Input: serio - add support for Alwinner A10/A20 PS/2 controller

This driver implements support for PS2 controller found on Allwinner A10,
A20 SOCs. It has been tested on A20 Olimex-Lime2 board and also on A10.
Signed-off-by: Vishnu Patekar <vishnupatekar0510@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/serio/allwinner,sun4i-ps2.txt

+* Device tree bindings for Allwinner A10, A20 PS2 host controller
+
+A20 PS2 is dual role controller (PS2 host and PS2 device). These bindings are
+for PS2 A10/A20 host controller. IBM compliant IBM PS2 and AT-compatible keyboard
+and mouse can be connected.
+
+Required properties:
+
+ - reg             : Offset and length of the register set for the device.
+ - compatible      : Should be as of the following:
+                     - "allwinner,sun4i-a10-ps2"
+ - interrupts      : The interrupt line connected to the PS2.
+ - clocks          : The gate clk connected to the PS2.
+
+
+Example:
+	ps20: ps2@0x01c2a000 {
+		compatible = "allwinner,sun4i-a10-ps2";
+		reg = <0x01c2a000 0x400>;
+		interrupts = <0 62 4>;
+		clocks = <&apb1_gates 6>;
+		status = "disabled";
+	};

drivers/input/serio/Kconfig

@@ -281,4 +281,14 @@ config HYPERV_KEYBOARD
 	  To compile this driver as a module, choose M here: the module will
 	  be called hyperv_keyboard.
 
+config SERIO_SUN4I_PS2
+	tristate "Allwinner A10 PS/2 controller support"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	help
+	  This selects support for the PS/2 Host Controller on
+	  Allwinner A10.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sun4i-ps2.
+
 endif

drivers/input/serio/Makefile

@@ -29,3 +29,4 @@ obj-$(CONFIG_SERIO_ARC_PS2)	+= arc_ps2.o
 obj-$(CONFIG_SERIO_APBPS2)	+= apbps2.o
 obj-$(CONFIG_SERIO_OLPC_APSP)	+= olpc_apsp.o
 obj-$(CONFIG_HYPERV_KEYBOARD)	+= hyperv-keyboard.o
+obj-$(CONFIG_SERIO_SUN4I_PS2)	+= sun4i-ps2.o

drivers/input/serio/sun4i-ps2.c

+/*
+ *	Driver for Allwinner A10 PS2 host controller
+ *
+ *	Author: Vishnu Patekar <vishnupatekar0510@gmail.com>
+ *		Aaron.maoye <leafy.myeh@newbietech.com>
+ */
+
+#include <linux/module.h>
+#include <linux/serio.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+
+#define DRIVER_NAME		"sun4i-ps2"
+
+/* register offset definitions */
+#define PS2_REG_GCTL		0x00	/* PS2 Module Global Control Reg */
+#define PS2_REG_DATA		0x04	/* PS2 Module Data Reg		*/
+#define PS2_REG_LCTL		0x08	/* PS2 Module Line Control Reg */
+#define PS2_REG_LSTS		0x0C	/* PS2 Module Line Status Reg	*/
+#define PS2_REG_FCTL		0x10	/* PS2 Module FIFO Control Reg */
+#define PS2_REG_FSTS		0x14	/* PS2 Module FIFO Status Reg	*/
+#define PS2_REG_CLKDR		0x18	/* PS2 Module Clock Divider Reg*/
+
+/*  PS2 GLOBAL CONTROL REGISTER PS2_GCTL */
+#define PS2_GCTL_INTFLAG	BIT(4)
+#define PS2_GCTL_INTEN		BIT(3)
+#define PS2_GCTL_RESET		BIT(2)
+#define PS2_GCTL_MASTER		BIT(1)
+#define PS2_GCTL_BUSEN		BIT(0)
+
+/* PS2 LINE CONTROL REGISTER */
+#define PS2_LCTL_NOACK		BIT(18)
+#define PS2_LCTL_TXDTOEN	BIT(8)
+#define PS2_LCTL_STOPERREN	BIT(3)
+#define PS2_LCTL_ACKERREN	BIT(2)
+#define PS2_LCTL_PARERREN	BIT(1)
+#define PS2_LCTL_RXDTOEN	BIT(0)
+
+/* PS2 LINE STATUS REGISTER */
+#define PS2_LSTS_TXTDO		BIT(8)
+#define PS2_LSTS_STOPERR	BIT(3)
+#define PS2_LSTS_ACKERR		BIT(2)
+#define PS2_LSTS_PARERR		BIT(1)
+#define PS2_LSTS_RXTDO		BIT(0)
+
+#define PS2_LINE_ERROR_BIT \
+	(PS2_LSTS_TXTDO | PS2_LSTS_STOPERR | PS2_LSTS_ACKERR | \
+	PS2_LSTS_PARERR | PS2_LSTS_RXTDO)
+
+/* PS2 FIFO CONTROL REGISTER */
+#define PS2_FCTL_TXRST		BIT(17)
+#define PS2_FCTL_RXRST		BIT(16)
+#define PS2_FCTL_TXUFIEN	BIT(10)
+#define PS2_FCTL_TXOFIEN	BIT(9)
+#define PS2_FCTL_TXRDYIEN	BIT(8)
+#define PS2_FCTL_RXUFIEN	BIT(2)
+#define PS2_FCTL_RXOFIEN	BIT(1)
+#define PS2_FCTL_RXRDYIEN	BIT(0)
+
+/* PS2 FIFO STATUS REGISTER */
+#define PS2_FSTS_TXUF		BIT(10)
+#define PS2_FSTS_TXOF		BIT(9)
+#define PS2_FSTS_TXRDY		BIT(8)
+#define PS2_FSTS_RXUF		BIT(2)
+#define PS2_FSTS_RXOF		BIT(1)
+#define PS2_FSTS_RXRDY		BIT(0)
+
+#define PS2_FIFO_ERROR_BIT \
+	(PS2_FSTS_TXUF | PS2_FSTS_TXOF | PS2_FSTS_RXUF | PS2_FSTS_RXOF)
+
+#define PS2_SAMPLE_CLK		1000000
+#define PS2_SCLK		125000
+
+struct sun4i_ps2data {
+	struct serio *serio;
+	struct device *dev;
+
+	/* IO mapping base */
+	void __iomem	*reg_base;
+
+	/* clock management */
+	struct clk	*clk;
+
+	/* irq */
+	spinlock_t	lock;
+	int		irq;
+};
+
+static irqreturn_t sun4i_ps2_interrupt(int irq, void *dev_id)
+{
+	struct sun4i_ps2data *drvdata = dev_id;
+	u32 intr_status;
+	u32 fifo_status;
+	unsigned char byte;
+	unsigned int rxflags = 0;
+	u32 rval;
+
+	spin_lock(&drvdata->lock);
+
+	/* Get the PS/2 interrupts and clear them */
+	intr_status  = readl(drvdata->reg_base + PS2_REG_LSTS);
+	fifo_status  = readl(drvdata->reg_base + PS2_REG_FSTS);
+
+	/* Check line status register */
+	if (intr_status & PS2_LINE_ERROR_BIT) {
+		rxflags = (intr_status & PS2_LINE_ERROR_BIT) ? SERIO_FRAME : 0;
+		rxflags |= (intr_status & PS2_LSTS_PARERR) ? SERIO_PARITY : 0;
+		rxflags |= (intr_status & PS2_LSTS_PARERR) ? SERIO_TIMEOUT : 0;
+
+		rval = PS2_LSTS_TXTDO | PS2_LSTS_STOPERR | PS2_LSTS_ACKERR |
+			PS2_LSTS_PARERR | PS2_LSTS_RXTDO;
+		writel(rval, drvdata->reg_base + PS2_REG_LSTS);
+	}
+
+	/* Check FIFO status register */
+	if (fifo_status & PS2_FIFO_ERROR_BIT) {
+		rval = PS2_FSTS_TXUF | PS2_FSTS_TXOF | PS2_FSTS_TXRDY |
+			PS2_FSTS_RXUF | PS2_FSTS_RXOF | PS2_FSTS_RXRDY;
+		writel(rval, drvdata->reg_base + PS2_REG_FSTS);
+	}
+
+	rval = (fifo_status >> 16) & 0x3;
+	while (rval--) {
+		byte = readl(drvdata->reg_base + PS2_REG_DATA) & 0xff;
+		serio_interrupt(drvdata->serio, byte, rxflags);
+	}
+
+	writel(intr_status, drvdata->reg_base + PS2_REG_LSTS);
+	writel(fifo_status, drvdata->reg_base + PS2_REG_FSTS);
+
+	spin_unlock(&drvdata->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int sun4i_ps2_open(struct serio *serio)
+{
+	struct sun4i_ps2data *drvdata = serio->port_data;
+	u32 src_clk = 0;
+	u32 clk_scdf;
+	u32 clk_pcdf;
+	u32 rval;
+	unsigned long flags;
+
+	/* Set line control and enable interrupt */
+	rval = PS2_LCTL_STOPERREN | PS2_LCTL_ACKERREN
+		| PS2_LCTL_PARERREN | PS2_LCTL_RXDTOEN;
+	writel(rval, drvdata->reg_base + PS2_REG_LCTL);
+
+	/* Reset FIFO */
+	rval = PS2_FCTL_TXRST | PS2_FCTL_RXRST | PS2_FCTL_TXUFIEN
+		| PS2_FCTL_TXOFIEN | PS2_FCTL_RXUFIEN
+		| PS2_FCTL_RXOFIEN | PS2_FCTL_RXRDYIEN;
+
+	writel(rval, drvdata->reg_base + PS2_REG_FCTL);
+
+	src_clk = clk_get_rate(drvdata->clk);
+	/* Set clock divider register */
+	clk_scdf = src_clk / PS2_SAMPLE_CLK - 1;
+	clk_pcdf = PS2_SAMPLE_CLK / PS2_SCLK - 1;
+	rval = (clk_scdf << 8) | clk_pcdf;
+	writel(rval, drvdata->reg_base + PS2_REG_CLKDR);
+
+	/* Set global control register */
+	rval = PS2_GCTL_RESET | PS2_GCTL_INTEN | PS2_GCTL_MASTER
+		| PS2_GCTL_BUSEN;
+
+	spin_lock_irqsave(&drvdata->lock, flags);
+	writel(rval, drvdata->reg_base + PS2_REG_GCTL);
+	spin_unlock_irqrestore(&drvdata->lock, flags);
+
+	return 0;
+}
+
+static void sun4i_ps2_close(struct serio *serio)
+{
+	struct sun4i_ps2data *drvdata = serio->port_data;
+	u32 rval;
+
+	/* Shut off the interrupt */
+	rval = readl(drvdata->reg_base + PS2_REG_GCTL);
+	writel(rval & ~(PS2_GCTL_INTEN), drvdata->reg_base + PS2_REG_GCTL);
+
+	synchronize_irq(drvdata->irq);
+}
+
+static int sun4i_ps2_write(struct serio *serio, unsigned char val)
+{
+	unsigned long expire = jiffies + msecs_to_jiffies(10000);
+	struct sun4i_ps2data *drvdata = serio->port_data;
+
+	do {
+		if (readl(drvdata->reg_base + PS2_REG_FSTS) & PS2_FSTS_TXRDY) {
+			writel(val, drvdata->reg_base + PS2_REG_DATA);
+			return 0;
+		}
+	} while (time_before(jiffies, expire));
+
+	return SERIO_TIMEOUT;
+}
+
+static int sun4i_ps2_probe(struct platform_device *pdev)
+{
+	struct resource *res; /* IO mem resources */
+	struct sun4i_ps2data *drvdata;
+	struct serio *serio;
+	struct device *dev = &pdev->dev;
+	unsigned int irq;
+	int error;
+
+	drvdata = kzalloc(sizeof(struct sun4i_ps2data), GFP_KERNEL);
+	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
+	if (!drvdata || !serio) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	spin_lock_init(&drvdata->lock);
+
+	/* IO */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "failed to locate registers\n");
+		error = -ENXIO;
+		goto err_free_mem;
+	}
+
+	drvdata->reg_base = ioremap(res->start, resource_size(res));
+	if (!drvdata->reg_base) {
+		dev_err(dev, "failed to map registers\n");
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	drvdata->clk = clk_get(dev, NULL);
+	if (IS_ERR(drvdata->clk)) {
+		error = PTR_ERR(drvdata->clk);
+		dev_err(dev, "couldn't get clock %d\n", error);
+		goto err_ioremap;
+	}
+
+	error = clk_prepare_enable(drvdata->clk);
+	if (error) {
+		dev_err(dev, "failed to enable clock %d\n", error);
+		goto err_clk;
+	}
+
+	serio->id.type = SERIO_8042;
+	serio->write = sun4i_ps2_write;
+	serio->open = sun4i_ps2_open;
+	serio->close = sun4i_ps2_close;
+	serio->port_data = drvdata;
+	serio->dev.parent = dev;
+	strlcpy(serio->name, dev_name(dev), sizeof(serio->name));
+	strlcpy(serio->phys, dev_name(dev), sizeof(serio->phys));
+
+	/* shutoff interrupt */
+	writel(0, drvdata->reg_base + PS2_REG_GCTL);
+
+	/* Get IRQ for the device */
+	irq = platform_get_irq(pdev, 0);
+	if (!irq) {
+		dev_err(dev, "no IRQ found\n");
+		error = -ENXIO;
+		goto err_disable_clk;
+	}
+
+	drvdata->irq = irq;
+	drvdata->serio = serio;
+	drvdata->dev = dev;
+
+	error = request_irq(drvdata->irq, sun4i_ps2_interrupt, 0,
+			    DRIVER_NAME, drvdata);
+	if (error) {
+		dev_err(drvdata->dev, "failed to allocate interrupt %d: %d\n",
+			drvdata->irq, error);
+		goto err_disable_clk;
+	}
+
+	serio_register_port(serio);
+	platform_set_drvdata(pdev, drvdata);
+
+	return 0;	/* success */
+
+err_disable_clk:
+	clk_disable_unprepare(drvdata->clk);
+err_clk:
+	clk_put(drvdata->clk);
+err_ioremap:
+	iounmap(drvdata->reg_base);
+err_free_mem:
+	kfree(serio);
+	kfree(drvdata);
+	return error;
+}
+
+static int sun4i_ps2_remove(struct platform_device *pdev)
+{
+	struct sun4i_ps2data *drvdata = platform_get_drvdata(pdev);
+
+	serio_unregister_port(drvdata->serio);
+
+	free_irq(drvdata->irq, drvdata);
+
+	clk_disable_unprepare(drvdata->clk);
+	clk_put(drvdata->clk);
+
+	iounmap(drvdata->reg_base);
+
+	kfree(drvdata);
+
+	return 0;
+}
+
+static const struct of_device_id sun4i_ps2_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-ps2", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, sun4i_ps2_match);
+
+static struct platform_driver sun4i_ps2_driver = {
+	.probe		= sun4i_ps2_probe,
+	.remove		= sun4i_ps2_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = sun4i_ps2_match,
+	},
+};
+module_platform_driver(sun4i_ps2_driver);
+
+MODULE_AUTHOR("Vishnu Patekar <vishnupatekar0510@gmail.com>");
+MODULE_AUTHOR("Aaron.maoye <leafy.myeh@newbietech.com>");
+MODULE_DESCRIPTION("Allwinner A10/Sun4i PS/2 driver");
+MODULE_LICENSE("GPL v2");