Re: [PATCH 2/4] soc: qcom: Add GSBI driver

[Josh Cartwright <joshc@codeaurora.org>]

On Mon, Apr 21, 2014 at 12:30:42AM -0500, Andy Gross wrote:
> The GSBI (General Serial Bus Interface) driver controls the overarching
> configuration of the shared serial bus infrastructure on APQ8064, IPQ8064, and
> earlier QCOM processors.  The GSBI supports UART, I2C, SPI, and UIM
> functionality in various combinations.
> 
> Signed-off-by: Andy Gross <agross@codeaurora.org>
[..]
> +++ b/drivers/soc/qcom/qcom_gsbi.c
[..]
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +
> +#define GSBI_CTRL_REG		0x0000
> +#define GSBI_PROTOCOL_SHIFT	4
> +
> +struct gsbi_dev {
> +	struct device	*dev;
> +	void __iomem	*base;

You don't really need these.

> +
> +	struct clk	*hclk;
> +};
> +
> +static int gsbi_probe(struct platform_device *pdev)
> +{
> +	struct device_node *node = pdev->dev.of_node;
> +	struct gsbi_dev *gsbi;
> +	struct resource *res;
> +	u32 mode;
> +
> +	gsbi = devm_kzalloc(&pdev->dev, sizeof(*gsbi), GFP_KERNEL);
> +	if (!gsbi)
> +		return -ENOMEM;
> +
> +	gsbi->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, gsbi);
> +
> +	if (of_property_read_u32(node, "qcom,mode", &mode)) {
> +		dev_err(gsbi->dev, "missing mode configuration\n");
> +		return -EINVAL;
> +	}

I'm wondering if you should really be a (very simple) pinctrl driver
proper.

> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	gsbi->base = devm_ioremap_resource(gsbi->dev, res);
> +	if (IS_ERR(gsbi->base))
> +		return PTR_ERR(gsbi->base);
> +
> +	gsbi->hclk = devm_clk_get(gsbi->dev, "iface");
> +	if (IS_ERR(gsbi->hclk)) {
> +		dev_err(gsbi->dev, "Could not get core clock\n");
> +		return PTR_ERR(gsbi->hclk);
> +	}
> +	clk_prepare_enable(gsbi->hclk);
> +
> +	writel_relaxed((mode << GSBI_PROTOCOL_SHIFT), gsbi + GSBI_CTRL_REG);

Did you mean: gsbi->base + GSBI_CTRL_REG ?

> +
> +	/* make sure the gsbi control write is not reordered */
> +	wmb();
> +
> +	return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> +}
> +
> +static int gsbi_remove(struct platform_device *pdev)
> +{
> +	struct gsbi_dev *gsbi = platform_get_drvdata(pdev);
> +
> +	clk_disable_unprepare(gsbi->hclk);
> +
> +	return 0;
> +}
> +
> +static struct of_device_id gsbi_dt_match[] = {

const

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