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From ea3e732d2c4a609e621346a96d37713820640196 Mon Sep 17 00:00:00 2001
From: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
Date: Fri, 27 Jul 2018 12:36:24 -0700
Subject: [PATCH 3/3] 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@google.com>
Signed-off-by: Kun Yi <kunyi@google.com>
Signed-off-by: Benjamin Fair <benjaminfair@google.com>
---
drivers/misc/Kconfig | 8 ++
# drivers/misc/Makefile | 2 ++
drivers/misc/seven_seg_gpio.c | 205 ++++++++++++++++++++++++++++++++++
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 d443de886346..e10984e3288f 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -481,6 +481,14 @@ config SEVEN_SEGMENT_DISPLAY
any conversion methods necessary to map the user input
to two 7-segment displays.
+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.
+
config PCI_ENDPOINT_TEST
depends on PCI
select CRC32
# diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
# index 402bcc3c9961..f39bec664d92 100644
# --- a/drivers/misc/Makefile
# +++ b/drivers/misc/Makefile
# @@ -53,6 +53,8 @@ obj-$(CONFIG_GENWQE) += genwqe/
# obj-$(CONFIG_ECHO) += echo/
# obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
# obj-$(CONFIG_CXL_BASE) += cxl/
# +obj-$(CONFIG_SEVEN_SEGMENT_DISPLAY) += seven_seg_disp.o
# +obj-$(CONFIG_SEVEN_SEGMENT_GPIO) += seven_seg_gpio.o
# obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o
# obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
# obj-$(CONFIG_ASPEED_LPC_MBOX) += aspeed-lpc-mbox.o
diff --git a/drivers/misc/seven_seg_gpio.c b/drivers/misc/seven_seg_gpio.c
new file mode 100644
index 000000000000..e03ea7f8b848
--- /dev/null
+++ b/drivers/misc/seven_seg_gpio.c
@@ -0,0 +1,205 @@
+/*
+ * 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(struct timer_list *t)
+{
+ u16 disp_data;
+ struct seven_seg_gpio_info *gpio_info =
+ from_timer(gpio_info, t, update_timer);
+ 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 */
+ timer_setup(&gpio_info->update_timer, disp_refresh_timer_handler, 0);
+ 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");
--
2.22.0.770.g0f2c4a37fd-goog
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