This function sets the OCR mask bits according to provided voltage
ranges. Will be used by the mmc_spi OpenFirmware bindings.
Signed-off-by: Anton Vorontsov <[EMAIL PROTECTED]>
---
drivers/mmc/core/core.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/core.h | 3 ++
2 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 044d84e..d4afae8 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -20,6 +20,7 @@
#include <linux/err.h>
#include <linux/leds.h>
#include <linux/scatterlist.h>
+#include <linux/log2.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -444,6 +445,60 @@ void mmc_set_bus_width(struct mmc_host *host, unsigned int
width)
mmc_set_ios(host);
}
+static int mmc_vdd_to_ocrbit(int vdd)
+{
+ int bit;
+ const int max_bit = ilog2(MMC_VDD_35_36);
+
+ if (vdd < 1650 || vdd > 3600)
+ return -EINVAL;
+
+ if (vdd >= 1650 && vdd <= 1950)
+ return ilog2(MMC_VDD_165_195);
+
+ /* base 2000 mV, step 100 mV, bit's base 8 */
+ bit = (vdd - 2000) / 100 + 8;
+ if (bit > max_bit)
+ return max_bit;
+ return bit;
+}
+
+/**
+ * mmc_vddrange_to_ocrmask - Convert a voltage range to the OCR mask
+ * @vdd_min: minimum voltage value (mV)
+ * @vdd_max: maximum voltage value (mV)
+ * @mask: pointer to the mask
+ *
+ * This function sets the OCR mask bits according to the provided @vdd_min
+ * and @vdd_max values.
+ *
+ * NOTE: You _must_ set the mask value to 0 before calling this function the
+ * first time. This is done so that you can call this function several
+ * times to set OCR mask for discontinuous voltage ranges.
+ *
+ * The function returns 0 on success and a negative errno value when
+ * a conversion is not possible.
+ */
+int mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max, unsigned int *mask)
+{
+ if (vdd_max < vdd_min)
+ return -EINVAL;
+
+ vdd_max = mmc_vdd_to_ocrbit(vdd_max);
+ if (vdd_max < 0)
+ return -EINVAL;
+
+ vdd_min = mmc_vdd_to_ocrbit(vdd_min);
+ if (vdd_min < 0)
+ return -EINVAL;
+
+ /* fill the mask, from max bit to min bit */
+ while (vdd_max >= vdd_min)
+ *mask |= 1 << vdd_max--;
+ return 0;
+}
+EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);
+
/*
* Mask off any voltages we don't support and select
* the lowest voltage
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 143cebf..3b139b0 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -151,4 +151,7 @@ static inline void mmc_claim_host(struct mmc_host *host)
__mmc_claim_host(host, NULL);
}
+extern int mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max,
+ unsigned int *mask);
+
#endif
--
1.5.6.3
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