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path: root/drivers/mux/gpio.c
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-rw-r--r--drivers/mux/gpio.c106
1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/mux/gpio.c b/drivers/mux/gpio.c
new file mode 100644
index 0000000000..cc5f2c1861
--- /dev/null
+++ b/drivers/mux/gpio.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPIO-controlled multiplexer driver
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ *
+ * Author: Peter Rosin <peda@axentia.se>
+ */
+
+#include <linux/bitmap.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mux/driver.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+struct mux_gpio {
+ struct gpio_descs *gpios;
+};
+
+static int mux_gpio_set(struct mux_control *mux, int state)
+{
+ struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
+ DECLARE_BITMAP(values, BITS_PER_TYPE(state));
+ u32 value = state;
+
+ bitmap_from_arr32(values, &value, BITS_PER_TYPE(value));
+
+ gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
+ mux_gpio->gpios->desc,
+ mux_gpio->gpios->info, values);
+
+ return 0;
+}
+
+static const struct mux_control_ops mux_gpio_ops = {
+ .set = mux_gpio_set,
+};
+
+static const struct of_device_id mux_gpio_dt_ids[] = {
+ { .compatible = "gpio-mux", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
+
+static int mux_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mux_chip *mux_chip;
+ struct mux_gpio *mux_gpio;
+ int pins;
+ s32 idle_state;
+ int ret;
+
+ pins = gpiod_count(dev, "mux");
+ if (pins < 0)
+ return pins;
+
+ mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio));
+ if (IS_ERR(mux_chip))
+ return PTR_ERR(mux_chip);
+
+ mux_gpio = mux_chip_priv(mux_chip);
+ mux_chip->ops = &mux_gpio_ops;
+
+ mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
+ if (IS_ERR(mux_gpio->gpios))
+ return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios),
+ "failed to get gpios\n");
+ WARN_ON(pins != mux_gpio->gpios->ndescs);
+ mux_chip->mux->states = BIT(pins);
+
+ ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
+ if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
+ if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
+ dev_err(dev, "invalid idle-state %u\n", idle_state);
+ return -EINVAL;
+ }
+
+ mux_chip->mux->idle_state = idle_state;
+ }
+
+ ret = devm_mux_chip_register(dev, mux_chip);
+ if (ret < 0)
+ return ret;
+
+ dev_info(dev, "%u-way mux-controller registered\n",
+ mux_chip->mux->states);
+
+ return 0;
+}
+
+static struct platform_driver mux_gpio_driver = {
+ .driver = {
+ .name = "gpio-mux",
+ .of_match_table = mux_gpio_dt_ids,
+ },
+ .probe = mux_gpio_probe,
+};
+module_platform_driver(mux_gpio_driver);
+
+MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
+MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
+MODULE_LICENSE("GPL v2");