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Commit 0a0e8d75 authored by Andrew Jeffery's avatar Andrew Jeffery Committed by Ulf Hansson
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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: default avatarAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 7b954cdf

drivers/mmc/host/sdhci-of-aspeed.c

+18 −2
Original line number Original line Diff line number Diff line
@@ -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)

static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)

{

{

	struct sdhci_pltfm_host *pltfm_host;

	unsigned long parent;

	int div;

	int div;

	u16 clk;

	u16 clk;





	pltfm_host = sdhci_priv(host);

	parent = clk_get_rate(pltfm_host->clk);



	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);

	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);





	if (clock == 0)

	if (clock == 0)

		return;

		return;





	if (WARN_ON(clock > host->max_clk))

		clock = host->max_clk;



	for (div = 1; div < 256; div *= 2) {

	for (div = 1; div < 256; div *= 2) {

		if ((host->max_clk / div) <= clock)

		if ((parent / div) <= clock)

			break;

			break;

	}

	}

	div >>= 1;

	div >>= 1;
@@ -71,6 +79,14 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock) 
	sdhci_enable_clk(host, clk);

	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)

static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)

{

{

	struct sdhci_pltfm_host *pltfm_priv;

	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 = {

static const struct sdhci_ops aspeed_sdhci_ops = {

	.set_clock = aspeed_sdhci_set_clock,

	.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,

	.set_bus_width = aspeed_sdhci_set_bus_width,

	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,

	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,

	.reset = sdhci_reset,

	.reset = sdhci_reset,