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Unverified Commit 3bafc09e authored by Baolin Wang's avatar Baolin Wang Committed by Mark Brown
Browse files

mfd: syscon: Add hardware spinlock support 



Some system control registers need hardware spinlock to synchronize
between the multiple subsystems, so we should add hardware spinlock
support for syscon.

Signed-off-by: default avatarBaolin Wang <baolin.wang@linaro.org>
Acked-by: default avatarRob Herring <robh@kernel.org>
Acked-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a4887813

Documentation/devicetree/bindings/mfd/syscon.txt

+8 −0
Original line number Diff line number Diff line
@@ -16,9 +16,17 @@ Required properties: 
Optional property:

- reg-io-width: the size (in bytes) of the IO accesses that should be

  performed on the device.

- hwlocks: reference to a phandle of a hardware spinlock provider node.



Examples:

gpr: iomuxc-gpr@20e0000 {

	compatible = "fsl,imx6q-iomuxc-gpr", "syscon";

	reg = <0x020e0000 0x38>;

	hwlocks = <&hwlock1 1>;

};



hwlock1: hwspinlock@40500000 {

	...

	reg = <0x40500000 0x1000>;

	#hwlock-cells = <1>;

};

drivers/mfd/syscon.c

+19 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 */



#include <linux/err.h>

#include <linux/hwspinlock.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/list.h>
@@ -87,6 +88,24 @@ static struct syscon *of_syscon_register(struct device_node *np) 
	if (ret)

		reg_io_width = 4;



	ret = of_hwspin_lock_get_id(np, 0);

	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {

		syscon_config.use_hwlock = true;

		syscon_config.hwlock_id = ret;

		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;

	} else if (ret < 0) {

		switch (ret) {

		case -ENOENT:

			/* Ignore missing hwlock, it's optional. */

			break;

		default:

			pr_err("Failed to retrieve valid hwlock: %d\n", ret);

			/* fall-through */

		case -EPROBE_DEFER:

			goto err_regmap;

		}

	}



	syscon_config.reg_stride = reg_io_width;

	syscon_config.val_bits = reg_io_width * 8;

	syscon_config.max_register = resource_size(&res) - reg_io_width;