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nvmem: add a driver for the Amlogic Meson6/Meson8/Meson8b SoCs
This adds a driver to access the efuse on Amlogic Meson6, Meson8 and Meson8b SoCs. These SoCs are accessing the efuse IP block directly through the registers in the "secbus" region. This makes it different from the Meson GX efuse driver which uses the "secure monitor" firmware to access the efuse. The efuse on Meson6 can only read one byte at a time, while the efuse on Meson8 and Meson8b always reads 4 bytes at a time. The new driver supports both, but due to lack of hardware Meson6 support was not tested. The hardware also supports writing. However, this is currently not supported by the driver. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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‎drivers/nvmem/Kconfig

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@@ -144,6 +144,16 @@ config MESON_EFUSE
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This driver can also be built as a module. If so, the module
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will be called nvmem_meson_efuse.
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config MESON_MX_EFUSE
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tristate "Amlogic Meson6/Meson8/Meson8b eFuse Support"
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depends on ARCH_MESON || COMPILE_TEST
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help
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This is a driver to retrieve specific values from the eFuse found on
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the Amlogic Meson6, Meson8 and Meson8b SoCs.
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This driver can also be built as a module. If so, the module
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will be called nvmem_meson_mx_efuse.
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config NVMEM_SNVS_LPGPR
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tristate "Support for Low Power General Purpose Register"
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depends on SOC_IMX6 || COMPILE_TEST

‎drivers/nvmem/Makefile

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@@ -30,5 +30,7 @@ obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
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nvmem-vf610-ocotp-y := vf610-ocotp.o
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obj-$(CONFIG_MESON_EFUSE) += nvmem_meson_efuse.o
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nvmem_meson_efuse-y := meson-efuse.o
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obj-$(CONFIG_MESON_MX_EFUSE) += nvmem_meson_mx_efuse.o
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nvmem_meson_mx_efuse-y := meson-mx-efuse.o
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obj-$(CONFIG_NVMEM_SNVS_LPGPR) += nvmem_snvs_lpgpr.o
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nvmem_snvs_lpgpr-y := snvs_lpgpr.o

‎drivers/nvmem/meson-mx-efuse.c

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/*
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* Amlogic Meson6, Meson8 and Meson8b eFuse Driver
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*
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* Copyright (c) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/bitfield.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/nvmem-provider.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/sizes.h>
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#include <linux/slab.h>
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#define MESON_MX_EFUSE_CNTL1 0x04
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#define MESON_MX_EFUSE_CNTL1_PD_ENABLE BIT(27)
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#define MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY BIT(26)
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#define MESON_MX_EFUSE_CNTL1_AUTO_RD_START BIT(25)
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#define MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE BIT(24)
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#define MESON_MX_EFUSE_CNTL1_BYTE_WR_DATA GENMASK(23, 16)
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#define MESON_MX_EFUSE_CNTL1_AUTO_WR_BUSY BIT(14)
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#define MESON_MX_EFUSE_CNTL1_AUTO_WR_START BIT(13)
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#define MESON_MX_EFUSE_CNTL1_AUTO_WR_ENABLE BIT(12)
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#define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET BIT(11)
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#define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK GENMASK(10, 0)
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#define MESON_MX_EFUSE_CNTL2 0x08
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#define MESON_MX_EFUSE_CNTL4 0x10
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#define MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE BIT(10)
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struct meson_mx_efuse_platform_data {
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const char *name;
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unsigned int word_size;
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};
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struct meson_mx_efuse {
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void __iomem *base;
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struct clk *core_clk;
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struct nvmem_device *nvmem;
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struct nvmem_config config;
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};
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static void meson_mx_efuse_mask_bits(struct meson_mx_efuse *efuse, u32 reg,
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u32 mask, u32 set)
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{
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u32 data;
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data = readl(efuse->base + reg);
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data &= ~mask;
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data |= (set & mask);
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writel(data, efuse->base + reg);
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}
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static int meson_mx_efuse_hw_enable(struct meson_mx_efuse *efuse)
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{
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int err;
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err = clk_prepare_enable(efuse->core_clk);
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if (err)
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return err;
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/* power up the efuse */
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_PD_ENABLE, 0);
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL4,
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MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE, 0);
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return 0;
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}
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static void meson_mx_efuse_hw_disable(struct meson_mx_efuse *efuse)
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{
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_PD_ENABLE,
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MESON_MX_EFUSE_CNTL1_PD_ENABLE);
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clk_disable_unprepare(efuse->core_clk);
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}
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static int meson_mx_efuse_read_addr(struct meson_mx_efuse *efuse,
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unsigned int addr, u32 *value)
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{
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int err;
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u32 regval;
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/* write the address to read */
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regval = FIELD_PREP(MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, addr);
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, regval);
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/* inform the hardware that we changed the address */
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET,
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MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET);
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET, 0);
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/* start the read process */
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_START,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_START);
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_START, 0);
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/*
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* perform a dummy read to ensure that the HW has the RD_BUSY bit set
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* when polling for the status below.
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*/
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readl(efuse->base + MESON_MX_EFUSE_CNTL1);
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err = readl_poll_timeout_atomic(efuse->base + MESON_MX_EFUSE_CNTL1,
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regval,
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(!(regval & MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY)),
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1, 1000);
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if (err) {
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dev_err(efuse->config.dev,
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"Timeout while reading efuse address %u\n", addr);
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return err;
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}
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*value = readl(efuse->base + MESON_MX_EFUSE_CNTL2);
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return 0;
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}
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static int meson_mx_efuse_read(void *context, unsigned int offset,
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void *buf, size_t bytes)
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{
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struct meson_mx_efuse *efuse = context;
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u32 tmp;
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int err, i, addr;
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err = meson_mx_efuse_hw_enable(efuse);
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if (err)
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return err;
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE);
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for (i = offset; i < offset + bytes; i += efuse->config.word_size) {
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addr = i / efuse->config.word_size;
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err = meson_mx_efuse_read_addr(efuse, addr, &tmp);
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if (err)
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break;
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memcpy(buf + i, &tmp, efuse->config.word_size);
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}
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meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
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MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE, 0);
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meson_mx_efuse_hw_disable(efuse);
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return err;
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}
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static const struct meson_mx_efuse_platform_data meson6_efuse_data = {
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.name = "meson6-efuse",
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.word_size = 1,
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};
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static const struct meson_mx_efuse_platform_data meson8_efuse_data = {
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.name = "meson8-efuse",
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.word_size = 4,
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};
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static const struct meson_mx_efuse_platform_data meson8b_efuse_data = {
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.name = "meson8b-efuse",
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.word_size = 4,
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};
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static const struct of_device_id meson_mx_efuse_match[] = {
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{ .compatible = "amlogic,meson6-efuse", .data = &meson6_efuse_data },
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{ .compatible = "amlogic,meson8-efuse", .data = &meson8_efuse_data },
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{ .compatible = "amlogic,meson8b-efuse", .data = &meson8b_efuse_data },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, meson_mx_efuse_match);
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static int meson_mx_efuse_probe(struct platform_device *pdev)
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{
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const struct meson_mx_efuse_platform_data *drvdata;
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struct meson_mx_efuse *efuse;
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struct resource *res;
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drvdata = of_device_get_match_data(&pdev->dev);
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if (!drvdata)
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return -EINVAL;
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efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
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if (!efuse)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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efuse->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(efuse->base))
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return PTR_ERR(efuse->base);
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efuse->config.name = devm_kstrdup(&pdev->dev, drvdata->name,
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GFP_KERNEL);
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efuse->config.owner = THIS_MODULE;
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efuse->config.dev = &pdev->dev;
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efuse->config.priv = efuse;
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efuse->config.stride = drvdata->word_size;
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efuse->config.word_size = drvdata->word_size;
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efuse->config.size = SZ_512;
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efuse->config.read_only = true;
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efuse->config.reg_read = meson_mx_efuse_read;
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efuse->core_clk = devm_clk_get(&pdev->dev, "core");
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if (IS_ERR(efuse->core_clk)) {
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dev_err(&pdev->dev, "Failed to get core clock\n");
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return PTR_ERR(efuse->core_clk);
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}
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efuse->nvmem = nvmem_register(&efuse->config);
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if (IS_ERR(efuse->nvmem))
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return PTR_ERR(efuse->nvmem);
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platform_set_drvdata(pdev, efuse);
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return 0;
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}
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static int meson_mx_efuse_remove(struct platform_device *pdev)
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{
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struct meson_mx_efuse *efuse = platform_get_drvdata(pdev);
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return nvmem_unregister(efuse->nvmem);
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}
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static struct platform_driver meson_mx_efuse_driver = {
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.probe = meson_mx_efuse_probe,
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.remove = meson_mx_efuse_remove,
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.driver = {
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.name = "meson-mx-efuse",
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.of_match_table = meson_mx_efuse_match,
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},
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};
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module_platform_driver(meson_mx_efuse_driver);
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MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
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MODULE_DESCRIPTION("Amlogic Meson MX eFuse NVMEM driver");
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MODULE_LICENSE("GPL v2");

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