On 09.03.23 12:52, Sascha Hauer wrote:
> Implement rescan to register and probe newly added devices via device
> tree overlays.
>
> While this is easy to do at SPI core level this is not the whole truth.
> Many SPI controllers do not use their native chipselects for the SPI
> devices, but GPIOs instead. These currently won't be rescanned when new
> devices are added, so the chipselects for the new devices must be be
> present in the base device tree already. You have been warned.
>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> ---
> drivers/spi/spi.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 3684647f6e..ee467d055b 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -29,6 +29,7 @@ struct boardinfo {
> };
>
> static LIST_HEAD(board_list);
> +static LIST_HEAD(spi_controller_list);
>
> /**
> * spi_new_device - instantiate one new SPI device
> @@ -120,6 +121,12 @@ static void spi_of_register_slaves(struct spi_controller *ctrl)
> for_each_available_child_of_node(node, n) {
> struct spi_board_info chip = {};
>
> + if (n->dev) {
> + dev_dbg(ctrl->dev, "of_i2c: skipping already registered %s\n",
> + dev_name(n->dev));
s/of_i2c/of_spi/
> + continue;
> + }
> +
> chip.name = xstrdup(n->name);
> chip.bus_num = ctrl->bus_num;
> /* Mode (clock phase/polarity/etc.) */
> @@ -142,6 +149,17 @@ static void spi_of_register_slaves(struct spi_controller *ctrl)
> }
> }
>
> +static void spi_controller_rescan(struct device *dev)
> +{
> + struct spi_controller *ctrl;
> +
> + list_for_each_entry(ctrl, &spi_controller_list, list) {
> + if (ctrl->dev != dev)
> + continue;
> + spi_of_register_slaves(ctrl);
> + }
> +}
> +
> /**
> * spi_register_board_info - register SPI devices for a given board
> * @info: array of chip descriptors
> @@ -196,8 +214,6 @@ static void scan_boardinfo(struct spi_controller *ctrl)
> }
> }
>
> -static LIST_HEAD(spi_controller_list);
> -
> static int spi_controller_check_ops(struct spi_controller *ctlr)
> {
> /*
> @@ -274,6 +290,9 @@ int spi_register_controller(struct spi_controller *ctrl)
> scan_boardinfo(ctrl);
> status = 0;
>
> + if (!ctrl->dev->rescan)
> + ctrl->dev->rescan = spi_controller_rescan;
> +
> return status;
> }
> EXPORT_SYMBOL(spi_register_controller);
--
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