Re: [PATCH v9 1/5] mfd: mxs-lradc: Add support for mxs-lradc MFD

[Stefan Wahren]

Hi Ksenija,

> Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx> hat am 2. November 2016 um
> 08:38 geschrieben:
> 
> 
> Add core files for low resolution analog-to-digital converter (mxs-lradc)
> MFD driver.
> 
> Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx>
> ---
> Changes in v9:
>  - improve commit message.
> 
> Changes in v8:
>  - rebase onto 4.9-rc1
> 
> Changes in v7:
>  - define macros ADC_CELL and TSC_CELL
>  - remove one cell and dynamically set them in the switch()
>  - fail in the touchscreen driver instead of mfd driver if
>    hardware doesn't contain a touchscreen
> 
> Changes in v6:
>  - update copyright
>  - add kernel-doc header for struct mxs-lradc
>  - add error message
>  - change EINVAL to ENODEV
>  - use PLATFORM_DEVID_NONE instead -1
>  - cosmetic fixes
> 
> Changes in v5:
>  - use DEFINE_RES_MEM
>  - don't pass ioreammaped adress to platform cells
>  - move comment outside of struct mxs_lradc
>  - change type of argument in mxs_lradc_reg_set, mxs_lradc_reg_clear,
>    mxs_lradc_reg_wrt (struct mxs_lradc * -> void __iomem *)
> 
> Changes in v4:
>  - update copyright
>  - use DEFINE_RES_IRQ_NAMED
>  - remove mxs_lradc_add_device function
>  - use struct mfd_cell in static form
>  - improve spacing
>  - remove unnecessary comment
>  - remove platform_get_irq
>  - remove touch_ret and use ret instead
>  - rename use_touchscreen to touchscreen_wire
>  - use goto statements
>  - remove irq[13], irq_count and irq_name from struct mxs_lradc
>  - remove all defines from inside the struct definition
> 
> Changes in v3:
>  - add note to commit message
>  - move switch statement into if(touch_ret == 0) branch
>  - add MODULE_AUTHOR
> 
> Changes in v2:
>  - do not change spacing in Kconfig
>  - make struct mfd_cell part of struct mxs_lradc
>  - use switch instead of if in mxs_lradc_irq_mask
>  - use only necessary header files in mxs_lradc.h
>  - use devm_mfd_add_device
>  - use separate function to register mfd device
>  - change licence to GPL
>  - add copyright
> 
>  drivers/mfd/Kconfig           |  17 +++
>  drivers/mfd/Makefile          |   1 +
>  drivers/mfd/mxs-lradc.c       | 249
> ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/mxs-lradc.h | 203 ++++++++++++++++++++++++++++++++++
>  4 files changed, 470 insertions(+)
>  create mode 100644 drivers/mfd/mxs-lradc.c
>  create mode 100644 include/linux/mfd/mxs-lradc.h
> 
> ...
> diff --git a/drivers/mfd/mxs-lradc.c b/drivers/mfd/mxs-lradc.c
> new file mode 100644
> index 0000000..ffc8f2e
> --- /dev/null
> +++ b/drivers/mfd/mxs-lradc.c
> @@ -0,0 +1,249 @@
> ...
> +
> +static const struct of_device_id mxs_lradc_dt_ids[] = {
> +	{ .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
> +	{ .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
> +
> +static int mxs_lradc_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *of_id;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct mxs_lradc *lradc;
> +	struct mfd_cell *cells = mxs_cells;
> +	int ret = 0;
> +	u32 ts_wires = 0;
> +
> +	lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> +	if (!lradc)
> +		return -ENOMEM;
> +
> +	of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);

since you already plan to make a V10, please add a NULL check here.
So we can avoid a possible NULL pointer dereference in the following line.

Thanks
Stefan

> +	lradc->soc = (enum mxs_lradc_id)of_id->data;
> +
> +	lradc->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(lradc->clk)) {
> +		dev_err(dev, "Failed to get the delay unit clock\n");
> +		return PTR_ERR(lradc->clk);
> +	}
> +
> +	ret = clk_prepare_enable(lradc->clk);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable the delay unit clock\n");
> +		return ret;
> +	}
> +