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authorMarek Vasut <marex@denx.de>2012-08-22 22:38:35 +0200
committerMark Brown <broonie@opensource.wolfsonmicro.com>2012-09-06 07:45:53 +0800
commite64d07a2dae569fc3c938adac777562a1d6f151e (patch)
treee0afe0d63e206c50bb43cd6521879be3b6b68785 /drivers/spi
parentf13639dc6043eb67e308aa5cf96717a86c10f8b9 (diff)
downloadlinux-linaro-stable-e64d07a2dae569fc3c938adac777562a1d6f151e.tar.gz
spi/mxs: Make the SPI block clock speed configurable via DT
Add "clock-frequency" property, which allows configuring the SPI block's base speed. Signed-off-by: Marek Vasut <marex@denx.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-mxs.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c
index 556e5ef907fa..edf1360ab09e 100644
--- a/drivers/spi/spi-mxs.c
+++ b/drivers/spi/spi-mxs.c
@@ -520,10 +520,17 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev)
struct pinctrl *pinctrl;
struct clk *clk;
void __iomem *base;
- int devid, dma_channel;
+ int devid, dma_channel, clk_freq;
int ret = 0, irq_err, irq_dma;
dma_cap_mask_t mask;
+ /*
+ * Default clock speed for the SPI core. 160MHz seems to
+ * work reasonably well with most SPI flashes, so use this
+ * as a default. Override with "clock-frequency" DT prop.
+ */
+ const int clk_freq_default = 160000000;
+
iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq_err = platform_get_irq(pdev, 0);
irq_dma = platform_get_irq(pdev, 1);
@@ -555,12 +562,18 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev)
"Failed to get DMA channel\n");
return -EINVAL;
}
+
+ ret = of_property_read_u32(np, "clock-frequency",
+ &clk_freq);
+ if (ret)
+ clk_freq = clk_freq_default;
} else {
dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (!dmares)
return -EINVAL;
devid = pdev->id_entry->driver_data;
dma_channel = dmares->start;
+ clk_freq = clk_freq_default;
}
master = spi_alloc_master(&pdev->dev, sizeof(*spi));
@@ -598,12 +611,8 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev)
goto out_master_free;
}
- /*
- * Crank up the clock to 120MHz, this will be further divided onto a
- * proper speed.
- */
clk_prepare_enable(ssp->clk);
- clk_set_rate(ssp->clk, 120 * 1000 * 1000);
+ clk_set_rate(ssp->clk, clk_freq);
ssp->clk_rate = clk_get_rate(ssp->clk) / 1000;
stmp_reset_block(ssp->base);