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

[Kumar Gala <galak@codeaurora.org>]

On Jun 10, 2014, at 9:31 AM, Srinivas Kandagatla <srinivas.kandagatla@linaro.org> 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(-)

It seems like we shouldn’t need this change.  Adding Stephen to see if there is a reason we don’t have the clk’s enable_count adjusted for how the bootloader setup clks.

- k

> 
> 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);
> -- 
> 1.9.1
> 
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