Re: [PATCH v7 09/10] iio: adc: qcom-spmi-iadc: Migrate to devm_spmi_subdevice_alloc_and_add()

From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: jic23@kernel.org, dlechner@baylibre.com, nuno.sa@analog.com,
	andy@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org,
	srini@kernel.org, vkoul@kernel.org, neil.armstrong@linaro.org,
	sre@kernel.org, sboyd@kernel.org, krzk@kernel.org,
	dmitry.baryshkov@oss.qualcomm.com, quic_wcheng@quicinc.com,
	melody.olvera@oss.qualcomm.com, quic_nsekar@quicinc.com,
	ivo.ivanov.ivanov1@gmail.com, abelvesa@kernel.org,
	luca.weiss@fairphone.com, konrad.dybcio@oss.qualcomm.com,
	mitltlatltl@gmail.com, krishna.kurapati@oss.qualcomm.com,
	linux-arm-msm@vger.kernel.org, linux-iio@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-pm@vger.kernel.org, kernel@collabora.com,
	Jonathan Cameron <jonathan.cameron@huawei.com>
Subject: Re: [PATCH v7 09/10] iio: adc: qcom-spmi-iadc: Migrate to devm_spmi_subdevice_alloc_and_add()
Date: Wed, 14 Jan 2026 11:05:51 +0200	[thread overview]
Message-ID: <aWdcb9bTLJqhZ4Bf@smile.fi.intel.com> (raw)
In-Reply-To: <20260114083957.9945-10-angelogioacchino.delregno@collabora.com>

On Wed, Jan 14, 2026 at 09:39:56AM +0100, AngeloGioacchino Del Regno wrote:
> Some Qualcomm PMICs integrate an Current ADC device, reachable
> in a specific address range over SPMI.
> 
> Instead of using the parent SPMI device (the main PMIC) as a kind
> of syscon in this driver, register a new SPMI sub-device and
> initialize its own regmap with this sub-device's specific base
> address, retrieved from the devicetree.
> 
> This allows to stop manually adding the register base address to
> every R/W call in this driver, as this can be, and is now, handled
> by the regmap API instead.

> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-QRD

I see these tags, but just again pointing out that max_register in regmap !=
MAX! It's MAX - 1, i.e. the last *accessible* register. So, I find personally
weird the configurations which has 257 registers instead of 256.

This can be easily checked when dumping register contents via debugfs.

Plus the same comments applies here as I gave previously.

-- 
With Best Regards,
Andy Shevchenko