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From: Patrice CHOTARD <patrice.chotard@st.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v3 0/5] Add get_alt_function ops
Date: Tue, 11 Sep 2018 07:31:54 +0000	[thread overview]
Message-ID: <af4058ba-fb38-4e16-c454-3be663fce51a@st.com> (raw)
In-Reply-To: <2593e82a-13d5-9a63-4ddd-7fe378f9e1f2@xilinx.com>

Hi Michal

On 09/11/2018 07:51 AM, Michal Simek wrote:
> On 10.9.2018 18:11, Patrice Chotard wrote:
>>
>> This series :
>>   - Add new gpio ops get_alt_function
>>   - Add get_function and get_alt_function support to stm32 gpio driver
>>   - Add get_alt_function test
> 
> 
> I went quickly over this series and TBH I am not getting what this is
> for. It looks like that this is the part of pinmux.
> 
> Can you please elaborate more what this is for?

Currently, get_function callback returns the state of a gpio
(GPIOF_INPUT, GPIOF_OUTPUT or GPIO_FUNC).

If a pin's state is GPIO_FUNC, it's useful to know which alternate
function is selected for debug purpose.

As example, on STM32 SoCs, a pins can be configured as GPIO or also
configured with up to 16 alternate function. Using command "gpio", user
can retrieve this information as shown below:

STM32MP> gpio state -a

Bank GPIOA:
GPIOA0: unused: 0 [ ]
GPIOA1: unused: 0 [ ]
GPIOA2: unused: 0 [ ]
GPIOA3: unused: 0 [ ]
GPIOA4: unused: 0 [ ]
GPIOA5: unused: 0 [ ]
GPIOA6: unused: 0 [ ]
GPIOA7: unused: 0 [ ]
GPIOA8: func: 9
GPIOA9: func: 10
GPIOA10: unused: 0 [ ]
GPIOA11: unused: 0 [ ]
GPIOA12: unused: 0 [ ]
GPIOA13: output: 1 [x] red.gpios
GPIOA14: output: 0 [x] green.gpios
GPIOA15: unused: 0 [ ]

It shows that pin 8 and 9 of bank A are configured respectively in
alternate function 9 and 10.

Patrice



> 
> Thanks,
> Michal
> 

  reply	other threads:[~2018-09-11  7:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-10 16:11 [U-Boot] [PATCH v3 0/5] Add get_alt_function ops Patrice Chotard
2018-09-10 16:11 ` [U-Boot] [PATCH v3 1/5] dm: gpio: " Patrice Chotard
2018-09-10 16:11 ` [U-Boot] [PATCH v3 2/5] gpio: stm32f7: Add ops get_function Patrice Chotard
2018-09-10 16:11 ` [U-Boot] [PATCH v3 3/5] gpio: stm32f7: Add ops get_alt_function Patrice Chotard
2018-09-10 16:11 ` [U-Boot] [PATCH v3 4/5] gpio: sandbox: Rename GPIOF_(OUTPUT|HIGH|ODR) to SANDBOX_GPIO_(OUTPUT|HIGH|ODR) Patrice Chotard
2018-09-10 16:11 ` [U-Boot] [PATCH v3 5/5] test: dm: Add gpio get_alt_function ops test Patrice Chotard
2018-09-11  5:51 ` [U-Boot] [PATCH v3 0/5] Add get_alt_function ops Michal Simek
2018-09-11  7:31   ` Patrice CHOTARD [this message]
2018-09-11 10:24     ` Michal Simek
2018-09-11 11:12       ` Patrice CHOTARD
2018-09-11 12:17         ` Michal Simek
2018-09-11 13:31           ` [U-Boot] [Uboot-stm32] " Patrice CHOTARD
2018-09-11 13:45             ` Michal Simek
2018-09-11 17:03     ` [U-Boot] " Stephen Warren
2018-09-12  7:09       ` Patrice CHOTARD

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