mmc: sunxi: Make sample clocks optional

It turns out that sun4i (A10) and sun5i (A13 & co) do not have sample clocks, so make them optional.

Since these do not have sample clocks, they cannot (reliably) do DDR rates, so only set MMC_CAP_1_8V_DDR when we do have sample clks.

Note this patch only changes the devm_clk_get error checking and sets the clocks to NULL if they don't exists. All the clk_foo calls accept a NULL clk and will return success when called with a NULL clk, so this is all that is necessary.

Signed-off-by Hans de Goede <[email protected]>

---
 drivers/mmc/host/sunxi-mmc.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

drivers/mmc/host/sunxi-mmc.c +0 -0

index 71a480b..4552ee0 100644

drivers/mmc/host/sunxi-mmc.c +12 -4

+                       dev_err(&pdev->dev, "Could not get output clock\n");
+                       return PTR_ERR(host->clk_output);
+               }
+               host->clk_output = NULL;
        }
 
        host->clk_sample = devm_clk_get(&pdev->dev, "sample");
        if (IS_ERR(host->clk_sample)) {
-               dev_err(&pdev->dev, "Could not get sample clock\n");
-               return PTR_ERR(host->clk_sample);
+               if (PTR_ERR(host->clk_sample) != -ENOENT) {
+                       dev_err(&pdev->dev, "Could not get sample clock\n");
+                       return PTR_ERR(host->clk_sample);
+               }
+               host->clk_sample = NULL;
        }
 
        host->reset = devm_reset_control_get_optional(&pdev->dev, "ahb");

@@ -1126,9 +1132,11 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
        mmc->f_min              =   400000;
        mmc->f_max              = 52000000;
        mmc->caps              |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
-                                 MMC_CAP_1_8V_DDR |
                                  MMC_CAP_ERASE | MMC_CAP_SDIO_IRQ;
 
+       if (host->clk_output && host->clk_sample)
+               mmc->caps      |= MMC_CAP_1_8V_DDR;
+
        ret = mmc_of_parse(mmc);
        if (ret)
                goto error_free_dma;
--

2.7.4

It turns out that sun4i (A10) and sun5i (A13 & co) do not have sample clocks, so make them optional.

Since these do not have sample clocks, they cannot (reliably) do DDR rates, so only set MMC_CAP_1_8V_DDR when we do have sample clks.

Note this patch only changes the devm_clk_get error checking and sets the clocks to NULL if they don't exists. All the clk_foo calls accept a NULL clk and will return success when called with a NULL clk, so this is all that is necessary.

Hi,

Quoted 10 lines · Hans de Goede

It turns out that sun4i (A10) and sun5i (A13 & co) do not have sample clocks, so make them optional.

Since these do not have sample clocks, they cannot (reliably) do DDR rates, so only set MMC_CAP_1_8V_DDR when we do have sample clks.

Note this patch only changes the devm_clk_get error checking and sets the clocks to NULL if they don't exists. All the clk_foo calls accept a NULL clk and will return success when called with a NULL clk, so this is all that is necessary.

The clocks aren't really optional. They're not needed for the A10 / A13, and mandatory for the A20 and later.

Having a new compatible for the A20 that would require that clock and not require it for the A10/A13 anymore seems more appropriate.

Hi All,

It turns out that sun4i / sun5i do not have sample clocks at all, so make them optional. Also remove the DDR capability when there are no sample clocks because DDR modes do not work reliably without them (observed on an UTOO P66 tablet with eMMC).

Ulf, can you please merge the first 2 patches, patches 3-4 should be merged through Maxime's sunxi/dts tree, but not before the first 2 have hit linux-next.

Regards,

Hans

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