[PATCH linux v1 0/4] Seven segment display support

[PATCH linux v1 0/4] Seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

Hi Joel,
Nancy mentioned this patch can be included into openbmc linux tree now.
Some other member will take up the work of addressing the comments from
upstream reviewers and send the patch upstream.

This patchset includes:

Documentation for the binding which provides an interface for adding clock,
data and clear signal GPIO lines to control seven segment display.

The platform device driver 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.

The character device driver 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.

Adding clock, data and clear signal GPIO lines in the devicetree to control
seven segment display on zaius platform.

The platform driver matches on the device tree node; the platform driver also
initializes the character device.

Tested that the seven segment display works properly by writing to the
character device file on a EVB AST2500 board which also has 74HC164 wired
to two 7-segment displays.

Jaghathiswari Rankappagounder Natarajan (4):
  Documentation: dt-bindings: Document bindings for seven segment
    display support
  drivers: misc: Character device driver for seven segment display
  drivers: misc: Platform driver for seven segment display support
  arm: dts: Add dt-binding to support seven segment display on zaius

 .../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

--
2.11.0.483.g087da7b7c-goog

[PATCH linux v1 1/4] Documentation: dt-bindings: Document bindings for seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

This binding provides interface for adding clock, data and clear signal GPIO
lines to control seven segment display.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 .../devicetree/bindings/misc/seven-seg-gpio.txt    | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/seven-seg-gpio.txt

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..9a4e25540104
--- /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 = "1000";
+	clock-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+	data-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+	clear-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+};
--
2.11.0.483.g087da7b7c-goog

[PATCH linux v1 2/4] drivers: misc: Character device driver for seven segment display

[Jaghathiswari Rankappagounder Natarajan]

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.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 drivers/misc/Kconfig          |   8 ++
 drivers/misc/Makefile         |   1 +
 drivers/misc/seven_seg_disp.c | 201 ++++++++++++++++++++++++++++++++++++++++++
 drivers/misc/seven_seg_disp.h |  34 +++++++
 4 files changed, 244 insertions(+)
 create mode 100644 drivers/misc/seven_seg_disp.c
 create mode 100644 drivers/misc/seven_seg_disp.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index c802d2245108..4a221c1667c1 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"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index cdcd1af48971..5ac8b2637174 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,4 +57,5 @@ obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)		+= cxl/
 obj-$(CONFIG_PANEL)             += panel.o
+obj-$(CONFIG_SEVEN_SEGMENT_DISPLAY)     += seven_seg_disp.o
 obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.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@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..e4432a420159
--- /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 400
+
+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
--
2.11.0.483.g087da7b7c-goog

[PATCH linux v1 3/4] drivers: misc: Platform driver for seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

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.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 drivers/misc/Kconfig          |   8 ++
 drivers/misc/Makefile         |   1 +
 drivers/misc/seven_seg_gpio.c | 206 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 215 insertions(+)
 create mode 100644 drivers/misc/seven_seg_gpio.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 4a221c1667c1..c2914476e49e 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -820,6 +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 5ac8b2637174..463798e395f1 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_CXL_BASE)		+= cxl/
 obj-$(CONFIG_PANEL)             += panel.o
 obj-$(CONFIG_SEVEN_SEGMENT_DISPLAY)     += seven_seg_disp.o
 obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.o
+obj-$(CONFIG_SEVEN_SEGMENT_GPIO)        += seven_seg_gpio.o
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@google.com>");
+MODULE_DESCRIPTION("Seven segment display driver using GPIO config");
--
2.11.0.483.g087da7b7c-goog

[PATCH linux v1 4/4] arm: dts: Add dt-binding to support seven segment display on zaius

[Jaghathiswari Rankappagounder Natarajan]

Add clock, data and clear signal GPIO lines to control seven segment display on
zaius platform.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts b/arch/arm/boot/dts/aspeed-bmc-opp-zaius.dts
index e2195a641414..2c3297bec9b7 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 = "400";
+		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 {
--
2.11.0.483.g087da7b7c-goog

Re: [PATCH linux v1 0/4] Seven segment display support

[Joel Stanley]

Hello Jagha,

On Tue, Feb 7, 2017 at 2:33 PM, Jaghathiswari Rankappagounder
Natarajan <jaghu@google.com> wrote:
> Hi Joel,
> Nancy mentioned this patch can be included into openbmc linux tree now.
> Some other member will take up the work of addressing the comments from
> upstream reviewers and send the patch upstream.

Just before you sent these patches we had a chat on the topic. I
thought we decided to give the rest of this week for people to review
the new process, and then on Monday I would publish a tree based on
4.10 that you could submit patches to. Sorry for not making this
clear.

I suspect this set will apply to 4.10 as-is, so I will consider this
your submission for the 4.10 tree next week.

Next time please have a read of the development process[1] and the
rules for submitting patches[2] before sending patches. In particular,
you need to set the target branch in the subject line so I know where
you want the patches applied. If you you have any questions about the
process please let me know so I can update the documentation.

[1] https://github.com/openbmc/linux/wiki/DevelopmentProcess
[2] https://github.com/openbmc/linux/wiki/SubmittingPatches

Cheers,

Joel

>
> This patchset includes:
>
> Documentation for the binding which provides an interface for adding clock,
> data and clear signal GPIO lines to control seven segment display.
>
> The platform device driver 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.
>
> The character device driver 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.
>
> Adding clock, data and clear signal GPIO lines in the devicetree to control
> seven segment display on zaius platform.
>
> The platform driver matches on the device tree node; the platform driver also
> initializes the character device.
>
> Tested that the seven segment display works properly by writing to the
> character device file on a EVB AST2500 board which also has 74HC164 wired
> to two 7-segment displays.
>
> Jaghathiswari Rankappagounder Natarajan (4):
>   Documentation: dt-bindings: Document bindings for seven segment
>     display support
>   drivers: misc: Character device driver for seven segment display
>   drivers: misc: Platform driver for seven segment display support
>   arm: dts: Add dt-binding to support seven segment display on zaius
>
>  .../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
>
> --
> 2.11.0.483.g087da7b7c-goog
>

[PATCH linux v1 1/4] Documentation: dt-bindings: Document bindings for seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

This binding provides interface for adding clock, data and clear signal GPIO
lines to control seven segment display.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 .../devicetree/bindings/misc/seven-seg-gpio.txt    | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/seven-seg-gpio.txt

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 0000000..9a4e255
--- /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 = "1000";
+	clock-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+	data-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+	clear-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+};
--
2.8.0.rc3.226.g39d4020

[PATCH linux v1 1/4] Documentation: dt-bindings: Document bindings for seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

This binding provides interface for adding clock, data and clear signal GPIO
lines to control seven segment display.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
---
 .../devicetree/bindings/misc/seven-seg-gpio.txt    | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/seven-seg-gpio.txt

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 0000000..9a4e255
--- /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 = "1000";
+	clock-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+	data-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+	clear-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+};
--
2.8.0.rc3.226.g39d4020

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[PATCH linux v1 1/4] Documentation: dt-bindings: Document bindings for seven segment display support

[Jaghathiswari Rankappagounder Natarajan]

This binding provides interface for adding clock, data and clear signal GPIO
lines to control seven segment display.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
---
 .../devicetree/bindings/misc/seven-seg-gpio.txt    | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/seven-seg-gpio.txt

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 0000000..9a4e255
--- /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 = "1000";
+	clock-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+	data-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+	clear-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+};
--
2.8.0.rc3.226.g39d4020