Open Source and information security mailing list archives

Message-ID: <b387ebdd-ae5d-4711-9e10-c61cb06f4b5b@riscstar.com>
Date: Mon, 25 Aug 2025 11:08:45 -0500
From: Alex Elder <elder@...cstar.com>
To: Troy Mitchell <troy.mitchell@...ux.spacemit.com>, lee@...nel.org,
 lgirdwood@...il.com, broonie@...nel.org, alexandre.belloni@...tlin.com,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org
Cc: mat.jonczyk@...pl, dlan@...too.org, paul.walmsley@...ive.com,
 palmer@...belt.com, aou@...s.berkeley.edu, alex@...ti.fr,
 linux.amoon@...il.com, troymitchell988@...il.com, guodong@...cstar.com,
 linux-rtc@...r.kernel.org, devicetree@...r.kernel.org,
 linux-riscv@...ts.infradead.org, spacemit@...ts.linux.dev,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v12 2/7] mfd: simple-mfd-i2c: add SpacemiT P1 support

On 8/14/25 9:28 PM, Troy Mitchell wrote:
> Hi, Alex,
> 
> I did not find any accesses to the P1 shutdown or reboot registers here.
> Does this mean that the current series does not support reboot or shutdown?

Yes, that is correct.

> If so, do you have any plans to support this functionality?

At this time I personally don't have any plans to add this, but
it could be added later (by anyone).

I actually attempted to do this initially, but gave up.  The PMIC
is accessed via I2C, and I needed to implement a non-blocking
version of the I2C register write operation.  I tried that, but
then found that the shutdown or reboot still did not work reliably.
As it was, this was more than I originally planned to do, so I just
implemented the simple RTC operations instead.

					-Alex

> If I have misunderstood, please correct me.
> 
> Best regards,
> Troy
> 
> 
> On Tue, Aug 12, 2025 at 09:45:03PM -0500, Alex Elder wrote:
>> Enable support for the RTC and regulators found in the SpacemiT P1
>> PMIC.  Support is implemented by the simple I2C MFD driver.
>>
>> The P1 PMIC is normally implemented with the SpacemiT K1 SoC.  This
>> PMIC provides 6 buck converters and 12 LDO regulators.  It also
>> implements a switch, watchdog timer, real-time clock, and more.
>> Initially its RTC and regulators are supported.
>>
>> Signed-off-by: Alex Elder <elder@...cstar.com>
>> ---
>>   drivers/mfd/Kconfig          | 11 +++++++++++
>>   drivers/mfd/simple-mfd-i2c.c | 18 ++++++++++++++++++
>>   2 files changed, 29 insertions(+)
>>
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 425c5fba6cb1e..4d6a5a3a27220 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -1238,6 +1238,17 @@ config MFD_QCOM_RPM
>>   	  Say M here if you want to include support for the Qualcomm RPM as a
>>   	  module. This will build a module called "qcom_rpm".
>>   
>> +config MFD_SPACEMIT_P1
>> +	tristate "SpacemiT P1 PMIC"
>> +	depends on I2C
>> +	select MFD_SIMPLE_MFD_I2C
>> +	help
>> +	  This option supports the I2C-based SpacemiT P1 PMIC, which
>> +	  contains regulators, a power switch, GPIOs, an RTC, and more.
>> +	  This option is selected when any of the supported sub-devices
>> +	  is configured.  The basic functionality is implemented by the
>> +	  simple MFD I2C driver.
>> +
>>   config MFD_SPMI_PMIC
>>   	tristate "Qualcomm SPMI PMICs"
>>   	depends on ARCH_QCOM || COMPILE_TEST
>> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
>> index 22159913bea03..47ffaac035cae 100644
>> --- a/drivers/mfd/simple-mfd-i2c.c
>> +++ b/drivers/mfd/simple-mfd-i2c.c
>> @@ -93,12 +93,30 @@ static const struct simple_mfd_data maxim_mon_max77705 = {
>>   	.mfd_cell_size = ARRAY_SIZE(max77705_sensor_cells),
>>   };
>>   
>> +
>> +static const struct regmap_config spacemit_p1_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +};
>> +
>> +static const struct mfd_cell spacemit_p1_cells[] = {
>> +	{ .name = "spacemit-p1-regulator", },
>> +	{ .name = "spacemit-p1-rtc", },
>> +};
>> +
>> +static const struct simple_mfd_data spacemit_p1 = {
>> +	.regmap_config = &spacemit_p1_regmap_config,
>> +	.mfd_cell = spacemit_p1_cells,
>> +	.mfd_cell_size = ARRAY_SIZE(spacemit_p1_cells),
>> +};
>> +
>>   static const struct of_device_id simple_mfd_i2c_of_match[] = {
>>   	{ .compatible = "kontron,sl28cpld" },
>>   	{ .compatible = "silergy,sy7636a", .data = &silergy_sy7636a},
>>   	{ .compatible = "maxim,max5970", .data = &maxim_max5970},
>>   	{ .compatible = "maxim,max5978", .data = &maxim_max5970},
>>   	{ .compatible = "maxim,max77705-battery", .data = &maxim_mon_max77705},
>> +	{ .compatible = "spacemit,p1", .data = &spacemit_p1, },
>>   	{}
>>   };
>>   MODULE_DEVICE_TABLE(of, simple_mfd_i2c_of_match);
>> -- 
>> 2.48.1
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives