[PATCH linux v1] drivers: misc: Seven segment support
Jaghathiswari Rankappagounder Natarajan
jaghu at google.com
Sat Feb 11 05:20:19 AEDT 2017
Hi Xo,
Please use this patch for the zaius bmc image
On Fri, Feb 10, 2017 at 10:19 AM, Jaghathiswari Rankappagounder
Natarajan <jaghu at google.com> wrote:
> 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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