Hi Paul,
Some minor comments / suggestions

On Saturday 31 December 2011 07:16 PM, Paul Parsons wrote:

Maybe some help on module building as tristate.

Could this be bool ?

+	unsigned		code;		/* Code of last key pressed */
+};
+
+static const u32 sscr0 = 0
+	| SSCR0_TUM		/* TIM = 1; No TUR interrupts */
+	| SSCR0_RIM		/* RIM = 1; No ROR interrupts */
+	| SSCR0_SSE		/* SSE = 1; SSP enabled */
+	| SSCR0_Motorola	/* FRF = 0; Motorola SPI */
+	| SSCR0_DataSize(16)	/* DSS = 15; Data size = 16-bit */
+	;
+static const u32 sscr1 = 0
+	| SSCR1_SCFR		/* SCFR = 1; SSPSCLK only during transfers */
+	| SSCR1_SCLKDIR		/* SCLKDIR = 1; Slave mode */
+	| SSCR1_SFRMDIR		/* SFRMDIR = 1; Slave mode */
+	| SSCR1_RWOT		/* RWOT = 1; Receive without transmit mode */
+	| SSCR1_RxTresh(1)	/* RFT = 0; Receive FIFO threshold = 1 */
+	| SSCR1_SPH		/* SPH = 1; SSPSCLK inactive 0.5 + 1 cycles */
+	| SSCR1_RIE		/* RIE = 1; Receive FIFO interrupt enabled */
+	;
+static const u32 sssr = 0
+	| SSSR_BCE		/* BCE = 1; Clear BCE */
+	| SSSR_TUR		/* TUR = 1; Clear TUR */
+	| SSSR_EOC		/* EOC = 1; Clear EOC */
+	| SSSR_TINT		/* TINT = 1; Clear TINT */
+	| SSSR_PINT		/* PINT = 1; Clear PINT */
+	| SSSR_ROR		/* ROR = 1; Clear ROR */
+	;
+
+/*
+ *	MEP Query $22: Touchpad Coordinate Range Query is not supported by
+ *	the NavPoint module, so sampled values provide the default limits.
+ */
+
+static int west = 2416;		/* 1/3 width */
+module_param(west, int, 0644);
+MODULE_PARM_DESC(west, "X coordinate limit for KEY_LEFT. Default = 2416");
+static int east = 3904;		/* 2/3 width */
+module_param(east, int, 0644);
+MODULE_PARM_DESC(east, "X coordinate limit for KEY_RIGHT. Default = 3904");
+static int south = 2480;	/* 1/3 height */
+module_param(south, int, 0644);
+MODULE_PARM_DESC(south, "Y coordinate limit for KEY_DOWN. Default = 2480");
+static int north = 3424;	/* 2/3 height */
+module_param(north, int, 0644);
+MODULE_PARM_DESC(north, "Y coordinate limit for KEY_UP. Default = 3424");
+
+static void navpoint_packet(struct device *dev)
+{
+	struct driver_data *drv_data = dev_get_drvdata(dev);
+	int pressed;
+	unsigned x, y;
+	unsigned code;
+
+	switch (drv_data->data[0]) {
+	case 0xff:	/* Garbage (packet?) between reset and Hello packet */
+	case 0x00:	/* Module 0, NULL packet */
+		break;
+	case 0x0e:	/* Module 0, Absolute packet */
+		pressed = (drv_data->data[1] & 0x01);
+		if ((drv_data->pressed ^ pressed) == 0)	/* No change */
+			break;
+		drv_data->pressed = pressed;
+		x = ((drv_data->data[2] & 0x1f) << 8) | drv_data->data[3];
+		y = ((drv_data->data[4] & 0x1f) << 8) | drv_data->data[5];
+		if (x < west)
+			code = KEY_LEFT;
+		else if (x > east)
+			code = KEY_RIGHT;
+		else if (y < south)
+			code = KEY_DOWN;
+		else if (y > north)
+			code = KEY_UP;
+		else
+			code = KEY_ENTER;
+		if (pressed)
+			drv_data->code = code;
+		input_report_key(drv_data->input, drv_data->code, pressed);
+		input_sync(drv_data->input);
+		break;
+	case 0x19:	/* Module 0, Hello packet */
+		if ((drv_data->data[1] & 0xf0) == 0x10)
+			break;
+		/* FALLTHROUGH */
+	default:
+		dev_warn(dev, "spurious packet: 0x%02x,0x%02x,...\n",
+			drv_data->data[0],
+			drv_data->data[1]);
+		break;
+	}
+
+	drv_data->index = 0;
+}
+
+static irqreturn_t navpoint_int(int irq, void *dev_id)
+{
+	struct device *dev = dev_id;
+	struct driver_data *drv_data = dev_get_drvdata(dev);
+	struct ssp_device *ssp = drv_data->ssp;
+	u32 status;
+	irqreturn_t ret;
+
+	status = pxa_ssp_read_reg(ssp, SSSR);
+	ret = IRQ_NONE;
+
+	if (status & sssr) {
+		dev_warn(dev, "spurious interrupt: 0x%02x\n", status);
+		pxa_ssp_write_reg(ssp, SSSR, (status & sssr));
+		ret = IRQ_HANDLED;
+	}
+
+	if (status & SSSR_RFS) {
+		while (status & SSSR_RNE) {
+			u32 data;
+
+			data = pxa_ssp_read_reg(ssp, SSDR);
+			drv_data->data[drv_data->index + 0] = (data >> 8);
+			drv_data->data[drv_data->index + 1] = data;
+			drv_data->index += 2;
+			if (HEADER_LENGTH(drv_data->data[0]) < drv_data->index)
+				navpoint_packet(dev);
+			status = pxa_ssp_read_reg(ssp, SSSR);
+		}
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static int navpoint_suspend(struct device *dev)
+{
+	struct driver_data *drv_data = dev_get_drvdata(dev);
+	struct ssp_device *ssp = drv_data->ssp;
+
+	gpio_set_value(drv_data->gpio, 0);
+
+	pxa_ssp_write_reg(ssp, SSCR0, 0);
+
+	clk_disable(ssp->clk);
+
+	return 0;
+}
+
+static int navpoint_resume(struct device *dev)
+{
+	struct driver_data *drv_data = dev_get_drvdata(dev);
+	struct ssp_device *ssp = drv_data->ssp;
+	int timeout;
+
+	clk_enable(ssp->clk);
+
+	pxa_ssp_write_reg(ssp, SSCR1, sscr1);
+	pxa_ssp_write_reg(ssp, SSSR, sssr);
+	pxa_ssp_write_reg(ssp, SSTO, 0);
+	pxa_ssp_write_reg(ssp, SSCR0, sscr0);	/* SSCR0_SSE written last */
+
+	/* Wait until SSP port is ready for slave clock operations */
+	for (timeout = 100; timeout != 0; --timeout) {
+		if (!(pxa_ssp_read_reg(ssp, SSSR) & SSSR_CSS))
+			break;
+		msleep(1);
+	}
+	if (timeout == 0)
+		dev_err(dev, "timeout waiting for SSSR[CSS] to clear\n");
+
+	gpio_set_value(drv_data->gpio, 1);
+
+	return 0;
+}
+
+#ifdef CONFIG_SUSPEND
+static const struct dev_pm_ops navpoint_pm_ops = {
+	.suspend	= navpoint_suspend,
+	.resume		= navpoint_resume,
+};
+#endif
+
+static int __devinit navpoint_probe(struct platform_device *pdev)
+{
+	struct navpoint_platform_data *pdata = pdev->dev.platform_data;
+	int ret;
+	struct driver_data *drv_data;
+	struct ssp_device *ssp;
+	struct input_dev *input;
+
+	drv_data = kzalloc(sizeof(*drv_data), GFP_KERNEL);
+	if (!drv_data) {
+		ret = -ENOMEM;
+		goto ret0;
+	}
+
+	ssp = pxa_ssp_request(pdata->port, pdev->name);
+	if (!ssp) {
+		ret = -ENODEV;
+		goto ret1;
+	}
+
+	/* HaRET does not disable devices before jumping into Linux */
+	if (pxa_ssp_read_reg(ssp, SSCR0) & SSCR0_SSE) {
+		gpio_set_value(pdata->gpio, 0);
+		pxa_ssp_write_reg(ssp, SSCR0, 0);
+		dev_warn(&pdev->dev, "ssp%d already enabled\n", pdata->port);
+	}
+
+	input = input_allocate_device();
+	if (!input) {
+		ret = -ENOMEM;
+		goto ret2;
+	}
+	input->name = pdev->name;
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(KEY_ENTER, input->keybit);
+	__set_bit(KEY_UP, input->keybit);
+	__set_bit(KEY_LEFT, input->keybit);
+	__set_bit(KEY_RIGHT, input->keybit);
+	__set_bit(KEY_DOWN, input->keybit);
+	input->dev.parent = &pdev->dev;
+	ret = input_register_device(input);
+	if (ret) {
+		input_free_device(input);
+		goto ret2;
+	}
+
+	drv_data->ssp = ssp;
+	drv_data->gpio = pdata->gpio;
+	drv_data->input = input;
+
+	platform_set_drvdata(pdev, drv_data);
+
+	ret = request_irq(ssp->irq, navpoint_int, 0, pdev->name, &pdev->dev);

Could this be a threadded irq?

+	if (ret)
+		goto ret3;
+
+	navpoint_resume(&pdev->dev);

Could this be pushed to open instead?