--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Rockchip OTP Driver
+ *
+ * Copyright (c) 2018 Rockchip Electronics Co. Ltd.
+ * Author: Finley Xiao <finley.xiao@rock-chips.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+/* OTP Register Offsets */
+#define OTPC_SBPI_CTRL 0x0020
+#define OTPC_SBPI_CMD_VALID_PRE 0x0024
+#define OTPC_SBPI_CS_VALID_PRE 0x0028
+#define OTPC_SBPI_STATUS 0x002C
+#define OTPC_USER_CTRL 0x0100
+#define OTPC_USER_ADDR 0x0104
+#define OTPC_USER_ENABLE 0x0108
+#define OTPC_USER_Q 0x0124
+#define OTPC_INT_STATUS 0x0304
+#define OTPC_SBPI_CMD0_OFFSET 0x1000
+#define OTPC_SBPI_CMD1_OFFSET 0x1004
+
+/* OTP Register bits and masks */
+#define OTPC_USER_ADDR_MASK GENMASK(31, 16)
+#define OTPC_USE_USER BIT(0)
+#define OTPC_USE_USER_MASK GENMASK(16, 16)
+#define OTPC_USER_FSM_ENABLE BIT(0)
+#define OTPC_USER_FSM_ENABLE_MASK GENMASK(16, 16)
+#define OTPC_SBPI_DONE BIT(1)
+#define OTPC_USER_DONE BIT(2)
+
+#define SBPI_DAP_ADDR 0x02
+#define SBPI_DAP_ADDR_SHIFT 8
+#define SBPI_DAP_ADDR_MASK GENMASK(31, 24)
+#define SBPI_CMD_VALID_MASK GENMASK(31, 16)
+#define SBPI_DAP_CMD_WRF 0xC0
+#define SBPI_DAP_REG_ECC 0x3A
+#define SBPI_ECC_ENABLE 0x00
+#define SBPI_ECC_DISABLE 0x09
+#define SBPI_ENABLE BIT(0)
+#define SBPI_ENABLE_MASK GENMASK(16, 16)
+
+#define OTPC_TIMEOUT 10000
+
+struct rockchip_otp {
+ struct device *dev;
+ void __iomem *base;
+ struct clk_bulk_data *clks;
+ int num_clks;
+ struct reset_control *rst;
+};
+
+/* list of required clocks */
+static const char * const rockchip_otp_clocks[] = {
+ "otp", "apb_pclk", "phy",
+};
+
+struct rockchip_data {
+ int size;
+};
+
+static int rockchip_otp_reset(struct rockchip_otp *otp)
+{
+ int ret;
+
+ ret = reset_control_assert(otp->rst);
+ if (ret) {
+ dev_err(otp->dev, "failed to assert otp phy %d\n", ret);
+ return ret;
+ }
+
+ udelay(2);
+
+ ret = reset_control_deassert(otp->rst);
+ if (ret) {
+ dev_err(otp->dev, "failed to deassert otp phy %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rockchip_otp_wait_status(struct rockchip_otp *otp, u32 flag)
+{
+ u32 status = 0;
+ int ret;
+
+ ret = readl_poll_timeout_atomic(otp->base + OTPC_INT_STATUS, status,
+ (status & flag), 1, OTPC_TIMEOUT);
+ if (ret)
+ return ret;
+
+ /* clean int status */
+ writel(flag, otp->base + OTPC_INT_STATUS);
+
+ return 0;
+}
+
+static int rockchip_otp_ecc_enable(struct rockchip_otp *otp, bool enable)
+{
+ int ret = 0;
+
+ writel(SBPI_DAP_ADDR_MASK | (SBPI_DAP_ADDR << SBPI_DAP_ADDR_SHIFT),
+ otp->base + OTPC_SBPI_CTRL);
+
+ writel(SBPI_CMD_VALID_MASK | 0x1, otp->base + OTPC_SBPI_CMD_VALID_PRE);
+ writel(SBPI_DAP_CMD_WRF | SBPI_DAP_REG_ECC,
+ otp->base + OTPC_SBPI_CMD0_OFFSET);
+ if (enable)
+ writel(SBPI_ECC_ENABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);
+ else
+ writel(SBPI_ECC_DISABLE, otp->base + OTPC_SBPI_CMD1_OFFSET);
+
+ writel(SBPI_ENABLE_MASK | SBPI_ENABLE, otp->base + OTPC_SBPI_CTRL);
+
+ ret = rockchip_otp_wait_status(otp, OTPC_SBPI_DONE);
+ if (ret < 0)
+ dev_err(otp->dev, "timeout during ecc_enable\n");
+
+ return ret;
+}
+
+static int rockchip_otp_read(void *context, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct rockchip_otp *otp = context;
+ u8 *buf = val;
+ int ret = 0;
+
+ ret = clk_bulk_prepare_enable(otp->num_clks, otp->clks);
+ if (ret < 0) {
+ dev_err(otp->dev, "failed to prepare/enable clks\n");
+ return ret;
+ }
+
+ ret = rockchip_otp_reset(otp);
+ if (ret) {
+ dev_err(otp->dev, "failed to reset otp phy\n");
+ goto disable_clks;
+ }
+
+ ret = rockchip_otp_ecc_enable(otp, false);
+ if (ret < 0) {
+ dev_err(otp->dev, "rockchip_otp_ecc_enable err\n");
+ goto disable_clks;
+ }
+
+ writel(OTPC_USE_USER | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
+ udelay(5);
+ while (bytes--) {
+ writel(offset++ | OTPC_USER_ADDR_MASK,
+ otp->base + OTPC_USER_ADDR);
+ writel(OTPC_USER_FSM_ENABLE | OTPC_USER_FSM_ENABLE_MASK,
+ otp->base + OTPC_USER_ENABLE);
+ ret = rockchip_otp_wait_status(otp, OTPC_USER_DONE);
+ if (ret < 0) {
+ dev_err(otp->dev, "timeout during read setup\n");
+ goto read_end;
+ }
+ *buf++ = readb(otp->base + OTPC_USER_Q);
+ }
+
+read_end:
+ writel(0x0 | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
+disable_clks:
+ clk_bulk_disable_unprepare(otp->num_clks, otp->clks);
+
+ return ret;
+}
+
+static struct nvmem_config otp_config = {
+ .name = "rockchip-otp",
+ .owner = THIS_MODULE,
+ .read_only = true,
+ .stride = 1,
+ .word_size = 1,
+ .reg_read = rockchip_otp_read,
+};
+
+static const struct rockchip_data px30_data = {
+ .size = 0x40,
+};
+
+static const struct of_device_id rockchip_otp_match[] = {
+ {
+ .compatible = "rockchip,px30-otp",
+ .data = (void *)&px30_data,
+ },
+ {
+ .compatible = "rockchip,rk3308-otp",
+ .data = (void *)&px30_data,
+ },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, rockchip_otp_match);
+
+static int rockchip_otp_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rockchip_otp *otp;
+ const struct rockchip_data *data;
+ struct nvmem_device *nvmem;
+ int ret, i;
+
+ data = of_device_get_match_data(dev);
+ if (!data) {
+ dev_err(dev, "failed to get match data\n");
+ return -EINVAL;
+ }
+
+ otp = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_otp),
+ GFP_KERNEL);
+ if (!otp)
+ return -ENOMEM;
+
+ otp->dev = dev;
+ otp->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(otp->base))
+ return PTR_ERR(otp->base);
+
+ otp->num_clks = ARRAY_SIZE(rockchip_otp_clocks);
+ otp->clks = devm_kcalloc(dev, otp->num_clks,
+ sizeof(*otp->clks), GFP_KERNEL);
+ if (!otp->clks)
+ return -ENOMEM;
+
+ for (i = 0; i < otp->num_clks; ++i)
+ otp->clks[i].id = rockchip_otp_clocks[i];
+
+ ret = devm_clk_bulk_get(dev, otp->num_clks, otp->clks);
+ if (ret)
+ return ret;
+
+ otp->rst = devm_reset_control_get(dev, "phy");
+ if (IS_ERR(otp->rst))
+ return PTR_ERR(otp->rst);
+
+ otp_config.size = data->size;
+ otp_config.priv = otp;
+ otp_config.dev = dev;
+ nvmem = devm_nvmem_register(dev, &otp_config);
+
+ return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static struct platform_driver rockchip_otp_driver = {
+ .probe = rockchip_otp_probe,
+ .driver = {
+ .name = "rockchip-otp",
+ .of_match_table = rockchip_otp_match,
+ },
+};
+
+module_platform_driver(rockchip_otp_driver);
+MODULE_DESCRIPTION("Rockchip OTP driver");
+MODULE_LICENSE("GPL v2");
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