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    SubjectRE: [RFC net-next 15/15] net: lora: Add Semtech SX1301
    Date
    Hi Andreas,

    Excellent work on doing this I have also been working on and off
    this personally for some time.
    Have a look at my repository [1] for sx1301 and sx1257 drivers,
    I use regmaps capability of switching pages which should simplify
    your driver considerably, I also have a full register map and bit field.

    I have also been trying to use the clk framework to capture the various
    routing that the cards have.

    I will dig into this series this evening.

    [1] https://github.com/BWhitten/linux-stable/tree/971aadc8fdfe842020d912449bdd71b33d576fe3/drivers/net/lora


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

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