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[v7,0/7] MIPS: CI20: Add efuse driver for Ingenic JZ4780 and attach to DM9000 for stable MAC addresses

Message ID cover.1582898302.git.hns@goldelico.com
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Series MIPS: CI20: Add efuse driver for Ingenic JZ4780 and attach to DM9000 for stable MAC addresses | expand

Message

H. Nikolaus Schaller Feb. 28, 2020, 1:58 p.m. UTC
* use devm_add_action_or_reset to unprepare clock in case of error (suggested by Paul Cercueil <paul@crapouillou.net>)
* use already existing constants to check for overflow of rd_adj and rd_strobe
* remove clock-names from bindings example and DTS (suggested by Paul Cercueil <paul@crapouillou.net>)
* addition for nemc driver to handle this correctly (contributed by Paul Cercueil <paul@crapouillou.net>)
* make efuse a child node of nemc to avoid problems with overlapping
  reg address ranges (suggested by Paul Cercueil <paul@crapouillou.net>)

PATCH V6 2020-02-26 12:16:07:
* add dependency on CONFIG_OF and select REGMAP_MMIO (suggested by Paul Cercueil <paul@crapouillou.net>)
* add clk_prepare_enable() (suggested by Paul Cercueil <paul@crapouillou.net>)
* inline jz4780_efuse_read_32bytes() since it is only used once
* remove read optimization for full block (suggested by Paul Cercueil <paul@crapouillou.net>)
* simplify calculations for rd_adj and rd_strobe (suggested by Paul Cercueil <paul@crapouillou.net>)
* do calculations for rd_adj and rd_strobe in local variables
* fix overflow check (did allow for 5 bit values although register is 4 bit wide)
* fixes for yaml (sugested by Andreas Kemnade <andreas@kemnade.info>)

PATCH V5 2020-02-22 11:25:35:
* no longer RFC but PATCH
* add yaml bindings (by Andreas Kemnade <andreas@kemnade.info>)
* fixes to yaml (suggested by Rob Herring <robh@kernel.org>)

RFC V4 2020-02-17 17:55:35:
* removed read_only for nvmem config because there is no write method
* Kconfig: replaced depends MACH_JZ4780 with MACH_INGENIC
* run through checkpatch and fixed issues
* made use of devm_nvram_register() and get rid of jz4780_efuse_remove()
  (suggested by Srinivas Kandagatla <srinivas.kandagatla@linaro.org>)
* squashed previous patch 1/9 and 2/9 into single (regmap based) driver

RFC V3 2020-02-16 20:20:59:

This series is based on and a follow up for

https://lore.kernel.org/patchwork/cover/868157/

("[v2,0/2] Add efuse driver for Ingenic JZ4780 SoC")

Original authors were
PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Mathieu Malaterre <malat@debian.org>

and there are additions / code improvements by
H. Nikolaus Schaller <hns@goldelico.com>
Paul Cercueil <paul@crapouillou.net>

This setup works, if the dm9000 driver is compiled
as a module.

Therefore it is all RFC level. It is also not completely
checkpatched.


H. Nikolaus Schaller (1):
  MIPS: DTS: CI20: make DM9000 Ethernet controller use NVMEM to find the
    default MAC address

Paul Cercueil (1):
  memory: jz4780_nemc: Only request IO memory the driver will use

PrasannaKumar Muralidharan (5):
  nvmem: add driver for JZ4780 efuse
  Bindings: nvmem: add bindings for JZ4780 efuse
  Documentation: ABI: nvmem: add documentation for JZ4780 efuse ABI
  nvmem: MAINTAINERS: add maintainer for JZ4780 efuse driver
  MIPS: DTS: JZ4780: define node for JZ4780 efuse

 .../ABI/testing/sysfs-driver-jz4780-efuse     |  16 ++
 .../bindings/nvmem/ingenic,jz4780-efuse.yaml  |  49 ++++
 MAINTAINERS                                   |   5 +
 arch/mips/boot/dts/ingenic/ci20.dts           |   3 +
 arch/mips/boot/dts/ingenic/jz4780.dtsi        |  19 +-
 drivers/memory/jz4780-nemc.c                  |  15 +-
 drivers/nvmem/Kconfig                         |  12 +
 drivers/nvmem/Makefile                        |   2 +
 drivers/nvmem/jz4780-efuse.c                  | 234 ++++++++++++++++++
 9 files changed, 352 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-jz4780-efuse
 create mode 100644 Documentation/devicetree/bindings/nvmem/ingenic,jz4780-efuse.yaml
 create mode 100644 drivers/nvmem/jz4780-efuse.c

Comments

Paul Cercueil Feb. 28, 2020, 2:48 p.m. UTC | #1
Hi Nikolaus,

Le ven., févr. 28, 2020 at 14:58, H. Nikolaus Schaller 
<hns@goldelico.com> a écrit :
> From: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
> 
> This patch brings support for the JZ4780 efuse. Currently it only 
> exposes
> a read only access to the entire 8K bits efuse memory and nvmem cells.
> 
> To fetch for example the MAC address:
> 
> dd if=/sys/devices/platform/134100d0.efuse/jz4780-efuse0/nvmem bs=1 
> skip=34 count=6 status=none | xxd
> 
> Tested-by: Mathieu Malaterre <malat@debian.org>
> Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
> Signed-off-by: Mathieu Malaterre <malat@debian.org>
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/nvmem/Kconfig        |  12 ++
>  drivers/nvmem/Makefile       |   2 +
>  drivers/nvmem/jz4780-efuse.c | 234 
> +++++++++++++++++++++++++++++++++++
>  3 files changed, 248 insertions(+)
>  create mode 100644 drivers/nvmem/jz4780-efuse.c
> 
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 35efab1ba8d9..d7b7f6d688e7 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -55,6 +55,18 @@ config NVMEM_IMX_OCOTP_SCU
>  	  This is a driver for the SCU On-Chip OTP Controller (OCOTP)
>  	  available on i.MX8 SoCs.
> 
> +config JZ4780_EFUSE
> +	tristate "JZ4780 EFUSE Memory Support"
> +	depends on MACH_INGENIC || COMPILE_TEST
> +	depends on HAS_IOMEM
> +	depends on OF
> +	select REGMAP_MMIO
> +	help
> +	  Say Y here to include support for JZ4780 efuse memory found on
> +	  all JZ4780 SoC based devices.
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called nvmem_jz4780_efuse.
> +
>  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 6b466cd1427b..65a268d17807 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -18,6 +18,8 @@ obj-$(CONFIG_NVMEM_IMX_OCOTP)	+= nvmem-imx-ocotp.o
>  nvmem-imx-ocotp-y		:= imx-ocotp.o
>  obj-$(CONFIG_NVMEM_IMX_OCOTP_SCU)	+= nvmem-imx-ocotp-scu.o
>  nvmem-imx-ocotp-scu-y		:= imx-ocotp-scu.o
> +obj-$(CONFIG_JZ4780_EFUSE)		+= nvmem_jz4780_efuse.o
> +nvmem_jz4780_efuse-y		:= jz4780-efuse.o
>  obj-$(CONFIG_NVMEM_LPC18XX_EEPROM)	+= nvmem_lpc18xx_eeprom.o
>  nvmem_lpc18xx_eeprom-y	:= lpc18xx_eeprom.o
>  obj-$(CONFIG_NVMEM_LPC18XX_OTP)	+= nvmem_lpc18xx_otp.o
> diff --git a/drivers/nvmem/jz4780-efuse.c 
> b/drivers/nvmem/jz4780-efuse.c
> new file mode 100644
> index 000000000000..4e9dd340e33a
> --- /dev/null
> +++ b/drivers/nvmem/jz4780-efuse.c
> @@ -0,0 +1,234 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * JZ4780 EFUSE Memory Support driver
> + *
> + * Copyright (c) 2017 PrasannaKumar Muralidharan 
> <prasannatsmkumar@gmail.com>
> + * Copyright (c) 2020 H. Nikolaus Schaller <hns@goldelico.com>
> + */
> +
> +/*
> + * Currently supports JZ4780 efuse which has 8K programmable bit.
> + * Efuse is separated into seven segments as below:
> + *
> + * 
> -----------------------------------------------------------------------
> + * | 64 bit | 128 bit | 128 bit | 3520 bit | 8 bit | 2296 bit | 2048 
> bit |
> + * 
> -----------------------------------------------------------------------
> + *
> + * The rom itself is accessed using a 9 bit address line and an 8 
> word wide bus
> + * which reads/writes based on strobes. The strobe is configured in 
> the config
> + * register and is based on number of cycles of the bus clock.
> + *
> + * Driver supports read only as the writes are done in the Factory.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/timer.h>
> +
> +#define JZ_EFUCTRL		(0x0)	/* Control Register */
> +#define JZ_EFUCFG		(0x4)	/* Configure Register*/
> +#define JZ_EFUSTATE		(0x8)	/* Status Register */
> +#define JZ_EFUDATA(n)		(0xC + (n) * 4)
> +
> +/* We read 32 byte chunks to avoid complexity in the driver. */
> +#define JZ_EFU_READ_SIZE 32
> +
> +#define EFUCTRL_ADDR_MASK	0x3FF
> +#define EFUCTRL_ADDR_SHIFT	21
> +#define EFUCTRL_LEN_MASK	0x1F
> +#define EFUCTRL_LEN_SHIFT	16
> +#define EFUCTRL_PG_EN		BIT(15)
> +#define EFUCTRL_WR_EN		BIT(1)
> +#define EFUCTRL_RD_EN		BIT(0)
> +
> +#define EFUCFG_INT_EN		BIT(31)
> +#define EFUCFG_RD_ADJ_MASK	0xF
> +#define EFUCFG_RD_ADJ_SHIFT	20
> +#define EFUCFG_RD_STR_MASK	0xF
> +#define EFUCFG_RD_STR_SHIFT	16
> +#define EFUCFG_WR_ADJ_MASK	0xF
> +#define EFUCFG_WR_ADJ_SHIFT	12
> +#define EFUCFG_WR_STR_MASK	0xFFF
> +#define EFUCFG_WR_STR_SHIFT	0
> +
> +#define EFUSTATE_WR_DONE	BIT(1)
> +#define EFUSTATE_RD_DONE	BIT(0)
> +
> +struct jz4780_efuse {
> +	struct device *dev;
> +	struct regmap *map;
> +	struct clk *clk;
> +};
> +
> +/* main entry point */
> +static int jz4780_efuse_read(void *context, unsigned int offset,
> +			     void *val, size_t bytes)
> +{
> +	struct jz4780_efuse *efuse = context;
> +
> +	while (bytes > 0) {
> +		unsigned int start = offset & ~(JZ_EFU_READ_SIZE - 1);
> +		unsigned int chunk = min(bytes, (start + JZ_EFU_READ_SIZE)
> +					 - offset);
> +		char buf[JZ_EFU_READ_SIZE];
> +		unsigned int tmp;
> +		u32 ctrl;
> +		int ret;
> +
> +		ctrl = (start << EFUCTRL_ADDR_SHIFT)
> +			| ((JZ_EFU_READ_SIZE - 1) << EFUCTRL_LEN_SHIFT)
> +			| EFUCTRL_RD_EN;
> +
> +		regmap_update_bits(efuse->map, JZ_EFUCTRL,
> +				   (EFUCTRL_ADDR_MASK << EFUCTRL_ADDR_SHIFT) |
> +				   (EFUCTRL_LEN_MASK << EFUCTRL_LEN_SHIFT) |
> +				   EFUCTRL_PG_EN | EFUCTRL_WR_EN |
> +				   EFUCTRL_RD_EN,
> +				   ctrl);
> +
> +		ret = regmap_read_poll_timeout(efuse->map, JZ_EFUSTATE,
> +					       tmp, tmp & EFUSTATE_RD_DONE,
> +					       1 * MSEC_PER_SEC,
> +					       50 * MSEC_PER_SEC);
> +		if (ret < 0) {
> +			dev_err(efuse->dev, "Time out while reading efuse data");
> +			return ret;
> +		}
> +
> +		ret = regmap_bulk_read(efuse->map, JZ_EFUDATA(0),
> +				       buf, JZ_EFU_READ_SIZE / sizeof(u32));
> +		if (ret < 0)
> +			return ret;
> +
> +		memcpy(val, &buf[offset - start], chunk);
> +
> +		val += chunk;
> +		offset += chunk;
> +		bytes -= chunk;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct nvmem_config jz4780_efuse_nvmem_config = {
> +	.name = "jz4780-efuse",
> +	.size = 1024,
> +	.word_size = 1,
> +	.stride = 1,
> +	.owner = THIS_MODULE,
> +	.reg_read = jz4780_efuse_read,
> +};
> +
> +static const struct regmap_config jz4780_efuse_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = JZ_EFUDATA(7),
> +};
> +
> +static int jz4780_efuse_probe(struct platform_device *pdev)
> +{
> +	struct nvmem_device *nvmem;
> +	struct jz4780_efuse *efuse;
> +	struct nvmem_config cfg;
> +	unsigned long clk_rate;
> +	unsigned long rd_adj;
> +	unsigned long rd_strobe;
> +	struct device *dev = &pdev->dev;
> +	void __iomem *regs;
> +	int ret;
> +
> +	efuse = devm_kzalloc(dev, sizeof(*efuse), GFP_KERNEL);
> +	if (!efuse)
> +		return -ENOMEM;
> +
> +	regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(regs))
> +		return PTR_ERR(regs);
> +
> +	efuse->map = devm_regmap_init_mmio(dev, regs,
> +					   &jz4780_efuse_regmap_config);
> +	if (IS_ERR(efuse->map))
> +		return PTR_ERR(efuse->map);
> +
> +	efuse->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(efuse->clk))
> +		return PTR_ERR(efuse->clk);
> +
> +	ret = clk_prepare_enable(efuse->clk);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = devm_add_action_or_reset(&pdev->dev,
> +				       &clk_disable_unprepare,
> +				       efuse->clk);

That's what I thought, this does not build:

  CC      drivers/nvmem/jz4780-efuse.o
drivers/nvmem/jz4780-efuse.c: In function 'jz4780_efuse_probe':
drivers/nvmem/jz4780-efuse.c:168:12: error: passing argument 2 of 
'devm_add_action_or_reset' from incompatible pointer type 
[-Werror=incompatible-pointer-types]
  168 |            &clk_disable_unprepare,
      |            ^~~~~~~~~~~~~~~~~~~~~~
      |            |
      |            void (*)(struct clk *)
In file included from ./include/linux/platform_device.h:13,
                 from drivers/nvmem/jz4780-efuse.c:29:
./include/linux/device.h:256:16: note: expected 'void (*)(void *)' but 
argument is of type 'void (*)(struct clk *)'
  256 |         void (*action)(void *), void *data)
      |         ~~~~~~~^~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:268: drivers/nvmem/jz4780-efuse.o] 
Error 1
make[1]: *** [scripts/Makefile.build:505: drivers/nvmem] Error 2
make: *** [Makefile:1681: drivers] Error 2


You need a local function of type 'void foo(void *data)' that just 
calls clk_disable_unprepare(data) and the compiler will be happy.
(btw - no need to deference functions pointers, since they are already 
pointers)

With that said, I expect you to at least compile-test the patchset 
before sending it upstream...

The rest of the patch looks good, so just fix that, and it'll be good 
to go.

Cheers,
-Paul

> +	if (ret < 0)
> +		return ret;
> +
> +	clk_rate = clk_get_rate(efuse->clk);
> +
> +	efuse->dev = dev;
> +
> +	/*
> +	 * rd_adj and rd_strobe are 4 bit values
> +	 * conditions:
> +	 *   bus clk_period * (rd_adj + 1) > 6.5ns
> +	 *   bus clk_period * (rd_adj + 5 + rd_strobe) > 35ns
> +	 *   i.e. rd_adj >= 6.5ns / clk_period
> +	 *   i.e. rd_strobe >= 35 ns / clk_period - 5 - rd_adj + 1
> +	 * constants:
> +	 *   1 / 6.5ns == 153846154 Hz
> +	 *   1 / 35ns == 28571429 Hz
> +	 */
> +
> +	rd_adj = clk_rate / 153846154;
> +	rd_strobe = clk_rate / 28571429 - 5 - rd_adj + 1;
> +
> +	if (rd_adj > EFUCFG_RD_ADJ_MASK ||
> +	    rd_strobe > EFUCFG_RD_STR_MASK) {
> +		dev_err(&pdev->dev, "Cannot set clock configuration\n");
> +		return -EINVAL;
> +	}
> +
> +	regmap_update_bits(efuse->map, JZ_EFUCFG,
> +			   (EFUCFG_RD_ADJ_MASK << EFUCFG_RD_ADJ_SHIFT) |
> +			   (EFUCFG_RD_STR_MASK << EFUCFG_RD_STR_SHIFT),
> +			   (rd_adj << EFUCFG_RD_ADJ_SHIFT) |
> +			   (rd_strobe << EFUCFG_RD_STR_SHIFT));
> +
> +	cfg = jz4780_efuse_nvmem_config;
> +	cfg.dev = &pdev->dev;
> +	cfg.priv = efuse;
> +
> +	nvmem = devm_nvmem_register(dev, &cfg);
> +	if (IS_ERR(nvmem))
> +		return PTR_ERR(nvmem);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id jz4780_efuse_match[] = {
> +	{ .compatible = "ingenic,jz4780-efuse" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, jz4780_efuse_match);
> +
> +static struct platform_driver jz4780_efuse_driver = {
> +	.probe  = jz4780_efuse_probe,
> +	.driver = {
> +		.name = "jz4780-efuse",
> +		.of_match_table = jz4780_efuse_match,
> +	},
> +};
> +module_platform_driver(jz4780_efuse_driver);
> +
> +MODULE_AUTHOR("PrasannaKumar Muralidharan 
> <prasannatsmkumar@gmail.com>");
> +MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
> +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
> +MODULE_DESCRIPTION("Ingenic JZ4780 efuse driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.23.0
>
H. Nikolaus Schaller Feb. 28, 2020, 2:57 p.m. UTC | #2
> Am 28.02.2020 um 15:48 schrieb Paul Cercueil <paul@crapouillou.net>:
> 
> Hi Nikolaus,
> 
> Le ven., févr. 28, 2020 at 14:58, H. Nikolaus Schaller <hns@goldelico.com> a écrit :
>> From: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
>> This patch brings support for the JZ4780 efuse. Currently it only exposes
>> a read only access to the entire 8K bits efuse memory and nvmem cells.
>> To fetch for example the MAC address:
>> dd if=/sys/devices/platform/134100d0.efuse/jz4780-efuse0/nvmem bs=1 skip=34 count=6 status=none | xxd
>> Tested-by: Mathieu Malaterre <malat@debian.org>
>> Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
>> Signed-off-by: Mathieu Malaterre <malat@debian.org>
>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>> drivers/nvmem/Kconfig        |  12 ++
>> drivers/nvmem/Makefile       |   2 +
>> drivers/nvmem/jz4780-efuse.c | 234 +++++++++++++++++++++++++++++++++++
>> 3 files changed, 248 insertions(+)
>> create mode 100644 drivers/nvmem/jz4780-efuse.c
>> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
>> index 35efab1ba8d9..d7b7f6d688e7 100644
>> --- a/drivers/nvmem/Kconfig
>> +++ b/drivers/nvmem/Kconfig
>> @@ -55,6 +55,18 @@ config NVMEM_IMX_OCOTP_SCU
>> 	  This is a driver for the SCU On-Chip OTP Controller (OCOTP)
>> 	  available on i.MX8 SoCs.
>> +config JZ4780_EFUSE
>> +	tristate "JZ4780 EFUSE Memory Support"
>> +	depends on MACH_INGENIC || COMPILE_TEST
>> +	depends on HAS_IOMEM
>> +	depends on OF
>> +	select REGMAP_MMIO
>> +	help
>> +	  Say Y here to include support for JZ4780 efuse memory found on
>> +	  all JZ4780 SoC based devices.
>> +	  To compile this driver as a module, choose M here: the module
>> +	  will be called nvmem_jz4780_efuse.
>> +
>> 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 6b466cd1427b..65a268d17807 100644
>> --- a/drivers/nvmem/Makefile
>> +++ b/drivers/nvmem/Makefile
>> @@ -18,6 +18,8 @@ obj-$(CONFIG_NVMEM_IMX_OCOTP)	+= nvmem-imx-ocotp.o
>> nvmem-imx-ocotp-y		:= imx-ocotp.o
>> obj-$(CONFIG_NVMEM_IMX_OCOTP_SCU)	+= nvmem-imx-ocotp-scu.o
>> nvmem-imx-ocotp-scu-y		:= imx-ocotp-scu.o
>> +obj-$(CONFIG_JZ4780_EFUSE)		+= nvmem_jz4780_efuse.o
>> +nvmem_jz4780_efuse-y		:= jz4780-efuse.o
>> obj-$(CONFIG_NVMEM_LPC18XX_EEPROM)	+= nvmem_lpc18xx_eeprom.o
>> nvmem_lpc18xx_eeprom-y	:= lpc18xx_eeprom.o
>> obj-$(CONFIG_NVMEM_LPC18XX_OTP)	+= nvmem_lpc18xx_otp.o
>> diff --git a/drivers/nvmem/jz4780-efuse.c b/drivers/nvmem/jz4780-efuse.c
>> new file mode 100644
>> index 000000000000..4e9dd340e33a
>> --- /dev/null
>> +++ b/drivers/nvmem/jz4780-efuse.c
>> @@ -0,0 +1,234 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * JZ4780 EFUSE Memory Support driver
>> + *
>> + * Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
>> + * Copyright (c) 2020 H. Nikolaus Schaller <hns@goldelico.com>
>> + */
>> +
>> +/*
>> + * Currently supports JZ4780 efuse which has 8K programmable bit.
>> + * Efuse is separated into seven segments as below:
>> + *
>> + * -----------------------------------------------------------------------
>> + * | 64 bit | 128 bit | 128 bit | 3520 bit | 8 bit | 2296 bit | 2048 bit |
>> + * -----------------------------------------------------------------------
>> + *
>> + * The rom itself is accessed using a 9 bit address line and an 8 word wide bus
>> + * which reads/writes based on strobes. The strobe is configured in the config
>> + * register and is based on number of cycles of the bus clock.
>> + *
>> + * Driver supports read only as the writes are done in the Factory.
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/clk.h>
>> +#include <linux/module.h>
>> +#include <linux/nvmem-provider.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/timer.h>
>> +
>> +#define JZ_EFUCTRL		(0x0)	/* Control Register */
>> +#define JZ_EFUCFG		(0x4)	/* Configure Register*/
>> +#define JZ_EFUSTATE		(0x8)	/* Status Register */
>> +#define JZ_EFUDATA(n)		(0xC + (n) * 4)
>> +
>> +/* We read 32 byte chunks to avoid complexity in the driver. */
>> +#define JZ_EFU_READ_SIZE 32
>> +
>> +#define EFUCTRL_ADDR_MASK	0x3FF
>> +#define EFUCTRL_ADDR_SHIFT	21
>> +#define EFUCTRL_LEN_MASK	0x1F
>> +#define EFUCTRL_LEN_SHIFT	16
>> +#define EFUCTRL_PG_EN		BIT(15)
>> +#define EFUCTRL_WR_EN		BIT(1)
>> +#define EFUCTRL_RD_EN		BIT(0)
>> +
>> +#define EFUCFG_INT_EN		BIT(31)
>> +#define EFUCFG_RD_ADJ_MASK	0xF
>> +#define EFUCFG_RD_ADJ_SHIFT	20
>> +#define EFUCFG_RD_STR_MASK	0xF
>> +#define EFUCFG_RD_STR_SHIFT	16
>> +#define EFUCFG_WR_ADJ_MASK	0xF
>> +#define EFUCFG_WR_ADJ_SHIFT	12
>> +#define EFUCFG_WR_STR_MASK	0xFFF
>> +#define EFUCFG_WR_STR_SHIFT	0
>> +
>> +#define EFUSTATE_WR_DONE	BIT(1)
>> +#define EFUSTATE_RD_DONE	BIT(0)
>> +
>> +struct jz4780_efuse {
>> +	struct device *dev;
>> +	struct regmap *map;
>> +	struct clk *clk;
>> +};
>> +
>> +/* main entry point */
>> +static int jz4780_efuse_read(void *context, unsigned int offset,
>> +			     void *val, size_t bytes)
>> +{
>> +	struct jz4780_efuse *efuse = context;
>> +
>> +	while (bytes > 0) {
>> +		unsigned int start = offset & ~(JZ_EFU_READ_SIZE - 1);
>> +		unsigned int chunk = min(bytes, (start + JZ_EFU_READ_SIZE)
>> +					 - offset);
>> +		char buf[JZ_EFU_READ_SIZE];
>> +		unsigned int tmp;
>> +		u32 ctrl;
>> +		int ret;
>> +
>> +		ctrl = (start << EFUCTRL_ADDR_SHIFT)
>> +			| ((JZ_EFU_READ_SIZE - 1) << EFUCTRL_LEN_SHIFT)
>> +			| EFUCTRL_RD_EN;
>> +
>> +		regmap_update_bits(efuse->map, JZ_EFUCTRL,
>> +				   (EFUCTRL_ADDR_MASK << EFUCTRL_ADDR_SHIFT) |
>> +				   (EFUCTRL_LEN_MASK << EFUCTRL_LEN_SHIFT) |
>> +				   EFUCTRL_PG_EN | EFUCTRL_WR_EN |
>> +				   EFUCTRL_RD_EN,
>> +				   ctrl);
>> +
>> +		ret = regmap_read_poll_timeout(efuse->map, JZ_EFUSTATE,
>> +					       tmp, tmp & EFUSTATE_RD_DONE,
>> +					       1 * MSEC_PER_SEC,
>> +					       50 * MSEC_PER_SEC);
>> +		if (ret < 0) {
>> +			dev_err(efuse->dev, "Time out while reading efuse data");
>> +			return ret;
>> +		}
>> +
>> +		ret = regmap_bulk_read(efuse->map, JZ_EFUDATA(0),
>> +				       buf, JZ_EFU_READ_SIZE / sizeof(u32));
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		memcpy(val, &buf[offset - start], chunk);
>> +
>> +		val += chunk;
>> +		offset += chunk;
>> +		bytes -= chunk;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static struct nvmem_config jz4780_efuse_nvmem_config = {
>> +	.name = "jz4780-efuse",
>> +	.size = 1024,
>> +	.word_size = 1,
>> +	.stride = 1,
>> +	.owner = THIS_MODULE,
>> +	.reg_read = jz4780_efuse_read,
>> +};
>> +
>> +static const struct regmap_config jz4780_efuse_regmap_config = {
>> +	.reg_bits = 32,
>> +	.val_bits = 32,
>> +	.reg_stride = 4,
>> +	.max_register = JZ_EFUDATA(7),
>> +};
>> +
>> +static int jz4780_efuse_probe(struct platform_device *pdev)
>> +{
>> +	struct nvmem_device *nvmem;
>> +	struct jz4780_efuse *efuse;
>> +	struct nvmem_config cfg;
>> +	unsigned long clk_rate;
>> +	unsigned long rd_adj;
>> +	unsigned long rd_strobe;
>> +	struct device *dev = &pdev->dev;
>> +	void __iomem *regs;
>> +	int ret;
>> +
>> +	efuse = devm_kzalloc(dev, sizeof(*efuse), GFP_KERNEL);
>> +	if (!efuse)
>> +		return -ENOMEM;
>> +
>> +	regs = devm_platform_ioremap_resource(pdev, 0);
>> +	if (IS_ERR(regs))
>> +		return PTR_ERR(regs);
>> +
>> +	efuse->map = devm_regmap_init_mmio(dev, regs,
>> +					   &jz4780_efuse_regmap_config);
>> +	if (IS_ERR(efuse->map))
>> +		return PTR_ERR(efuse->map);
>> +
>> +	efuse->clk = devm_clk_get(&pdev->dev, NULL);
>> +	if (IS_ERR(efuse->clk))
>> +		return PTR_ERR(efuse->clk);
>> +
>> +	ret = clk_prepare_enable(efuse->clk);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = devm_add_action_or_reset(&pdev->dev,
>> +				       &clk_disable_unprepare,
>> +				       efuse->clk);
> 
> That's what I thought, this does not build:
> 
> CC      drivers/nvmem/jz4780-efuse.o
> drivers/nvmem/jz4780-efuse.c: In function 'jz4780_efuse_probe':
> drivers/nvmem/jz4780-efuse.c:168:12: error: passing argument 2 of 'devm_add_action_or_reset' from incompatible pointer type [-Werror=incompatible-pointer-types]
> 168 |            &clk_disable_unprepare,
>     |            ^~~~~~~~~~~~~~~~~~~~~~
>     |            |
>     |            void (*)(struct clk *)
> In file included from ./include/linux/platform_device.h:13,
>                from drivers/nvmem/jz4780-efuse.c:29:
> ./include/linux/device.h:256:16: note: expected 'void (*)(void *)' but argument is of type 'void (*)(struct clk *)'
> 256 |         void (*action)(void *), void *data)
>     |         ~~~~~~~^~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> make[2]: *** [scripts/Makefile.build:268: drivers/nvmem/jz4780-efuse.o] Error 1
> make[1]: *** [scripts/Makefile.build:505: drivers/nvmem] Error 2
> make: *** [Makefile:1681: drivers] Error 2
> 
> 
> You need a local function of type 'void foo(void *data)' that just calls clk_disable_unprepare(data) and the compiler will be happy.
> (btw - no need to deference functions pointers, since they are already pointers)

Well, this asks for a devm_clk_enable_prepare but it was apparently rejected...

https://lore.kernel.org/patchwork/patch/755667/

> 
> With that said, I expect you to at least compile-test the patchset before sending it upstream...

I have compiled and tested it on real hardware. But missed the warning because my cross-compiler seems to emit a warning only.

Sorry, I don't have a good day and after 7 rounds one wants to get things through the door and with least effort as quick as possible :)

BR,
Nikolaus