Date:	Tue, 16 Jun 2015 11:54:40 +0100
From:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:	Caesar Wang <wxt@...k-chips.com>,
	Stefan Wahren <stefan.wahren@...e.com>
CC:	heiko@...ech.de, mark.rutland@....com, devicetree@...r.kernel.org,
	linux@....linux.org.uk, pawel.moll@....com,
	ijc+devicetree@...lion.org.uk, linus.walleij@...aro.org,
	linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
	robh+dt@...nel.org, galak@...eaurora.org, matthias.bgg@...il.com,
	jay.xu@...k-chips.com, linux-arm-kernel@...ts.infradead.org,
	Maxime Ripard <maxime.ripard@...e-electrons.com>
Subject: Re: [PATCH v2 0/3] Add the efuse driver on rockchip platform



On 16/06/15 11:06, Caesar Wang wrote:
> Hi Srinivas,
>
> 在 2015年06月16日 17:21, Srinivas Kandagatla 写道:
>> Hi Stefan,
>>
>>
>> On 16/06/15 09:52, Stefan Wahren wrote:
>>> Hi Caesar,
>>>
>>> [add Maxime and Srinivas]
>>>
>>> Am 16.06.2015 um 09:27 schrieb Caesar Wang:
>>>> The original driver is uploaded by Jianqun.
>>>> Here is his patchs:
>>>>      https://patchwork.kernel.org/patch/5410341/
>>>>      https://patchwork.kernel.org/patch/5410351/
>>>>
>>>> Jianqun, nevermind!
>>>> I check-pick it and re-upload the driver for the upstream.
>>>> e.g.:
>>>>      Tested by on minnie board.(kernel-4.1-rc8)
>>>>      cd /sys/devices/platform/ffb40000.efuse
>>>>      localhost ffb40000.efuse # cat cpu_leakage_show
>>>>      cpu_version_show
>>>>      The results:
>>>>              19
>>>>              2
>>>>
>>>> Changes in v2:
>>>> - Change the document decription.
>>>> - Move the efuse driver into driver/soc/vendor.
>>>> - update the efuse driver.
>>>> - Add the dts node on RK3288.
>>>>
>>>>
>>>
>>> i want to mention that there is a upcoming new framework suitable for
>>> efuse drivers:
>>>
>>> https://lkml.org/lkml/2015/5/21/643
>>>
>>> Unfortunately i don't know the current development state.
>>>
>>
>> Currently this framework is used by atleast 3 drivers(qcom-tsens,
>> qcom-cpr, begel-bone-cape manager) which are still floating in the
>> mailing list.
>>
>> I was hoping that these 3 users would getback with tested-by.. which
>> did not happen for last 3-4 weeks.
>>
>> I would appreciate, If you could try framework too, and let me know.
>
> Okay,
> I will do that...
>
> Doing.....
> 203d56b WIP: nvmem: add device tree helper functions
> 7d822d7 nvmem: sunxi: Move the SID driver to the nvmem framework
> f54130d nvmem: qfprom: Add bindings for qfprom
> 6e078d2 nvmem: qfprom: Add Qualcomm QFPROM support.
> 750d32b nvmem: Add simple nvmem-mmio consumer helper functions.
> 6390111 nvmem: Add bindings for simple nvmem framework
> 1c02217 nvmem: Add nvmem_device based consumer apis.
> 61ce74f nvmem: Add a simple NVMEM framework for consumers
> 0f82237 nvmem: Add a simple NVMEM framework for nvmem providers
> 7547598 regmap: Introduce regmap_get_reg_stride.
> f3bc1c0 regmap: Introduce regmap_get_max_register.
> f0b3b70 ARM: rockchip: fix the SMP code style
> 8a28ee6 ARM: rockchip: ensure CPU to enter WFI/WFE state
> 609deeb ARM: rockchip: fix the CPU soft reset
> 2a876e4 ARM: rockchip: restore dapswjdp after suspend
> e260818 Linux 4.1-rc4
> ab992dc watchdog: Fix merge 'conflict'
> ....
>
> At the moment, I don't know how to use this framework.
> I need some time to dig it, I'm happy if you some reference(driver or
> document).
These are very simple apis which are listed in nvmem-consumer.h 
nvmem-provider.h. I will try to come up with some doc very soon.. thanks 
for your patience.

I just had a look at the efuse driver and all you need is(I did not do 
any compile testing) : Have a look at qfprom.c file, the drivers are 
based on regmap, so you get lot of flexibility to add custom 
reads/caches and lot of other regmap features.

dt:
/* Provider */
	efuse: efuse@...40000 {
		compatible = "rockchip,rk3066-efuse";
		reg = <0xffb40000 0x10000>;
		cpu_leakage: cpu_leakage {
			reg = <17 0x4>;
		};
		chip_version: chip_version {
			reg = <0x6 0x1>;
		};
	};

/* Consumer dt: */

	consumer-driver@0 {
		nvmem-cell = <&cpu_leakage>;
		nvmem-cell-names = "cpu-leakage";

	};

/ * consumer driver */
nvmem_cell_get()/nvmem_cell_put();
nvmem_cell_read()/nvmem_cell_write();
	
/* Provider driver */ : drivers/nvmem/rockchip_efuse.c

#include <linux/module.h>
#include <linux/of.h>
#include "nvmem-mmio.h"

int rockchip_efuse_reg_read(void *context, unsigned int reg, unsigned 
int *val)
{
	/* efuse specific read sequence */
	...
}

static struct regmap_config rockchip_efuse_regmap_config = {
	.reg_bits = 32,
	.val_bits = 8,
	.reg_stride = 1,
	.reg_read = rockchip_efuse_reg_read,
};

static struct nvmem_config econfig = {
	.name = "rockchip-efuse",
	.owner = THIS_MODULE,
};

static struct nvmem_mmio_data rockchip_efuse_data = {
	.nvmem_config = &econfig,
	.regmap_config = &rockchip_efuse_regmap_config,
};

static const struct of_device_id rockchip_efuse_of_match[] = {
	{ .compatible = "rockchip,rk3066-efuse", .data = &rockchip_efuse_data},
	{/* sentinel */},
};
MODULE_DEVICE_TABLE(of, rockchip_efuse_of_match);

static struct platform_driver rockchip_efuse_driver = {
	.probe = nvmem_mmio_probe,
	.remove = nvmem_mmio_remove,
	.driver = {
		.name = "rockchip_efuse",
		.of_match_table = rockchip_efuse_of_match,
	},
};
module_platform_driver(rockchip_efuse_driver);
MODULE_DESCRIPTION("rockchip_efuse driver");
MODULE_LICENSE("GPL v2");
>
>>
>> I added two of wrappers on top of v5 at:
>> https://git.linaro.org/people/srinivas.kandagatla/linux.git/shortlog/refs/heads/nvmem-dev-v5
>>
>>
>>
>> I think I should request Mark to take the framework.
>>
>>
>>
>> --srini
>>> Regards
>>> Stefan
>>>
>>>
>>
>>
>>
>
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