From: Philipp Zabel <philipp.zabel@gmail.com> To: Joel Stanley <joel@jms.id.au> Cc: Jonathan Cameron <jic23@kernel.org>, Rick Altherr <raltherr@google.com>, Rob Herring <robh+dt@kernel.org>, Hartmut Knaack <knaack.h@gmx.de>, Lars-Peter Clausen <lars@metafoo.de>, Peter Meerwald-Stadler <pmeerw@pmeerw.net>, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v2] iio: adc: aspeed: Deassert reset in probe Date: Tue, 31 Oct 2017 12:58:25 +0100 [thread overview] Message-ID: <CA+gwMcdVpq1P5kWAWzkg2A+Ah-fKyTk0adhGdg4465gkOY3EKA@mail.gmail.com> (raw) In-Reply-To: <20171031021203.18248-1-joel@jms.id.au> On Tue, Oct 31, 2017 at 3:12 AM, Joel Stanley <joel@jms.id.au> wrote: > The ASPEED SoC must deassert a reset in order to use the ADC peripheral. > > The device tree bindings are updated to document the resets phandle, and > the example is updated to match what is expected for both the reset and > clock phandle. Note that the bindings should have always had the reset > controller, as the hardware is unusable without it. > > Signed-off-by: Joel Stanley <joel@jms.id.au> It is unfortunate that this has to break DT (theoretical) backwards compatibility, but given that the old bindings never worked, this is better than to pretend a required reset is optional. Reviewed-by: Philipp Zabel <philipp.zabel@gmail.com> regards Philipp > --- > v2: > - Ensure disabling path unwinds in opposite order as the enable path > - Note that the bindings were incorrect without the reset phandle, > and for the system to be usable we must update them. No one was > (successfully) using these bindings/driver before without out of tree > hacks in mach-aspeed, as it would not have worked. > > .../devicetree/bindings/iio/adc/aspeed_adc.txt | 4 +++- > drivers/iio/adc/aspeed_adc.c | 25 ++++++++++++++++------ > 2 files changed, 22 insertions(+), 7 deletions(-) > > diff --git a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > index 674e133b7cd7..034fc2ba100e 100644 > --- a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > +++ b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > @@ -8,6 +8,7 @@ Required properties: > - reg: memory window mapping address and length > - clocks: Input clock used to derive the sample clock. Expected to be the > SoC's APB clock. > +- resets: Reset controller phandle > - #io-channel-cells: Must be set to <1> to indicate channels are selected > by index. > > @@ -15,6 +16,7 @@ Example: > adc@1e6e9000 { > compatible = "aspeed,ast2400-adc"; > reg = <0x1e6e9000 0xb0>; > - clocks = <&clk_apb>; > + clocks = <&syscon ASPEED_CLK_APB>; > + resets = <&syscon ASPEED_RESET_ADC>; > #io-channel-cells = <1>; > }; > diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c > index 8a958d5f1905..327a49ba1991 100644 > --- a/drivers/iio/adc/aspeed_adc.c > +++ b/drivers/iio/adc/aspeed_adc.c > @@ -17,6 +17,7 @@ > #include <linux/module.h> > #include <linux/of_platform.h> > #include <linux/platform_device.h> > +#include <linux/reset.h> > #include <linux/spinlock.h> > #include <linux/types.h> > > @@ -53,11 +54,12 @@ struct aspeed_adc_model_data { > }; > > struct aspeed_adc_data { > - struct device *dev; > - void __iomem *base; > - spinlock_t clk_lock; > - struct clk_hw *clk_prescaler; > - struct clk_hw *clk_scaler; > + struct device *dev; > + void __iomem *base; > + spinlock_t clk_lock; > + struct clk_hw *clk_prescaler; > + struct clk_hw *clk_scaler; > + struct reset_control *rst; > }; > > #define ASPEED_CHAN(_idx, _data_reg_addr) { \ > @@ -217,6 +219,15 @@ static int aspeed_adc_probe(struct platform_device *pdev) > goto scaler_error; > } > > + data->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL); > + if (IS_ERR(data->rst)) { > + dev_err(&pdev->dev, > + "invalid or missing reset controller device tree entry"); > + ret = PTR_ERR(data->rst); > + goto reset_error; > + } > + reset_control_deassert(data->rst); > + > model_data = of_device_get_match_data(&pdev->dev); > > if (model_data->wait_init_sequence) { > @@ -263,9 +274,10 @@ static int aspeed_adc_probe(struct platform_device *pdev) > writel(ASPEED_OPERATION_MODE_POWER_DOWN, > data->base + ASPEED_REG_ENGINE_CONTROL); > clk_disable_unprepare(data->clk_scaler->clk); > +reset_error: > + reset_control_assert(data->rst); > clk_enable_error: > clk_hw_unregister_divider(data->clk_scaler); > - > scaler_error: > clk_hw_unregister_divider(data->clk_prescaler); > return ret; > @@ -280,6 +292,7 @@ static int aspeed_adc_remove(struct platform_device *pdev) > writel(ASPEED_OPERATION_MODE_POWER_DOWN, > data->base + ASPEED_REG_ENGINE_CONTROL); > clk_disable_unprepare(data->clk_scaler->clk); > + reset_control_assert(data->rst); > clk_hw_unregister_divider(data->clk_scaler); > clk_hw_unregister_divider(data->clk_prescaler); > > -- > 2.14.1 >
WARNING: multiple messages have this Message-ID (diff)
From: Philipp Zabel <philipp.zabel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> To: Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> Cc: Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Rick Altherr <raltherr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Hartmut Knaack <knaack.h-Mmb7MZpHnFY@public.gmane.org>, Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>, Peter Meerwald-Stadler <pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org>, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> Subject: Re: [PATCH v2] iio: adc: aspeed: Deassert reset in probe Date: Tue, 31 Oct 2017 12:58:25 +0100 [thread overview] Message-ID: <CA+gwMcdVpq1P5kWAWzkg2A+Ah-fKyTk0adhGdg4465gkOY3EKA@mail.gmail.com> (raw) In-Reply-To: <20171031021203.18248-1-joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> On Tue, Oct 31, 2017 at 3:12 AM, Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> wrote: > The ASPEED SoC must deassert a reset in order to use the ADC peripheral. > > The device tree bindings are updated to document the resets phandle, and > the example is updated to match what is expected for both the reset and > clock phandle. Note that the bindings should have always had the reset > controller, as the hardware is unusable without it. > > Signed-off-by: Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> It is unfortunate that this has to break DT (theoretical) backwards compatibility, but given that the old bindings never worked, this is better than to pretend a required reset is optional. Reviewed-by: Philipp Zabel <philipp.zabel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> regards Philipp > --- > v2: > - Ensure disabling path unwinds in opposite order as the enable path > - Note that the bindings were incorrect without the reset phandle, > and for the system to be usable we must update them. No one was > (successfully) using these bindings/driver before without out of tree > hacks in mach-aspeed, as it would not have worked. > > .../devicetree/bindings/iio/adc/aspeed_adc.txt | 4 +++- > drivers/iio/adc/aspeed_adc.c | 25 ++++++++++++++++------ > 2 files changed, 22 insertions(+), 7 deletions(-) > > diff --git a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > index 674e133b7cd7..034fc2ba100e 100644 > --- a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > +++ b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt > @@ -8,6 +8,7 @@ Required properties: > - reg: memory window mapping address and length > - clocks: Input clock used to derive the sample clock. Expected to be the > SoC's APB clock. > +- resets: Reset controller phandle > - #io-channel-cells: Must be set to <1> to indicate channels are selected > by index. > > @@ -15,6 +16,7 @@ Example: > adc@1e6e9000 { > compatible = "aspeed,ast2400-adc"; > reg = <0x1e6e9000 0xb0>; > - clocks = <&clk_apb>; > + clocks = <&syscon ASPEED_CLK_APB>; > + resets = <&syscon ASPEED_RESET_ADC>; > #io-channel-cells = <1>; > }; > diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c > index 8a958d5f1905..327a49ba1991 100644 > --- a/drivers/iio/adc/aspeed_adc.c > +++ b/drivers/iio/adc/aspeed_adc.c > @@ -17,6 +17,7 @@ > #include <linux/module.h> > #include <linux/of_platform.h> > #include <linux/platform_device.h> > +#include <linux/reset.h> > #include <linux/spinlock.h> > #include <linux/types.h> > > @@ -53,11 +54,12 @@ struct aspeed_adc_model_data { > }; > > struct aspeed_adc_data { > - struct device *dev; > - void __iomem *base; > - spinlock_t clk_lock; > - struct clk_hw *clk_prescaler; > - struct clk_hw *clk_scaler; > + struct device *dev; > + void __iomem *base; > + spinlock_t clk_lock; > + struct clk_hw *clk_prescaler; > + struct clk_hw *clk_scaler; > + struct reset_control *rst; > }; > > #define ASPEED_CHAN(_idx, _data_reg_addr) { \ > @@ -217,6 +219,15 @@ static int aspeed_adc_probe(struct platform_device *pdev) > goto scaler_error; > } > > + data->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL); > + if (IS_ERR(data->rst)) { > + dev_err(&pdev->dev, > + "invalid or missing reset controller device tree entry"); > + ret = PTR_ERR(data->rst); > + goto reset_error; > + } > + reset_control_deassert(data->rst); > + > model_data = of_device_get_match_data(&pdev->dev); > > if (model_data->wait_init_sequence) { > @@ -263,9 +274,10 @@ static int aspeed_adc_probe(struct platform_device *pdev) > writel(ASPEED_OPERATION_MODE_POWER_DOWN, > data->base + ASPEED_REG_ENGINE_CONTROL); > clk_disable_unprepare(data->clk_scaler->clk); > +reset_error: > + reset_control_assert(data->rst); > clk_enable_error: > clk_hw_unregister_divider(data->clk_scaler); > - > scaler_error: > clk_hw_unregister_divider(data->clk_prescaler); > return ret; > @@ -280,6 +292,7 @@ static int aspeed_adc_remove(struct platform_device *pdev) > writel(ASPEED_OPERATION_MODE_POWER_DOWN, > data->base + ASPEED_REG_ENGINE_CONTROL); > clk_disable_unprepare(data->clk_scaler->clk); > + reset_control_assert(data->rst); > clk_hw_unregister_divider(data->clk_scaler); > clk_hw_unregister_divider(data->clk_prescaler); > > -- > 2.14.1 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-10-31 11:58 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-31 2:12 [PATCH v2] iio: adc: aspeed: Deassert reset in probe Joel Stanley 2017-10-31 11:58 ` Philipp Zabel [this message] 2017-10-31 11:58 ` Philipp Zabel 2017-10-31 23:45 ` Joel Stanley 2017-10-31 23:45 ` Joel Stanley 2017-11-02 14:49 ` Jonathan Cameron 2017-11-02 14:49 ` Jonathan Cameron 2017-11-19 16:03 ` Jonathan Cameron 2017-11-19 16:03 ` Jonathan Cameron 2017-11-20 4:52 ` Joel Stanley 2017-11-20 4:52 ` Joel Stanley 2017-11-25 14:22 ` Jonathan Cameron 2017-11-25 14:22 ` Jonathan Cameron 2017-11-01 21:54 ` Rob Herring
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