platform/x86: winmate-fm07-keys: Winmate FM07/FM07P buttons

Winmate FM07 and FM07P in-vehicle computers have a row of five buttons
below the display. This module adds an input device that delivers key
events when these buttons are pressed.

Signed-off-by: Daniel Beer <daniel.beer@tirotech.co.nz>
Link: https://lore.kernel.org/r/623a110a.1c69fb81.64f39.0118@mx.google.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/Kconfig

@@ -1152,6 +1152,14 @@ config SIEMENS_SIMATIC_IPC
 	  To compile this driver as a module, choose M here: the module
 	  will be called simatic-ipc.
 
+config WINMATE_FM07_KEYS
+	tristate "Winmate FM07/FM07P front-panel keys driver"
+	depends on INPUT
+	help
+	  Winmate FM07 and FM07P in-vehicle computers have a row of five
+	  buttons below the display. This module adds an input device
+	  that delivers key events when these buttons are pressed.
+
 endif # X86_PLATFORM_DEVICES
 
 config PMC_ATOM

drivers/platform/x86/Makefile

@@ -130,3 +130,6 @@ obj-$(CONFIG_PMC_ATOM)			+= pmc_atom.o
 
 # Siemens Simatic Industrial PCs
 obj-$(CONFIG_SIEMENS_SIMATIC_IPC)	+= simatic-ipc.o
+
+# Winmate
+obj-$(CONFIG_WINMATE_FM07_KEYS)		+= winmate-fm07-keys.o

drivers/platform/x86/winmate-fm07-keys.c

@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Driver for the Winmate FM07 front-panel keys
+//
+// Author: Daniel Beer <daniel.beer@tirotech.co.nz>
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/dmi.h>
+#include <linux/io.h>
+
+#define DRV_NAME	"winmate-fm07keys"
+
+#define PORT_CMD	0x6c
+#define PORT_DATA	0x68
+
+#define EC_ADDR_KEYS	0x3b
+#define EC_CMD_READ	0x80
+
+#define BASE_KEY	KEY_F13
+#define NUM_KEYS	5
+
+/* Typically we're done in fewer than 10 iterations */
+#define LOOP_TIMEOUT	1000
+
+static void fm07keys_poll(struct input_dev *input)
+{
+	uint8_t k;
+	int i;
+
+	/* Flush output buffer */
+	i = 0;
+	while (inb(PORT_CMD) & 0x01) {
+		if (++i >= LOOP_TIMEOUT)
+			goto timeout;
+		inb(PORT_DATA);
+	}
+
+	/* Send request and wait for write completion */
+	outb(EC_CMD_READ, PORT_CMD);
+	i = 0;
+	while (inb(PORT_CMD) & 0x02)
+		if (++i >= LOOP_TIMEOUT)
+			goto timeout;
+
+	outb(EC_ADDR_KEYS, PORT_DATA);
+	i = 0;
+	while (inb(PORT_CMD) & 0x02)
+		if (++i >= LOOP_TIMEOUT)
+			goto timeout;
+
+	/* Wait for data ready */
+	i = 0;
+	while (!(inb(PORT_CMD) & 0x01))
+		if (++i >= LOOP_TIMEOUT)
+			goto timeout;
+	k = inb(PORT_DATA);
+
+	/* Notify of new key states */
+	for (i = 0; i < NUM_KEYS; i++) {
+		input_report_key(input, BASE_KEY + i, (~k) & 1);
+		k >>= 1;
+	}
+
+	input_sync(input);
+	return;
+
+timeout:
+	dev_warn_ratelimited(&input->dev, "timeout polling IO memory\n");
+}
+
+static int fm07keys_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct input_dev *input;
+	int ret;
+	int i;
+
+	input = devm_input_allocate_device(dev);
+	if (!input) {
+		dev_err(dev, "no memory for input device\n");
+		return -ENOMEM;
+	}
+
+	if (!devm_request_region(dev, PORT_CMD, 1, "Winmate FM07 EC"))
+		return -EBUSY;
+	if (!devm_request_region(dev, PORT_DATA, 1, "Winmate FM07 EC"))
+		return -EBUSY;
+
+	input->name = "Winmate FM07 front-panel keys";
+	input->phys = DRV_NAME "/input0";
+
+	input->id.bustype = BUS_HOST;
+	input->id.vendor = 0x0001;
+	input->id.product = 0x0001;
+	input->id.version = 0x0100;
+
+	__set_bit(EV_KEY, input->evbit);
+
+	for (i = 0; i < NUM_KEYS; i++)
+		__set_bit(BASE_KEY + i, input->keybit);
+
+	ret = input_setup_polling(input, fm07keys_poll);
+	if (ret) {
+		dev_err(dev, "unable to set up polling, err=%d\n", ret);
+		return ret;
+	}
+
+	/* These are silicone buttons. They can't be pressed in rapid
+	 * succession too quickly, and 50 Hz seems to be an adequate
+	 * sampling rate without missing any events when tested.
+	 */
+	input_set_poll_interval(input, 20);
+
+	ret = input_register_device(input);
+	if (ret) {
+		dev_err(dev, "unable to register polled device, err=%d\n",
+			ret);
+		return ret;
+	}
+
+	input_sync(input);
+	return 0;
+}
+
+static struct platform_driver fm07keys_driver = {
+	.probe		= fm07keys_probe,
+	.driver		= {
+		.name	= DRV_NAME
+	},
+};
+
+static struct platform_device *dev;
+
+static const struct dmi_system_id fm07keys_dmi_table[] __initconst = {
+	{
+		/* FM07 and FM07P */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Winmate Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "IP30"),
+		},
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(dmi, fm07keys_dmi_table);
+
+static int __init fm07keys_init(void)
+{
+	int ret;
+
+	if (!dmi_check_system(fm07keys_dmi_table))
+		return -ENODEV;
+
+	ret = platform_driver_register(&fm07keys_driver);
+	if (ret) {
+		pr_err("fm07keys: failed to register driver, err=%d\n", ret);
+		return ret;
+	}
+
+	dev = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
+	if (IS_ERR(dev)) {
+		ret = PTR_ERR(dev);
+		pr_err("fm07keys: failed to allocate device, err = %d\n", ret);
+		goto fail_register;
+	}
+
+	return 0;
+
+fail_register:
+	platform_driver_unregister(&fm07keys_driver);
+	return ret;
+}
+
+static void __exit fm07keys_exit(void)
+{
+	platform_driver_unregister(&fm07keys_driver);
+	platform_device_unregister(dev);
+}
+
+module_init(fm07keys_init);
+module_exit(fm07keys_exit);
+
+MODULE_AUTHOR("Daniel Beer <daniel.beer@tirotech.co.nz>");
+MODULE_DESCRIPTION("Winmate FM07 front-panel keys driver");
+MODULE_LICENSE("GPL");