Re: [RFC PATCH 1/2] soc: qcom: do not disable the iface clock in probe

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

Hi Andy/Kumar,

If its not too late,
Can we queue this fix for 3.17-rc1 or rc2?


thanks,
srini
On 10/06/14 15:31, Srinivas Kandagatla wrote:
> The use case here is when we have a bootconsole which is printing the
> characters on serial console and gsbi driver comes up after some time.
> As gsbi driver disables the clock in probe the bootconsole locks up.
>
> This patch fixes the problem by disabling the clock in platform remove
> rather than in probe.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---
>   drivers/soc/qcom/qcom_gsbi.c | 46 +++++++++++++++++++++++++++++++-------------
>   1 file changed, 33 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/soc/qcom/qcom_gsbi.c b/drivers/soc/qcom/qcom_gsbi.c
> index ab7b441..64fb298 100644
> --- a/drivers/soc/qcom/qcom_gsbi.c
> +++ b/drivers/soc/qcom/qcom_gsbi.c
> @@ -22,44 +22,63 @@
>   #define GSBI_CTRL_REG		0x0000
>   #define GSBI_PROTOCOL_SHIFT	4
>
> +struct gsbi_info {
> +	struct clk *hclk;
> +	u32 mode;
> +	u32 crci;
> +};
> +
>   static int gsbi_probe(struct platform_device *pdev)
>   {
>   	struct device_node *node = pdev->dev.of_node;
>   	struct resource *res;
>   	void __iomem *base;
> -	struct clk *hclk;
> -	u32 mode, crci = 0;
> +	struct gsbi_info *gsbi;
> +
> +	gsbi = devm_kzalloc(&pdev->dev, sizeof(*gsbi), GFP_KERNEL);
> +
> +	if (!gsbi)
> +		return -ENOMEM;
>
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	base = devm_ioremap_resource(&pdev->dev, res);
>   	if (IS_ERR(base))
>   		return PTR_ERR(base);
>
> -	if (of_property_read_u32(node, "qcom,mode", &mode)) {
> +	if (of_property_read_u32(node, "qcom,mode", &gsbi->mode)) {
>   		dev_err(&pdev->dev, "missing mode configuration\n");
>   		return -EINVAL;
>   	}
>
>   	/* not required, so default to 0 if not present */
> -	of_property_read_u32(node, "qcom,crci", &crci);
> +	of_property_read_u32(node, "qcom,crci", &gsbi->crci);
>
> -	dev_info(&pdev->dev, "GSBI port protocol: %d crci: %d\n", mode, crci);
> +	dev_info(&pdev->dev, "GSBI port protocol: %d crci: %d\n",
> +		 gsbi->mode, gsbi->crci);
> +	gsbi->hclk = devm_clk_get(&pdev->dev, "iface");
> +	if (IS_ERR(gsbi->hclk))
> +		return PTR_ERR(gsbi->hclk);
>
> -	hclk = devm_clk_get(&pdev->dev, "iface");
> -	if (IS_ERR(hclk))
> -		return PTR_ERR(hclk);
> +	clk_prepare_enable(gsbi->hclk);
>
> -	clk_prepare_enable(hclk);
> -
> -	writel_relaxed((mode << GSBI_PROTOCOL_SHIFT) | crci,
> +	writel_relaxed((gsbi->mode << GSBI_PROTOCOL_SHIFT) | gsbi->crci,
>   				base + GSBI_CTRL_REG);
>
>   	/* make sure the gsbi control write is not reordered */
>   	wmb();
>
> -	clk_disable_unprepare(hclk);
> +	platform_set_drvdata(pdev, gsbi);
> +
> +	return of_platform_populate(node, NULL, NULL, &pdev->dev);
> +}
> +
> +static int gsbi_remove(struct platform_device *pdev)
> +{
> +	struct gsbi_info *gsbi = platform_get_drvdata(pdev);
> +
> +	clk_disable_unprepare(gsbi->hclk);
>
> -	return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> +	return 0;
>   }
>
>   static const struct of_device_id gsbi_dt_match[] = {
> @@ -76,6 +95,7 @@ static struct platform_driver gsbi_driver = {
>   		.of_match_table	= gsbi_dt_match,
>   	},
>   	.probe = gsbi_probe,
> +	.remove	= gsbi_remove,
>   };
>
>   module_platform_driver(gsbi_driver);
>