MLK-16204-1 nvmem: add imx-scu-ocotp driver

Add imx-scu-ocotp driver to support i.MX8QM/QXP.

The usage, add an entry in ocotp node, such as the test_1 entry:
	ocotp: ocotp {
               #address-cells = <1>;
               #size-cells = <1>;
               compatible = "fsl,imx8qm-ocotp", "syscon";

               test_1: test_1@40 {
                       reg = <0x41 0x8>;
                       bits = <4 40>;
               };
       };

Then in your device node, add this:
       node: node {
	        .....
                nvmem-cells = <&test_1>;
                nvmem-cell-names = "test_1";
       };

Then in your driver, using the following piece code:

       +#include <linux/nvmem-consumer.h>

       struct nvmem_cell *cell;
       u8 *val;
       size_t len;
       int i;
       cell = devm_nvmem_cell_get(&pdev->dev, "test_1");
       if (IS_ERR(cell)) {
               if (PTR_ERR(cell) == -EPROBE_DEFER)
                       return -EPROBE_DEFER;
       }
       val = nvmem_cell_read(cell, &len);

The val points the contents that you need.

After shutdown or driver remove, use this:
       devm_nvmem_cell_put(&pdev->dev, cell);

Note: we not reuse the imx-ocotp driver, because mix scu api with
legacy code will cost many maintenance efforts. When we have common
api support, we could merge the two.

Signed-off-by: Peng Fan <peng.fan@nxp.com>

3 files changed, 165 insertions, 0 deletions

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index ba140eaee5c8..29601e0b3e42 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -25,6 +25,18 @@ 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_IMX_SCU_OCOTP
+	tristate "i.MX8QM On-Chip OTP Controller support"
+	depends on ARCH_MXC_ARM64|| COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  This is a driver for the On-Chip OTP Controller (OCOTP) available on
+	  i.MX6 SoCs, providing access to 4 Kbits of one-time programmable
+	  eFuses.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem-imx-ocotp.
+
 config NVMEM_LPC18XX_EEPROM
 	tristate "NXP LPC18XX EEPROM Memory Support"
 	depends on ARCH_LPC18XX || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 8f942a0cdaec..dc6494bf7e05 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -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_IMX_SCU_OCOTP) += nvmem-imx-scu-ocotp.o
+nvmem-imx-scu-ocotp-y		:= imx-scu-ocotp.o
 obj-$(CONFIG_NVMEM_LPC18XX_EEPROM)	+= nvmem_lpc18xx_eeprom.o
 nvmem_lpc18xx_eeprom-y	:= lpc18xx_eeprom.o
 obj-$(CONFIG_NVMEM_MXS_OCOTP)	+= nvmem-mxs-ocotp.o
diff --git a/drivers/nvmem/imx-scu-ocotp.c b/drivers/nvmem/imx-scu-ocotp.c
new file mode 100644
index 000000000000..8c622df1ca54
--- /dev/null
+++ b/drivers/nvmem/imx-scu-ocotp.c
@@ -0,0 +1,151 @@
+/*
+ * i.MX6 OCOTP fusebox driver
+ *
+ * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
+ *
+ * Based on the barebox ocotp driver,
+ * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
+ *	Orex Computed Radiography
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <soc/imx8/sc/sci.h>
+
+struct ocotp_priv {
+	struct device *dev;
+	unsigned int nregs;
+	sc_ipc_t nvmem_ipc;
+};
+
+static int imx_scu_ocotp_read(void *context, unsigned int offset,
+			      void *val, size_t bytes)
+{
+	struct ocotp_priv *priv = context;
+	sc_err_t sciErr = SC_ERR_NONE;
+	unsigned int count;
+	u32 index;
+	u32 num_bytes;
+	int i;
+	u8 *buf, *p;
+
+	index = offset >> 2;
+	num_bytes = round_up((offset % 4) + bytes, 4);
+	count = num_bytes >> 2;
+
+	if (count > (priv->nregs - index))
+		count = priv->nregs - index;
+
+	p = kzalloc(num_bytes, GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	buf = p;
+
+	for (i = index; i < (index + count); i++) {
+		sciErr = sc_misc_otp_fuse_read(priv->nvmem_ipc, i, (u32 *)buf);
+		if (sciErr != SC_ERR_NONE) {
+			kfree(p);
+			return -EIO;
+		}
+		buf += 4;
+	}
+
+	index = offset % 4;
+	memcpy(val, &p[index], bytes);
+
+	kfree(p);
+
+	return 0;
+}
+
+static struct nvmem_config imx_scu_ocotp_nvmem_config = {
+	.name = "imx-ocotp",
+	.read_only = true,
+	.word_size = 4,
+	.stride = 1,
+	.owner = THIS_MODULE,
+	.reg_read = imx_scu_ocotp_read,
+};
+
+static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
+	{ .compatible = "fsl,imx8qm-ocotp", (void *)800 },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, imx_scu_ocotp_dt_ids);
+
+static int imx_scu_ocotp_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id;
+	struct device *dev = &pdev->dev;
+	struct ocotp_priv *priv;
+	struct nvmem_device *nvmem;
+	uint32_t mu_id;
+	sc_err_t sciErr = SC_ERR_NONE;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	sciErr = sc_ipc_getMuID(&mu_id);
+	if (sciErr != SC_ERR_NONE) {
+		pr_info("pinctrl: Cannot obtain MU ID\n");
+		return -EIO;
+	}
+
+	sciErr = sc_ipc_open(&priv->nvmem_ipc, mu_id);
+
+	if (sciErr != SC_ERR_NONE) {
+		pr_info("pinctrl: Cannot open MU channel to SCU\n");
+		return -EIO;
+	};
+
+	of_id = of_match_device(imx_scu_ocotp_dt_ids, dev);
+	priv->nregs = (unsigned long)of_id->data;
+	priv->dev = dev;
+	imx_scu_ocotp_nvmem_config.size = 4 * priv->nregs;
+	imx_scu_ocotp_nvmem_config.dev = dev;
+	imx_scu_ocotp_nvmem_config.priv = priv;
+	nvmem = nvmem_register(&imx_scu_ocotp_nvmem_config);
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	platform_set_drvdata(pdev, nvmem);
+
+	return 0;
+}
+
+static int imx_scu_ocotp_remove(struct platform_device *pdev)
+{
+	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+	return nvmem_unregister(nvmem);
+}
+
+static struct platform_driver imx_scu_ocotp_driver = {
+	.probe	= imx_scu_ocotp_probe,
+	.remove	= imx_scu_ocotp_remove,
+	.driver = {
+		.name	= "imx_scu_ocotp",
+		.of_match_table = imx_scu_ocotp_dt_ids,
+	},
+};
+module_platform_driver(imx_scu_ocotp_driver);
+
+MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
+MODULE_DESCRIPTION("i.MX8QM OCOTP fuse box driver");
+MODULE_LICENSE("GPL v2");