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authorAndrew Jeffery <andrew@aj.id.au>2019-09-02 13:28:42 +0930
committerUlf Hansson <ulf.hansson@linaro.org>2019-09-11 15:58:39 +0200
commit0a0e8d7501cda79c9b20f6011814e2ec9b473ade (patch)
treea354f1351ed85a1979fba13605e49c9580dd26aa /drivers/mmc
parent7b954cdf33da3d3bd8046c499426b7433724f82e (diff)
downloadlinux-0a0e8d7501cda79c9b20f6011814e2ec9b473ade.tar.bz2
mmc: sdhci-of-aspeed: Allow max-frequency limitation of SDCLK
Add a get_max_clock() handler to sdhci-of-aspeed to report f_max as the maximum clock rate if it is set. This enables artificial limitation of the bus speed via max-frequency in the devicetree for e.g. the AST2600 evaluation board where I was seeing errors at 200MHz. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/sdhci-of-aspeed.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
index 0b75806ed69d..8962f6664381 100644
--- a/drivers/mmc/host/sdhci-of-aspeed.c
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -52,16 +52,24 @@ static void aspeed_sdc_configure_8bit_mode(struct aspeed_sdc *sdc,
static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
{
+ struct sdhci_pltfm_host *pltfm_host;
+ unsigned long parent;
int div;
u16 clk;
+ pltfm_host = sdhci_priv(host);
+ parent = clk_get_rate(pltfm_host->clk);
+
sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
if (clock == 0)
return;
+ if (WARN_ON(clock > host->max_clk))
+ clock = host->max_clk;
+
for (div = 1; div < 256; div *= 2) {
- if ((host->max_clk / div) <= clock)
+ if ((parent / div) <= clock)
break;
}
div >>= 1;
@@ -71,6 +79,14 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
sdhci_enable_clk(host, clk);
}
+static unsigned int aspeed_sdhci_get_max_clock(struct sdhci_host *host)
+{
+ if (host->mmc->f_max)
+ return host->mmc->f_max;
+
+ return sdhci_pltfm_clk_get_max_clock(host);
+}
+
static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
{
struct sdhci_pltfm_host *pltfm_priv;
@@ -97,7 +113,7 @@ static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
static const struct sdhci_ops aspeed_sdhci_ops = {
.set_clock = aspeed_sdhci_set_clock,
- .get_max_clock = sdhci_pltfm_clk_get_max_clock,
+ .get_max_clock = aspeed_sdhci_get_max_clock,
.set_bus_width = aspeed_sdhci_set_bus_width,
.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
.reset = sdhci_reset,