From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v7 2/2] mfd: syscon: Add hardware spinlock support Date: Tue, 2 Jan 2018 15:36:20 +0000 Message-ID: <20180102153620.hhrbov2g5torajim@dell> References: <29fa88f883dae4c1f8a3acb2656cbd7c5a539d40.1514180039.git.baolin.wang@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Baolin Wang Cc: arnd@arndb.de, robh+dt@kernel.org, mark.rutland@arm.com, broonie@kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org Arnd, > 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 > Acked-by: Rob Herring ... did you sign off on this in the end? > --- > Changes since v6: > - Treat hwlock id 0 as valid for regmap. > > Changes since v5: > - Fix the case that hwspinlock is not enabled. > > Changes since v4: > - Add one exapmle to show how to add hwlock. > - Fix the coding style issue. > > Changes since v3: > - Add error handling for of_hwspin_lock_get_id() > > Changes since v2: > - Add acked tag from Rob. > > Changes since v1: > - Remove timeout configuration. > - Modify the binding file to add hwlocks. > --- > Documentation/devicetree/bindings/mfd/syscon.txt | 8 ++++++++ > drivers/mfd/syscon.c | 19 +++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt > index 8b92d45..25d9e9c 100644 > --- a/Documentation/devicetree/bindings/mfd/syscon.txt > +++ b/Documentation/devicetree/bindings/mfd/syscon.txt > @@ -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>; > }; > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c > index b93fe4c..7eaa40b 100644 > --- a/drivers/mfd/syscon.c > +++ b/drivers/mfd/syscon.c > @@ -13,6 +13,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -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; -- Lee Jones Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog