diff mbox series

[2/2] gpio: gpio-adg1414: New driver

Message ID 20240121103505.26475-3-kimseer.paller@analog.com
State New
Headers show
Series ADG1414 for review | expand

Commit Message

Kim Seer Paller Jan. 21, 2024, 10:35 a.m. UTC 
The ADG1414 is a 9.5 Ω RON ±15 V/+12 V/±5 V iCMOS Serially-Controlled
Octal SPST Switches

Signed-off-by: Kim Seer Paller <kimseer.paller@analog.com>
---
 MAINTAINERS                 |   1 +
 drivers/gpio/Kconfig        |  10 +++
 drivers/gpio/Makefile       |   1 +
 drivers/gpio/gpio-adg1414.c | 141 ++++++++++++++++++++++++++++++++++++
 4 files changed, 153 insertions(+)
 create mode 100644 drivers/gpio/gpio-adg1414.c

Comments

Linus Walleij Jan. 23, 2024, 9:50 p.m. UTC | #1 
Hi Kim,

On Tue, Jan 23, 2024 at 11:31 AM Paller, Kim Seer
<KimSeer.Paller@analog.com> wrote:

> > Locking here is simple enough that you could use the SPI regmap and
> > get it to do the serialization for you. And then you could possibly
> > reuse the gpio-regmap abstraction and get an even smaller footprint.
>
> I could not seem to figure out how to use the SPI regmap in this case.
> Since the number of daisy-chained devices depends on the length of
> data transferred with continuous transaction, I could not determine
> how to implement that using the SPI regmap. Or maybe I misunderstood
> the statement. However, is it still acceptable to use the current approach?

You just override or wrap with your own read/write callbacks if necessary
by defining a custom static struct regmap_bus.

For example in drivers/gpu/drm/panel/panel-ilitek-ili9322.c
I do this.

It may not save a lot of code in this case but it's still worth it because
we understand what regmap_read/write/update_bits do and reading
and understanding adg1414_set/get cognitively require more from us
as maintainers.

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 526145e69..254ba7ea5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -466,6 +466,7 @@  M:	Kim Seer Paller <kimseer.paller@analog.com>
 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/gpio/gpio-adg1414.yaml
+F:	drivers/gpio/gpio-adg1414.c
 
 ADM1025 HARDWARE MONITOR DRIVER
 M:	Jean Delvare <jdelvare@suse.com>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1301cec94..25d467d70 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1728,6 +1728,16 @@  config GPIO_74X164
 	  shift registers. This driver can be used to provide access
 	  to more GPIO outputs.
 
+config GPIO_ADG1414
+	tristate "ADG1414 SPST Switch Driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices ADG1414 SPST
+	  Switch Driver
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gpio-adg1414.
+
 config GPIO_MAX3191X
 	tristate "Maxim MAX3191x industrial serializer"
 	select CRC8
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 9e40af196..9ab45d128 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -24,6 +24,7 @@  obj-$(CONFIG_GPIO_104_IDI_48)		+= gpio-104-idi-48.o
 obj-$(CONFIG_GPIO_104_IDIO_16)		+= gpio-104-idio-16.o
 obj-$(CONFIG_GPIO_74X164)		+= gpio-74x164.o
 obj-$(CONFIG_GPIO_74XX_MMIO)		+= gpio-74xx-mmio.o
+obj-$(CONFIG_GPIO_ADG1414)		+= gpio-adg1414.o
 obj-$(CONFIG_GPIO_ADNP)			+= gpio-adnp.o
 obj-$(CONFIG_GPIO_ADP5520)		+= gpio-adp5520.o
 obj-$(CONFIG_GPIO_AGGREGATOR)		+= gpio-aggregator.o
diff --git a/drivers/gpio/gpio-adg1414.c b/drivers/gpio/gpio-adg1414.c
new file mode 100644
index 000000000..6c0830ee2
--- /dev/null
+++ b/drivers/gpio/gpio-adg1414.c
@@ -0,0 +1,141 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADG1414 SPST Switch Driver
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/property.h>
+
+#define ADG1414_MAX_DEVICES		4
+
+struct adg1414_state {
+	struct spi_device		*spi;
+	struct gpio_chip		chip;
+	struct mutex			lock; /* protect sensor state */
+	u32				buf;
+
+	__be32				tx __aligned(ARCH_DMA_MINALIGN);
+};
+
+static void adg1414_set(struct gpio_chip *chip,
+			unsigned int offset,
+			int value)
+{
+	struct adg1414_state *st = gpiochip_get_data(chip);
+	int ret;
+
+	struct spi_transfer xfer = {
+		.tx_buf = &st->tx,
+		.len = st->chip.ngpio / 8,
+	};
+
+	mutex_lock(&st->lock);
+
+	if (value)
+		st->buf |= BIT(offset);
+	else
+		st->buf &= ~BIT(offset);
+
+	st->tx = cpu_to_be32(st->buf << (32 - st->chip.ngpio));
+
+	ret = spi_sync_transfer(st->spi, &xfer, 1);
+	if (ret)
+		goto out;
+
+out:
+	mutex_unlock(&st->lock);
+}
+
+static int adg1414_get(struct gpio_chip *chip,
+		       unsigned int offset)
+{
+	struct adg1414_state *st = gpiochip_get_data(chip);
+	int value;
+
+	mutex_lock(&st->lock);
+
+	value = st->buf & BIT(offset);
+
+	mutex_unlock(&st->lock);
+
+	return value;
+}
+
+static int adg1414_get_direction(struct gpio_chip *chip,
+				 unsigned int offset)
+{
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int adg1414_probe(struct spi_device *spi)
+{
+	struct adg1414_state *st;
+	struct gpio_desc *reset;
+	struct device *dev = &spi->dev;
+	u32 num_devices;
+	int ret;
+
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+	if (!st)
+		return -ENOMEM;
+
+	st->spi = spi;
+
+	/* Use reset pin to reset the device */
+	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset),
+				     "Failed to get reset gpio");
+
+	if (reset) {
+		fsleep(1);
+		gpiod_set_value_cansleep(reset, 0);
+	}
+
+	num_devices = 1;
+	ret = device_property_read_u32(dev, "#daisy-chained-devices",
+				       &num_devices);
+	if (!ret) {
+		if (!num_devices || num_devices > ADG1414_MAX_DEVICES)
+			return dev_err_probe(dev, ret,
+			       "Failed to get daisy-chained-devices property\n");
+	}
+
+	st->chip.label = "adg1414";
+	st->chip.parent = dev;
+	st->chip.get_direction = adg1414_get_direction;
+	st->chip.set = adg1414_set;
+	st->chip.get = adg1414_get;
+	st->chip.base = -1;
+	st->chip.ngpio =  num_devices * 8;
+	st->chip.can_sleep = true;
+
+	mutex_init(&st->lock);
+
+	return devm_gpiochip_add_data(dev, &st->chip, st);
+}
+
+static const struct of_device_id adg1414_of_match[] = {
+	{ .compatible = "adi,adg1414" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adg1414_of_match);
+
+static struct spi_driver adg1414_driver = {
+	.driver = {
+		.name = "adg1414",
+		.of_match_table = adg1414_of_match,
+	},
+	.probe = adg1414_probe,
+};
+module_spi_driver(adg1414_driver);
+
+MODULE_AUTHOR("Kim Seer Paller <kimseer.paller@analog.com>");
+MODULE_DESCRIPTION("ADG1414 SPST Switch Driver");
+MODULE_LICENSE("GPL");