[media] media: rc: nuvoton: support reading / writing wakeup sequence via sysfs

This patch adds a binary attribute /sys/class/rc/rc?/wakeup_data which
allows to read / write the wakeup sequence.

In combination with the core extension for exposing the most recent raw
packet this allows to easily define and set a wakeup sequence.

At least on my Zotac CI321 the BIOS resets the wakeup sequence at each boot
to a factory default. Therefore I use a udev rule
SUBSYSTEM=="rc", DRIVERS=="nuvoton-cir", ACTION=="add", RUN+="<script>"
with the script basically doing
cat <stored wakeup sequence> >/sys${DEVPATH}/wakeup_data
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/rc/nuvoton-cir.c

@@ -39,6 +39,8 @@
 
 #include "nuvoton-cir.h"
 
+static void nvt_clear_cir_wake_fifo(struct nvt_dev *nvt);
+
 static const struct nvt_chip nvt_chips[] = {
 	{ "w83667hg", NVT_W83667HG },
 	{ "NCT6775F", NVT_6775F },
@@ -177,6 +179,83 @@ static void nvt_set_ioaddr(struct nvt_dev *nvt, unsigned long *ioaddr)
 	}
 }
 
+static ssize_t wakeup_data_read(struct file *fp, struct kobject *kobj,
+				struct bin_attribute *bin_attr,
+				char *buf, loff_t off, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct rc_dev *rc_dev = to_rc_dev(dev);
+	struct nvt_dev *nvt = rc_dev->priv;
+	int fifo_len, len;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&nvt->nvt_lock, flags);
+
+	fifo_len = nvt_cir_wake_reg_read(nvt, CIR_WAKE_FIFO_COUNT);
+	len = min(fifo_len, WAKEUP_MAX_SIZE);
+
+	if (off >= len) {
+		spin_unlock_irqrestore(&nvt->nvt_lock, flags);
+		return 0;
+	}
+
+	if (len > count)
+		len = count;
+
+	/* go to first element to be read */
+	while (nvt_cir_wake_reg_read(nvt, CIR_WAKE_RD_FIFO_ONLY_IDX) != off)
+		nvt_cir_wake_reg_read(nvt, CIR_WAKE_RD_FIFO_ONLY);
+
+	for (i = 0; i < len; i++)
+		buf[i] = nvt_cir_wake_reg_read(nvt, CIR_WAKE_RD_FIFO_ONLY);
+
+	spin_unlock_irqrestore(&nvt->nvt_lock, flags);
+
+	return len;
+}
+
+static ssize_t wakeup_data_write(struct file *fp, struct kobject *kobj,
+				struct bin_attribute *bin_attr,
+				char *buf, loff_t off, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct rc_dev *rc_dev = to_rc_dev(dev);
+	struct nvt_dev *nvt = rc_dev->priv;
+	unsigned long flags;
+	u8 tolerance, config;
+	int i;
+
+	if (off > 0)
+		return -EINVAL;
+
+	/* hardcode the tolerance to 10% */
+	tolerance = DIV_ROUND_UP(count, 10);
+
+	spin_lock_irqsave(&nvt->nvt_lock, flags);
+
+	nvt_clear_cir_wake_fifo(nvt);
+	nvt_cir_wake_reg_write(nvt, count, CIR_WAKE_FIFO_CMP_DEEP);
+	nvt_cir_wake_reg_write(nvt, tolerance, CIR_WAKE_FIFO_CMP_TOL);
+
+	config = nvt_cir_wake_reg_read(nvt, CIR_WAKE_IRCON);
+
+	/* enable writes to wake fifo */
+	nvt_cir_wake_reg_write(nvt, config | CIR_WAKE_IRCON_MODE1,
+			       CIR_WAKE_IRCON);
+
+	for (i = 0; i < count; i++)
+		nvt_cir_wake_reg_write(nvt, buf[i], CIR_WAKE_WR_FIFO_DATA);
+
+	nvt_cir_wake_reg_write(nvt, config, CIR_WAKE_IRCON);
+
+	spin_unlock_irqrestore(&nvt->nvt_lock, flags);
+
+	return count;
+}
+
+static BIN_ATTR_RW(wakeup_data, WAKEUP_MAX_SIZE);
+
 /* dump current cir register contents */
 static void cir_dump_regs(struct nvt_dev *nvt)
 {
@@ -1133,6 +1212,10 @@ static int nvt_probe(struct pnp_dev *pdev, const struct pnp_device_id *dev_id)
 			     NVT_DRIVER_NAME "-wake", (void *)nvt))
 		goto exit_unregister_device;
 
+	ret = device_create_bin_file(&rdev->dev, &bin_attr_wakeup_data);
+	if (ret)
+		goto exit_unregister_device;
+
 	device_init_wakeup(&pdev->dev, true);
 
 	dev_notice(&pdev->dev, "driver has been successfully loaded\n");
@@ -1156,6 +1239,8 @@ static void nvt_remove(struct pnp_dev *pdev)
 {
 	struct nvt_dev *nvt = pnp_get_drvdata(pdev);
 
+	device_remove_bin_file(&nvt->rdev->dev, &bin_attr_wakeup_data);
+
 	nvt_disable_cir(nvt);
 
 	/* enable CIR Wake (for IR power-on) */

drivers/media/rc/nuvoton-cir.h

@@ -417,3 +417,6 @@ struct nvt_dev {
 /* as VISTA MCE definition, valid carrier value */
 #define MAX_CARRIER 60000
 #define MIN_CARRIER 30000
+
+/* max wakeup sequence length */
+#define WAKEUP_MAX_SIZE 65