[PATCH 1/3] fpga: Add Efinix Trion & Titanium serial SPI programming driver

[iansdannapel@gmail.com]

From: Ian Dannapel <iansdannapel@gmail.com>

Add a new driver for loading binary firmware using "SPI passive
programming" on Efinix FPGAs.

Signed-off-by: Ian Dannapel <iansdannapel@gmail.com>
---
 drivers/fpga/Kconfig      |   8 ++
 drivers/fpga/Makefile     |   1 +
 drivers/fpga/efinix-spi.c | 219 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 228 insertions(+)
 create mode 100644 drivers/fpga/efinix-spi.c

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index 37b35f58f0df..cb3a6628fa71 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -83,6 +83,14 @@ config FPGA_MGR_XILINX_SPI
 	  FPGA manager driver support for Xilinx FPGA configuration
 	  over slave serial interface.
 
+config FPGA_MGR_EFINIX_SPI
+	tristate "Efinix FPGA configuration over SPI passive"
+	depends on SPI
+	help
+	  This option enables support for the FPGA manager driver to configure
+	  Efinix Trion and Titanium Series FPGAs over SPI using passive serial
+	  mode.
+
 config FPGA_MGR_ICE40_SPI
 	tristate "Lattice iCE40 SPI"
 	depends on OF && SPI
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index aeb89bb13517..adbd51d2cd1e 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_FPGA_MGR_TS73XX)		+= ts73xx-fpga.o
 obj-$(CONFIG_FPGA_MGR_XILINX_CORE)	+= xilinx-core.o
 obj-$(CONFIG_FPGA_MGR_XILINX_SELECTMAP)	+= xilinx-selectmap.o
 obj-$(CONFIG_FPGA_MGR_XILINX_SPI)	+= xilinx-spi.o
+obj-$(CONFIG_FPGA_MGR_EFINIX_SPI)	+= efinix-spi.o
 obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)	+= zynq-fpga.o
 obj-$(CONFIG_FPGA_MGR_ZYNQMP_FPGA)	+= zynqmp-fpga.o
 obj-$(CONFIG_FPGA_MGR_VERSAL_FPGA)	+= versal-fpga.o
diff --git a/drivers/fpga/efinix-spi.c b/drivers/fpga/efinix-spi.c
new file mode 100644
index 000000000000..7f7d7e6714ae
--- /dev/null
+++ b/drivers/fpga/efinix-spi.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Trion and Titanium Series FPGA SPI Passive Programming Driver
+ *
+ * Copyright (C) 2024 iris-GmbH infrared & intelligent sensors
+ *
+ * Ian Dannapel <iansdannapel@gmail.com>
+ *
+ * Manage Efinix FPGA firmware that is loaded over SPI using
+ * the serial configuration interface.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+#include <linux/sizes.h>
+
+struct efinix_spi_conf {
+	struct spi_device *spi;
+	struct gpio_desc *done;
+	struct gpio_desc *reset;
+	struct gpio_desc *cs;
+	enum fpga_mgr_states state;
+};
+
+static int get_done_gpio(struct fpga_manager *mgr)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+	int ret = 0;
+
+	if (conf->done) {
+		ret = gpiod_get_value(conf->done);
+		if (ret < 0)
+			dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
+	}
+
+	return ret;
+}
+
+static void reset(struct fpga_manager *mgr)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+
+	gpiod_set_value(conf->reset, 1);
+	/* wait tCRESET_N */
+	usleep_range(5, 15);
+	gpiod_set_value(conf->reset, 0);
+	conf->state = FPGA_MGR_STATE_RESET;
+}
+
+static enum fpga_mgr_states efinix_spi_state(struct fpga_manager *mgr)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+
+	return conf->state;
+}
+
+static int efinix_spi_apply_clk_cycles(struct fpga_manager *mgr)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+	char data[13] = {0};
+
+	return spi_write(conf->spi, data, sizeof(data));
+}
+
+static int efinix_spi_write_init(struct fpga_manager *mgr,
+				 struct fpga_image_info *info,
+				 const char *buf, size_t count)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+
+	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
+		dev_err(&mgr->dev, "Partial reconfiguration not supported\n");
+		return -EINVAL;
+	}
+
+	/* reset with chip select active */
+	gpiod_set_value(conf->cs, 1);
+	usleep_range(5, 15);
+	reset(mgr);
+
+	/* wait tDMIN */
+	usleep_range(100, 150);
+
+	return 0;
+}
+
+static int efinix_spi_write(struct fpga_manager *mgr, const char *buf,
+			    size_t count)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+	int ret;
+
+	ret = spi_write(conf->spi, buf, count);
+	if (ret) {
+		dev_err(&mgr->dev, "SPI error in firmware write: %d\n",
+			ret);
+		return ret;
+	}
+
+	/* append at least 100 clock cycles */
+	efinix_spi_apply_clk_cycles(mgr);
+
+	/* release chip select */
+	gpiod_set_value(conf->cs, 0);
+
+	return 0;
+}
+
+static int efinix_spi_write_complete(struct fpga_manager *mgr,
+				     struct fpga_image_info *info)
+{
+	struct efinix_spi_conf *conf = mgr->priv;
+	unsigned long timeout =
+		jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
+	bool expired = false;
+	int done;
+
+	if (conf->done) {
+		while (!expired) {
+			expired = time_after(jiffies, timeout);
+
+			done = get_done_gpio(mgr);
+			if (done < 0)
+				return done;
+
+			if (done)
+				break;
+		}
+	}
+
+	if (expired)
+		return -ETIMEDOUT;
+
+	/* wait tUSER */
+	usleep_range(75, 125);
+
+	return 0;
+}
+
+static const struct fpga_manager_ops efinix_spi_ops = {
+	.state = efinix_spi_state,
+	.write_init = efinix_spi_write_init,
+	.write = efinix_spi_write,
+	.write_complete = efinix_spi_write_complete,
+};
+
+static int efinix_spi_probe(struct spi_device *spi)
+{
+	struct efinix_spi_conf *conf;
+	struct fpga_manager *mgr;
+
+	conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
+	if (!conf)
+		return -ENOMEM;
+
+	conf->spi = spi;
+	conf->state = FPGA_MGR_STATE_UNKNOWN;
+
+	conf->reset = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(conf->reset))
+		return dev_err_probe(&spi->dev, PTR_ERR(conf->reset),
+				"Failed to get RESET gpio\n");
+
+	conf->cs = devm_gpiod_get(&spi->dev, "cs", GPIOD_OUT_HIGH);
+	if (IS_ERR(conf->cs))
+		return dev_err_probe(&spi->dev, PTR_ERR(conf->cs),
+				"Failed to get CHIP_SELECT gpio\n");
+
+	if (!(spi->mode & SPI_CPHA) || !(spi->mode & SPI_CPOL))
+		return dev_err_probe(&spi->dev, PTR_ERR(conf->cs),
+				"Unsupported SPI mode, set CPHA and CPOL\n");
+
+	conf->done = devm_gpiod_get_optional(&spi->dev, "done", GPIOD_IN);
+	if (IS_ERR(conf->done))
+		return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
+				"Failed to get DONE gpio\n");
+
+	mgr = devm_fpga_mgr_register(&spi->dev,
+				"Efinix SPI Passive Programming FPGA Manager",
+					&efinix_spi_ops, conf);
+
+	return PTR_ERR_OR_ZERO(mgr);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id efnx_spi_of_match[] = {
+	{ .compatible = "efnx,fpga-spi-passive", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, efnx_spi_of_match);
+#endif
+
+static const struct spi_device_id efinix_ids[] = {
+	{ "fpga-spi-passive", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, efinix_ids);
+
+
+static struct spi_driver efinix_spi_passive_driver = {
+	.driver = {
+		.name = "efnx-fpga-spi-passive",
+		.of_match_table = of_match_ptr(efnx_spi_of_match),
+	},
+	.probe = efinix_spi_probe,
+	.id_table = efinix_ids,
+};
+
+module_spi_driver(efinix_spi_passive_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ian Dannapel <iansdannapel@gmail.com>");
+MODULE_DESCRIPTION("Load Efinix FPGA firmware over SPI passive");
-- 
2.34.1