Input: ili210x - export ili251x version details via sysfs

The ili251x firmware protocol permits readout of firmware version,
protocol version, mcu version and current mode (application, boot
loader, forced update). These information are useful when updating
the firmware on the il251x, e.g. to avoid updating the same firmware
into the device multiple times. The locking is now necessary to avoid
races between interrupt handler and the sysfs readouts.

Note that the protocol differs considerably between the ili2xxx devices,
this patch therefore implements this functionality only for ili251x that
I can test.
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20210831202506.181927-2-marex@denx.deSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/ili210x.c

@@ -22,6 +22,12 @@
 /* Touchscreen commands */
 #define REG_TOUCHDATA		0x10
 #define REG_PANEL_INFO		0x20
+#define REG_FIRMWARE_VERSION	0x40
+#define REG_PROTOCOL_VERSION	0x42
+#define REG_KERNEL_VERSION	0x61
+#define REG_GET_MODE		0xc0
+#define REG_GET_MODE_AP		0x5a
+#define REG_GET_MODE_BL		0x55
 #define REG_CALIBRATE		0xcc
 
 struct ili2xxx_chip {
@@ -45,6 +51,10 @@ struct ili210x {
 	struct gpio_desc *reset_gpio;
 	struct touchscreen_properties prop;
 	const struct ili2xxx_chip *chip;
+	u8 version_firmware[8];
+	u8 version_kernel[5];
+	u8 version_proto[2];
+	u8 ic_mode[2];
 	bool stop;
 };
 
@@ -353,6 +363,69 @@ static int ili251x_firmware_update_resolution(struct device *dev)
 	return 0;
 }
 
+static ssize_t ili251x_firmware_update_firmware_version(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	int error;
+	u8 fw[8];
+
+	/* Get firmware version */
+	error = priv->chip->read_reg(client, REG_FIRMWARE_VERSION,
+				     &fw, sizeof(fw));
+	if (!error)
+		memcpy(priv->version_firmware, fw, sizeof(fw));
+
+	return error;
+}
+
+static ssize_t ili251x_firmware_update_kernel_version(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	int error;
+	u8 kv[5];
+
+	/* Get kernel version */
+	error = priv->chip->read_reg(client, REG_KERNEL_VERSION,
+				     &kv, sizeof(kv));
+	if (!error)
+		memcpy(priv->version_kernel, kv, sizeof(kv));
+
+	return error;
+}
+
+static ssize_t ili251x_firmware_update_protocol_version(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	int error;
+	u8 pv[2];
+
+	/* Get protocol version */
+	error = priv->chip->read_reg(client, REG_PROTOCOL_VERSION,
+				     &pv, sizeof(pv));
+	if (!error)
+		memcpy(priv->version_proto, pv, sizeof(pv));
+
+	return error;
+}
+
+static ssize_t ili251x_firmware_update_ic_mode(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	int error;
+	u8 md[2];
+
+	/* Get chip boot mode */
+	error = priv->chip->read_reg(client, REG_GET_MODE, &md, sizeof(md));
+	if (!error)
+		memcpy(priv->ic_mode, md, sizeof(md));
+
+	return error;
+}
+
 static int ili251x_firmware_update_cached_state(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
@@ -370,9 +443,83 @@ static int ili251x_firmware_update_cached_state(struct device *dev)
 	if (error)
 		return error;
 
+	error = ili251x_firmware_update_firmware_version(dev);
+	if (error)
+		return error;
+
+	error = ili251x_firmware_update_kernel_version(dev);
+	if (error)
+		return error;
+
+	error = ili251x_firmware_update_protocol_version(dev);
+	if (error)
+		return error;
+
+	error = ili251x_firmware_update_ic_mode(dev);
+	if (error)
+		return error;
+
 	return 0;
 }
 
+static ssize_t ili251x_firmware_version_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	u8 *fw = priv->version_firmware;
+
+	return sysfs_emit(buf, "%02x%02x.%02x%02x.%02x%02x.%02x%02x\n",
+			  fw[0], fw[1], fw[2], fw[3],
+			  fw[4], fw[5], fw[6], fw[7]);
+}
+static DEVICE_ATTR(firmware_version, 0444, ili251x_firmware_version_show, NULL);
+
+static ssize_t ili251x_kernel_version_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	u8 *kv = priv->version_kernel;
+
+	return sysfs_emit(buf, "%02x.%02x.%02x.%02x.%02x\n",
+			  kv[0], kv[1], kv[2], kv[3], kv[4]);
+}
+static DEVICE_ATTR(kernel_version, 0444, ili251x_kernel_version_show, NULL);
+
+static ssize_t ili251x_protocol_version_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	u8 *pv = priv->version_proto;
+
+	return sysfs_emit(buf, "%02x.%02x\n", pv[0], pv[1]);
+}
+static DEVICE_ATTR(protocol_version, 0444, ili251x_protocol_version_show, NULL);
+
+static ssize_t ili251x_mode_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ili210x *priv = i2c_get_clientdata(client);
+	u8 *md = priv->ic_mode;
+	char *mode = "AP";
+
+	if (md[0] == REG_GET_MODE_AP)		/* Application Mode */
+		mode = "AP";
+	else if (md[0] == REG_GET_MODE_BL)	/* BootLoader Mode */
+		mode = "BL";
+	else					/* Unknown Mode */
+		mode = "??";
+
+	return sysfs_emit(buf, "%02x.%02x:%s\n", md[0], md[1], mode);
+}
+static DEVICE_ATTR(mode, 0444, ili251x_mode_show, NULL);
+
 static ssize_t ili210x_calibrate(struct device *dev,
 				 struct device_attribute *attr,
 				 const char *buf, size_t count)
@@ -401,22 +548,34 @@ static DEVICE_ATTR(calibrate, S_IWUSR, NULL, ili210x_calibrate);
 
 static struct attribute *ili210x_attributes[] = {
 	&dev_attr_calibrate.attr,
+	&dev_attr_firmware_version.attr,
+	&dev_attr_kernel_version.attr,
+	&dev_attr_protocol_version.attr,
+	&dev_attr_mode.attr,
 	NULL,
 };
 
-static umode_t ili210x_calibrate_visible(struct kobject *kobj,
+static umode_t ili210x_attributes_visible(struct kobject *kobj,
 					  struct attribute *attr, int index)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ili210x *priv = i2c_get_clientdata(client);
 
-	return priv->chip->has_calibrate_reg ? attr->mode : 0;
+	/* Calibrate is present on all ILI2xxx which have calibrate register */
+	if (attr == &dev_attr_calibrate.attr)
+		return priv->chip->has_calibrate_reg ? attr->mode : 0;
+
+	/* Firmware/Kernel/Protocol/BootMode is implememted only for ILI251x */
+	if (!priv->chip->has_firmware_proto)
+		return 0;
+
+	return attr->mode;
 }
 
 static const struct attribute_group ili210x_attr_group = {
 	.attrs = ili210x_attributes,
-	.is_visible = ili210x_calibrate_visible,
+	.is_visible = ili210x_attributes_visible,
 };
 
 static void ili210x_power_down(void *data)