drm/komeda: Add sysfs attribute: core_id and config_id

Add two sysfs node: core_id, config_id, user can read them to fetch the
HW product information.

Also, use memset to initialize config_id, rather than quirky C syntax.
Courtesy of Nathan Chancellor <natechancellor@gmail.com>.
Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
[Merged Nathan's patch that uses memset to initialize config_id into
original patch as the fixes tag changed due to rebase, reworded the
commit to reference the merged patch]
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drivers/gpu/drm/arm/display/include/malidp_product.h

@@ -20,4 +20,16 @@
 /* Mali-display product IDs */
 #define MALIDP_D71_PRODUCT_ID   0x0071
 
+union komeda_config_id {
+	struct {
+		__u32	max_line_sz:16,
+			n_pipelines:2,
+			n_scalers:2, /* number of scalers per pipeline */
+			n_layers:3, /* number of layers per pipeline */
+			n_richs:3, /* number of rich layers per pipeline */
+			reserved_bits:6;
+	};
+	__u32 value;
+};
+
 #endif /* _MALIDP_PRODUCT_H_ */

drivers/gpu/drm/arm/display/komeda/komeda_dev.c

@@ -59,6 +59,48 @@ static void komeda_debugfs_init(struct komeda_dev *mdev)
 }
 #endif
 
+static ssize_t
+core_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct komeda_dev *mdev = dev_to_mdev(dev);
+
+	return snprintf(buf, PAGE_SIZE, "0x%08x\n", mdev->chip.core_id);
+}
+static DEVICE_ATTR_RO(core_id);
+
+static ssize_t
+config_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct komeda_dev *mdev = dev_to_mdev(dev);
+	struct komeda_pipeline *pipe = mdev->pipelines[0];
+	union komeda_config_id config_id;
+	int i;
+
+	memset(&config_id, 0, sizeof(config_id));
+
+	config_id.max_line_sz = pipe->layers[0]->hsize_in.end;
+	config_id.n_pipelines = mdev->n_pipelines;
+	config_id.n_scalers = pipe->n_scalers;
+	config_id.n_layers = pipe->n_layers;
+	config_id.n_richs = 0;
+	for (i = 0; i < pipe->n_layers; i++) {
+		if (pipe->layers[i]->layer_type == KOMEDA_FMT_RICH_LAYER)
+			config_id.n_richs++;
+	}
+	return snprintf(buf, PAGE_SIZE, "0x%08x\n", config_id.value);
+}
+static DEVICE_ATTR_RO(config_id);
+
+static struct attribute *komeda_sysfs_entries[] = {
+	&dev_attr_core_id.attr,
+	&dev_attr_config_id.attr,
+	NULL,
+};
+
+static struct attribute_group komeda_sysfs_attr_group = {
+	.attrs = komeda_sysfs_entries,
+};
+
 static int komeda_parse_pipe_dt(struct komeda_dev *mdev, struct device_node *np)
 {
 	struct komeda_pipeline *pipe;
@@ -207,6 +249,12 @@ struct komeda_dev *komeda_dev_create(struct device *dev)
 		goto err_cleanup;
 	}
 
+	err = sysfs_create_group(&dev->kobj, &komeda_sysfs_attr_group);
+	if (err) {
+		DRM_ERROR("create sysfs group failed.\n");
+		goto err_cleanup;
+	}
+
 #ifdef CONFIG_DEBUG_FS
 	komeda_debugfs_init(mdev);
 #endif
@@ -224,6 +272,8 @@ void komeda_dev_destroy(struct komeda_dev *mdev)
 	struct komeda_dev_funcs *funcs = mdev->funcs;
 	int i;
 
+	sysfs_remove_group(&dev->kobj, &komeda_sysfs_attr_group);
+
 #ifdef CONFIG_DEBUG_FS
 	debugfs_remove_recursive(mdev->debugfs_root);
 #endif

drivers/gpu/drm/arm/display/komeda/komeda_dev.h

@@ -190,4 +190,6 @@ d71_identify(u32 __iomem *reg, struct komeda_chip_info *chip);
 struct komeda_dev *komeda_dev_create(struct device *dev);
 void komeda_dev_destroy(struct komeda_dev *mdev);
 
+struct komeda_dev *dev_to_mdev(struct device *dev);
+
 #endif /*_KOMEDA_DEV_H_*/

drivers/gpu/drm/arm/display/komeda/komeda_drv.c

@@ -17,6 +17,13 @@ struct komeda_drv {
 	struct komeda_kms_dev *kms;
 };
 
+struct komeda_dev *dev_to_mdev(struct device *dev)
+{
+	struct komeda_drv *mdrv = dev_get_drvdata(dev);
+
+	return mdrv ? mdrv->mdev : NULL;
+}
+
 static void komeda_unbind(struct device *dev)
 {
 	struct komeda_drv *mdrv = dev_get_drvdata(dev);