2018-09-13 08:25:28

by Jisheng Zhang

Subject: [PATCH v2] i2c: designware: select gpio/default pin when prepare/unprepare recovery

On some platforms, the sda/scl pins are muxed with gpio functions, so
they could be used for recovery. Select the gpio/default pin function
when prepare/unprepare recovery.

Signed-off-by: Jisheng Zhang <[email protected]>
---

since v1:
- use IS_ERR_OR_NULL

drivers/i2c/busses/i2c-designware-core.h | 3 +++
drivers/i2c/busses/i2c-designware-master.c | 22 ++++++++++++++++++++++
2 files changed, 25 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index e367b1af4ab2..01d5f01691a4 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -271,6 +271,9 @@ struct dw_i2c_dev {
int (*init)(struct dw_i2c_dev *dev);
int mode;
struct i2c_bus_recovery_info rinfo;
+ struct pinctrl *pinctrl;
+ struct pinctrl_state *pins_default;
+ struct pinctrl_state *pins_gpio;
};

#define ACCESS_SWAP 0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 94d94b4a9a0d..384d6630366a 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

@@ -629,6 +630,9 @@ static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);

+ if (dev->pinctrl && dev->pins_gpio)
+ pinctrl_select_state(dev->pinctrl, dev->pins_gpio);
+
i2c_dw_disable(dev);
reset_control_assert(dev->rst);
i2c_dw_prepare_clk(dev, false);
@@ -641,6 +645,9 @@ static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
i2c_dw_prepare_clk(dev, true);
reset_control_deassert(dev->rst);
i2c_dw_init_master(dev);
+
+ if (dev->pinctrl && dev->pins_default)
+ pinctrl_select_state(dev->pinctrl, dev->pins_default);
}

static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
@@ -648,6 +655,8 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
struct i2c_adapter *adap = &dev->adapter;
struct gpio_desc *gpio;
+ struct pinctrl *pinctrl;
+ struct pinctrl_state *s;
int r;

gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
@@ -664,6 +673,19 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
return PTR_ERR(gpio);
rinfo->sda_gpiod = gpio;

+ pinctrl = devm_pinctrl_get(dev->dev);
+ if (PTR_ERR(pinctrl) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ if (!IS_ERR_OR_NULL(pinctrl)) {
+ dev->pinctrl = pinctrl;
+ s = pinctrl_lookup_state(pinctrl, PINCTRL_STATE_DEFAULT);
+ if (!IS_ERR_OR_NULL(s))
+ dev->pins_default = s;
+ s = pinctrl_lookup_state(pinctrl, "gpio");
+ if (!IS_ERR_OR_NULL(s))
+ dev->pins_gpio = s;
+ }
+
rinfo->recover_bus = i2c_generic_scl_recovery;
rinfo->prepare_recovery = i2c_dw_prepare_recovery;
rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
--
2.19.0

2018-09-13 13:51:38

by Jarkko Nikula

Subject: Re: [PATCH v2] i2c: designware: select gpio/default pin when prepare/unprepare recovery

On 09/13/2018 11:21 AM, Jisheng Zhang wrote:
> On some platforms, the sda/scl pins are muxed with gpio functions, so
> they could be used for recovery. Select the gpio/default pin function
> when prepare/unprepare recovery.
>
> Signed-off-by: Jisheng Zhang <[email protected]>
> ---
>
> since v1:
> - use IS_ERR_OR_NULL
>
> drivers/i2c/busses/i2c-designware-core.h | 3 +++
> drivers/i2c/busses/i2c-designware-master.c | 22 ++++++++++++++++++++++
> 2 files changed, 25 insertions(+)
>
...
> + pinctrl = devm_pinctrl_get(dev->dev);
> + if (PTR_ERR(pinctrl) == -EPROBE_DEFER)
> + return -EPROBE_DEFER;
> + if (!IS_ERR_OR_NULL(pinctrl)) {
> + dev->pinctrl = pinctrl;
> + s = pinctrl_lookup_state(pinctrl, PINCTRL_STATE_DEFAULT);
> + if (!IS_ERR_OR_NULL(s))
> + dev->pins_default = s;
> + s = pinctrl_lookup_state(pinctrl, "gpio");
> + if (!IS_ERR_OR_NULL(s))
> + dev->pins_gpio = s;
> + }
> +

Should these be documented in
Documentation/devicetree/bindings/i2c/i2c-designware.txt?

--
Jarkko