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Commit 6e9e318b authored by Haijun Zhang's avatar Haijun Zhang Committed by Chris Ball
Browse files

mmc: core: parse voltage from device-tree 



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: default avatarHaijun Zhang <haijun.zhang@freescale.com>
Acked-by: default avatarAnton Vorontsov <anton@enomsg.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent bcf24e1d

Documentation/devicetree/bindings/mmc/fsl-esdhc.txt

+4 −0
Original line number Diff line number Diff line
@@ -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>;

};

drivers/mmc/core/core.c

+44 −0
Original line number Diff line number Diff line
@@ -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



/**

include/linux/mmc/core.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */