forked from Minki/linux
b6b7ef932a
Apple SoCs contain eFuses used to store factory-programmed data such as calibration values for the PCIe or the Type-C PHY. They are organized as 32bit values exposed as MMIO. Signed-off-by: Sven Peter <sven@svenpeter.dev> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20220429162701.2222-6-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Apple SoC eFuse driver
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*
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* Copyright (C) The Asahi Linux Contributors
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*/
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#include <linux/io.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/nvmem-provider.h>
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#include <linux/platform_device.h>
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struct apple_efuses_priv {
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void __iomem *fuses;
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};
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static int apple_efuses_read(void *context, unsigned int offset, void *val,
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size_t bytes)
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{
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struct apple_efuses_priv *priv = context;
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u32 *dst = val;
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while (bytes >= sizeof(u32)) {
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*dst++ = readl_relaxed(priv->fuses + offset);
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bytes -= sizeof(u32);
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offset += sizeof(u32);
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}
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return 0;
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}
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static int apple_efuses_probe(struct platform_device *pdev)
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{
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struct apple_efuses_priv *priv;
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struct resource *res;
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struct nvmem_config config = {
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.dev = &pdev->dev,
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.read_only = true,
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.reg_read = apple_efuses_read,
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.stride = sizeof(u32),
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.word_size = sizeof(u32),
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.name = "apple_efuses_nvmem",
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.id = NVMEM_DEVID_AUTO,
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.root_only = true,
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};
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priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->fuses = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
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if (IS_ERR(priv->fuses))
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return PTR_ERR(priv->fuses);
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config.priv = priv;
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config.size = resource_size(res);
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return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
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}
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static const struct of_device_id apple_efuses_of_match[] = {
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{ .compatible = "apple,efuses", },
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{}
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};
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MODULE_DEVICE_TABLE(of, apple_efuses_of_match);
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static struct platform_driver apple_efuses_driver = {
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.driver = {
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.name = "apple_efuses",
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.of_match_table = apple_efuses_of_match,
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},
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.probe = apple_efuses_probe,
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};
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module_platform_driver(apple_efuses_driver);
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MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
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MODULE_LICENSE("GPL");
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