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mmc: core: parse voltage from device-tree

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Add function to support getting voltage from device-tree.
If voltage-range is specified in device-tree node, this function
will parse it and return the available voltage mask.

Signed-off-by: Haijun Zhang <haijun.zhang@freescale.com>
Acked-by: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Haijun Zhang 2013-08-26 09:19:22 +08:00 committed by Chris Ball
parent bcf24e1daa
commit 6e9e318b30
3 changed files with 50 additions and 0 deletions
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4
Documentation/devicetree/bindings/mmc/fsl-esdhc.txt
View File

@ -19,6 +19,9 @@ Optional properties:
"bus-width = <1>" property.
- sdhci,auto-cmd12: specifies that a controller can only handle auto
CMD12.
- voltage-ranges : two cells are required, first cell specifies minimum
slot voltage (mV), second cell specifies maximum slot voltage (mV).
Several ranges could be specified.
Example:
@ -29,4 +32,5 @@ sdhci@2e000 {
interrupt-parent = <&ipic>;
/* Filled in by U-Boot */
clock-frequency = <0>;
voltage-ranges = <3300 3300>;
};

44
drivers/mmc/core/core.c
View File

@ -27,6 +27,7 @@
#include <linux/fault-inject.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@ -1196,6 +1197,49 @@ u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max)
}
EXPORT_SYMBOL(mmc_vddrange_to_ocrmask);
#ifdef CONFIG_OF
/**
* mmc_of_parse_voltage - return mask of supported voltages
* @np: The device node need to be parsed.
* @mask: mask of voltages available for MMC/SD/SDIO
*
* 1. Return zero on success.
* 2. Return negative errno: voltage-range is invalid.
*/
int mmc_of_parse_voltage(struct device_node *np, u32 *mask)
{
const u32 *voltage_ranges;
int num_ranges, i;
voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
if (!voltage_ranges || !num_ranges) {
pr_info("%s: voltage-ranges unspecified\n", np->full_name);
return -EINVAL;
}
for (i = 0; i < num_ranges; i++) {
const int j = i * 2;
u32 ocr_mask;
ocr_mask = mmc_vddrange_to_ocrmask(
be32_to_cpu(voltage_ranges[j]),
be32_to_cpu(voltage_ranges[j + 1]));
if (!ocr_mask) {
pr_err("%s: voltage-range #%d is invalid\n",
np->full_name, i);
return -EINVAL;
}
*mask |= ocr_mask;
}
return 0;
}
EXPORT_SYMBOL(mmc_of_parse_voltage);
#endif /* CONFIG_OF */
#ifdef CONFIG_REGULATOR
/**

2
include/linux/mmc/core.h
View File

@ -208,6 +208,8 @@ static inline void mmc_claim_host(struct mmc_host *host)
__mmc_claim_host(host, NULL);
}
struct device_node;
extern u32 mmc_vddrange_to_ocrmask(int vdd_min, int vdd_max);
extern int mmc_of_parse_voltage(struct device_node *np, u32 *mask);
#endif /* LINUX_MMC_CORE_H */