linux/drivers/nvmem/qfprom.c
Stephen Boyd 3b2b9ead32 nvmem: qfprom: Specify LE device endianness
The qfprom is a little endian device, but so far we've been
relying on the regmap mmio bus handling this for us without
explicitly stating that fact. After commit 4a98da2164cf
(regmap-mmio: Use native endianness for read/write, 2015-10-29),
the regmap mmio bus will read/write with the __raw_*() IO
accessors, instead of using the readl/writel() APIs that do
proper byte swapping for little endian devices.

So if we're running on a big endian processor and haven't
specified the endianness explicitly in the regmap config or in
DT, we're going to switch from doing little endian byte swapping
to big endian accesses without byte swapping, leading to some
confusing results. Specify the endianness explicitly so that the
regmap core properly byte swaps the accesses for us.

Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Tyler Baker <tyler.baker@linaro.org>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07 23:09:13 -08:00

87 lines
2.2 KiB
C

/*
* Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
static struct regmap_config qfprom_regmap_config = {
.reg_bits = 32,
.val_bits = 8,
.reg_stride = 1,
.val_format_endian = REGMAP_ENDIAN_LITTLE,
};
static struct nvmem_config econfig = {
.name = "qfprom",
.owner = THIS_MODULE,
};
static int qfprom_remove(struct platform_device *pdev)
{
struct nvmem_device *nvmem = platform_get_drvdata(pdev);
return nvmem_unregister(nvmem);
}
static int qfprom_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct resource *res;
struct nvmem_device *nvmem;
struct regmap *regmap;
void __iomem *base;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
qfprom_regmap_config.max_register = resource_size(res) - 1;
regmap = devm_regmap_init_mmio(dev, base, &qfprom_regmap_config);
if (IS_ERR(regmap)) {
dev_err(dev, "regmap init failed\n");
return PTR_ERR(regmap);
}
econfig.dev = dev;
nvmem = nvmem_register(&econfig);
if (IS_ERR(nvmem))
return PTR_ERR(nvmem);
platform_set_drvdata(pdev, nvmem);
return 0;
}
static const struct of_device_id qfprom_of_match[] = {
{ .compatible = "qcom,qfprom",},
{/* sentinel */},
};
MODULE_DEVICE_TABLE(of, qfprom_of_match);
static struct platform_driver qfprom_driver = {
.probe = qfprom_probe,
.remove = qfprom_remove,
.driver = {
.name = "qcom,qfprom",
.of_match_table = qfprom_of_match,
},
};
module_platform_driver(qfprom_driver);
MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org>");
MODULE_DESCRIPTION("Qualcomm QFPROM driver");
MODULE_LICENSE("GPL v2");