Input: keyboard - imx_sc: Add i.MX system controller key support

i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
inside, the system controller is in charge of controlling power,
clock and scu key etc..

Adds i.MX system controller key driver support, Linux kernel has
to communicate with system controller via MU (message unit) IPC
to get scu key's status.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1570412509-7893-2-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/drivers/input/keyboard/imx_sc_key.c b/drivers/input/keyboard/imx_sc_key.c
new file mode 100644
index 000000000000..dd57daa67e5f
--- /dev/null
+++ b/drivers/input/keyboard/imx_sc_key.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP.
+ */
+
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/firmware/imx/sci.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define DEBOUNCE_TIME				30
+#define REPEAT_INTERVAL				60
+
+#define SC_IRQ_BUTTON				1
+#define SC_IRQ_GROUP_WAKE			3
+
+#define IMX_SC_MISC_FUNC_GET_BUTTON_STATUS	18
+
+struct imx_key_drv_data {
+	u32 keycode;
+	bool keystate;  /* true: pressed, false: released */
+	struct delayed_work check_work;
+	struct input_dev *input;
+	struct imx_sc_ipc *key_ipc_handle;
+	struct notifier_block key_notifier;
+};
+
+struct imx_sc_msg_key {
+	struct imx_sc_rpc_msg hdr;
+	u8 state;
+};
+
+static int imx_sc_key_notify(struct notifier_block *nb,
+			     unsigned long event, void *group)
+{
+	struct imx_key_drv_data *priv =
+				 container_of(nb,
+					      struct imx_key_drv_data,
+					      key_notifier);
+
+	if ((event & SC_IRQ_BUTTON) && (*(u8 *)group == SC_IRQ_GROUP_WAKE)) {
+		schedule_delayed_work(&priv->check_work,
+				      msecs_to_jiffies(DEBOUNCE_TIME));
+		pm_wakeup_event(priv->input->dev.parent, 0);
+	}
+
+	return 0;
+}
+
+static void imx_sc_check_for_events(struct work_struct *work)
+{
+	struct imx_key_drv_data *priv =
+				 container_of(work,
+					      struct imx_key_drv_data,
+					      check_work.work);
+	struct input_dev *input = priv->input;
+	struct imx_sc_msg_key msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	bool state;
+	int error;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_MISC;
+	hdr->func = IMX_SC_MISC_FUNC_GET_BUTTON_STATUS;
+	hdr->size = 1;
+
+	error = imx_scu_call_rpc(priv->key_ipc_handle, &msg, true);
+	if (error) {
+		dev_err(&input->dev, "read imx sc key failed, error %d\n", error);
+		return;
+	}
+
+	state = (bool)msg.state;
+
+	if (state ^ priv->keystate) {
+		priv->keystate = state;
+		input_event(input, EV_KEY, priv->keycode, state);
+		input_sync(input);
+		if (!priv->keystate)
+			pm_relax(priv->input->dev.parent);
+	}
+
+	if (state)
+		schedule_delayed_work(&priv->check_work,
+				      msecs_to_jiffies(REPEAT_INTERVAL));
+}
+
+static int imx_sc_key_probe(struct platform_device *pdev)
+{
+	struct imx_key_drv_data *priv;
+	struct input_dev *input;
+	int error;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	error = imx_scu_get_handle(&priv->key_ipc_handle);
+	if (error)
+		return error;
+
+	if (device_property_read_u32(&pdev->dev, "linux,keycodes",
+				     &priv->keycode)) {
+		dev_err(&pdev->dev, "missing linux,keycodes property\n");
+		return -EINVAL;
+	}
+
+	INIT_DELAYED_WORK(&priv->check_work, imx_sc_check_for_events);
+
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input) {
+		dev_err(&pdev->dev, "failed to allocate the input device\n");
+		return -ENOMEM;
+	}
+
+	input->name = pdev->name;
+	input->phys = "imx-sc-key/input0";
+	input->id.bustype = BUS_HOST;
+
+	input_set_capability(input, EV_KEY, priv->keycode);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		return error;
+	}
+
+	priv->input = input;
+	platform_set_drvdata(pdev, priv);
+
+	error = imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON,
+					 true);
+	if (error) {
+		dev_err(&pdev->dev, "failed to enable scu group irq\n");
+		return error;
+	}
+
+	priv->key_notifier.notifier_call = imx_sc_key_notify;
+	error = imx_scu_irq_register_notifier(&priv->key_notifier);
+	if (error) {
+		imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON,
+					 false);
+		dev_err(&pdev->dev, "failed to register scu notifier\n");
+		return error;
+	}
+
+	return 0;
+}
+
+static int imx_sc_key_remove(struct platform_device *pdev)
+{
+	struct imx_key_drv_data *priv = platform_get_drvdata(pdev);
+
+	imx_scu_irq_group_enable(SC_IRQ_GROUP_WAKE, SC_IRQ_BUTTON, false);
+	imx_scu_irq_unregister_notifier(&priv->key_notifier);
+	cancel_delayed_work_sync(&priv->check_work);
+
+	return 0;
+}
+
+static const struct of_device_id imx_sc_key_ids[] = {
+	{ .compatible = "fsl,imx-sc-key" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx_sc_key_ids);
+
+static struct platform_driver imx_sc_key_driver = {
+	.driver = {
+		.name = "imx-sc-key",
+		.of_match_table = imx_sc_key_ids,
+	},
+	.probe = imx_sc_key_probe,
+	.remove = imx_sc_key_remove,
+};
+module_platform_driver(imx_sc_key_driver);
+
+MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
+MODULE_DESCRIPTION("i.MX System Controller Key Driver");
+MODULE_LICENSE("GPL v2");