Hello Yamada-san,

Thank you for your comment.

From: Masahiro Yamada [mailto:yamada.masahiro@socionext.com]
Sent: Monday, September 4, 2017 9:58 PM

2017-09-01 8:20 GMT+09:00 Keiji Hayashibara
[off-list ref]:

quoted

Add eFuse driver for Socionext UniPhier series SoC.
Note that eFuse device is under soc-glue and this register implements
as read only.

Signed-off-by: Keiji Hayashibara <redacted>
---
 arch/arm64/configs/defconfig   |  1 +
 drivers/nvmem/Kconfig          | 11 +++++
 drivers/nvmem/Makefile         |  2 +
 drivers/nvmem/uniphier-efuse.c | 98
++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 drivers/nvmem/uniphier-efuse.c

diff --git a/arch/arm64/configs/defconfig

b/arch/arm64/configs/defconfig index 6c7d147..5c38b4a 100644

--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig

@@ -514,6 +514,7 @@ CONFIG_PHY_XGENE=y  CONFIG_PHY_TEGRA_XUSB=y

CONFIG_QCOM_L2_PMU=y  CONFIG_QCOM_L3_PMU=y
+CONFIG_UNIPHIER_EFUSE=y
 CONFIG_ARM_SCPI_PROTOCOL=y
 CONFIG_RASPBERRYPI_FIRMWARE=y
 CONFIG_EFI_CAPSULE_LOADER=y

You need to send this separately
(after this driver is accepted)

I see.
Next I will post this separately.

quoted

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index

101ced4..aaeaebe 100644

--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig

@@ -123,6 +123,17 @@ config NVMEM_SUNXI_SID
          This driver can also be built as a module. If so, the module
          will be called nvmem_sunxi_sid.

+config UNIPHIER_EFUSE
+       tristate "UniPhier SoCs eFuse support"
+       depends on ARCH_UNIPHIER || COMPILE_TEST
+       depends on OF && MFD_SYSCON
+       help
+         This is a simple drive to dump specified values of UniPhier

SoC

quoted

+         from eFuse.

s/drive/driver/


I see the same typo in ROCKCHIP_EFUSE.

You copied it verbatim.

I will fix it...

quoted

+         This driver can also be built as a module. If so, the module
+         will be called nvmem_uniphier-efuse.

I do not like a mixture of '_' and '-' though...

I will fix it.

quoted

 config NVMEM_VF610_OCOTP
        tristate "VF610 SoC OCOTP support"
        depends on SOC_VF610 || COMPILE_TEST diff --git
a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index
1731406..f5277c3 100644

--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile

@@ -26,6 +26,8 @@ obj-$(CONFIG_ROCKCHIP_EFUSE)  +=

nvmem_rockchip_efuse.o

quoted

 nvmem_rockchip_efuse-y         := rockchip-efuse.o
 obj-$(CONFIG_NVMEM_SUNXI_SID)  += nvmem_sunxi_sid.o
 nvmem_sunxi_sid-y              := sunxi_sid.o
+obj-$(CONFIG_UNIPHIER_EFUSE)   += nvmem_uniphier-efuse.o
+nvmem_uniphier-efuse-y         := uniphier-efuse.o
 obj-$(CONFIG_NVMEM_VF610_OCOTP)        += nvmem-vf610-ocotp.o
 nvmem-vf610-ocotp-y            := vf610-ocotp.o
 obj-$(CONFIG_MESON_EFUSE)      += nvmem_meson_efuse.o

diff --git a/drivers/nvmem/uniphier-efuse.c

b/drivers/nvmem/uniphier-efuse.c new file mode 100644 index
0000000..d553fa3

--- /dev/null
+++ b/drivers/nvmem/uniphier-efuse.c

@@ -0,0 +1,98 @@
+/*
+ * UniPhier eFuse driver
+ *
+ * Copyright (C) 2017 Socionext Inc.
+ *
+ * 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.
+ *
+ * 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/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define UNIPHIER_EFUSE_WORD_SIZE       4
+#define UNIPHIER_EFUSE_STRIDE          4
+
+static int uniphier_reg_read(void *context,
+                            unsigned int offset, void *val, size_t
+bytes) {
+       int words = bytes / UNIPHIER_EFUSE_WORD_SIZE;
+
+       return regmap_bulk_read(context, offset, val, words); }
+
+static struct nvmem_config econfig = {
+       .name = "uniphier-efuse",
+       .owner = THIS_MODULE,
+       .read_only = true,
+       .reg_read = uniphier_reg_read,
+       .word_size = UNIPHIER_EFUSE_WORD_SIZE,
+       .stride = UNIPHIER_EFUSE_STRIDE, };

"struct nvmem_config" exists for the purpose of containing driver-specific
parameters.
Do you still want to use
UNIPHIER_EFUSE_WORD_SIZE / UNIPHIER_EFUSE_STRIDE macros here?




static struct nvmem_config econfig = {
       .name = "uniphier-efuse",
       .owner = THIS_MODULE,
       .read_only = true,
       .reg_read = uniphier_reg_read,
       .word_size = 4,
       .stride = 4,
};

looks nicer in my taste.

I will fix it.

BTW, is there really no possibility
where the unphier_efuse_probe() is run concurrently?

Many other drivers pass statically allocated memory to nvmem_register()
like this...

In the case of the uniphier system, since there is only one efuse device,
it will not run concurrently. 
I would like to fix it when I need it in the future.

quoted

+static int uniphier_efuse_probe(struct platform_device *pdev) {
+       struct device *dev = &pdev->dev;
+       struct nvmem_device *nvmem;
+       struct regmap *regmap;
+       struct resource res;
+       int ret;
+
+       ret = of_address_to_resource(dev->of_node, 0, &res);
+       if (ret)
+               return ret;
+
+       regmap = syscon_node_to_regmap(dev->of_node);
+       if (IS_ERR(regmap))
+               return PTR_ERR(regmap);

In my understanding,
syscon_node_to_regmap() is generally useful to get regmap of another node,
i.e. it is often used together with of_get_parent / of_parse_phandle etc.

You can use devm_regmap_init_mmio()
to init regmap for itself.


BTW, what is your motivation of using regmap?


I think what you want to do is
the same as mtk-efuse.c, right?
(and qfprom.c is similar, the difference is just register width)

Since redundancy can be omitted, implementation is easier, I think so.
However, since I can't find the merit of using regmap,
I will implement it in a method that does not use it.

quoted

+       econfig.size = resource_size(&res);
+       econfig.priv = regmap;
+       econfig.dev = dev;
+
+       nvmem = nvmem_register(&econfig);
+       if (IS_ERR(nvmem))
+               return PTR_ERR(nvmem);
+
+       platform_set_drvdata(pdev, nvmem);
+
+       return 0;
+}
+
+static int uniphier_efuse_remove(struct platform_device *pdev) {
+       struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+       return nvmem_unregister(nvmem); }
+
+static const struct of_device_id uniphier_efuse_of_match[] = {
+       { .compatible = "socionext,uniphier-efuse",},
+       {/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match);
+
+static struct platform_driver uniphier_efuse_driver = {
+       .probe = uniphier_efuse_probe,
+       .remove = uniphier_efuse_remove,
+       .driver = {
+               .name = "uniphier-efuse",
+               .of_match_table = uniphier_efuse_of_match,
+       },
+};
+module_platform_driver(uniphier_efuse_driver);
+
+MODULE_AUTHOR("Keiji Hayashibara [off-list ref]");
+MODULE_DESCRIPTION("UniPhier eFuse driver"); MODULE_LICENSE("GPL
+v2");
--
2.7.4

--
Best Regards
Masahiro Yamada

Best Regards,
Keiji Hayashibara