Messages in this thread Patch in this message | | | From | Charles Mirabile <> | Subject | [PATCH 3/5] drivers/auxdisplay: senshat: Raspberry Pi Sense HAT display driver | Date | Fri, 29 Oct 2021 17:55:14 -0400 |
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This patch implements control of the 8x8 RGB LED matrix display.
Signed-off-by: Charles Mirabile <cmirabil@redhat.com> Signed-off-by: Mwesigwa Guma <mguma@redhat.com> Signed-off-by: Joel Savitz <jsavitz@redhat.com> --- drivers/auxdisplay/Kconfig | 7 + drivers/auxdisplay/Makefile | 1 + drivers/auxdisplay/sensehat-display.c | 258 ++++++++++++++++++++++++++ 3 files changed, 266 insertions(+) create mode 100644 drivers/auxdisplay/sensehat-display.c
diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig index 1509cb74705a..24f5d68cfbff 100644 --- a/drivers/auxdisplay/Kconfig +++ b/drivers/auxdisplay/Kconfig @@ -193,6 +193,13 @@ config ARM_CHARLCD line and the Linux version on the second line, but that's still useful. +config SENSEHAT_DISPLAY + tristate "Raspberry pi Sense HAT display driver" + select MFD_SENSEHAT_CORE + help + This is a driver for the Raspberry Pi Sensehat 8x8 RBG-LED matrix + you can access it as a misc device at /dev/sense-hat + menuconfig PARPORT_PANEL tristate "Parallel port LCD/Keypad Panel support" depends on PARPORT diff --git a/drivers/auxdisplay/Makefile b/drivers/auxdisplay/Makefile index 307771027c89..7e9aa479586a 100644 --- a/drivers/auxdisplay/Makefile +++ b/drivers/auxdisplay/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_HD44780) += hd44780.o obj-$(CONFIG_HT16K33) += ht16k33.o obj-$(CONFIG_PARPORT_PANEL) += panel.o obj-$(CONFIG_LCD2S) += lcd2s.o +obj-$(CONFIG_SENSEHAT_DISPLAY) += sensehat-display.o diff --git a/drivers/auxdisplay/sensehat-display.c b/drivers/auxdisplay/sensehat-display.c new file mode 100644 index 000000000000..5980ad23fd4f --- /dev/null +++ b/drivers/auxdisplay/sensehat-display.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Raspberry Pi Sense HAT 8x8 LED matrix display driver + * http://raspberrypi.org + * + * Copyright (C) 2015 Raspberry Pi + * Copyright (C) 2021 Charles Mirabile, Mwesigwa Guma, Joel Savitz + * + * Original Author: Serge Schneider + * Revised for upstream Linux by: Charles Mirabile, Mwesigwa Guma, Joel Savitz + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/mod_devicetable.h> +#include <linux/regmap.h> + +#include "sensehat.h" + +#define GAMMA_SIZE sizeof_field(struct sensehat_display, gamma) +#define VMEM_SIZE sizeof_field(struct sensehat_display, vmem) + +static int sensehat_update_display(struct sensehat *sensehat); + +static bool lowlight; +module_param(lowlight, bool, 0); +MODULE_PARM_DESC(lowlight, "Reduce LED matrix brightness to one third"); + +static const u8 gamma_presets[][GAMMA_SIZE] = { + [GAMMA_DEFAULT] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, + 0x02, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0E, 0x0F, 0x11, + 0x12, 0x14, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F, + }, + [GAMMA_LOWLIGHT] = { + 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, + 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, + 0x03, 0x03, 0x03, 0x04, 0x04, 0x05, 0x05, 0x06, + 0x06, 0x07, 0x07, 0x08, 0x08, 0x09, 0x0A, 0x0A, + }, +}; + +static const struct file_operations sensehat_display_fops; + +static int sensehat_display_probe(struct platform_device *pdev) +{ + int ret; + + struct sensehat *sensehat = dev_get_drvdata(&pdev->dev); + struct sensehat_display *sensehat_display = &sensehat->display; + + memcpy(sensehat_display->gamma, gamma_presets[lowlight], GAMMA_SIZE); + + memset(sensehat_display->vmem, 0, VMEM_SIZE); + + mutex_init(&sensehat_display->rw_mtx); + + sensehat_display->mdev = (struct miscdevice) { + .minor = MISC_DYNAMIC_MINOR, + .name = "sense-hat", + .mode = 0666, + .fops = &sensehat_display_fops, + }; + + ret = misc_register(&sensehat_display->mdev); + if (ret < 0) { + dev_err(&pdev->dev, "Could not register 8x8 LED matrix display.\n"); + return ret; + } + + dev_info(&pdev->dev, "8x8 LED matrix display registered with minor number %i", + sensehat_display->mdev.minor); + + sensehat_update_display(sensehat); + return 0; +} + +static int sensehat_display_remove(struct platform_device *pdev) +{ + struct sensehat *sensehat = dev_get_drvdata(&pdev->dev); + struct sensehat_display *sensehat_display = &sensehat->display; + + misc_deregister(&sensehat_display->mdev); + return 0; +} + +static loff_t sensehat_display_llseek(struct file *filp, loff_t pos, int whence) +{ + loff_t base; + + switch (whence) { + case SEEK_SET: + base = 0; + break; + case SEEK_CUR: + base = filp->f_pos; + break; + case SEEK_END: + base = VMEM_SIZE; + break; + default: + return -EINVAL; + } + base += pos; + if (base < 0 || base >= VMEM_SIZE) + return -EINVAL; + filp->f_pos = base; + return base; +} + +static ssize_t +sensehat_display_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) +{ + struct sensehat *sensehat = container_of(filp->private_data, struct sensehat, display.mdev); + struct sensehat_display *sensehat_display = &sensehat->display; + ssize_t retval = -EFAULT; + + if (*f_pos >= VMEM_SIZE) + return 0; + if (*f_pos + count > VMEM_SIZE) + count = VMEM_SIZE - *f_pos; + if (mutex_lock_interruptible(&sensehat_display->rw_mtx)) + return -ERESTARTSYS; + if (copy_to_user(buf, sensehat_display->vmem + *f_pos, count)) + goto out; + *f_pos += count; + retval = count; +out: + mutex_unlock(&sensehat_display->rw_mtx); + return retval; +} + +static ssize_t +sensehat_display_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) +{ + struct sensehat *sensehat = container_of(filp->private_data, struct sensehat, display.mdev); + struct sensehat_display *sensehat_display = &sensehat->display; + u8 temp[VMEM_SIZE]; + + if (*f_pos >= VMEM_SIZE) + return -EFBIG; + if (*f_pos + count > VMEM_SIZE) + count = VMEM_SIZE - *f_pos; + if (copy_from_user(temp, buf, count)) + return -EFAULT; + if (mutex_lock_interruptible(&sensehat_display->rw_mtx)) + return -ERESTARTSYS; + memcpy(sensehat_display->vmem + *f_pos, temp, count); + sensehat_update_display(sensehat); + *f_pos += count; + mutex_unlock(&sensehat_display->rw_mtx); + return count; +} + +static long sensehat_display_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct sensehat *sensehat = container_of(filp->private_data, struct sensehat, display.mdev); + struct sensehat_display *sensehat_display = &sensehat->display; + void __user *user_ptr = (void __user *)arg; + u8 temp[GAMMA_SIZE]; + int ret; + + if (mutex_lock_interruptible(&sensehat_display->rw_mtx)) + return -ERESTARTSYS; + switch (cmd) { + case SENSEDISP_IOGET_GAMMA: + if (copy_to_user(user_ptr, sensehat_display->gamma, GAMMA_SIZE)) { + ret = -EFAULT; + goto out_unlock; + } + ret = 0; + goto out_unlock; + case SENSEDISP_IOSET_GAMMA: + if (copy_from_user(temp, user_ptr, GAMMA_SIZE)) { + ret = -EFAULT; + goto out_unlock; + } + ret = 0; + goto out_update; + case SENSEDISP_IORESET_GAMMA: + if (arg < GAMMA_DEFAULT || arg >= GAMMA_PRESET_COUNT) { + ret = -EINVAL; + goto out_unlock; + } + memcpy(temp, gamma_presets[arg], GAMMA_SIZE); + ret = 0; + goto out_update; + default: + ret = -EINVAL; + goto out_unlock; + } +out_update: + memcpy(sensehat_display->gamma, temp, GAMMA_SIZE); + sensehat_update_display(sensehat); +out_unlock: + mutex_unlock(&sensehat_display->rw_mtx); + return ret; +} + +int sensehat_update_display(struct sensehat *sensehat) +{ + int i, j, ret; + struct sensehat_display *display = &sensehat->display; + sensehat_fb_t pixel_data; + + for (i = 0; i < 8; ++i) { + for (j = 0; j < 8; ++j) { + pixel_data[i][0][j] = display->gamma[display->vmem[i][j].r]; + pixel_data[i][1][j] = display->gamma[display->vmem[i][j].g]; + pixel_data[i][2][j] = display->gamma[display->vmem[i][j].b]; + } + } + + ret = regmap_bulk_write(sensehat->regmap, SENSEHAT_DISPLAY, + pixel_data, sizeof(pixel_data)); + if (ret < 0) + dev_err(sensehat->dev, "Update to 8x8 LED matrix display failed"); + return ret; +} + +static const struct file_operations sensehat_display_fops = { + .owner = THIS_MODULE, + .llseek = sensehat_display_llseek, + .read = sensehat_display_read, + .write = sensehat_display_write, + .unlocked_ioctl = sensehat_display_ioctl, +}; + +static struct platform_device_id sensehat_display_device_id[] = { + { .name = "sensehat-display" }, + { }, +}; +MODULE_DEVICE_TABLE(platform, sensehat_display_device_id); + +static struct platform_driver sensehat_display_driver = { + .probe = sensehat_display_probe, + .remove = sensehat_display_remove, + .driver = { + .name = "sensehat-display", + }, +}; + +module_platform_driver(sensehat_display_driver); + +MODULE_DESCRIPTION("Raspberry Pi Sense HAT 8x8 LED matrix display driver"); +MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>"); +MODULE_LICENSE("GPL"); -- 2.31.1
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