Dear Srinivas, On 2015?06?18? 16:29, Srinivas Kandagatla wrote: > > > On 18/06/15 08:05, Stefan Wahren wrote: >> Hi Srinivas, >> >> Am 16.06.2015 um 12:54 schrieb Srinivas Kandagatla: >>> >>> >>> On 16/06/15 11:06, Caesar Wang wrote: >>>> Hi Srinivas, >>>> >>>> ? 2015?06?16? 17:21, Srinivas Kandagatla ??: >>>>> 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. >>>> >> >> yes i work on OCOTP driver for MXS platform and i will try ... >> >>> >>> int rockchip_efuse_reg_read(void *context, unsigned int reg, unsigned >>> int *val) >>> { >>> /* efuse specific read sequence */ >>> ... >>> } >> >> I will need a specific read sequence too. > > You can have a look at > https://git.linaro.org/people/srinivas.kandagatla/linux.git/blob/b4c3ad253747767511233687436f20144e850d67:/drivers/nvmem/rockchip-efuse.c > > I did modify the rockchip driver, which I guess should be very much > similar to what OCOTP driver would need. I'm testing the rockchip-efuse.c driver based on nvmem framework v8, it works on RK3288-soc except: 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; 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. 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? 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. Thank you very much, Shunqian Zheng > > >> >> Sorry for these newbie questions: >> >> What data structure does context points to for this reg_read opteration? >> >> Do we need range checking of reg or is it handled by the framework? >> > We already have that in place. > >> Are there any limitation for reg_read regarding sleeping or locking >> operations? > There are no limitaions as such from nvmem framework, regmap might > have limitations w.r.t to sleeping and fast_io, as fast_io would take > spinlocks, AFAIK the providers would not have fast_io, as they not IO > devices. >> >> In case of a read only driver, is everything handle by devicetree or do >> we need an empty write operation? > Yes, if you pass read-only flag in the provider, the framework would > not attempt to even write. > > You will find answers to most of your question in the rochip-efuse.c > file. > > > --srini >> >> Best regards >> Stefan >> > > _______________________________________________ > Linux-rockchip mailing list > Linux-rockchip at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-rockchip
