From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 4 Jun 2019 17:44:24 +0530
From: Vinod Koul <vkoul@kernel.org>
Subject: Re: [PATCH 2/2] dmagengine: pl330: add code to get reset property
Message-ID: <20190604121424.GW15118@vkoul-mobl>
References: <20190524002847.30961-1-dinguyen@kernel.org>
 <20190524002847.30961-2-dinguyen@kernel.org>
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In-Reply-To: <20190524002847.30961-2-dinguyen@kernel.org>
To: Dinh Nguyen <dinguyen@kernel.org>
Cc: dmaengine@vger.kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org
List-ID: <devicetree@vger.kernel.org>

On 23-05-19, 19:28, Dinh Nguyen wrote:
> The DMA controller on some SoCs can be held in reset, and thus requires
> the reset signal(s) to deasserted. Most SoCs will have just one reset
> signal, but there are others, i.e. Arria10/Stratix10 will have an
> additional reset signal, referred to as the OCP.
> 
> Add code to get the reset property from the device tree for deassert and
> assert.
> 
> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
> ---
>  drivers/dma/pl330.c | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index 6e6837214210..6018c43e785d 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -29,6 +29,7 @@
>  #include <linux/err.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/bug.h>
> +#include <linux/reset.h>
>  
>  #include "dmaengine.h"
>  #define PL330_MAX_CHAN		8
> @@ -500,6 +501,9 @@ struct pl330_dmac {
>  	unsigned int num_peripherals;
>  	struct dma_pl330_chan *peripherals; /* keep at end */
>  	int quirks;
> +
> +	struct reset_control	*rstc;
> +	struct reset_control	*rstc_ocp;
>  };
>  
>  static struct pl330_of_quirks {
> @@ -3028,6 +3032,30 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>  
>  	amba_set_drvdata(adev, pl330);
>  
> +	pl330->rstc = devm_reset_control_get_optional(&adev->dev, "dma");
> +	if (IS_ERR(pl330->rstc)) {
> +		dev_err(&adev->dev, "No reset controller specified.\n");

Wasnt this optional??

> +		return PTR_ERR(pl330->rstc);
> +	} else {
> +		ret = reset_control_deassert(pl330->rstc);
> +		if (ret) {
> +			dev_err(&adev->dev, "Couldn't deassert the device from reset!\n");
> +			return ret;
> +		}
> +	}
> +
> +	pl330->rstc_ocp = devm_reset_control_get_optional(&adev->dev, "dma-ocp");
> +	if (IS_ERR(pl330->rstc_ocp)) {
> +		dev_err(&adev->dev, "No reset controller specified.\n");
> +		return PTR_ERR(pl330->rstc_ocp);
> +	} else {
> +		ret = reset_control_deassert(pl330->rstc_ocp);
> +		if (ret) {
> +			dev_err(&adev->dev, "Couldn't deassert the device from OCP reset!\n");
> +			return ret;
> +		}
> +	}
> +
>  	for (i = 0; i < AMBA_NR_IRQS; i++) {
>  		irq = adev->irq[i];
>  		if (irq) {
> @@ -3168,6 +3196,11 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
>  probe_err2:
>  	pl330_del(pl330);
>  
> +	if (pl330->rstc_ocp)
> +		reset_control_assert(pl330->rstc_ocp);
> +
> +	if (pl330->rstc)
> +		reset_control_assert(pl330->rstc);
>  	return ret;
>  }
>  
> @@ -3206,6 +3239,11 @@ static int pl330_remove(struct amba_device *adev)
>  
>  	pl330_del(pl330);
>  
> +	if (pl330->rstc_ocp)
> +		reset_control_assert(pl330->rstc_ocp);
> +
> +	if (pl330->rstc)
> +		reset_control_assert(pl330->rstc);
>  	return 0;
>  }
>  
> -- 
> 2.20.0

-- 
~Vinod