On 2015?08?05? 00:11, Srinivas Kandagatla wrote:
> Hi Shunqian,
>
> Sorry for delay in reply, I was on Holidays..
>
> Thanks for testing.
>
> On 31/07/15 10:27, Shunqian Zheng wrote:
>>
>> 1. Without the following diff, `hexdump
>> /sys/bus/nvmem/devices/rockchip-efuse0/nvmem` is wrong with "INVALID
>> ARGUMENT":
>>
>> +++ b/drivers/nvmem/core.c
>> @@ -67,7 +67,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp,
>> struct kobject *kobj,
>> int rc;
>>
>> /* Stop the user from reading */
>> - if (pos > nvmem->size)
>> + if (pos > nvmem->size - 1)
>> return 0;
>
> Yes, this should have been something like this
> - if (pos > nvmem->size)
> + if (pos >= nvmem->size)
> return 0;
>
> We can send a fix on top of v9 once its merged.
>
>>
>> if (pos + count > nvmem->size)
>>
>> RK3288-efuse has 32 x 8bit regs, in dts "reg = <0xffb40000 0x20>;"
>> Here is the message dump from nvmem_device:
>> [ 2.158314] nvmem:
>> [ 2.158314] name (null)
>> [ 2.158314] stride 1
>> [ 2.158314] word_size 1
>> [ 2.158314] ncells 0
>> [ 2.158314] id 0
>> [ 2.158314] users 0
>> [ 2.158314] size 32
>> [ 2.158314] read_only 0
>>
>> Do you think there is a leak or I'm messing up ?
>>
>> 2. About the read operation, eFuse data can be read during device
>> probe() and cached, OR,
>> read from eFuse when needed every time. I prefer the second one but
>> then, the clock of eFuse may be
>> gated. So before/after reading I have to enable/disable clk like :
>> devm_clk_get(dev, "hclk_efuse256");
>> The trouble is I can't find a way to get the "dev" hander in :
>> static int rockchip_efuse_read(void *context, const void
>> *reg, size_t reg_size, void *val, size_t val_size)
>> I am appreciated if you can give some advice.
>
>
> May be you should use regmap_init_mmio_clk() instead of
> regmap_init_mmio() it will take care of clks.
Thank you for you reply.
Although the regmap_init_mmio_clk() and it's series interface deal with
the clks, but
MMIO uses its own regmap_bus{}, while the eFuse of RK3X need special
read/write
callback functions.
I still can't find a good way to resolve this. Can you help?
Shunqian
>
>> Or, do you think it's reasonable to add hooks before/after read in
>> nvmem/core.c like :
>> + before_read(dev, ...);
>> rc = regmap_raw_read(nvmem->regmap, pos, buf,
>> count);
>> + after_read(dev, ...);
>>
>
>
>> 3. In the /sys/bus/nvmem/devices/rockchip-efuse0/, there are files:
>> /sys/devices/platform/ffb40000.efuse/rockchip-efuse0 # ls
>> nvmem of_node power subsystem uevent
>> Do you have a plan to add the nvmem consumers to /sys/ in nvmem
>> framework?
> yes, Am waiting for the framework to be merged, I have plans to add
> this feature.
>
>> For example, in dts defined the "cpu_leakage":
>> efuse: efuse at ffb40000 {
>> compatible = "rockchip,rk3x-efuse";
>> reg = <0xffb40000 0x20>;
>> #address-cells = <1>;
>> #size-cells = <1>;
>> clocks = <&cru PCLK_EFUSE256>;
>> clock-names = "pclk_efuse_256";
>>
>> cpu_leakage: cpu_leakage {
>> reg = <0x17 0x1>;
>> };
>> };
>> Then nvmem exposes the "cpu_leakage" file in /sys which can be
>> read/write.
>
> --srini
