This adds support for clock stretching to the i2c-gpio driver. This is
accomplished by switching the GPIO used for the SCL line to an input
when it should be driven high, and polling on the SCL line value until
it goes high (indicating that the I2C slave is no longer pulling it
low).
This is enabled by default; for gpios which cannot be configured as
inputs, the i2c-gpio,scl-output-only property can be used to fall back
to the previous behavior.
Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Cc: Heiko Schocher <hs@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
This patch reworks i2c-gpio to make it easier to switch out the
implementation of the sda/scl get/set functions. This is in preparation
for a patch to conditionally implement clock stretching support.
Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Cc: Heiko Schocher <hs@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
Add deblock dequence for the I2C bus, needed on some devices. This sequence
is issued once, when probing the driver, and is controlled by DT property,
"i2c-gpio,deblock".
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
U-Boot widely uses error() as a bit noisier variant of printf().
This macro causes name conflict with the following line in
include/linux/compiler-gcc.h:
# define __compiletime_error(message) __attribute__((error(message)))
This prevents us from using __compiletime_error(), and makes it
difficult to fully sync BUILD_BUG macros with Linux. (Notice
Linux's BUILD_BUG_ON_MSG is implemented by using compiletime_assert().)
Let's convert error() into now treewide-available pr_err().
Done with the help of Coccinelle, excluing tools/ directory.
The semantic patch I used is as follows:
// <smpl>
@@@@
-error
+pr_err
(...)
// </smpl>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Re-run Coccinelle]
Signed-off-by: Tom Rini <trini@konsulko.com>
At present devices use a simple integer offset to record the device tree
node associated with the device. In preparation for supporting a live
device tree, which uses a node pointer instead, refactor existing code to
access this field through an inline function.
Signed-off-by: Simon Glass <sjg@chromium.org>
dm_gpio_set_dir_flags() will also set gpio output value when switching to
gpio output. So it's not necessary to call dm_gpio_set_value() after
dm_gpio_set_dir_flags() call.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit adds driver model support to software emulated i2c bus driver.
This driver supports kernel-style device tree bindings. Fdt properties in use:
- compatible - "i2c-gpio"
- gpios - data and clock GPIO pin phandles
- delay-us - micro seconds delay between GPIOs toggle operations,
which is 1/4 of I2C speed clock period.
Added:
- Config: CONFIG_DM_I2C_GPIO
- File: drivers/i2c/i2c-gpio.c
- File: doc/device-tree-bindings/i2c/i2c-gpio.txt
Driver base code is taken from: drivers/i2c/soft-i2c.c, changes:
- use "i2c-gpio" naming
- update comments style
- move preprocesor macros into functions
- add device tree support
- add driver model i2c support
- code cleanup,
- add Kconfig entry
Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Added braces in i2c_gpio_xfer() to fix style nit:
Signed-off-by: Simon Glass <sjg@chromium.org>
