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authorAndreas Kaessens <akaessens@gmail.com>2021-06-10 16:24:37 +0300
committerLinus Walleij <linus.walleij@linaro.org>2021-06-12 02:58:10 +0300
commit4e73bfa3ee37277e3f3e636786fd52d89273bd79 (patch)
treeb454c349471be824e1c10deeb3e7f92a413c9824 /drivers/pinctrl
parentca199e1952cc7cfce9b416547108b52df05f61d4 (diff)
downloadlinux-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.c3
-rw-r--r--drivers/pinctrl/pinctrl-mcp23s08.h1
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;