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path: root/drivers/gpio/gpio-zynqmp-modepin.c
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Diffstat (limited to 'drivers/gpio/gpio-zynqmp-modepin.c')
-rw-r--r--drivers/gpio/gpio-zynqmp-modepin.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-zynqmp-modepin.c b/drivers/gpio/gpio-zynqmp-modepin.c
new file mode 100644
index 0000000000..a0d69387c1
--- /dev/null
+++ b/drivers/gpio/gpio-zynqmp-modepin.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the ps-mode pin configuration.
+ *
+ * Copyright (c) 2021 Xilinx, Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/firmware/xlnx-zynqmp.h>
+
+/* 4-bit boot mode pins */
+#define MODE_PINS 4
+
+/**
+ * modepin_gpio_get_value - Get the state of the specified pin of GPIO device
+ * @chip: gpio_chip instance to be worked on
+ * @pin: gpio pin number within the device
+ *
+ * This function reads the state of the specified pin of the GPIO device.
+ *
+ * Return: 0 if the pin is low, 1 if pin is high, -EINVAL wrong pin configured
+ * or error value.
+ */
+static int modepin_gpio_get_value(struct gpio_chip *chip, unsigned int pin)
+{
+ u32 regval = 0;
+ int ret;
+
+ ret = zynqmp_pm_bootmode_read(&regval);
+ if (ret)
+ return ret;
+
+ /* When [0:3] corresponding bit is set, then read output bit [8:11],
+ * if the bit is clear then read input bit [4:7] for status or value.
+ */
+ if (regval & BIT(pin))
+ return !!(regval & BIT(pin + 8));
+ else
+ return !!(regval & BIT(pin + 4));
+}
+
+/**
+ * modepin_gpio_set_value - Modify the state of the pin with specified value
+ * @chip: gpio_chip instance to be worked on
+ * @pin: gpio pin number within the device
+ * @state: value used to modify the state of the specified pin
+ *
+ * This function reads the state of the specified pin of the GPIO device, mask
+ * with the capture state of GPIO pin, and update pin of GPIO device.
+ *
+ * Return: None.
+ */
+static void modepin_gpio_set_value(struct gpio_chip *chip, unsigned int pin,
+ int state)
+{
+ u32 bootpin_val = 0;
+ int ret;
+
+ zynqmp_pm_bootmode_read(&bootpin_val);
+
+ /* Configure pin as an output by set bit [0:3] */
+ bootpin_val |= BIT(pin);
+
+ if (state)
+ bootpin_val |= BIT(pin + 8);
+ else
+ bootpin_val &= ~BIT(pin + 8);
+
+ /* Configure bootpin value */
+ ret = zynqmp_pm_bootmode_write(bootpin_val);
+ if (ret)
+ pr_err("modepin: set value error %d for pin %d\n", ret, pin);
+}
+
+/**
+ * modepin_gpio_dir_in - Set the direction of the specified GPIO pin as input
+ * @chip: gpio_chip instance to be worked on
+ * @pin: gpio pin number within the device
+ *
+ * Return: 0 always
+ */
+static int modepin_gpio_dir_in(struct gpio_chip *chip, unsigned int pin)
+{
+ return 0;
+}
+
+/**
+ * modepin_gpio_dir_out - Set the direction of the specified GPIO pin as output
+ * @chip: gpio_chip instance to be worked on
+ * @pin: gpio pin number within the device
+ * @state: value to be written to specified pin
+ *
+ * Return: 0 always
+ */
+static int modepin_gpio_dir_out(struct gpio_chip *chip, unsigned int pin,
+ int state)
+{
+ return 0;
+}
+
+/**
+ * modepin_gpio_probe - Initialization method for modepin_gpio
+ * @pdev: platform device instance
+ *
+ * Return: 0 on success, negative error otherwise.
+ */
+static int modepin_gpio_probe(struct platform_device *pdev)
+{
+ struct gpio_chip *chip;
+ int status;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, chip);
+
+ /* configure the gpio chip */
+ chip->base = -1;
+ chip->ngpio = MODE_PINS;
+ chip->owner = THIS_MODULE;
+ chip->parent = &pdev->dev;
+ chip->get = modepin_gpio_get_value;
+ chip->set = modepin_gpio_set_value;
+ chip->direction_input = modepin_gpio_dir_in;
+ chip->direction_output = modepin_gpio_dir_out;
+ chip->label = dev_name(&pdev->dev);
+
+ /* modepin gpio registration */
+ status = devm_gpiochip_add_data(&pdev->dev, chip, chip);
+ if (status)
+ return dev_err_probe(&pdev->dev, status,
+ "Failed to add GPIO chip\n");
+
+ return status;
+}
+
+static const struct of_device_id modepin_platform_id[] = {
+ { .compatible = "xlnx,zynqmp-gpio-modepin", },
+ { }
+};
+
+static struct platform_driver modepin_platform_driver = {
+ .driver = {
+ .name = "modepin-gpio",
+ .of_match_table = modepin_platform_id,
+ },
+ .probe = modepin_gpio_probe,
+};
+
+module_platform_driver(modepin_platform_driver);
+
+MODULE_AUTHOR("Piyush Mehta <piyush.mehta@xilinx.com>");
+MODULE_DESCRIPTION("ZynqMP Boot PS_MODE Configuration");
+MODULE_LICENSE("GPL v2");