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Commit 93e3a9e9 authored by Sifan Naeem's avatar Sifan Naeem Committed by Mark Brown
Browse files

spi: img-spfi: check for max speed supported by the spfi block 



Maximum speed supported by spfi is limited to 1/4 of the spfi clock.

But in some SoCs the maximum speed supported by the spfi block can
be limited to less than 1/4 of the spfi clock. In such cases we have
to define the limit in the device tree so that the driver can pick
it up.

Signed-off-by: default avatarSifan Naeem <sifan.naeem@imgtec.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent d770e558

Documentation/devicetree/bindings/spi/spi-img-spfi.txt

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ Required properties: 
Optional properties:

- img,supports-quad-mode: Should be set if the interface supports quad mode

  SPI transfers.

- spfi-max-frequency: Maximum speed supported by the spfi block.



Example:

drivers/spi/spi-img-spfi.c

+14 −0
Original line number Diff line number Diff line
@@ -546,6 +546,7 @@ static int img_spfi_probe(struct platform_device *pdev) 
	struct img_spfi *spfi;

	struct resource *res;

	int ret;

	u32 max_speed_hz;



	master = spi_alloc_master(&pdev->dev, sizeof(*spfi));

	if (!master)
@@ -610,6 +611,19 @@ static int img_spfi_probe(struct platform_device *pdev) 
	master->max_speed_hz = clk_get_rate(spfi->spfi_clk) / 4;

	master->min_speed_hz = clk_get_rate(spfi->spfi_clk) / 512;



	/*

	 * Maximum speed supported by spfi is limited to the lower value

	 * between 1/4 of the SPFI clock or to "spfi-max-frequency"

	 * defined in the device tree.

	 * If no value is defined in the device tree assume the maximum

	 * speed supported to be 1/4 of the SPFI clock.

	 */

	if (!of_property_read_u32(spfi->dev->of_node, "spfi-max-frequency",

				  &max_speed_hz)) {

		if (master->max_speed_hz > max_speed_hz)

			master->max_speed_hz = max_speed_hz;

	}



	master->setup = img_spfi_setup;

	master->cleanup = img_spfi_cleanup;

	master->transfer_one = img_spfi_transfer_one;