Hi Kamal,
On 5/17/2022 11:04 AM, Kamal Dasu wrote:
From: Al Cooper <alcooperx@xxxxxxxxx>
The 72116B0 has improved SDIO controllers that allow the max clock
rate to be increased from a max of 100MHz to a max of 150MHz. The
driver will need to get the clock and increase it's default rate
and override the caps register, that still indicates a max of 100MHz.
The new clock will be named "sdio_freq" in the DT node's "clock-names"
list. The driver will use a DT property, "max-frequency", to
enable this functionality and will get the actual rate in MHz
from the property to allow various speeds to be requested.
Signed-off-by: Al Cooper <alcooperx@xxxxxxxxx>
Signed-off-by: Kamal Dasu <kdasu.kdev@xxxxxxxxx>
---
drivers/mmc/host/sdhci-brcmstb.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
index 8eb57de48e0c..bb614a5e1ea4 100644
--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -250,6 +250,8 @@ static int sdhci_brcmstb_probe(struct platform_device *pdev)
struct sdhci_pltfm_host *pltfm_host;
const struct of_device_id *match;
struct sdhci_brcmstb_priv *priv;
+ struct clk *master_clk;
+ u32 actual_clock_mhz;
struct sdhci_host *host;
struct resource *iomem;
struct clk *clk;
@@ -330,6 +332,32 @@ static int sdhci_brcmstb_probe(struct platform_device *pdev)
if (match_priv->flags & BRCMSTB_MATCH_FLAGS_BROKEN_TIMEOUT)
host->quirks |= SDHCI_QUIRK_BROKEN_TIMEOUT_VAL;
+ /* Change the base clock frequency if the DT property exists */
+ if (!(host->mmc->f_max))
+ goto add_host;
+
+ master_clk = devm_clk_get(&pdev->dev, "sdio_freq");
This looks like a candidate for devm_clk_get_optional() since the clock
is optional. Then you can call clk_prepare_enable() unconditionally even
if it is NULL/non-existent.
+ if (IS_ERR(master_clk)) {
+ dev_warn(&pdev->dev, "Clock for \"sdio_freq\" not found\n");
+ goto add_host;
+ } else {
+ res = clk_prepare_enable(master_clk);
+ if (res)
+ goto err;
It looks like we may be leaving the clock enabled even when we did not
want to (e.g.: error path) and do not we need to turn if off,
respectively turn it back on in .suspend() and .resume()?
+ }
+
+ /* set improved clock rate */
+ clk_set_rate(master_clk, host->mmc->f_max);
+ actual_clock_mhz = clk_get_rate(master_clk) / 1000000;
+
+ host->caps &= ~SDHCI_CLOCK_V3_BASE_MASK;
+ host->caps |= (actual_clock_mhz << SDHCI_CLOCK_BASE_SHIFT);
+ /* Disable presets because they are now incorrect */
+ host->quirks2 |= SDHCI_QUIRK2_PRESET_VALUE_BROKEN;
+ dev_dbg(&pdev->dev, "Base Clock Frequency changed to %dMHz\n",
+ actual_clock_mhz);
+
+add_host:
res = sdhci_brcmstb_add_host(host, priv);
if (res)
goto err;
It looks like we would need to unwind the clk_prepare_enable(master_clk)
in case of failures here.
--
Florian
