diff options
| author | Andreas Kaessens <akaessens@gmail.com> | 2021-06-10 16:24:37 +0300 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2021-06-12 02:58:10 +0300 |
| commit | 4e73bfa3ee37277e3f3e636786fd52d89273bd79 (patch) | |
| tree | b454c349471be824e1c10deeb3e7f92a413c9824 /drivers/pinctrl | |
| parent | ca199e1952cc7cfce9b416547108b52df05f61d4 (diff) | |
| download | linux-4e73bfa3ee37277e3f3e636786fd52d89273bd79.tar.xz | |
pinctrl: mcp23s08: Add optional reset GPIO
The MCP23x port expander RESET# line can be connected to a host GPIO.
The optional reset-gpio must be set to LOW if the reset is asserted
at probing time.
On page 5 in the datasheet [0] the "Device Active After Reset high"
time is specified at 0 µs. Therefore no waiting is needed after the
reset transition.
[0] https://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf
Signed-off-by: Andreas Kaessens <akaessens@gmail.com>
Signed-off-by: Darian Biastoch <d.biastoch@gmail.com>
Link: https://lore.kernel.org/r/20210610132438.3085841-1-akaessens@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl')
| -rw-r--r-- | drivers/pinctrl/pinctrl-mcp23s08.c | 3 | ||||
| -rw-r--r-- | drivers/pinctrl/pinctrl-mcp23s08.h | 1 |
2 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pinctrl/pinctrl-mcp23s08.c b/drivers/pinctrl/pinctrl-mcp23s08.c index d0259577934e..bccebe43dd6a 100644 --- a/drivers/pinctrl/pinctrl-mcp23s08.c +++ b/drivers/pinctrl/pinctrl-mcp23s08.c @@ -9,6 +9,7 @@ #include <linux/module.h> #include <linux/export.h> #include <linux/gpio/driver.h> +#include <linux/gpio/consumer.h> #include <linux/slab.h> #include <asm/byteorder.h> #include <linux/interrupt.h> @@ -558,6 +559,8 @@ int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev, mcp->chip.parent = dev; mcp->chip.owner = THIS_MODULE; + mcp->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + /* verify MCP_IOCON.SEQOP = 0, so sequential reads work, * and MCP_IOCON.HAEN = 1, so we work with all chips. */ diff --git a/drivers/pinctrl/pinctrl-mcp23s08.h b/drivers/pinctrl/pinctrl-mcp23s08.h index 90dc27081a3c..b8d15939e0c2 100644 --- a/drivers/pinctrl/pinctrl-mcp23s08.h +++ b/drivers/pinctrl/pinctrl-mcp23s08.h @@ -43,6 +43,7 @@ struct mcp23s08 { struct pinctrl_dev *pctldev; struct pinctrl_desc pinctrl_desc; + struct gpio_desc *reset_gpio; }; extern const struct regmap_config mcp23x08_regmap; |