[PATCH linux v1] drivers: misc: Seven segment support
Jaghathiswari Rankappagounder Natarajan
jaghu at google.com
Sat Feb 11 05:19:43 AEDT 2017
Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu at google.com>
---
.../devicetree/bindings/misc/seven-seg-gpio.txt | 27 +++
arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts | 8 +
drivers/misc/Kconfig | 16 ++
drivers/misc/Makefile | 2 +
drivers/misc/seven_seg_disp.c | 201 ++++++++++++++++++++
drivers/misc/seven_seg_disp.h | 34 ++++
drivers/misc/seven_seg_gpio.c | 206 +++++++++++++++++++++
7 files changed, 494 insertions(+)
create mode 100644 Documentation/devicetree/bindings/misc/seven-seg-gpio.txt
create mode 100644 drivers/misc/seven_seg_disp.c
create mode 100644 drivers/misc/seven_seg_disp.h
create mode 100644 drivers/misc/seven_seg_gpio.c
diff --git a/Documentation/devicetree/bindings/misc/seven-seg-gpio.txt b/Documentation/devicetree/bindings/misc/seven-seg-gpio.txt
new file mode 100644
index 000000000000..248e3ecc538b
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/seven-seg-gpio.txt
@@ -0,0 +1,27 @@
+This binding defines interface to add clock, data and clear GPIO lines required
+for seven segment display support.
+
+Required properties:
+- compatible : should be "seven-seg-gpio-dev".
+- clock-gpios : Should specify the GPIO pin connected to the Clock line on the
+ hardware.
+- data-gpios : Should specify the GPIO pin connected to Data line on the
+ hardware.
+- clear-gpios : Should specify the GPIO pin connected to Clear line on the
+ hardware.
+
+Optional properties:
+- refresh-interval-ms : The interval at which to refresh the display.
+ If this property is not present, the default value is 1000.
+
+Examples:
+
+#include <dt-bindings/gpio/gpio.h>
+
+seven-seg-disp {
+ compatible = "seven-seg-gpio-dev";
+ refresh-interval-ms = /bits/ 16 <600>;
+ clock-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+ data-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+ clear-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+};
diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts b/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts
index e2195a641414..d70ede74735d 100644
--- a/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts
+++ b/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts
@@ -74,6 +74,14 @@
gpios = <&gpio ASPEED_GPIO(AA, 2) GPIO_ACTIVE_LOW>;
};
};
+
+ seven-seg-disp {
+ compatible = "seven-seg-gpio-dev";
+ refresh-interval-ms = /bits/ 16 <600>;
+ clock-gpios = <&gpio ASPEED_GPIO(J, 0) GPIO_ACTIVE_HIGH>;
+ data-gpios = <&gpio ASPEED_GPIO(J, 2) GPIO_ACTIVE_HIGH>;
+ clear-gpios = <&gpio ASPEED_GPIO(J, 1) GPIO_ACTIVE_HIGH>;
+ };
};
&fmc {
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index c802d2245108..c2914476e49e 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -804,6 +804,14 @@ config PANEL_BOOT_MESSAGE
An empty message will only clear the display at driver init time. Any other
printf()-formatted message is valid with newline and escape codes.
+config SEVEN_SEGMENT_DISPLAY
+ tristate "Character driver for seven segment display support"
+ help
+ Character device driver which implements the user-space
+ API for letting a user write to two 7-segment displays including
+ any conversion methods necessary to map the user input
+ to two 7-segment displays.
+
config ASPEED_LPC_CTRL
depends on (ARCH_ASPEED || COMPILE_TEST) && REGMAP && MFD_SYSCON
bool "Aspeed BMC to HOST LPC bus controller"
@@ -812,6 +820,14 @@ config ASPEED_LPC_CTRL
through ioctl()s, the driver aso provides a read/write interface to a
BMC ram region where host LPC read/write region can be buffered.
+config SEVEN_SEGMENT_GPIO
+ tristate "Platform driver to update seven segment display"
+ depends on SEVEN_SEGMENT_DISPLAY
+ help
+ Platform device driver which provides an API for displaying on two
+ 7-segment displays, and implements the required bit-banging.
+ The hardware assumed is 74HC164 wired to two 7-segment displays.
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index cdcd1af48971..be1852bc3282 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,4 +57,6 @@ obj-$(CONFIG_ECHO) += echo/
obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_PANEL) += panel.o
+obj-SEVEN_SEGMENT_DISPLAY += seven_seg_disp.o
obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o
+obj-SEVEN_SEGMENT_GPIO += seven_seg_gpio.o
diff --git a/drivers/misc/seven_seg_disp.c b/drivers/misc/seven_seg_disp.c
new file mode 100644
index 000000000000..c5350c904188
--- /dev/null
+++ b/drivers/misc/seven_seg_disp.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/kdev_t.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/ctype.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+#include "seven_seg_disp.h"
+
+#define LED_DOT 0x01
+
+/*
+ * 0 1 2 3 4 5 6 7 8 9 A B C D E F
+ * _ _ _ _ _ _ _ _ _ _ _ _
+ * | | | _| _| |_| |_ |_ | |_| |_| |_| |_ | _| |_ |_
+ * |_| | |_ _| | _| |_| | |_| | | | |_| |_ |_| |_ |
+ *
+ * data[7:1] = led[a:g]
+ */
+const u8 seven_seg_bits[] = {
+ 0xFC, 0x60, 0xDA, 0xF2, 0x66, 0xB6, 0xBE, 0xE0,
+ 0xFE, 0xF6, 0xEE, 0x3E, 0x9C, 0x7A, 0x9E, 0x8E
+ };
+
+/*
+ * 0 1 2 3 4 5 6 7 8 9 A B C D E F
+ * _ _ _ _ _
+ * | |_ |_| |_ _ _ _ _ _ _ _ |_ _| _| | |
+ * |_ |_ | | _| |_| |_| | |
+ *
+ * data[7:1] = led[a:g]
+ */
+const u8 special_seven_seg_bits[] = {
+ 0x00, 0x9C, 0x1E, 0xCE, 0x8E, 0x02, 0x02, 0x02,
+ 0x02, 0x02, 0x02, 0x02, 0xB6, 0x7A, 0x7A, 0xEC
+ };
+
+static dev_t seven_seg_devno;
+static struct class *seven_seg_disp_class;
+
+static int seven_seg_disp_open(struct inode *inode, struct file *filp)
+{
+ struct seven_seg_disp_dev *disp_dev;
+
+ disp_dev = container_of(inode->i_cdev,
+ struct seven_seg_disp_dev, cdev);
+ filp->private_data = disp_dev;
+ return 0;
+}
+
+static int seven_seg_disp_close(struct inode *inode, struct file *filp)
+{
+ filp->private_data = NULL;
+ return 0;
+}
+
+static ssize_t seven_seg_disp_read(struct file *filp, char __user *buf, size_t
+ len, loff_t *off)
+{
+ struct seven_seg_disp_dev *disp_dev = filp->private_data;
+
+ if (disp_dev->disp_data_valid)
+ return -EINVAL;
+
+ if (copy_to_user(buf, disp_dev->seven_seg_disp_data_array,
+ MAX_DISP_CHAR_SIZE) != 0) {
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+static u16 convert_to_disp_data(char *buf)
+{
+ u8 low_display;
+ u8 high_display;
+ u16 led_value;
+
+ low_display = seven_seg_bits[hex_to_bin(buf[2])];
+
+ high_display = (buf[0] == '1') ?
+ special_seven_seg_bits[hex_to_bin(buf[1])] :
+ seven_seg_bits[hex_to_bin(buf[1])];
+
+ led_value = low_display | (high_display << 8);
+ if (buf[0] == '1')
+ led_value |= LED_DOT | (LED_DOT << 8);
+
+ return led_value;
+}
+
+static ssize_t seven_seg_disp_write(struct file *filp, const char __user *buf,
+ size_t len, loff_t *off)
+{
+ int length = len - 1;
+ int i;
+
+ struct seven_seg_disp_dev *disp_dev = filp->private_data;
+
+ if (length != MAX_DISP_CHAR_SIZE)
+ return -EINVAL;
+
+ if (copy_from_user(disp_dev->seven_seg_disp_data_array,
+ buf, length) != 0) {
+ return -EFAULT;
+ }
+
+ for (i = 0; i < MAX_DISP_CHAR_SIZE; i++) {
+ if (!isxdigit(disp_dev->seven_seg_disp_data_array[i]))
+ return -EINVAL;
+ }
+
+ disp_dev->current_seven_seg_disp_data = convert_to_disp_data(
+ disp_dev->seven_seg_disp_data_array);
+ disp_dev->disp_data_valid = true;
+ disp_dev->update_seven_seg_data(&disp_dev->parent,
+ disp_dev->current_seven_seg_disp_data);
+
+ return len;
+}
+
+static const struct file_operations seven_seg_disp_fops = {
+
+ .owner = THIS_MODULE,
+ .open = seven_seg_disp_open,
+ .release = seven_seg_disp_close,
+ .read = seven_seg_disp_read,
+ .write = seven_seg_disp_write
+};
+
+void seven_seg_rem_cdev(struct seven_seg_disp_dev *disp_dev)
+{
+ cdev_del(&disp_dev->cdev);
+ device_destroy(seven_seg_disp_class, seven_seg_devno);
+}
+
+int seven_seg_setup_cdev(struct seven_seg_disp_dev *disp_dev,
+ void (*update_disp_data)(struct device *, u16 data))
+{
+ struct device *dev;
+ int err;
+
+ dev = device_create(seven_seg_disp_class, &disp_dev->parent,
+ seven_seg_devno,
+ NULL, "seven_seg_disp_val");
+ if (dev == NULL)
+ return -EIO;
+ disp_dev->dev = dev;
+ disp_dev->update_seven_seg_data = update_disp_data;
+ disp_dev->disp_data_valid = false;
+
+ cdev_init(&disp_dev->cdev, &seven_seg_disp_fops);
+ err = cdev_add(&disp_dev->cdev, seven_seg_devno, 1);
+ if (err)
+ device_destroy(seven_seg_disp_class, seven_seg_devno);
+ return err;
+}
+
+static int __init seven_seg_disp_init(void)
+{
+ int err = alloc_chrdev_region(&seven_seg_devno, 0, 1, "disp_state");
+
+ if (err < 0)
+ return err;
+
+ seven_seg_disp_class = class_create(THIS_MODULE, "disp_state");
+ if (seven_seg_disp_class == NULL)
+ goto unreg_chrdev;
+
+ return 0;
+
+unreg_chrdev:
+ unregister_chrdev_region(seven_seg_devno, 1);
+ return -EIO;
+}
+
+static void __exit seven_seg_disp_exit(void)
+{
+ class_destroy(seven_seg_disp_class);
+ unregister_chrdev_region(seven_seg_devno, 1);
+}
+
+module_init(seven_seg_disp_init);
+module_exit(seven_seg_disp_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jaghathiswari Rankappagounder Natarajan <jaghu at google.com>");
+MODULE_DESCRIPTION("Seven segment display character driver");
diff --git a/drivers/misc/seven_seg_disp.h b/drivers/misc/seven_seg_disp.h
new file mode 100644
index 000000000000..0ebed0802747
--- /dev/null
+++ b/drivers/misc/seven_seg_disp.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef SEVEN_SEG_DISP_H
+#define SEVEN_SEG_DISP_H
+
+#include <linux/device.h>
+#include <linux/cdev.h>
+
+#define MAX_DISP_CHAR_SIZE 3
+
+#define DEFAULT_REFRESH_INTERVAL_MS 600
+
+struct seven_seg_disp_dev {
+ bool disp_data_valid;
+ u16 current_seven_seg_disp_data;
+ char seven_seg_disp_data_array[MAX_DISP_CHAR_SIZE];
+ struct device parent;
+ struct device *dev;
+ struct cdev cdev;
+ void (*update_seven_seg_data)(struct device *, u16 data);
+};
+
+int seven_seg_setup_cdev(struct seven_seg_disp_dev *disp_dev,
+ void (*update_disp_data)(struct device *, u16 data));
+
+void seven_seg_rem_cdev(struct seven_seg_disp_dev *disp_dev);
+
+#endif
diff --git a/drivers/misc/seven_seg_gpio.c b/drivers/misc/seven_seg_gpio.c
new file mode 100644
index 000000000000..3dcb9034e263
--- /dev/null
+++ b/drivers/misc/seven_seg_gpio.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/sizes.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/gpio/consumer.h>
+
+#include "seven_seg_disp.h"
+
+#define DELAY_INTVL_US 1
+
+#define CLOCK_GPIO_NAME "clock"
+#define DATA_GPIO_NAME "data"
+#define CLEAR_GPIO_NAME "clear"
+
+struct seven_seg_gpio_info {
+ u16 curr_disp_value;
+ u16 refresh_interval;
+ struct timer_list update_timer;
+ struct gpio_desc *clock_gpio;
+ struct gpio_desc *data_gpio;
+ struct gpio_desc *clear_gpio;
+};
+
+static void update_seven_seg_gpio_data(struct device *dev, u16 data)
+{
+ struct platform_device *pdev;
+ struct seven_seg_gpio_info *gpio_info;
+
+ pdev = container_of(dev, struct platform_device, dev);
+ if (pdev == NULL) {
+ pr_err("invalid NULL platform_device\n");
+ return;
+ }
+
+ gpio_info = platform_get_drvdata(pdev);
+ if (gpio_info == NULL) {
+ pr_err("invalid NULL gpio_info\n");
+ return;
+ }
+
+ gpio_info->curr_disp_value = data;
+}
+
+static void clear_seven_seg_gpio_data(struct device *dev, u16 data)
+{
+ struct platform_device *pdev;
+ struct seven_seg_gpio_info *gpio_info;
+
+ pdev = container_of(dev, struct platform_device, dev);
+ if (pdev == NULL) {
+ pr_err("invalid NULL platform_device\n");
+ return;
+ }
+
+ gpio_info = platform_get_drvdata(pdev);
+ if (gpio_info == NULL) {
+ pr_err("invalid NULL gpio_info\n");
+ return;
+ }
+
+ gpio_info->curr_disp_value = 0;
+}
+
+static void send_seven_seg_gpio_data(u16 disp_data,
+ struct seven_seg_gpio_info *gpio_info)
+{
+ int i;
+
+ gpiod_set_value(gpio_info->clear_gpio, 0);
+ udelay(DELAY_INTVL_US);
+ gpiod_set_value(gpio_info->clear_gpio, 1);
+ udelay(DELAY_INTVL_US);
+
+ for (i = 0; i < 16; i++) {
+ if (disp_data & 0x01)
+ gpiod_set_value(gpio_info->data_gpio, 1);
+ else
+ gpiod_set_value(gpio_info->data_gpio, 0);
+
+ udelay(DELAY_INTVL_US);
+
+ gpiod_set_value(gpio_info->clock_gpio, 0);
+ udelay(DELAY_INTVL_US);
+ gpiod_set_value(gpio_info->clock_gpio, 1);
+ udelay(DELAY_INTVL_US);
+
+ disp_data >>= 1;
+ }
+}
+
+static void disp_refresh_timer_handler(unsigned long data)
+{
+ u16 disp_data;
+ struct seven_seg_gpio_info *gpio_info =
+ (struct seven_seg_gpio_info *)data;
+ disp_data = gpio_info->curr_disp_value;
+
+ send_seven_seg_gpio_data(disp_data, gpio_info);
+ mod_timer(&gpio_info->update_timer,
+ jiffies + msecs_to_jiffies(gpio_info->refresh_interval));
+}
+
+static const struct of_device_id of_seven_seg_gpio_match[] = {
+ { .compatible = "seven-seg-gpio-dev" },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, of_seven_seg_gpio_match);
+
+static int seven_seg_gpio_probe(struct platform_device *pdev)
+{
+ u16 interval;
+ int result;
+ struct seven_seg_gpio_info *gpio_info;
+ struct device *dev = &pdev->dev;
+ struct seven_seg_disp_dev *disp_dev;
+
+ gpio_info = devm_kzalloc(dev,
+ sizeof(struct seven_seg_gpio_info),
+ GFP_KERNEL);
+ if (gpio_info == NULL)
+ return -ENOMEM;
+
+ /* Requesting the clock gpio */
+ gpio_info->clock_gpio = devm_gpiod_get(dev, CLOCK_GPIO_NAME,
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(gpio_info->clock_gpio))
+ return PTR_ERR(gpio_info->clock_gpio);
+
+ /* Requesting the data gpio */
+ gpio_info->data_gpio = devm_gpiod_get(dev, DATA_GPIO_NAME,
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(gpio_info->data_gpio))
+ return PTR_ERR(gpio_info->data_gpio);
+
+ /* Requesting the clear gpio */
+ gpio_info->clear_gpio = devm_gpiod_get(dev, CLEAR_GPIO_NAME,
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(gpio_info->clear_gpio))
+ return PTR_ERR(gpio_info->clear_gpio);
+
+ result = of_property_read_u16(pdev->dev.of_node,
+ "refresh-interval-ms", &interval);
+ gpio_info->refresh_interval = result ? DEFAULT_REFRESH_INTERVAL_MS :
+ interval;
+
+ /* Start timer to update seven segment display every second */
+ setup_timer(&gpio_info->update_timer, disp_refresh_timer_handler,
+ (unsigned long)gpio_info);
+ result = mod_timer(&gpio_info->update_timer,
+ jiffies +
+ msecs_to_jiffies(gpio_info->refresh_interval));
+ if (result)
+ return result;
+
+ gpio_info->curr_disp_value = 0;
+
+ platform_set_drvdata(pdev, gpio_info);
+
+ disp_dev = devm_kzalloc(dev, sizeof(struct seven_seg_disp_dev),
+ GFP_KERNEL);
+ disp_dev->parent = *dev;
+ seven_seg_setup_cdev(disp_dev, &update_seven_seg_gpio_data);
+ return 0;
+}
+
+static int seven_seg_gpio_remove(struct platform_device *pdev)
+{
+ struct seven_seg_gpio_info *gpio_info = platform_get_drvdata(pdev);
+ struct seven_seg_disp_dev *disp_dev =
+ container_of(&pdev->dev,
+ struct seven_seg_disp_dev, parent);
+ seven_seg_rem_cdev(disp_dev);
+ del_timer_sync(&gpio_info->update_timer);
+ platform_set_drvdata(pdev, NULL);
+ return 0;
+}
+
+static struct platform_driver seven_seg_gpio_driver = {
+ .probe = seven_seg_gpio_probe,
+ .remove = seven_seg_gpio_remove,
+ .driver = {
+ .name = "seven-seg-gpio",
+ .of_match_table = of_seven_seg_gpio_match,
+ },
+};
+
+module_platform_driver(seven_seg_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jaghathiswari Rankappagounder Natarajan <jaghu at google.com>");
+MODULE_DESCRIPTION("Seven segment display driver using GPIO config");
--
2.11.0.483.g087da7b7c-goog
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