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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: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
hifive-unleashed-5.1
Baolin Wang 2017-12-25 14:37:10 +08:00 committed by Mark Brown
parent a4887813c3
commit 3bafc09e77
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2 changed files with 27 additions and 0 deletions
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8
Documentation/devicetree/bindings/mfd/syscon.txt
View File

@ -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>;
};

19
drivers/mfd/syscon.c
View File

@ -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;