comment inline below, plus adding to cc: and to: list
On 8/26/22 09:43, Wei Yongjun wrote:
> Add a runtime device tree overlay interface for device need dts file.
> With it its possible to use device tree overlays without having to use
> a per-platform overlay manager.
Why is an overlay needed? The documentation in patch 4 shows providing
a dtb as an argument to the qemu-system-x86_64 command, which should be
sufficient to supply the appropriate dtb.
-Frank
>
> Add a new device by command:
> $ cat test.dtbo > /sys/class/spi_master/spi0/overlay_fdto
>
> Remove the device by command:
> $ echo remove > /sys/class/spi_master/spi0/overlay_fdto
>
> Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> ---
> drivers/spi/Kconfig | 2 ++
> drivers/spi/spi-mockup.c | 48 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index e0f0fa2746ad..4b7c84ddb367 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -1161,6 +1161,8 @@ config SPI_TLE62X0
> config SPI_MOCKUP
> tristate "SPI controller Testing Driver"
> depends on OF
> + select OF_EARLY_FLATTREE
> + select OF_RESOLVE
> select BPF_EVENTS
> help
> This enables SPI controller testing driver, which provides a way to
> diff --git a/drivers/spi/spi-mockup.c b/drivers/spi/spi-mockup.c
> index 7a93b194ee53..404ad821bf6a 100644
> --- a/drivers/spi/spi-mockup.c
> +++ b/drivers/spi/spi-mockup.c
> @@ -21,6 +21,9 @@
> struct mockup_spi {
> struct mutex lock;
> struct spi_device *devs[MOCKUP_CHIPSELECT_MAX];
> +
> + void *fdto;
> + int ovcs_id;
> };
>
> static struct spi_master *to_spi_master(struct device *dev)
> @@ -145,9 +148,53 @@ delete_device_store(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_WO(delete_device);
>
> +static ssize_t
> +overlay_fdto_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct spi_master *master = to_spi_master(dev);
> + struct mockup_spi *mock = spi_master_get_devdata(master);
> + int ret;
> +
> + mutex_lock(&mock->lock);
> +
> + if (strncmp(buf, "remove\n", count) == 0) {
> + if (mock->ovcs_id < 0) {
> + ret = -ENOENT;
> + goto out_unlock;
> + }
> + of_overlay_remove(&mock->ovcs_id);
> + kfree(mock->fdto);
> + mock->ovcs_id = -1;
> + mock->fdto = NULL;
> + } else {
> + if (mock->ovcs_id >= 0) {
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> + mock->fdto = kmemdup(buf, count, GFP_KERNEL);
> + if (!mock->fdto) {
> + ret = -ENOMEM;
> + goto out_unlock;
> + }
> + ret = of_overlay_fdt_apply(mock->fdto, count, &mock->ovcs_id);
> + if (ret < 0)
> + goto out_unlock;
> + }
> +
> + mutex_unlock(&mock->lock);
> + return count;
> +
> +out_unlock:
> + mutex_unlock(&mock->lock);
> + return ret;
> +}
> +static DEVICE_ATTR_WO(overlay_fdto);
> +
> static struct attribute *spi_mockup_attrs[] = {
> &dev_attr_new_device.attr,
> &dev_attr_delete_device.attr,
> + &dev_attr_overlay_fdto.attr,
> NULL
> };
> ATTRIBUTE_GROUPS(spi_mockup);
> @@ -227,6 +274,7 @@ static int spi_mockup_probe(struct platform_device *pdev)
>
> mock = spi_master_get_devdata(master);
> mutex_init(&mock->lock);
> + mock->ovcs_id = -1;
>
> ret = spi_register_master(master);
> if (ret) {
