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From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
To: Johan Hovold <johan+linaro@kernel.org>,
	Lee Jones <lee@kernel.org>, Mark Brown <broonie@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Das Srinagesh <quic_gurus@quicinc.com>,
	Satya Priya <quic_c_skakit@quicinc.com>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org
Subject: Re: [PATCH 03/13] mfd: pm8008: deassert reset on probe
Date: Wed, 8 May 2024 17:12:51 +0100	[thread overview]
Message-ID: <4468becb-dc03-4832-aa03-5f597023fcb2@linaro.org> (raw)
In-Reply-To: <20240506150830.23709-4-johan+linaro@kernel.org>

On 06/05/2024 16:08, Johan Hovold wrote:
> Request and deassert any (optional) reset gpio during probe in case it
> has been left asserted by the boot firmware.
> 
> Note the reset line is not asserted to avoid reverting to the default
> I2C address in case the firmware has configured an alternate address.
> 
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>   drivers/mfd/qcom-pm8008.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/mfd/qcom-pm8008.c b/drivers/mfd/qcom-pm8008.c
> index d53c987b0d49..d0f190c2ea2b 100644
> --- a/drivers/mfd/qcom-pm8008.c
> +++ b/drivers/mfd/qcom-pm8008.c
> @@ -4,6 +4,7 @@
>    */
>   
>   #include <linux/bitops.h>
> +#include <linux/gpio/consumer.h>
>   #include <linux/i2c.h>
>   #include <linux/interrupt.h>
>   #include <linux/irq.h>
> @@ -158,6 +159,7 @@ static struct regmap_config qcom_mfd_regmap_cfg = {
>   static int pm8008_probe(struct i2c_client *client)
>   {
>   	struct regmap_irq_chip_data *irq_data;
> +	struct gpio_desc *reset;
>   	int rc;
>   	struct device *dev;
>   	struct regmap *regmap;
> @@ -169,6 +171,10 @@ static int pm8008_probe(struct i2c_client *client)
>   
>   	i2c_set_clientdata(client, regmap);
>   
> +	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(reset))
> +		return PTR_ERR(reset);
> +
>   	if (of_property_read_bool(dev->of_node, "interrupt-controller")) {
>   		rc = devm_regmap_add_irq_chip(dev, regmap, client->irq,
>   				IRQF_SHARED, 0, &pm8008_irq_chip, &irq_data);

So not resetting is fine and I understand you want to retain the address 
given by the firmware, I think that's the right thing to do.

You can add this now

Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

In addition to adding a small delay suggested by Andy - a few 
microseconds pick a number, I think you should verify the chip is out of 
reset as we would do with many other i2c devices.

A common pattern with i2c devices is take the device out of reset then 
read back an identity register as a smoke test.

Take drivers/media/i2c/ov8856.c::ov8856_identify_module() as an example.

In this case, suggest reading REVID_PERPH_TYPE @ 0x104 and 
REVID_PERPH_SUBTYPE @ 0x105

REVID_PERPH_TYPE @ 0x104 == 0x51 (PMIC)
REVID_PERPH_SUBYTE @ 0x105 == 0x2C (PM8008)

You can then add my

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

---
bod

  parent reply	other threads:[~2024-05-08 16:12 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-06 15:08 [PATCH 00/13] arm64: dts: qcom: sc8280xp-x13s: enable pm8008 camera pmic Johan Hovold
2024-05-06 15:08 ` [PATCH 01/13] dt-bindings: mfd: pm8008: add reset gpio Johan Hovold
2024-05-07  6:38   ` Krzysztof Kozlowski
2024-05-08 21:39   ` Stephen Boyd
2024-05-27 13:32   ` Linus Walleij
2024-05-06 15:08 ` [PATCH 02/13] mfd: pm8008: fix regmap irq chip initialisation Johan Hovold
2024-05-06 18:56   ` Andy Shevchenko
2024-05-07 15:01     ` Johan Hovold
2024-05-07 17:16       ` Andy Shevchenko
2024-05-09  8:49         ` Johan Hovold
2024-05-09 13:26           ` Andy Shevchenko
2024-05-06 15:08 ` [PATCH 03/13] mfd: pm8008: deassert reset on probe Johan Hovold
2024-05-06 18:57   ` Andy Shevchenko
2024-05-07 15:15     ` Johan Hovold
2024-05-08 16:12   ` Bryan O'Donoghue [this message]
2024-05-09  9:31     ` Johan Hovold
2024-05-29 16:17       ` Johan Hovold
2024-05-29 18:52         ` Bryan O'Donoghue
2024-05-27 13:39   ` Linus Walleij
2024-05-06 15:08 ` [PATCH 04/13] mfd: pm8008: mark regmap structures as const Johan Hovold
2024-05-08 17:37   ` Bryan O'Donoghue
2024-05-08 22:03   ` Stephen Boyd
2024-05-06 15:08 ` [PATCH 05/13] mfd: pm8008: use lower case hex notation Johan Hovold
2024-05-08 17:38   ` Bryan O'Donoghue
2024-05-08 22:03   ` Stephen Boyd
2024-05-06 15:08 ` [PATCH 06/13] mfd: pm8008: rename irq chip Johan Hovold
2024-05-08 17:38   ` Bryan O'Donoghue
2024-05-08 22:04   ` Stephen Boyd
2024-05-06 15:08 ` [PATCH 07/13] mfd: pm8008: drop unused driver data Johan Hovold
2024-05-08 17:40   ` Bryan O'Donoghue
2024-05-08 22:05   ` Stephen Boyd
2024-05-06 15:08 ` [PATCH 08/13] dt-bindings: pinctrl: qcom,pmic-gpio: drop pm8008 Johan Hovold
2024-05-07  6:41   ` Krzysztof Kozlowski
2024-05-08 22:06   ` Stephen Boyd
2024-05-06 15:08 ` [PATCH 09/13] pinctrl: qcom: spmi-gpio: drop broken pm8008 support Johan Hovold
2024-05-08 17:43   ` Bryan O'Donoghue
2024-05-08 22:06   ` Stephen Boyd
2024-05-27 13:35   ` Linus Walleij
2024-05-29 16:12     ` Johan Hovold
2024-05-06 15:08 ` [PATCH 10/13] dt-bindings: mfd: pm8008: rework binding Johan Hovold
2024-05-07  6:43   ` Krzysztof Kozlowski
2024-05-07 15:23     ` Johan Hovold
2024-05-08 22:09       ` Stephen Boyd
2024-05-09  6:57         ` Krzysztof Kozlowski
2024-05-06 15:08 ` [PATCH 11/13] mfd: pm8008: rework driver Johan Hovold
2024-05-06 19:18   ` Andy Shevchenko
2024-05-09  9:42     ` Johan Hovold
2024-05-10 13:15       ` Andy Shevchenko
2024-05-22  6:49         ` Johan Hovold
2024-05-22  7:13           ` Andy Shevchenko
2024-05-22  8:00             ` Johan Hovold
2024-05-08 17:56   ` Bryan O'Donoghue
2024-05-06 15:08 ` [PATCH 12/13] regulator: add pm8008 pmic regulator driver Johan Hovold
2024-05-06 19:09   ` Andy Shevchenko
2024-05-07 15:44     ` Johan Hovold
2024-05-07 17:22       ` Andy Shevchenko
2024-05-07 18:14         ` Krzysztof Kozlowski
2024-05-09  8:57           ` Johan Hovold
2024-05-09 10:48             ` Krzysztof Kozlowski
2024-05-09 12:26               ` Johan Hovold
2024-05-17  9:15                 ` Krzysztof Kozlowski
2024-05-08 11:41         ` Mark Brown
2024-05-09  8:53         ` Johan Hovold
2024-05-09 13:24           ` Andy Shevchenko
2024-05-14 13:43       ` Satya Priya Kakitapalli
2024-05-14 22:14         ` Konrad Dybcio
2024-05-29 16:04         ` Johan Hovold
2024-05-14 14:04       ` Satya Priya Kakitapalli
2024-05-14 14:18         ` Andy Shevchenko
2024-05-14 15:04           ` Satya Priya Kakitapalli (Temp)
2024-05-14 16:04             ` Andy Shevchenko
2024-05-07 11:48   ` Konrad Dybcio
2024-05-07 15:52     ` Johan Hovold
2024-05-08 17:55   ` Bryan O'Donoghue
2024-05-08 22:37   ` Stephen Boyd
2024-05-09  9:10     ` Johan Hovold
2024-05-29 15:55       ` Johan Hovold
2024-05-09 12:07     ` Andy Shevchenko
2024-05-09 12:20       ` Johan Hovold
2024-05-06 15:08 ` [PATCH 13/13] arm64: dts: qcom: sc8280xp-x13s: enable pm8008 camera pmic Johan Hovold
2024-05-08 17:53   ` Bryan O'Donoghue
2024-05-06 20:40 ` [PATCH 00/13] " Rob Herring (Arm)
2024-05-09  8:42   ` Johan Hovold

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