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Message-Id: <1481702104-8617-4-git-send-email-jaghu@google.com>
Date: Tue, 13 Dec 2016 23:55:03 -0800
From: Jaghathiswari Rankappagounder Natarajan <jaghu@...gle.com>
To: openbmc@...ts.ozlabs.org, robh+dt@...nel.org, mark.rutland@....com,
linux@...linux.org.uk, arnd@...db.de, gregkh@...uxfoundation.org
Cc: Jaghathiswari Rankappagounder Natarajan <jaghu@...gle.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, joel@....id.au
Subject: [PATCH linux v1 3/4] drivers: misc: Platform driver for seven segment display support
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@...gle.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 a21aec1..6508108 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -812,6 +812,14 @@ 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_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 c2defbd..d9c0d20 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -58,3 +58,4 @@ obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_SEVEN_SEGMENT_DISPLAY) += seven_seg_disp.o
obj-$(CONFIG_PANEL) += panel.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 0000000..3dcb903
--- /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@...gle.com>");
+MODULE_DESCRIPTION("Seven segment display driver using GPIO config");
--
2.8.0.rc3.226.g39d4020
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