Re: [RFC v2 1/5] drm/dsi: Refactor device creation

[Andrzej Hajda]

On 10/06/2015 11:24 AM, Archit Taneja wrote:
> Simplify the mipi dsi device creation process. device_initialize and
> device_add don't need to be called separately when creating
> mipi_dsi_device's. Use device_register instead to simplify things.
>
> Create a helper function mipi_dsi_device_new which takes in struct
> mipi_dsi_device_info and mipi_dsi_host. It clubs the functions
> mipi_dsi_device_alloc and mipi_dsi_device_add into one.
>
> mipi_dsi_device_info acts as a template to populate the dsi device
> information. This is populated by of_mipi_dsi_device_add and passed to
> mipi_dsi_device_new.
>
> Later on, we'll provide mipi_dsi_device_new as a standalone way to create
> a dsi device not available via DT.
>
> The new device creation process tries to closely follow what's been done
> in i2c_new_device in i2c-core.
>
> Signed-off-by: Archit Taneja <architt@xxxxxxxxxxxxxx>

Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>

Regards
Andrzej

> ---
>  drivers/gpu/drm/drm_mipi_dsi.c | 61 +++++++++++++++++-------------------------
>  include/drm/drm_mipi_dsi.h     | 15 +++++++++++
>  2 files changed, 40 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> index 2d5ca8ee..245ecfe 100644
> --- a/drivers/gpu/drm/drm_mipi_dsi.c
> +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> @@ -102,9 +102,18 @@ static const struct device_type mipi_dsi_device_type = {
>  	.release = mipi_dsi_dev_release,
>  };
>  
> -static struct mipi_dsi_device *mipi_dsi_device_alloc(struct mipi_dsi_host *host)
> +struct mipi_dsi_device *mipi_dsi_device_new(struct mipi_dsi_host *host,
> +					    struct mipi_dsi_device_info *info)
>  {
>  	struct mipi_dsi_device *dsi;
> +	struct device *dev = host->dev;
> +	int r;

> +
> +	if (info->reg > 3) {
> +		dev_err(dev, "device node has invalid reg property: %u\n",
> +			info->reg);
> +		return ERR_PTR(-EINVAL);
> +	}
>  
>  	dsi = kzalloc(sizeof(*dsi), GFP_KERNEL);
>  	if (!dsi)
> @@ -114,26 +123,27 @@ static struct mipi_dsi_device *mipi_dsi_device_alloc(struct mipi_dsi_host *host)
>  	dsi->dev.bus = &mipi_dsi_bus_type;
>  	dsi->dev.parent = host->dev;
>  	dsi->dev.type = &mipi_dsi_device_type;
> +	dsi->dev.of_node = info->node;
> +	dsi->channel = info->reg;
>  
> -	device_initialize(&dsi->dev);
> -
> -	return dsi;
> -}
> -
> -static int mipi_dsi_device_add(struct mipi_dsi_device *dsi)
> -{
> -	struct mipi_dsi_host *host = dsi->host;
> +	dev_set_name(&dsi->dev, "%s.%d", dev_name(host->dev), info->reg);
>  
> -	dev_set_name(&dsi->dev, "%s.%d", dev_name(host->dev),  dsi->channel);
> +	r = device_register(&dsi->dev);
> +	if (r) {
> +		dev_err(dev, "failed to register device: %d\n", r);
> +		kfree(dsi);
> +		return ERR_PTR(r);
> +	}
>  
> -	return device_add(&dsi->dev);
> +	return dsi;
>  }
> +EXPORT_SYMBOL(mipi_dsi_device_new);
>  
>  static struct mipi_dsi_device *
>  of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
>  {
> -	struct mipi_dsi_device *dsi;
>  	struct device *dev = host->dev;
> +	struct mipi_dsi_device_info info = { };
>  	int ret;
>  	u32 reg;
>  
> @@ -144,31 +154,10 @@ of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
>  		return ERR_PTR(-EINVAL);
>  	}
>  
> -	if (reg > 3) {
> -		dev_err(dev, "device node %s has invalid reg property: %u\n",
> -			node->full_name, reg);
> -		return ERR_PTR(-EINVAL);
> -	}
> -
> -	dsi = mipi_dsi_device_alloc(host);
> -	if (IS_ERR(dsi)) {
> -		dev_err(dev, "failed to allocate DSI device %s: %ld\n",
> -			node->full_name, PTR_ERR(dsi));
> -		return dsi;
> -	}
> -
> -	dsi->dev.of_node = of_node_get(node);
> -	dsi->channel = reg;
> +	info.reg = reg;
> +	info.node = of_node_get(node);
>  
> -	ret = mipi_dsi_device_add(dsi);
> -	if (ret) {
> -		dev_err(dev, "failed to add DSI device %s: %d\n",
> -			node->full_name, ret);
> -		kfree(dsi);
> -		return ERR_PTR(ret);
> -	}
> -
> -	return dsi;
> +	return mipi_dsi_device_new(host, &info);
>  }
>  
>  int mipi_dsi_host_register(struct mipi_dsi_host *host)
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index f1d8d0d..90f4f3c 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -140,6 +140,19 @@ enum mipi_dsi_pixel_format {
>  };
>  
>  /**
> + * struct mipi_dsi_device_info - template for creating a mipi_dsi_device
> + * @reg: DSI virtual channel assigned to peripheral
> + * @node: pointer to OF device node
> + *
> + * This is populated and passed to mipi_dsi_device_new to create a new
> + * DSI device
> + */
> +struct mipi_dsi_device_info {
> +	u32 reg;
> +	struct device_node *node;
> +};
> +
> +/**
>   * struct mipi_dsi_device - DSI peripheral device
>   * @host: DSI host for this peripheral
>   * @dev: driver model device node for this peripheral
> @@ -174,6 +187,8 @@ ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
>  ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
>  			      size_t num_params, void *data, size_t size);
>  
> +struct mipi_dsi_device *mipi_dsi_device_new(struct mipi_dsi_host *host,
> +					    struct mipi_dsi_device_info *info);
>  /**
>   * enum mipi_dsi_dcs_tear_mode - Tearing Effect Output Line mode
>   * @MIPI_DSI_DCS_TEAR_MODE_VBLANK: the TE output line consists of V-Blanking

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