Re: [PATCH v13 2/9] mfd: qcom-spmi-pmic: expose the PMIC revid information to clients

From: Caleb Connolly <caleb.connolly@linaro.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Rob Herring <robh+dt@kernel.org>, Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, sumit.semwal@linaro.org,
	amit.pundir@linaro.org, john.stultz@linaro.org,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Subject: Re: [PATCH v13 2/9] mfd: qcom-spmi-pmic: expose the PMIC revid information to clients
Date: Thu, 28 Apr 2022 17:30:42 +0100	[thread overview]
Message-ID: <cce2f4b7-3620-7a33-ef21-579eff9a7dac@linaro.org> (raw)
In-Reply-To: <Ymq9Su3UE5IYiHnI@google.com>


On 28/04/2022 17:14, Lee Jones wrote:
> On Wed, 27 Apr 2022, Caleb Connolly wrote:
>> On 25/04/2022 16:03, Lee Jones wrote:
>>>
>>> On Wed, 23 Mar 2022, Caleb Connolly wrote:
>>>> From: Caleb Connolly <caleb.connolly@linaro.org>
>>>>
>>>> Some PMIC functions such as the RRADC need to be aware of the PMIC
>>>> chip revision information to implement errata or otherwise adjust
>>>> behaviour, export the PMIC information to enable this.
>>>>
>>>> This is specifically required to enable the RRADC to adjust
>>>> coefficients based on which chip fab the PMIC was produced in,
>>>> this can vary per unique device and therefore has to be read at
>>>> runtime.
>>>>
>>>> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
>>>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>>> Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>>> ---
>>>>    drivers/mfd/qcom-spmi-pmic.c      | 261 +++++++++++++++++++-----------
>>>>    include/soc/qcom/qcom-spmi-pmic.h |  60 +++++++
>>>>    2 files changed, 231 insertions(+), 90 deletions(-)
>>>>    create mode 100644 include/soc/qcom/qcom-spmi-pmic.h
> 
> [...]
> 
>>>> +			/*
>>>> +			 * If the base USID for this PMIC hasn't probed yet
>>>> +			 * but the secondary USID has, then we need to defer
>>>> +			 * the function driver so that it will attempt to
>>>> +			 * probe again when the base USID is ready.
>>>> +			 */
>>>> +			if (pmic_addr == function_parent_usid  - (ctx->num_usids - 1))
>>>
>>> Double "  ".
>> Ack
>>>
>>> Over-bracketing of statements with matching operands.
>> I don't think x - (y - 1) is equal to x - y - 1? Or am I misunderstanding you here?
> 
> Can you give me an example when this would be the case?
According to the Python interpreter:
 >>> x=7
 >>> y=4
 >>> x - y - 1
2
 >>> x - (y - 1)
4

C does also respect the first rule of BODMAS - parenthesis are always evaluated 
first.
> 

-- 
Kind Regards,
Caleb (they/he)