Re: [PATCH 2/9] mtd: pxa3xx_nand: add a non mandatory ECC clock

Jisheng Zhang
2015-01-28T03:39:26Z

Dear Antoine,

On Tue, 27 Jan 2015 06:10:09 -0800
Antoine Tenart <antoine.tenart@free-electrons.com> wrote:

> Some controllers (as the coming Berlin nand controller) need to enable
> an ECC clock. Add support for this clock in the pxa3xx nand driver, and
> leave it as non mandatory.
>
> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
> ---
> drivers/mtd/nand/pxa3xx_nand.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> index d00ac392d1c4..2681ec4abafa 100644
> --- a/drivers/mtd/nand/pxa3xx_nand.c
> +++ b/drivers/mtd/nand/pxa3xx_nand.c
> @@ -180,7 +180,7 @@ struct pxa3xx_nand_info {
> struct nand_hw_control controller;
> struct platform_device *pdev;
>
> - struct clk *clk;
> + struct clk *clk, *ecc_clk;
> void __iomem *mmio_base;
> unsigned long mmio_phys;
> struct completion cmd_complete, dev_ready;
> @@ -1608,7 +1608,7 @@ static int alloc_nand_resource(struct platform_device
> *pdev)
> spin_lock_init(&chip->controller->lock);
> init_waitqueue_head(&chip->controller->wq);
> - info->clk = devm_clk_get(&pdev->dev, NULL);
> + info->clk = devm_clk_get(&pdev->dev, "nfc");
> if (IS_ERR(info->clk)) {

Do we need to fall back to unnamed clock here? Otherwise I guess it will break
other platforms.

> dev_err(&pdev->dev, "failed to get nand clock\n");
> return PTR_ERR(info->clk);
> @@ -1617,6 +1617,13 @@ static int alloc_nand_resource(struct
> platform_device *pdev) if (ret < 0)
> return ret;
>
> + info->ecc_clk = devm_clk_get(&pdev->dev, "ecc");
> + if (!IS_ERR(info->ecc_clk)) {
> + ret = clk_prepare_enable(info->ecc_clk);
> + if (ret < 0)
> + goto fail_disable_clk;
> + }
> +
> if (use_dma) {
> /*
> * This is a dirty hack to make this driver work from
> @@ -1633,7 +1640,7 @@ static int alloc_nand_resource(struct platform_device
> *pdev) dev_err(&pdev->dev,
> "no resource defined for data
> DMA\n"); ret = -ENXIO;
> - goto fail_disable_clk;
> + goto fail_disable_ecc_clk;
> }
> info->drcmr_dat = r->start;
>
> @@ -1642,7 +1649,7 @@ static int alloc_nand_resource(struct platform_device
> *pdev) dev_err(&pdev->dev,
> "no resource defined for cmd
> DMA\n"); ret = -ENXIO;
> - goto fail_disable_clk;
> + goto fail_disable_ecc_clk;
> }
> info->drcmr_cmd = r->start;
> }
> @@ -1652,14 +1659,14 @@ static int alloc_nand_resource(struct
> platform_device *pdev) if (irq < 0) {
> dev_err(&pdev->dev, "no IRQ resource defined\n");
> ret = -ENXIO;
> - goto fail_disable_clk;
> + goto fail_disable_ecc_clk;
> }
>
> r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
> if (IS_ERR(info->mmio_base)) {
> ret = PTR_ERR(info->mmio_base);
> - goto fail_disable_clk;
> + goto fail_disable_ecc_clk;
> }
> info->mmio_phys = r->start;
>
> @@ -1668,7 +1675,7 @@ static int alloc_nand_resource(struct platform_device
> *pdev) info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
> if (info->data_buff == NULL) {
> ret = -ENOMEM;
> - goto fail_disable_clk;
> + goto fail_disable_ecc_clk;
> }
>
> /* initialize all interrupts to be disabled */
> @@ -1687,6 +1694,9 @@ static int alloc_nand_resource(struct platform_device
> *pdev) fail_free_buf:
> free_irq(irq, info);
> kfree(info->data_buff);
> +fail_disable_ecc_clk:
> + if (!IS_ERR(info->ecc_clk))
> + clk_disable_unprepare(info->ecc_clk);

we can remove the IS_ERR check to simplify this error path since commit
63589e92c2d9("clk: Ignore error and NULL pointers passed to clk_{unprepare, disable}()")

> fail_disable_clk:
> clk_disable_unprepare(info->clk);
> return ret;
> @@ -1709,6 +1719,8 @@ static int pxa3xx_nand_remove(struct platform_device
> *pdev) pxa3xx_nand_free_buff(info);
>
> clk_disable_unprepare(info->clk);
> + if (!IS_ERR(info->ecc_clk))
> + clk_disable_unprepare(info->ecc_clk);

we can remove the IS_ERR check too.

>
> for (cs = 0; cs < pdata->num_cs; cs++)
> nand_release(info->host[cs]->mtd);