diff options
| author | Andrew Jeffery <andrew@aj.id.au> | 2019-09-02 06:58:42 +0300 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2019-09-11 16:58:39 +0300 |
| commit | 0a0e8d7501cda79c9b20f6011814e2ec9b473ade (patch) | |
| tree | a354f1351ed85a1979fba13605e49c9580dd26aa /drivers/mmc | |
| parent | 7b954cdf33da3d3bd8046c499426b7433724f82e (diff) | |
| download | linux-0a0e8d7501cda79c9b20f6011814e2ec9b473ade.tar.xz | |
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.c | 20 |
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, |