0001.litex-ps2.patch

diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
index f39b7b3f7942..c48a34bf5480 100644
--- a/drivers/input/serio/Kconfig
+++ b/drivers/input/serio/Kconfig
@@ -304,6 +304,15 @@ config SERIO_GPIO_PS2
 
 	  If you are unsure, say N.
 
+config SERIO_LITEX_PS2
+	tristate "LiteX PS/2 controller"
+	depends on HAS_IOMEM
+	help
+	  Say Y here if you have LiteX PS/2 ports.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called litex_ps2.
+
 config USERIO
 	tristate "User space serio port driver support"
 	help
diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
index 6d97bad7b844..3613768f1d9b 100644
--- a/drivers/input/serio/Makefile
+++ b/drivers/input/serio/Makefile
@@ -32,4 +32,5 @@ obj-$(CONFIG_SERIO_OLPC_APSP)	+= olpc_apsp.o
 obj-$(CONFIG_HYPERV_KEYBOARD)	+= hyperv-keyboard.o
 obj-$(CONFIG_SERIO_SUN4I_PS2)	+= sun4i-ps2.o
 obj-$(CONFIG_SERIO_GPIO_PS2)	+= ps2-gpio.o
+obj-$(CONFIG_SERIO_LITEX_PS2)	+= litex_ps2.o
 obj-$(CONFIG_USERIO)		+= userio.o
diff --git a/drivers/input/serio/litex_ps2.c b/drivers/input/serio/litex_ps2.c
new file mode 100644
index 000000000000..45315f27d50f
--- /dev/null
+++ b/drivers/input/serio/litex_ps2.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LiteX PS2 controller driver
+ *
+ * Copyright (C) 2021 Romain Dolbeau <romain@dolbeau.org>
+ *
+ * Based on altera_ps2.c which is
+ * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Based on sa1111ps2.c, which is:
+ * Copyright (C) 2002 Russell King
+ */
+
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+#define DRV_NAME "litex_ps2"
+
+#include <linux/litex.h>
+
+struct ps2if {
+	struct serio *io;
+	void __iomem *base;
+	struct platform_device *pdev;
+};
+
+#define PS2IF_RX_DATA (ps2if->base + 0)
+#define PS2IF_TX_DATA (ps2if->base + 4)
+#define PS2IF_CTRL    (ps2if->base + 8)
+
+#define PS2IF_EV_STATUS (ps2if->base + 12)
+#define PS2IF_EV_PENDING (ps2if->base + 16)
+#define PS2IF_EV_ENABLE (ps2if->base + 20)
+
+#define PS2IF_CTRL_IRQENABLE 0x00000001
+#define PS2IF_CTRL_HWENABLE  0x00000002
+#define PS2IF_CTRL_DEF (PS2IF_CTRL_IRQENABLE | PS2IF_CTRL_HWENABLE)
+
+/*
+ * Read a byte from the PS2 port
+ */
+static irqreturn_t litex_ps2_rxint(int irq, void *dev_id)
+{
+	struct ps2if *ps2if = dev_id;
+	unsigned int status;
+	irqreturn_t handled = IRQ_NONE;
+	int reg;
+	status = litex_read32(PS2IF_EV_STATUS);
+	if (status) {
+		status = litex_read32(PS2IF_RX_DATA);
+		if (!(status & 0x80000000)) {
+			dev_info(&ps2if->pdev->dev, " rxint: interrupt but not data ?!?\n");
+			handled = IRQ_HANDLED;
+		} else {
+			litex_write32(PS2IF_CTRL, PS2IF_CTRL_DEF); // ack, keep irq enabled
+			serio_interrupt(ps2if->io, status & 0xff, 0);
+/* 			dev_info(&ps2if->pdev->dev, " rxint: handling 0x%08x\n", status); */
+			handled = IRQ_HANDLED;
+		}
+	} else {
+		handled = IRQ_HANDLED;
+	}
+	// clear IRQ
+	reg = litex_read32(PS2IF_EV_PENDING);
+	litex_write32(PS2IF_EV_PENDING, reg);
+
+	return handled;
+}
+
+/*
+ * Write a byte to the PS2 port.
+ */
+static int litex_ps2_write(struct serio *io, unsigned char val)
+{
+	struct ps2if *ps2if = io->port_data;
+	unsigned int status;
+	int count = 0;
+
+	while (((status = litex_read32(PS2IF_TX_DATA)) & 0x80000000) && count < 10)
+		count++;
+
+	if (status) dev_info(&ps2if->pdev->dev, " write: still seeing 0x%08x\n", status);
+
+	litex_write32(PS2IF_TX_DATA, (0x80000000 | val));
+
+/* 	dev_info(&ps2if->pdev->dev, " write: wrote 0x%08x", (0x80000000 | val)); */
+
+	return 0;
+}
+
+static int litex_ps2_open(struct serio *io)
+{
+	struct ps2if *ps2if = io->port_data;
+	unsigned int status;
+	int count = 0;
+	int reg;
+
+	/* clear fifo */
+	while (((status = litex_read32(PS2IF_RX_DATA)) & 0xFFFFFFFF) && count < 16) {
+		litex_write32(PS2IF_CTRL, PS2IF_CTRL_DEF); /* enable / ack */
+		dev_info(&ps2if->pdev->dev, " open: ignoring 0x%08x", status);
+		count ++;
+	}
+	if (status) dev_info(&ps2if->pdev->dev, " open: still seeing 0x%08x\n", status);
+
+	// clear pending IRQ
+	reg = litex_read32(PS2IF_EV_PENDING);
+	litex_write32(PS2IF_EV_PENDING, reg);
+	// enable IRQ
+	litex_write32(PS2IF_EV_ENABLE, 1);
+	
+/* 	dev_info(&ps2if->pdev->dev, " open: opened\n"); */
+
+	return 0;
+}
+
+static void litex_ps2_close(struct serio *io)
+{
+	struct ps2if *ps2if = io->port_data;
+	int reg;
+
+	litex_write32(PS2IF_CTRL, PS2IF_CTRL_DEF); /* don'( disable anything for now */
+
+	// disable IRQ
+	litex_write32(PS2IF_EV_ENABLE, 0);
+	// clear pending IRQ
+	reg = litex_read32(PS2IF_EV_PENDING);
+	litex_write32(PS2IF_EV_PENDING, reg);
+}
+
+/*
+ * Add one device to this driver.
+ */
+static int litex_ps2_probe(struct platform_device *pdev)
+{
+	struct ps2if *ps2if;
+	struct resource *res;
+	struct serio *serio;
+	int error, irq;
+
+	ps2if = devm_kzalloc(&pdev->dev, sizeof(struct ps2if), GFP_KERNEL);
+	if (!ps2if)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ps2if->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ps2if->base))
+		return PTR_ERR(ps2if->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -ENXIO;
+
+	error = devm_request_irq(&pdev->dev, irq, litex_ps2_rxint, 0,
+				 pdev->name, ps2if);
+	if (error) {
+		dev_err(&pdev->dev, "could not request IRQ %d\n", irq);
+		return error;
+	}
+
+	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
+	if (!serio)
+		return -ENOMEM;
+
+	serio->id.type		= SERIO_8042;
+	serio->write		= litex_ps2_write;
+	serio->open		= litex_ps2_open;
+	serio->close		= litex_ps2_close;
+	strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
+	strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
+	serio->port_data	= ps2if;
+	serio->dev.parent	= &pdev->dev;
+	ps2if->io		= serio;
+
+	dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, irq);
+
+	serio_register_port(ps2if->io);
+	ps2if->pdev = pdev;
+	platform_set_drvdata(pdev, ps2if);
+
+	return 0;
+}
+
+/*
+ * Remove one device from this driver.
+ */
+static int litex_ps2_remove(struct platform_device *pdev)
+{
+	struct ps2if *ps2if = platform_get_drvdata(pdev);
+
+	serio_unregister_port(ps2if->io);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id litex_ps2_match[] = {
+	{ .compatible = "litex,ps2-1.0", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, litex_ps2_match);
+#endif /* CONFIG_OF */
+
+/*
+ * Our device driver structure
+ */
+static struct platform_driver litex_ps2_driver = {
+	.probe		= litex_ps2_probe,
+	.remove		= litex_ps2_remove,
+	.driver	= {
+		.name	= DRV_NAME,
+		.of_match_table = of_match_ptr(litex_ps2_match),
+	},
+};
+module_platform_driver(litex_ps2_driver);
+
+MODULE_DESCRIPTION("LiteX PS2 controller driver");
+MODULE_AUTHOR("Romain Dolbeau <romain@dolbeau.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);