[PATCH v4 0/2] nvmem: lan9662-otpc: add support

[PATCH v4 0/2] nvmem: lan9662-otpc: add support

[Horatiu Vultur]

Add support for lan9662 OTP controller that is available on lan9662.
The driver gives access to non-volatile memory. It allows both write
and read access to it.

v3->v4:
- remove lan9668 compatible string from driver
- fix the bindings by changing the order of entries under items for
  compatible property

v2->v3:
- fix dt-bindings, make sure that make dt_binding_check passes
- remove lan9662_writel/readl/clrbits/setbits and use writel/readl
- remove WARN_ON(offset >= OTP_MEM_SIZE) as it can't happen

v1->v2:
- remove unneed quotes for $ref: nvmem.yaml#
- rename lan966x to lan9662 as not to have any wildcards
- remove compatible string syscon

Horatiu Vultur (2):
  dt-bindings: lan9662-otpc: document Lan9662 OTPC
  nvmem: lan9662-otp: add support.

 .../nvmem/microchip,lan9662-otpc.yaml         |  45 ++++
 drivers/nvmem/Kconfig                         |   8 +
 drivers/nvmem/Makefile                        |   2 +
 drivers/nvmem/lan9662-otpc.c                  | 222 ++++++++++++++++++
 4 files changed, 277 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/microchip,lan9662-otpc.yaml
 create mode 100644 drivers/nvmem/lan9662-otpc.c

-- 
2.33.0

[PATCH v4 1/2] dt-bindings: lan9662-otpc: document Lan9662 OTPC

[Horatiu Vultur]

Document Lan9662 OTP controller.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 .../nvmem/microchip,lan9662-otpc.yaml         | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/microchip,lan9662-otpc.yaml

diff --git a/Documentation/devicetree/bindings/nvmem/microchip,lan9662-otpc.yaml b/Documentation/devicetree/bindings/nvmem/microchip,lan9662-otpc.yaml
new file mode 100644
index 000000000000..f97c6beb4766
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/microchip,lan9662-otpc.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/microchip,lan9662-otpc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip LAN9662 OTP Controller (OTPC)
+
+maintainers:
+  - Horatiu Vultur <horatiu.vultur@microchip.com>
+
+description: |
+  OTP controller drives a NVMEM memory where system specific data
+  (e.g. hardware configuration settings, chip identifiers) or
+  user specific data could be stored.
+
+allOf:
+  - $ref: nvmem.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: microchip,lan9668-otpc
+          - const: microchip,lan9662-otpc
+      - enum:
+          - microchip,lan9662-otpc
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    otpc: otp@e0021000 {
+        compatible = "microchip,lan9662-otpc";
+        reg = <0xe0021000 0x300>;
+    };
+
+...
-- 
2.33.0

[PATCH v4 2/2] nvmem: lan9662-otp: add support.

[Horatiu Vultur]

Add support for OTP controller available on LAN9662. The OTPC controls
the access to a non-volatile memory. The size of the memory is 8KB.
The OTPC can access the memory based on an offset.
Implement both the read and the write functionality.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 drivers/nvmem/Kconfig        |   8 ++
 drivers/nvmem/Makefile       |   2 +
 drivers/nvmem/lan9662-otpc.c | 222 +++++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 drivers/nvmem/lan9662-otpc.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 967d0084800e..9399445a2f4c 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -84,6 +84,14 @@ config NVMEM_LPC18XX_OTP
 	  To compile this driver as a module, choose M here: the module
 	  will be called nvmem_lpc18xx_otp.
 
+config NVMEM_LAN9662_OTPC
+	tristate "Microchip LAN9662 OTP controller support"
+	depends on SOC_LAN966 || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  This driver enables the OTP controller available on Microchip LAN9662
+	  SoCs. It controls the access to the OTP memory connected to it.
+
 config NVMEM_MXS_OCOTP
 	tristate "Freescale MXS On-Chip OTP Memory Support"
 	depends on ARCH_MXS || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 00e136a0a123..e1baface2c53 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -21,6 +21,8 @@ obj-$(CONFIG_NVMEM_LPC18XX_EEPROM)	+= nvmem_lpc18xx_eeprom.o
 nvmem_lpc18xx_eeprom-y	:= lpc18xx_eeprom.o
 obj-$(CONFIG_NVMEM_LPC18XX_OTP)	+= nvmem_lpc18xx_otp.o
 nvmem_lpc18xx_otp-y		:= lpc18xx_otp.o
+obj-$(CONFIG_NVMEM_LAN9662_OTPC)	+= nvmem-lan9662-otpc.o
+nvmem-lan9662-otpc-y		:= lan9662-otpc.o
 obj-$(CONFIG_NVMEM_MXS_OCOTP)	+= nvmem-mxs-ocotp.o
 nvmem-mxs-ocotp-y		:= mxs-ocotp.o
 obj-$(CONFIG_NVMEM_NINTENDO_OTP)	+= nvmem-nintendo-otp.o
diff --git a/drivers/nvmem/lan9662-otpc.c b/drivers/nvmem/lan9662-otpc.c
new file mode 100644
index 000000000000..f6732fd216d8
--- /dev/null
+++ b/drivers/nvmem/lan9662-otpc.c
@@ -0,0 +1,222 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define OTP_OTP_PWR_DN(t)			(t + 0x00)
+#define OTP_OTP_PWR_DN_OTP_PWRDN_N		BIT(0)
+#define OTP_OTP_ADDR_HI(t)			(t + 0x04)
+#define OTP_OTP_ADDR_LO(t)			(t + 0x08)
+#define OTP_OTP_PRGM_DATA(t)			(t + 0x10)
+#define OTP_OTP_PRGM_MODE(t)			(t + 0x14)
+#define OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE	BIT(0)
+#define OTP_OTP_RD_DATA(t)			(t + 0x18)
+#define OTP_OTP_FUNC_CMD(t)			(t + 0x20)
+#define OTP_OTP_FUNC_CMD_OTP_PROGRAM		BIT(1)
+#define OTP_OTP_FUNC_CMD_OTP_READ		BIT(0)
+#define OTP_OTP_CMD_GO(t)			(t + 0x28)
+#define OTP_OTP_CMD_GO_OTP_GO			BIT(0)
+#define OTP_OTP_PASS_FAIL(t)			(t + 0x2c)
+#define OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED	BIT(3)
+#define OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED	BIT(2)
+#define OTP_OTP_PASS_FAIL_OTP_FAIL		BIT(0)
+#define OTP_OTP_STATUS(t)			(t + 0x30)
+#define OTP_OTP_STATUS_OTP_CPUMPEN		BIT(1)
+#define OTP_OTP_STATUS_OTP_BUSY			BIT(0)
+
+#define OTP_MEM_SIZE 8192
+#define OTP_SLEEP_US 10
+#define OTP_TIMEOUT_US 500000
+
+struct lan9662_otp {
+	struct device *dev;
+	void __iomem *base;
+};
+
+static bool lan9662_otp_wait_flag_clear(void __iomem *reg, u32 flag)
+{
+	u32 val;
+
+	return readl_poll_timeout(reg, val, !(val & flag),
+				  OTP_SLEEP_US, OTP_TIMEOUT_US);
+}
+
+static int lan9662_otp_power(struct lan9662_otp *otp, bool up)
+{
+	void __iomem *pwrdn = OTP_OTP_PWR_DN(otp->base);
+
+	if (up) {
+		writel(readl(pwrdn) & ~OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn);
+		if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base),
+						OTP_OTP_STATUS_OTP_CPUMPEN))
+			return -ETIMEDOUT;
+	} else {
+		writel(readl(pwrdn) | OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn);
+	}
+
+	return 0;
+}
+
+static int lan9662_otp_execute(struct lan9662_otp *otp)
+{
+	if (lan9662_otp_wait_flag_clear(OTP_OTP_CMD_GO(otp->base),
+					OTP_OTP_CMD_GO_OTP_GO))
+		return -ETIMEDOUT;
+
+	if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base),
+					OTP_OTP_STATUS_OTP_BUSY))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static void lan9662_otp_set_address(struct lan9662_otp *otp, u32 offset)
+{
+	writel(0xff & (offset >> 8), OTP_OTP_ADDR_HI(otp->base));
+	writel(0xff & offset, OTP_OTP_ADDR_LO(otp->base));
+}
+
+static int lan9662_otp_read_byte(struct lan9662_otp *otp, u32 offset, u8 *dst)
+{
+	u32 pass;
+	int rc;
+
+	lan9662_otp_set_address(otp, offset);
+	writel(OTP_OTP_FUNC_CMD_OTP_READ, OTP_OTP_FUNC_CMD(otp->base));
+	writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base));
+	rc = lan9662_otp_execute(otp);
+	if (!rc) {
+		pass = readl(OTP_OTP_PASS_FAIL(otp->base));
+		if (pass & OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED)
+			return -EACCES;
+		*dst = (u8) readl(OTP_OTP_RD_DATA(otp->base));
+	}
+	return rc;
+}
+
+static int lan9662_otp_write_byte(struct lan9662_otp *otp, u32 offset, u8 data)
+{
+	u32 pass;
+	int rc;
+
+	lan9662_otp_set_address(otp, offset);
+	writel(OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE, OTP_OTP_PRGM_MODE(otp->base));
+	writel(data, OTP_OTP_PRGM_DATA(otp->base));
+	writel(OTP_OTP_FUNC_CMD_OTP_PROGRAM, OTP_OTP_FUNC_CMD(otp->base));
+	writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base));
+
+	rc = lan9662_otp_execute(otp);
+	if (!rc) {
+		pass = readl(OTP_OTP_PASS_FAIL(otp->base));
+		if (pass & OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED)
+			return -EACCES;
+		if (pass & OTP_OTP_PASS_FAIL_OTP_FAIL)
+			return -EIO;
+	}
+	return rc;
+}
+
+static int lan9662_otp_read(void *context, unsigned int offset,
+			    void *_val, size_t bytes)
+{
+	struct lan9662_otp *otp = context;
+	u8 *val = _val;
+	uint8_t data;
+	int i, rc = 0;
+
+	lan9662_otp_power(otp, true);
+	for (i = 0; i < bytes; i++) {
+		rc = lan9662_otp_read_byte(otp, offset + i, &data);
+		if (rc < 0)
+			break;
+		*val++ = data;
+	}
+	lan9662_otp_power(otp, false);
+
+	return rc;
+}
+
+static int lan9662_otp_write(void *context, unsigned int offset,
+			     void *_val, size_t bytes)
+{
+	struct lan9662_otp *otp = context;
+	u8 *val = _val;
+	u8 data, newdata;
+	int i, rc = 0;
+
+	lan9662_otp_power(otp, true);
+	for (i = 0; i < bytes; i++) {
+		/* Skip zero bytes */
+		if (val[i]) {
+			rc = lan9662_otp_read_byte(otp, offset + i, &data);
+			if (rc < 0)
+				break;
+
+			newdata = data | val[i];
+			if (newdata == data)
+				continue;
+
+			rc = lan9662_otp_write_byte(otp, offset + i,
+						      newdata);
+			if (rc < 0)
+				break;
+		}
+	}
+	lan9662_otp_power(otp, false);
+
+	return rc;
+}
+
+static struct nvmem_config otp_config = {
+	.name = "lan9662-otp",
+	.stride = 1,
+	.word_size = 1,
+	.reg_read = lan9662_otp_read,
+	.reg_write = lan9662_otp_write,
+	.size = OTP_MEM_SIZE,
+};
+
+static int lan9662_otp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct nvmem_device *nvmem;
+	struct lan9662_otp *otp;
+
+	otp = devm_kzalloc(&pdev->dev, sizeof(*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_config.priv = otp;
+	otp_config.dev = dev;
+
+	nvmem = devm_nvmem_register(dev, &otp_config);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id lan9662_otp_match[] = {
+	{ .compatible = "microchip,lan9662-otp", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, lan9662_otp_match);
+
+static struct platform_driver lan9662_otp_driver = {
+	.probe = lan9662_otp_probe,
+	.driver = {
+		.name = "lan9662-otp",
+		.of_match_table = lan9662_otp_match,
+	},
+};
+module_platform_driver(lan9662_otp_driver);
+
+MODULE_AUTHOR("Horatiu Vultur <horatiu.vultur@microchip.com>");
+MODULE_DESCRIPTION("lan9662 OTP driver");
+MODULE_LICENSE("GPL");
-- 
2.33.0

Re: [PATCH v4 2/2] nvmem: lan9662-otp: add support.

[Krzysztof Kozlowski]

On 01/09/2022 09:44, Horatiu Vultur wrote:
> Add support for OTP controller available on LAN9662. The OTPC controls
> the access to a non-volatile memory. The size of the memory is 8KB.
> The OTPC can access the memory based on an offset.
> Implement both the read and the write functionality.

Drop the full-stop from subject.

Best regards,
Krzysztof

Re: [PATCH v4 1/2] dt-bindings: lan9662-otpc: document Lan9662 OTPC

[Krzysztof Kozlowski]

On 01/09/2022 09:44, Horatiu Vultur wrote:
> Document Lan9662 OTP controller.
> 
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof