From ea3e732d2c4a609e621346a96d37713820640196 Mon Sep 17 00:00:00 2001 From: Jaghathiswari Rankappagounder Natarajan 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 Signed-off-by: Kun Yi Signed-off-by: Benjamin Fair --- 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("Seven segment display driver using GPIO config"); -- 2.22.0.770.g0f2c4a37fd-goog