nvmem: add driver for ocotp in i.MX23 and i.MX28 (c01e9a11) · Commits · e / devices / android_kernel_teracube_mt6765

drivers/nvmem/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,17 @@ config NVMEM_IMX_OCOTP
		This driver can also be built as a module. If so, the module
		will be called nvmem-imx-ocotp.

		config NVMEM_MXS_OCOTP
		tristate "Freescale MXS On-Chip OTP Memory Support"
		depends on ARCH_MXS \|\| COMPILE_TEST
		help
		If you say Y here, you will get readonly access to the
		One Time Programmable memory pages that are stored
		on the Freescale i.MX23/i.MX28 processor.

		This driver can also be built as a module. If so, the module
		will be called nvmem-mxs-ocotp.

		config QCOM_QFPROM
		tristate "QCOM QFPROM Support"
		depends on ARCH_QCOM \|\| COMPILE_TEST

drivers/nvmem/Makefile

+2 −0

Original line number	Diff line number	Diff line
		@@ -8,6 +8,8 @@ nvmem_core-y := core.o
		# Devices
		obj-$(CONFIG_NVMEM_IMX_OCOTP) += nvmem-imx-ocotp.o
		nvmem-imx-ocotp-y := imx-ocotp.o
		obj-$(CONFIG_NVMEM_MXS_OCOTP) += nvmem-mxs-ocotp.o
		nvmem-mxs-ocotp-y := mxs-ocotp.o
		obj-$(CONFIG_QCOM_QFPROM) += nvmem_qfprom.o
		nvmem_qfprom-y := qfprom.o
		obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o

drivers/nvmem/mxs-ocotp.c

0 → 100644

+257 −0

Original line number	Diff line number	Diff line
		/*
		* Freescale MXS On-Chip OTP driver
		*
		* Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com>
		*
		* Based on the driver from Huang Shijie and Christoph G. Baumann
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* 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/clk.h>
		#include <linux/delay.h>
		#include <linux/device.h>
		#include <linux/err.h>
		#include <linux/io.h>
		#include <linux/module.h>
		#include <linux/nvmem-provider.h>
		#include <linux/of_device.h>
		#include <linux/platform_device.h>
		#include <linux/regmap.h>
		#include <linux/slab.h>
		#include <linux/stmp_device.h>

		/* OCOTP registers and bits */

		#define BM_OCOTP_CTRL_RD_BANK_OPEN BIT(12)
		#define BM_OCOTP_CTRL_ERROR BIT(9)
		#define BM_OCOTP_CTRL_BUSY BIT(8)

		#define OCOTP_TIMEOUT 10000
		#define OCOTP_DATA_OFFSET 0x20

		struct mxs_ocotp {
		struct clk *clk;
		void __iomem *base;
		struct nvmem_device *nvmem;
		};

		static int mxs_ocotp_wait(struct mxs_ocotp *otp)
		{
		int timeout = OCOTP_TIMEOUT;
		unsigned int status = 0;

		while (timeout--) {
		status = readl(otp->base);

		if (!(status & (BM_OCOTP_CTRL_BUSY \| BM_OCOTP_CTRL_ERROR)))
		break;

		cpu_relax();
		}

		if (status & BM_OCOTP_CTRL_BUSY)
		return -EBUSY;
		else if (status & BM_OCOTP_CTRL_ERROR)
		return -EIO;

		return 0;
		}

		static int mxs_ocotp_read(void context, const void reg, size_t reg_size,
		void *val, size_t val_size)
		{
		struct mxs_ocotp *otp = context;
		unsigned int offset = (u32 )reg;
		u32 *buf = val;
		int ret;

		ret = clk_enable(otp->clk);
		if (ret)
		return ret;

		writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR);

		ret = mxs_ocotp_wait(otp);
		if (ret)
		goto disable_clk;

		/* open OCOTP banks for read */
		writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET);

		/* approximately wait 33 hclk cycles */
		udelay(1);

		ret = mxs_ocotp_wait(otp);
		if (ret)
		goto close_banks;

		while (val_size) {
		if ((offset < OCOTP_DATA_OFFSET) \|\| (offset % 16)) {
		/* fill up non-data register */
		*buf = 0;
		} else {
		*buf = readl(otp->base + offset);
		}

		buf++;
		val_size--;
		offset += reg_size;
		}

		close_banks:
		/* close banks for power saving */
		writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR);

		disable_clk:
		clk_disable(otp->clk);

		return ret;
		}

		static int mxs_ocotp_write(void context, const void data, size_t count)
		{
		/* We don't want to support writing */
		return 0;
		}

		static bool mxs_ocotp_writeable_reg(struct device *dev, unsigned int reg)
		{
		return false;
		}

		static struct nvmem_config ocotp_config = {
		.name = "mxs-ocotp",
		.owner = THIS_MODULE,
		};

		static const struct regmap_range imx23_ranges[] = {
		regmap_reg_range(OCOTP_DATA_OFFSET, 0x210),
		};

		static const struct regmap_access_table imx23_access = {
		.yes_ranges = imx23_ranges,
		.n_yes_ranges = ARRAY_SIZE(imx23_ranges),
		};

		static const struct regmap_range imx28_ranges[] = {
		regmap_reg_range(OCOTP_DATA_OFFSET, 0x290),
		};

		static const struct regmap_access_table imx28_access = {
		.yes_ranges = imx28_ranges,
		.n_yes_ranges = ARRAY_SIZE(imx28_ranges),
		};

		static struct regmap_bus mxs_ocotp_bus = {
		.read = mxs_ocotp_read,
		.write = mxs_ocotp_write, /* make regmap_init() happy */
		.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
		.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
		};

		static struct regmap_config mxs_ocotp_config = {
		.reg_bits = 32,
		.val_bits = 32,
		.reg_stride = 16,
		.writeable_reg = mxs_ocotp_writeable_reg,
		};

		static const struct of_device_id mxs_ocotp_match[] = {
		{ .compatible = "fsl,imx23-ocotp", .data = &imx23_access },
		{ .compatible = "fsl,imx28-ocotp", .data = &imx28_access },
		{ /* sentinel */},
		};
		MODULE_DEVICE_TABLE(of, mxs_ocotp_match);

		static int mxs_ocotp_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct mxs_ocotp *otp;
		struct resource *res;
		const struct of_device_id *match;
		struct regmap *regmap;
		const struct regmap_access_table *access;
		int ret;

		match = of_match_device(dev->driver->of_match_table, dev);
		if (!match \|\| !match->data)
		return -EINVAL;

		otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL);
		if (!otp)
		return -ENOMEM;

		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		otp->base = devm_ioremap_resource(dev, res);
		if (IS_ERR(otp->base))
		return PTR_ERR(otp->base);

		otp->clk = devm_clk_get(&pdev->dev, NULL);
		if (IS_ERR(otp->clk))
		return PTR_ERR(otp->clk);

		ret = clk_prepare(otp->clk);
		if (ret < 0) {
		dev_err(dev, "failed to prepare clk: %d\n", ret);
		return ret;
		}

		access = match->data;
		mxs_ocotp_config.rd_table = access;
		mxs_ocotp_config.max_register = access->yes_ranges[0].range_max;

		regmap = devm_regmap_init(dev, &mxs_ocotp_bus, otp, &mxs_ocotp_config);
		if (IS_ERR(regmap)) {
		dev_err(dev, "regmap init failed\n");
		ret = PTR_ERR(regmap);
		goto err_clk;
		}

		ocotp_config.dev = dev;
		otp->nvmem = nvmem_register(&ocotp_config);
		if (IS_ERR(otp->nvmem)) {
		ret = PTR_ERR(otp->nvmem);
		goto err_clk;
		}

		platform_set_drvdata(pdev, otp);

		return 0;

		err_clk:
		clk_unprepare(otp->clk);

		return ret;
		}

		static int mxs_ocotp_remove(struct platform_device *pdev)
		{
		struct mxs_ocotp *otp = platform_get_drvdata(pdev);

		clk_unprepare(otp->clk);

		return nvmem_unregister(otp->nvmem);
		}

		static struct platform_driver mxs_ocotp_driver = {
		.probe = mxs_ocotp_probe,
		.remove = mxs_ocotp_remove,
		.driver = {
		.name = "mxs-ocotp",
		.of_match_table = mxs_ocotp_match,
		},
		};

		module_platform_driver(mxs_ocotp_driver);
		MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
		MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
		MODULE_LICENSE("GPL v2");