[PATCH v12 2/2] spi: loongson: add bus driver for the loongson spi controller

[Yinbo Zhu <zhuyinbo@loongson.cn>]

This bus driver supports the Loongson SPI hardware controller in the
Loongson platforms and supports to use DTS and PCI framework to
register SPI device resources.

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
---
 MAINTAINERS                     |   4 +
 drivers/spi/Kconfig             |  26 +++
 drivers/spi/Makefile            |   3 +
 drivers/spi/spi-loongson-core.c | 275 ++++++++++++++++++++++++++++++++
 drivers/spi/spi-loongson-pci.c  |  55 +++++++
 drivers/spi/spi-loongson-plat.c |  47 ++++++
 drivers/spi/spi-loongson.h      |  49 ++++++
 7 files changed, 459 insertions(+)
 create mode 100644 drivers/spi/spi-loongson-core.c
 create mode 100644 drivers/spi/spi-loongson-pci.c
 create mode 100644 drivers/spi/spi-loongson-plat.c
 create mode 100644 drivers/spi/spi-loongson.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 5e604dddd87b..69cb8fb2a0e1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12191,6 +12191,10 @@ M:	Yinbo Zhu <zhuyinbo@loongson.cn>
 L:	linux-spi@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
+F:	drivers/spi/spi-loongson-core.c
+F:	drivers/spi/spi-loongson-pci.c
+F:	drivers/spi/spi-loongson-plat.c
+F:	drivers/spi/spi-loongson.h
 
 LOONGSON-2 SOC SERIES GUTS DRIVER
 M:	Yinbo Zhu <zhuyinbo@loongson.cn>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 3de2ebe8294a..6b953904792e 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -516,6 +516,32 @@ config SPI_LM70_LLP
 	  which interfaces to an LM70 temperature sensor using
 	  a parallel port.
 
+config SPI_LOONGSON_CORE
+	tristate
+	depends on LOONGARCH || COMPILE_TEST
+
+config SPI_LOONGSON_PCI
+	tristate "Loongson SPI Controller PCI Driver Support"
+	select SPI_LOONGSON_CORE
+	depends on PCI && (LOONGARCH || COMPILE_TEST)
+	help
+	  This bus driver supports the Loongson SPI hardware controller in
+	  the Loongson platforms and supports to use PCI framework to
+	  register SPI device resources.
+	  Say Y or M here if you want to use the SPI controller on
+	  Loongson platform.
+
+config SPI_LOONGSON_PLATFORM
+	tristate "Loongson SPI Controller Platform Driver Support"
+	select SPI_LOONGSON_CORE
+	depends on OF && (LOONGARCH || COMPILE_TEST)
+	help
+	  This bus driver supports the Loongson SPI hardware controller in
+	  the Loongson platforms and supports to use DTS framework to
+	  register SPI device resources.
+	  Say Y or M here if you want to use the SPI controller on
+	  Loongson platform.
+
 config SPI_LP8841_RTC
 	tristate "ICP DAS LP-8841 SPI Controller for RTC"
 	depends on MACH_PXA27X_DT || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 28c4817a8a74..3e933064d237 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -71,6 +71,9 @@ obj-$(CONFIG_SPI_INTEL_PLATFORM)	+= spi-intel-platform.o
 obj-$(CONFIG_SPI_LANTIQ_SSC)		+= spi-lantiq-ssc.o
 obj-$(CONFIG_SPI_JCORE)			+= spi-jcore.o
 obj-$(CONFIG_SPI_LM70_LLP)		+= spi-lm70llp.o
+obj-$(CONFIG_SPI_LOONGSON_CORE)		+= spi-loongson-core.o
+obj-$(CONFIG_SPI_LOONGSON_PCI)		+= spi-loongson-pci.o
+obj-$(CONFIG_SPI_LOONGSON_PLATFORM)	+= spi-loongson-plat.o
 obj-$(CONFIG_SPI_LP8841_RTC)		+= spi-lp8841-rtc.o
 obj-$(CONFIG_SPI_MESON_SPICC)		+= spi-meson-spicc.o
 obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o
diff --git a/drivers/spi/spi-loongson-core.c b/drivers/spi/spi-loongson-core.c
new file mode 100644
index 000000000000..403b735bd0cf
--- /dev/null
+++ b/drivers/spi/spi-loongson-core.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Loongson SPI Support
+// Copyright (C) 2023 Loongson Technology Corporation Limited
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include "spi-loongson.h"
+
+static inline void loongson_spi_write_reg(struct loongson_spi *spi, unsigned char reg,
+					  unsigned char data)
+{
+	writeb(data, spi->base + reg);
+}
+
+static inline char loongson_spi_read_reg(struct loongson_spi *spi, unsigned char reg)
+{
+	return readb(spi->base + reg);
+}
+
+static void loongson_spi_set_cs(struct spi_device *spi, bool val)
+{
+	int cs;
+	struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller);
+
+	cs = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SFCS_REG)
+					   & ~(0x11 << spi_get_chipselect(spi, 0));
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SFCS_REG,
+				       (val ? (0x11 << spi_get_chipselect(spi, 0)) :
+				       (0x1 << spi_get_chipselect(spi, 0))) | cs);
+}
+
+static void loongson_spi_set_clk(struct loongson_spi *loongson_spi, unsigned int hz)
+{
+	unsigned char val;
+	unsigned int div, div_tmp;
+	static const char rdiv[12] = {0, 1, 4, 2, 3, 5, 6, 7, 8, 9, 10, 11};
+
+	div = clamp_val(DIV_ROUND_UP_ULL(loongson_spi->clk_rate, hz), 2, 4096);
+	div_tmp = rdiv[fls(div - 1)];
+	loongson_spi->spcr = (div_tmp & GENMASK(1, 0)) >> 0;
+	loongson_spi->sper = (div_tmp & GENMASK(3, 2)) >> 2;
+	val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, (val & ~3) |
+			       loongson_spi->spcr);
+	val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPER_REG);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPER_REG, (val & ~3) |
+			       loongson_spi->sper);
+	loongson_spi->hz = hz;
+}
+
+static void loongson_spi_set_mode(struct loongson_spi *loongson_spi,
+				  struct spi_device *spi)
+{
+	unsigned char val;
+
+	val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG);
+	val &= ~(LOONGSON_SPI_SPCR_CPOL | LOONGSON_SPI_SPCR_CPHA);
+	if (spi->mode & SPI_CPOL)
+		val |= LOONGSON_SPI_SPCR_CPOL;
+	if (spi->mode & SPI_CPHA)
+		val |= LOONGSON_SPI_SPCR_CPHA;
+
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, val);
+	loongson_spi->mode |= spi->mode;
+}
+
+static int loongson_spi_update_state(struct loongson_spi *loongson_spi,
+				struct spi_device *spi, struct spi_transfer *t)
+{
+	if (t && loongson_spi->hz != t->speed_hz)
+		loongson_spi_set_clk(loongson_spi, t->speed_hz);
+
+	if ((spi->mode ^ loongson_spi->mode) & SPI_MODE_X_MASK)
+		loongson_spi_set_mode(loongson_spi, spi);
+
+	return 0;
+}
+
+static int loongson_spi_setup(struct spi_device *spi)
+{
+	struct loongson_spi *loongson_spi;
+
+	loongson_spi = spi_controller_get_devdata(spi->controller);
+	if (spi->bits_per_word % 8)
+		return -EINVAL;
+
+	if (spi_get_chipselect(spi, 0) >= spi->controller->num_chipselect)
+		return -EINVAL;
+
+	loongson_spi->hz = 0;
+	loongson_spi_set_cs(spi, 1);
+
+	return 0;
+}
+
+static int loongson_spi_write_read_8bit(struct spi_device *spi, const u8 **tx_buf,
+					u8 **rx_buf, unsigned int num)
+{
+	int ret;
+	struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller);
+
+	if (tx_buf && *tx_buf)
+		loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_FIFO_REG, *((*tx_buf)++));
+	else
+		loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_FIFO_REG, 0);
+	ret = readb_poll_timeout(loongson_spi->base + LOONGSON_SPI_SPSR_REG, loongson_spi->spsr,
+			(loongson_spi->spsr & 0x1) != LOONGSON_SPI_SPSR_RFEMPTY, 1, MSEC_PER_SEC);
+
+	if (rx_buf && *rx_buf)
+		*(*rx_buf)++ = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_FIFO_REG);
+	else
+		loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_FIFO_REG);
+
+	return ret;
+}
+
+static int loongson_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
+{
+	int ret;
+	unsigned int count;
+	const u8 *tx = xfer->tx_buf;
+	u8 *rx = xfer->rx_buf;
+
+	count = xfer->len;
+
+	do {
+		ret = loongson_spi_write_read_8bit(spi, &tx, &rx, count);
+		if (ret)
+			break;
+	} while (--count);
+
+	return ret;
+}
+
+static int loongson_spi_prepare_message(struct spi_controller *ctlr, struct spi_message *m)
+{
+	struct loongson_spi *loongson_spi = spi_controller_get_devdata(ctlr);
+
+	loongson_spi->para = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_PARA_REG);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para & ~1);
+
+	return 0;
+}
+
+static int loongson_spi_transfer_one(struct spi_controller *ctrl, struct spi_device *spi,
+				     struct spi_transfer *xfer)
+{
+	struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller);
+
+	loongson_spi_update_state(loongson_spi, spi, xfer);
+	if (xfer->len)
+		return loongson_spi_write_read(spi, xfer);
+
+	return 0;
+}
+
+static int loongson_spi_unprepare_message(struct spi_controller *ctrl, struct spi_message *m)
+{
+	struct loongson_spi *loongson_spi = spi_controller_get_devdata(ctrl);
+
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para);
+
+	return 0;
+}
+
+static void loongson_spi_reginit(struct loongson_spi *loongson_spi_dev)
+{
+	unsigned char val;
+
+	val = loongson_spi_read_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG);
+	val &= ~LOONGSON_SPI_SPCR_SPE;
+	loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG, val);
+
+	loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPSR_REG,
+			       (LOONGSON_SPI_SPSR_SPIF | LOONGSON_SPI_SPSR_WCOL));
+
+	val = loongson_spi_read_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG);
+	val |= LOONGSON_SPI_SPCR_SPE;
+	loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG, val);
+}
+
+int loongson_spi_init_controller(struct device *dev, void __iomem *regs)
+{
+	struct spi_controller *controller;
+	struct loongson_spi *spi;
+	struct clk *clk;
+
+	controller = devm_spi_alloc_host(dev, sizeof(struct loongson_spi));
+	if (controller == NULL)
+		return -ENOMEM;
+
+	controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	controller->setup = loongson_spi_setup;
+	controller->prepare_message = loongson_spi_prepare_message;
+	controller->transfer_one = loongson_spi_transfer_one;
+	controller->unprepare_message = loongson_spi_unprepare_message;
+	controller->set_cs = loongson_spi_set_cs;
+	controller->num_chipselect = 4;
+	device_set_node(&controller->dev, dev_fwnode(dev));
+	dev_set_drvdata(dev, controller);
+
+	spi = spi_controller_get_devdata(controller);
+	spi->base = regs;
+	spi->controller = controller;
+
+	clk = devm_clk_get_optional(dev, NULL);
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "unable to get clock\n");
+
+	spi->clk_rate = clk_get_rate(clk);
+	loongson_spi_reginit(spi);
+
+	spi->mode = 0;
+
+	return devm_spi_register_controller(dev, controller);
+}
+EXPORT_SYMBOL_NS_GPL(loongson_spi_init_controller, SPI_LOONGSON_CORE);
+
+static int __maybe_unused loongson_spi_suspend(struct device *dev)
+{
+	struct loongson_spi *loongson_spi;
+	struct spi_controller *controller;
+
+	controller = dev_get_drvdata(dev);
+	spi_controller_suspend(controller);
+
+	loongson_spi = spi_controller_get_devdata(controller);
+
+	loongson_spi->spcr = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG);
+	loongson_spi->sper = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPER_REG);
+	loongson_spi->spsr = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPSR_REG);
+	loongson_spi->para = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_PARA_REG);
+	loongson_spi->sfcs = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SFCS_REG);
+	loongson_spi->timi = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_TIMI_REG);
+
+	return 0;
+}
+
+static int __maybe_unused loongson_spi_resume(struct device *dev)
+{
+	struct loongson_spi *loongson_spi;
+	struct spi_controller *controller;
+
+	controller = dev_get_drvdata(dev);
+	loongson_spi = spi_controller_get_devdata(controller);
+
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, loongson_spi->spcr);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPER_REG, loongson_spi->sper);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPSR_REG, loongson_spi->spsr);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SFCS_REG, loongson_spi->sfcs);
+	loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_TIMI_REG, loongson_spi->timi);
+
+	spi_controller_resume(controller);
+
+	return 0;
+}
+
+const struct dev_pm_ops loongson_spi_dev_pm_ops = {
+	.suspend = loongson_spi_suspend,
+	.resume = loongson_spi_resume,
+};
+EXPORT_SYMBOL_NS_GPL(loongson_spi_dev_pm_ops, SPI_LOONGSON_CORE);
+
+MODULE_DESCRIPTION("Loongson SPI core driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/spi/spi-loongson-pci.c b/drivers/spi/spi-loongson-pci.c
new file mode 100644
index 000000000000..134cda0c13a5
--- /dev/null
+++ b/drivers/spi/spi-loongson-pci.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+// PCI interface driver for Loongson SPI Support
+// Copyright (C) 2023 Loongson Technology Corporation Limited
+
+#include <linux/mod_devicetable.h>
+#include <linux/pci.h>
+
+#include "spi-loongson.h"
+
+static int loongson_spi_pci_register(struct pci_dev *pdev,
+			const struct pci_device_id *ent)
+{
+	int ret;
+	void __iomem *reg_base;
+	struct device *dev = &pdev->dev;
+	int pci_bar = 0;
+
+	ret = pcim_enable_device(pdev);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "cannot enable pci device\n");
+
+	ret = pcim_iomap_regions(pdev, BIT(pci_bar), pci_name(pdev));
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request and remap memory\n");
+
+	reg_base = pcim_iomap_table(pdev)[pci_bar];
+
+	ret = loongson_spi_init_controller(dev, reg_base);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to initialize controller\n");
+
+	return 0;
+}
+
+static struct pci_device_id loongson_spi_devices[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a0b) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x7a1b) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, loongson_spi_devices);
+
+static struct pci_driver loongson_spi_pci_driver = {
+	.name       = "loongson-spi-pci",
+	.id_table   = loongson_spi_devices,
+	.probe      = loongson_spi_pci_register,
+	.driver	= {
+		.bus = &pci_bus_type,
+		.pm = &loongson_spi_dev_pm_ops,
+	},
+};
+module_pci_driver(loongson_spi_pci_driver);
+
+MODULE_DESCRIPTION("Loongson spi pci driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(SPI_LOONGSON_CORE);
diff --git a/drivers/spi/spi-loongson-plat.c b/drivers/spi/spi-loongson-plat.c
new file mode 100644
index 000000000000..c066e5f5891e
--- /dev/null
+++ b/drivers/spi/spi-loongson-plat.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Platform driver for Loongson SPI Support
+// Copyright (C) 2023 Loongson Technology Corporation Limited
+
+#include <linux/err.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+
+#include "spi-loongson.h"
+
+static int loongson_spi_platform_probe(struct platform_device *pdev)
+{
+	int ret;
+	void __iomem *reg_base;
+	struct device *dev = &pdev->dev;
+
+	reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(reg_base))
+		return PTR_ERR(reg_base);
+
+	ret = loongson_spi_init_controller(dev, reg_base);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to initialize controller\n");
+
+	return 0;
+}
+
+static const struct of_device_id loongson_spi_id_table[] = {
+	{ .compatible = "loongson,ls2k1000-spi" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, loongson_spi_id_table);
+
+static struct platform_driver loongson_spi_plat_driver = {
+	.probe = loongson_spi_platform_probe,
+	.driver	= {
+		.name	= "loongson-spi",
+		.bus = &platform_bus_type,
+		.pm = &loongson_spi_dev_pm_ops,
+		.of_match_table = loongson_spi_id_table,
+	},
+};
+module_platform_driver(loongson_spi_plat_driver);
+
+MODULE_DESCRIPTION("Loongson spi platform driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(SPI_LOONGSON_CORE);
diff --git a/drivers/spi/spi-loongson.h b/drivers/spi/spi-loongson.h
new file mode 100644
index 000000000000..35f95b161842
--- /dev/null
+++ b/drivers/spi/spi-loongson.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Header File for Loongson SPI Driver. */
+/* Copyright (C) 2023 Loongson Technology Corporation Limited */
+
+#ifndef __LINUX_SPI_LOONGSON_H
+#define __LINUX_SPI_LOONGSON_H
+
+#include <linux/bits.h>
+#include <linux/pm.h>
+#include <linux/types.h>
+
+#define	LOONGSON_SPI_SPCR_REG	0x00
+#define	LOONGSON_SPI_SPSR_REG	0x01
+#define	LOONGSON_SPI_FIFO_REG	0x02
+#define	LOONGSON_SPI_SPER_REG	0x03
+#define	LOONGSON_SPI_PARA_REG	0x04
+#define	LOONGSON_SPI_SFCS_REG	0x05
+#define	LOONGSON_SPI_TIMI_REG	0x06
+
+/* Bits definition for Loongson SPI register */
+#define	LOONGSON_SPI_PARA_MEM_EN	BIT(0)
+#define	LOONGSON_SPI_SPCR_CPHA	BIT(2)
+#define	LOONGSON_SPI_SPCR_CPOL	BIT(3)
+#define	LOONGSON_SPI_SPCR_SPE	BIT(6)
+#define	LOONGSON_SPI_SPSR_RFEMPTY	BIT(0)
+#define	LOONGSON_SPI_SPSR_WCOL	BIT(6)
+#define	LOONGSON_SPI_SPSR_SPIF	BIT(7)
+
+struct device;
+struct spi_controller;
+
+struct loongson_spi {
+	struct	spi_controller	*controller;
+	void __iomem		*base;
+	int			cs_active;
+	unsigned int		hz;
+	unsigned char		spcr;
+	unsigned char		sper;
+	unsigned char		spsr;
+	unsigned char		para;
+	unsigned char		sfcs;
+	unsigned char		timi;
+	unsigned int		mode;
+	u64			clk_rate;
+};
+
+int loongson_spi_init_controller(struct device *dev, void __iomem *reg);
+extern const struct dev_pm_ops loongson_spi_dev_pm_ops;
+#endif /* __LINUX_SPI_LOONGSON_H */
-- 
2.20.1