Unverified Commit ab0b5a99 authored by Mark Brown's avatar Mark Brown
Browse files

Add optional reset control for Cadence SPI 

Merge series from Ji Sheng Teoh <jisheng.teoh@starfivetech.com>:

The first patch adds optional reset control to support assertion and
deassertion of reset signal to properly bring the SPI device into an
operating condition.
The second patch documents the optional reset control into dt-bindings.
parents 060bbd65 837e53f7

Documentation/devicetree/bindings/spi/spi-cadence.yaml

+7 −0
Original line number Diff line number Diff line
@@ -55,6 +55,13 @@ properties: 
  label:

    description: Descriptive name of the SPI controller.



  resets:

    maxItems: 1



  reset-names:

    items:

      - const: spi



required:

  - compatible

  - reg

drivers/spi/spi-cadence.c

+13 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/of_address.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

#include <linux/reset.h>

#include <linux/spi/spi.h>



/* Name of this driver */
@@ -111,6 +112,7 @@ 
 * @dev_busy:		Device busy flag

 * @is_decoded_cs:	Flag for decoder property set or not

 * @tx_fifo_depth:	Depth of the TX FIFO

 * @rstc:		Optional reset control for SPI controller

 */

struct cdns_spi {

	void __iomem *regs;
@@ -125,6 +127,7 @@ struct cdns_spi { 
	u8 dev_busy;

	u32 is_decoded_cs;

	unsigned int tx_fifo_depth;

	struct reset_control *rstc;

};



/* Macros for the SPI controller read/write */
@@ -588,6 +591,16 @@ static int cdns_spi_probe(struct platform_device *pdev) 
		goto remove_ctlr;

	}



	xspi->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, "spi");

	if (IS_ERR(xspi->rstc)) {

		ret = dev_err_probe(&pdev->dev, PTR_ERR(xspi->rstc),

				    "Cannot get SPI reset.\n");

		goto remove_ctlr;

	}



	reset_control_assert(xspi->rstc);

	reset_control_deassert(xspi->rstc);



	if (!spi_controller_is_target(ctlr)) {

		xspi->ref_clk = devm_clk_get_enabled(&pdev->dev, "ref_clk");

		if (IS_ERR(xspi->ref_clk)) {