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    Subject[PATCH v4 6/6] drm/dsi: Get DSI host by DT device node
    Date
    mipi_dsi_devices are inherently aware of their host because they
    share a parent-child hierarchy in the device tree.

    non-dsi drivers that create dsi device don't have this data. In order to
    get this information, they require to a phandle to the dsi host in the
    device tree.

    Maintain a list of all the hosts DSI that are currently registered.

    This list will be used to find the mipi_dsi_host corresponding to the
    device_node passed in of_find_mipi_dsi_host_by_node.

    Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
    Signed-off-by: Archit Taneja <architt@codeaurora.org>
    ---
    drivers/gpu/drm/drm_mipi_dsi.c | 38 ++++++++++++++++++++++++++++++++++++++
    include/drm/drm_mipi_dsi.h | 3 +++
    2 files changed, 41 insertions(+)

    diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
    index 7a81171..e40a665 100644
    --- a/drivers/gpu/drm/drm_mipi_dsi.c
    +++ b/drivers/gpu/drm/drm_mipi_dsi.c
    @@ -213,6 +213,36 @@ of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
    }
    #endif

    +static DEFINE_MUTEX(host_lock);
    +static LIST_HEAD(host_list);
    +
    +/**
    + * of_find_mipi_dsi_host_by_node() - find the MIPI DSI host matching a
    + * device tree node
    + * @node: device tree node
    + *
    + * Return: A pointer to the MIPI DSI host corresponding to @np or NULL if no
    + * such device exists (or has not been registered yet).
    + */
    +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node)
    +{
    + struct mipi_dsi_host *host;
    +
    + mutex_lock(&host_lock);
    +
    + list_for_each_entry(host, &host_list, list) {
    + if (host->dev->of_node == node) {
    + mutex_unlock(&host_lock);
    + return host;
    + }
    + }
    +
    + mutex_unlock(&host_lock);
    +
    + return NULL;
    +}
    +EXPORT_SYMBOL(of_find_mipi_dsi_host_by_node);
    +
    int mipi_dsi_host_register(struct mipi_dsi_host *host)
    {
    struct device_node *node;
    @@ -224,6 +254,10 @@ int mipi_dsi_host_register(struct mipi_dsi_host *host)
    of_mipi_dsi_device_add(host, node);
    }

    + mutex_lock(&host_lock);
    + list_add_tail(&host->list, &host_list);
    + mutex_unlock(&host_lock);
    +
    return 0;
    }
    EXPORT_SYMBOL(mipi_dsi_host_register);
    @@ -240,6 +274,10 @@ static int mipi_dsi_remove_device_fn(struct device *dev, void *priv)
    void mipi_dsi_host_unregister(struct mipi_dsi_host *host)
    {
    device_for_each_child(host->dev, NULL, mipi_dsi_remove_device_fn);
    +
    + mutex_lock(&host_lock);
    + list_del_init(&host->list);
    + mutex_unlock(&host_lock);
    }
    EXPORT_SYMBOL(mipi_dsi_host_unregister);

    diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
    index 410d8b5..e5c1df9 100644
    --- a/include/drm/drm_mipi_dsi.h
    +++ b/include/drm/drm_mipi_dsi.h
    @@ -96,14 +96,17 @@ struct mipi_dsi_host_ops {
    * struct mipi_dsi_host - DSI host device
    * @dev: driver model device node for this DSI host
    * @ops: DSI host operations
    + * @list: list management
    */
    struct mipi_dsi_host {
    struct device *dev;
    const struct mipi_dsi_host_ops *ops;
    + struct list_head list;
    };

    int mipi_dsi_host_register(struct mipi_dsi_host *host);
    void mipi_dsi_host_unregister(struct mipi_dsi_host *host);
    +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node);

    /* DSI mode flags */

    --
    The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
    hosted by The Linux Foundation


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