, "switching to page %u failed\n", (unsigned)page);
+ return ret;
+ }
+
+ priv->cur_page = page;
+
+ return 0;
+}
+
+static int sx1301_soft_reset(struct spi_device *spi)
+{
+ return sx1301_write(spi, REG_PAGE_RESET, REG_PAGE_RESET_SOFT_RESET);
+}
+
+#define REG_RADIO_X_DATA 0
+#define REG_RADIO_X_DATA_READBACK 1
+#define REG_RADIO_X_ADDR 2
+#define REG_RADIO_X_CS 4
+
+static int sx1301_radio_set_cs(struct spi_controller *ctrl, bool enable)
+{
+ struct spi_sx1301 *ssx = spi_controller_get_devdata(ctrl);
+ u8 cs;
+ int ret;
+
+ dev_dbg(&ctrl->dev, "setting CS to %s\n", enable ? "1" : "0");
+
+ ret = sx1301_page_switch(ssx->parent, ssx->page);
+ if (ret) {
+ dev_warn(&ctrl->dev, "failed to switch page for CS (%d)\n", ret);
+ return ret;
+ }
+
+ ret = sx1301_read(ssx->parent, ssx->regs + REG_RADIO_X_CS, &cs);
+ if (ret) {
+ dev_warn(&ctrl->dev, "failed to read CS (%d)\n", ret);
+ cs = 0;
+ }
+
+ if (enable)
+ cs |= BIT(0);
+ else
+ cs &= ~BIT(0);
+
+ ret = sx1301_write(ssx->parent, ssx->regs + REG_RADIO_X_CS, cs);
+ if (ret)
+ dev_warn(&ctrl->dev, "failed to write CS (%d)\n", ret);
+
+ return 0;
+}
+
+static void sx1301_radio_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ int ret;
+
+ dev_dbg(&spi->dev, "setting SPI CS to %s\n", enable ? "1" : "0");
+
+ if (enable)
+ return;
+
+ ret = sx1301_radio_set_cs(spi->controller, enable);
+ if (ret)
+ dev_warn(&spi->dev, "failed to write CS (%d)\n", ret);
+}
+
+static int sx1301_radio_spi_transfer_one(struct spi_controller *ctrl,
+ struct spi_device *spi, struct spi_transfer *xfr)
+{
+ struct spi_sx1301 *ssx = spi_controller_get_devdata(ctrl);
+ const u8 *tx_buf = xfr->tx_buf;
+ u8 *rx_buf = xfr->rx_buf;
+ int ret;
+
+ if (xfr->len == 0 || xfr->len > 3)
+ return -EINVAL;
+
+ dev_dbg(&spi->dev, "transferring one (%u)\n", xfr->len);
+
+ ret = sx1301_page_switch(ssx->parent, ssx->page);
+ if (ret) {
+ dev_err(&spi->dev, "failed to switch page for transfer (%d)\n", ret);
+ return ret;
+ }
+
+ if (tx_buf) {
+ ret = sx1301_write(ssx->parent, ssx->regs + REG_RADIO_X_ADDR, tx_buf ? tx_buf[0] : 0);
+ if (ret) {
+ dev_err(&spi->dev, "SPI radio address write failed\n");
+ return ret;
+ }
+
+ ret = sx1301_write(ssx->parent, ssx->regs + REG_RADIO_X_DATA, (tx_buf && xfr->len >= 2) ? tx_buf[1] : 0);
+ if (ret) {
+ dev_err(&spi->dev, "SPI radio data write failed\n");
+ return ret;
+ }
+
+ ret = sx1301_radio_set_cs(ctrl, true);
+ if (ret) {
+ dev_err(&spi->dev, "SPI radio CS set failed\n");
+ return ret;
+ }
+
+ ret = sx1301_radio_set_cs(ctrl, false);
+ if (ret) {
+ dev_err(&spi->dev, "SPI radio CS unset failed\n");
+ return ret;
+ }
+ }
+
+ if (rx_buf) {
+ ret = sx1301_read(ssx->parent, ssx->regs + REG_RADIO_X_DATA_READBACK, &rx_buf[xfr->len - 1]);
+ if (ret) {
+ dev_err(&spi->dev, "SPI radio data read failed\n");
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void sx1301_radio_setup(struct spi_controller *ctrl)
+{
+ ctrl->mode_bits = SPI_CS_HIGH | SPI_NO_CS;
+ ctrl->bits_per_word_mask = SPI_BPW_MASK(8);
+ ctrl->num_chipselect = 1;
+ ctrl->set_cs = sx1301_radio_spi_set_cs;
+ ctrl->transfer_one = sx1301_radio_spi_transfer_one;
+}
+
+static int sx1301_probe(struct spi_device *spi)
+{
+ struct net_device *netdev;
+ struct sx1301_priv *priv;
+ struct spi_sx1301 *radio;
+ struct gpio_desc *rst;
+ int ret;
+ u8 val;
+
+ rst = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(rst))
+ return PTR_ERR(rst);
+
+ gpiod_set_value_cansleep(rst, 1);
+ msleep(100);
+ gpiod_set_value_cansleep(rst, 0);
+ msleep(100);
+
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ ret = sx1301_read(spi, REG_VERSION, &val);
+ if (ret) {
+ dev_err(&spi->dev, "version read failed\n");
+ goto err_version;
+ }
+
+ if (val != 103) {
+ dev_err(&spi->dev, "unexpected version: %u\n", val);
+ ret = -ENXIO;
+ goto err_version;
+ }
+
+ netdev = alloc_loradev(sizeof(*priv));
+ if (!netdev) {
+ ret = -ENOMEM;
+ goto err_alloc_loradev;
+ }
+
+ priv = netdev_priv(netdev);
+ priv->rst_gpio = rst;
+ priv->cur_page = 0xff;
+
+ spi_set_drvdata(spi, netdev);
+ SET_NETDEV_DEV(netdev, &spi->dev);
+
+ ret = sx1301_write(spi, REG_PAGE_RESET, 0);
+ if (ret) {
+ dev_err(&spi->dev, "page/reset write failed\n");
+ return ret;
+ }
+
+ ret = sx1301_soft_reset(spi);
+ if (ret) {
+ dev_err(&spi->dev, "soft reset failed\n");
+ return ret;
+ }
+
+ ret = sx1301_read(spi, 16, &val);
+ if (ret) {
+ dev_err(&spi->dev, "16 read failed\n");
+ return ret;
+ }
+
+ val &= ~REG_16_GLOBAL_EN;
+
+ ret = sx1301_write(spi, 16, val);
+ if (ret) {
+ dev_err(&spi->dev, "16 write failed\n");
+ return ret;
+ }
+
+ ret = sx1301_read(spi, 17, &val);
+ if (ret) {
+ dev_err(&spi->dev, "17 read failed\n");
+ return ret;
+ }
+
+ val &= ~REG_17_CLK32M_EN;
+
+ ret = sx1301_write(spi, 17, val);
+ if (ret) {
+ dev_err(&spi->dev, "17 write failed\n");
+ return ret;
+ }
+
+ ret = sx1301_page_switch(spi, 2);
+ if (ret) {
+ dev_err(&spi->dev, "page 2 switch failed\n");
+ return ret;
+ }
+
+ ret = sx1301_read(spi, 43, &val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 read failed\n");
+ return ret;
+ }
+
+ val |= REG_2_43_RADIO_B_EN | REG_2_43_RADIO_A_EN;
+
+ ret = sx1301_write(spi, 43, val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 write failed\n");
+ return ret;
+ }
+
+ msleep(500);
+
+ ret = sx1301_read(spi, 43, &val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 read failed\n");
+ return ret;
+ }
+
+ val |= REG_2_43_RADIO_RST;
+
+ ret = sx1301_write(spi, 43, val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 write failed\n");
+ return ret;
+ }
+
+ msleep(5);
+
+ ret = sx1301_read(spi, 43, &val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 read failed\n");
+ return ret;
+ }
+
+ val &= ~REG_2_43_RADIO_RST;
+
+ ret = sx1301_write(spi, 43, val);
+ if (ret) {
+ dev_err(&spi->dev, "2|43 write failed\n");
+ return ret;
+ }
+
+ /* radio A */
+
+ priv->radio_a_ctrl = spi_alloc_master(&spi->dev, sizeof(*radio));
+ if (!priv->radio_a_ctrl) {
+ ret = -ENOMEM;
+ goto err_radio_a_alloc;
+ }
+
+ sx1301_radio_setup(priv->radio_a_ctrl);
+ priv->radio_a_ctrl->dev.of_node = of_get_child_by_name(spi->dev.of_node, "radio-a");
+
+ radio = spi_controller_get_devdata(priv->radio_a_ctrl);
+ radio->page = 2;
+ radio->regs = REG_2_SPI_RADIO_A_DATA;
+ radio->parent = spi;
+
+ dev_info(&spi->dev, "registering radio A SPI\n");
+
+ ret = devm_spi_register_controller(&spi->dev, priv->radio_a_ctrl);
+ if (ret) {
+ dev_err(&spi->dev, "radio A SPI register failed\n");
+ goto err_radio_a_register;
+ }
+
+ /* radio B */
+
+ priv->radio_b_ctrl = spi_alloc_master(&spi->dev, sizeof(*radio));
+ if (!priv->radio_b_ctrl) {
+ ret = -ENOMEM;
+ goto err_radio_b_alloc;
+ }
+
+ sx1301_radio_setup(priv->radio_b_ctrl);
+ priv->radio_b_ctrl->dev.of_node = of_get_child_by_name(spi->dev.of_node, "radio-b");
+
+ radio = spi_controller_get_devdata(priv->radio_b_ctrl);
+ radio->page = 2;
+ radio->regs = REG_2_SPI_RADIO_B_DATA;
+ radio->parent = spi;
+
+ dev_info(&spi->dev, "registering radio B SPI\n");
+
+ ret = devm_spi_register_controller(&spi->dev, priv->radio_b_ctrl);
+ if (ret) {
+ dev_err(&spi->dev, "radio B SPI register failed\n");
+ goto err_radio_b_register;
+ }
+
+ dev_info(&spi->dev, "SX1301 module probed\n");
+
+ return 0;
+err_radio_b_register:
+ spi_controller_put(priv->radio_b_ctrl);
+err_radio_b_alloc:
+err_radio_a_register:
+ spi_controller_put(priv->radio_a_ctrl);
+err_radio_a_alloc:
+ free_loradev(netdev);
+err_alloc_loradev:
+err_version:
+ return ret;
+}
+
+static int sx1301_remove(struct spi_device *spi)
+{
+ struct net_device *netdev = spi_get_drvdata(spi);
+
+ //unregister_loradev(netdev);
+ free_loradev(netdev);
+
+ dev_info(&spi->dev, "SX1301 module removed\n");
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id sx1301_dt_ids[] = {
+ { .compatible = "semtech,sx1301" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sx1301_dt_ids);
+#endif
+
+static struct spi_driver sx1301_spi_driver = {
+ .driver = {
+ .name = "sx1301",
+ .of_match_table = of_match_ptr(sx1301_dt_ids),
+ },
+ .probe = sx1301_probe,
+ .remove = sx1301_remove,
+};
+
+module_spi_driver(sx1301_spi_driver);
+
+MODULE_DESCRIPTION("SX1301 SPI driver");
+MODULE_AUTHOR("Andreas Färber <afaerber@suse.de>");
+MODULE_LICENSE("GPL");
--
2.16.4