abe4e4675d
These pins on the PocketBeagle P1 and P2 headers are connected to AM3358
balls with gpio lines, and these pins are not used for any other
peripherals by default. These GPIO lines are unclaimed and could be used
by userspace program through the gpiod ABI.
This patch adds a "default" state in the am33xx_pinmux node and sets the
mux for those pins to gpio (mode 7) and input enable.
The "pinctrl-single,bias-pullup" and "pinctrl-single,bias-pulldown"
pinconf properties are also set for each pin per the ball reset state in
section 4.2 of the datasheet [0].
This is the AM335x pin control register format in Table 9-60 [1]:
bit attribute value
----------------------------------
31-7 reserved 0 on reset
6 slew { 0: fast, 1: slow }
5 rx_active { 0: rx disable, 1: rx enabled }
4 pu_typesel { 0: pulldown select, 1: pullup select }
3 puden { 0: pud enable, 1: disabled }
2 mode 3 bits to selec mode 0 to 7
1 mode
0 mode
The values for the bias pinconf properties are derived as follows:
pinctrl-single,bias-pullup = <[input] [enabled] [disable] [mask]>;
pinctrl-single,bias-pullup = < 0x10 0x10 0x10 0x18 >;
2^5 2^4 2^3 2^2 2^1 2^0 |
0x20 0x10 0x08 0x04 0x02 0x01 |
--------------------------------------------------|
input x 1 0 x x x | 0x10
enabled x 1 0 x x x | 0x10
disabled x 0 0 x x x | 0x00
mask x 1 1 x x x | 0x18
pinctrl-single,bias-pulldown = <[input] [enabled] [disable] [mask]>;
pinctrl-single,bias-pulldown = < 0x0 0x0 0x10 0x18 >;
2^5 2^4 2^3 2^2 2^1 2^0 |
0x20 0x10 0x08 0x04 0x02 0x01 |
--------------------------------------------------|
input x 0 0 x x x | 0x00
enabled x 0 0 x x x | 0x00
disabled x 1 0 x x x | 0x10
mask x 1 1 x x x | 0x18
[0] http://www.ti.com/lit/ds/symlink/am3358.pdf
[1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
Signed-off-by: Drew Fustini <drew@beagleboard.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
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| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.