Implement i2c_idle_bus in driver, then setup_i2c can
be dropped for boards which enable DM_I2C/DM_GPIO/PINCTRL.
The i2c_idle_bus force bus idle flow follows setup_i2c in
arch/arm/imx-common/i2c-mxv7.c
This patch is an implementation following linux kernel patch:
"
commit 1c4b6c3bcf30d0804db0d0647d8ebeb862c6f7e5
Author: Gao Pan <b54642@freescale.com>
Date: Fri Oct 23 20:28:54 2015 +0800
i2c: imx: implement bus recovery
Implement bus recovery methods for i2c-imx so we can recover from
situations where SCL/SDA are stuck low.
Once i2c bus SCL/SDA are stuck low during transfer, config the i2c
pinctrl to gpio mode by calling pinctrl sleep set function, and then
use GPIO to emulate the i2c protocol to send nine dummy clock to recover
i2c device. After recovery, set i2c pinctrl to default group setting.
"
See Documentation/devicetree/bindings/i2c/i2c-imx.txt for detailed
description.
1. Introuduce scl_gpio/sda_gpio/bus in mxc_i2c_bus.
2. Discard the __weak attribute for i2c_idle_bus and implement it,
since we have pinctrl driver/driver model gpio driver. We can
use device tree, but not let board code to do this.
3. gpio state for mxc_i2c is not a must, but it is recommended. If
there is no gpio state, driver will give tips, but not fail.
4. The i2c controller was first probed, default pinctrl state will
be used, so when need to use gpio function, need to do
"pinctrl_select_state(dev, "gpio")" and after force bus idle,
need to switch back "pinctrl_select_state(dev, "default")".
This is example about how to use the gpio force bus
idle function:
"
&i2c1 {
clock-frequency = <100000>;
pinctrl-names = "default", "gpio";
pinctrl-0 = <&pinctrl_i2c1>;
pinctrl-1 = <&pinctrl_i2c1_gpio>;
scl-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>;
sda-gpios = <&gpio1 29 GPIO_ACTIVE_HIGH>;
status = "okay";
[....]
};
[.....]
pinctrl_i2c1_gpio: i2c1grp_gpio {
fsl,pins = <
MX6UL_PAD_UART4_TX_DATA__GPIO1_IO28 0x1b8b0
MX6UL_PAD_UART4_RX_DATA__GPIO1_IO29 0x1b8b0
>;
};
"
Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: York Sun <york.sun@nxp.com>
1. Introduce a new structure `struct mxc_i2c_bus`, this structure will
used for non-DM and DM.
2. Remove `struct mxc_i2c_regs` structure, but use register offset to access
registers based on `base` entry of `struct mxc_i2c_bus`.
3. Remove most `#ifdef I2C_QUIRK_REG`. Using driver_data to contain platform
flags. A new flag is introduced, I2C_QUIRK_FLAG.
4. Most functions use `struct mxc_i2c_bus` as one of the parameters.
Make most functions common to DM and non-DM, try to avoid duplicated code.
5. Support DM, but pinctrl is not included. Pinmux setting is still set
by setup_i2c, but we do not need bus_i2c_init for DM.
6. struct i2c_parms and struct sram_data are removed.
7. Remove bus_i2c_read bus_i2c_write prototype in header file. The frist
paramter of bus_i2c_init is modified to i2c index. Add new prototype
i2c_idle_bus and force_bus_idle. Since bus_i2c_init is not good for
DM I2C and pinctrl is missed, we use a weak function for i2c_idle_bus.
Board file take the responsibility to implement this function, like this:
"
int i2c_idle_bus(struct mxc_i2c_bus *i2c_bus)
{
if (i2c_bus->index == 0)
force_bus_idle(i2c_pads_info0);
else if (i2c_bus->index == 1)
force_bus_idle(i2c_pads_info1);
else
xxxxxx
}
"
8. Introduce a weak function, enable_i2c_clk
9. Tested on an i.MX7 platform. Log info:
=> dm tree
Class Probed Name
----------------------------------------
root [ + ] root_driver
simple_bus [ ] |-- soc
simple_bus [ ] | |-- aips-bus@30000000
simple_bus [ ] | | |-- anatop@30360000
simple_bus [ ] | | `-- snvs@30370000
simple_bus [ ] | |-- aips-bus@30400000
simple_bus [ ] | `-- aips-bus@30800000
i2c [ ] | |-- i2c@30a20000
i2c [ ] | `-- i2c@30a40000
simple_bus [ ] `-- regulators
=> i2c dev 0
Setting bus to 0
=> i2c probe
Valid chip addresses: 08 50
=> i2c md 8 31
0031: 08 08 08 08 08 08 08 08 08 08 08 08 08 08 08 08
Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Acked-by: Simon Glass <sjg@chromium.org>
Add macro which defines i2c_pads_info structs for multiple SoC types,
and a macro which selects the appropriate struct based on CPU type,
thus eliminating the need to manage multiple i2c pad configurations
manually when supporting multiple SoC types.
Cc: Stefano Babic <sbabic@denx.de>
Cc: Tim Harvey <tharvey@gateworks.com>
Acked-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
