Messages in this thread Patch in this message | | | From | Charles Mirabile <> | Subject | [PATCH 2/5] drivers/auxdisplay: sensehat: Raspberry Pi Sense HAT display driver | Date | Tue, 23 Aug 2022 13:41:55 -0400 |
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This patch adds the driver for the 8x8 RGB LED matrix display on the Sense HAT. It appears as a character device named sense-hat in /dev/. That special file is 192 bytes large and contains 64 RGB triplets (3 bytes each) one for each pixel in row major order.
Co-developed-by: Joel Savitz <jsavitz@redhat.com> Signed-off-by: Joel Savitz <jsavitz@redhat.com> Signed-off-by: Charles Mirabile <cmirabil@redhat.com> --- drivers/auxdisplay/Kconfig | 8 + drivers/auxdisplay/Makefile | 1 + drivers/auxdisplay/sensehat-display.c | 205 ++++++++++++++++++++++++++ 3 files changed, 214 insertions(+) create mode 100644 drivers/auxdisplay/sensehat-display.c
diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig index 64012cda4d12..9bad1aade7a0 100644 --- a/drivers/auxdisplay/Kconfig +++ b/drivers/auxdisplay/Kconfig @@ -203,6 +203,14 @@ 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" + depends on I2C + select MFD_SIMPLE_MFD_I2C + 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 6968ed4d3f0a..30b2b7934046 100644 --- a/drivers/auxdisplay/Makefile +++ b/drivers/auxdisplay/Makefile @@ -14,3 +14,4 @@ obj-$(CONFIG_HT16K33) += ht16k33.o obj-$(CONFIG_PARPORT_PANEL) += panel.o obj-$(CONFIG_LCD2S) += lcd2s.o obj-$(CONFIG_LINEDISP) += line-display.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..08c0c4338f3e --- /dev/null +++ b/drivers/auxdisplay/sensehat-display.c @@ -0,0 +1,205 @@ +// 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, Joel Savitz + * + * Original Author: Serge Schneider + * Revised for upstream Linux by: Charles Mirabile, 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/miscdevice.h> +#include <linux/regmap.h> +#include <linux/property.h> + +#define DISPLAY_SMB_REG 0x00 +#define RGB_555_MASK 0x1f +#define NUM_LEDS 8 +#define NUM_CHANNELS 3 + +struct sensehat_display { + struct platform_device *pdev; + struct miscdevice mdev; + struct mutex rw_mtx; + u8 vmem[NUM_LEDS][NUM_LEDS][NUM_CHANNELS]; + struct regmap *regmap; +}; + +#define VMEM_SIZE sizeof_field(struct sensehat_display, vmem) + + +static int sensehat_update_display(struct sensehat_display *display) +{ + int i, j, k, ret; + u8 buff[NUM_LEDS][NUM_CHANNELS][NUM_LEDS]; + + for (i = 0; i < NUM_LEDS; ++i) + for (j = 0; j < NUM_LEDS; ++j) + for (k = 0; k < NUM_CHANNELS; ++k) + buff[i][k][j] = + display->vmem[i][j][k] & RGB_555_MASK; + + ret = regmap_bulk_write(display->regmap, DISPLAY_SMB_REG, buff, + VMEM_SIZE); + if (ret < 0) + dev_err(&display->pdev->dev, + "Update to 8x8 LED matrix display failed"); + return ret; +} + +static loff_t sensehat_display_llseek(struct file *filp, loff_t offset, + int whence) +{ + return fixed_size_llseek(filp, offset, whence, VMEM_SIZE); +} + +static ssize_t sensehat_display_read(struct file *filp, char __user *buf, + size_t count, loff_t *f_pos) +{ + struct sensehat_display *sensehat_display = + container_of(filp->private_data, struct sensehat_display, mdev); + ssize_t ret = -EFAULT; + + if (*f_pos < 0 || *f_pos >= VMEM_SIZE) + return 0; + count = min_t(size_t, count, VMEM_SIZE - *f_pos); + + if (mutex_lock_interruptible(&sensehat_display->rw_mtx)) + return -ERESTARTSYS; + if (copy_to_user(buf, *f_pos + (u8 *)sensehat_display->vmem, count)) + goto out; + *f_pos += count; + ret = count; +out: + mutex_unlock(&sensehat_display->rw_mtx); + return ret; +} + +static ssize_t sensehat_display_write(struct file *filp, const char __user *buf, + size_t count, loff_t *f_pos) +{ + struct sensehat_display *sensehat_display = + container_of(filp->private_data, struct sensehat_display, mdev); + int ret = -EFAULT; + + if (*f_pos < 0 || *f_pos >= VMEM_SIZE) + return -EFBIG; + count = min_t(size_t, count, VMEM_SIZE - *f_pos); + + if (mutex_lock_interruptible(&sensehat_display->rw_mtx)) + return -ERESTARTSYS; + if (copy_from_user(*f_pos + (u8 *)sensehat_display->vmem, buf, count)) + goto out; + ret = sensehat_update_display(sensehat_display); + if (ret < 0) { + ret = -EIO; + goto out; + } + *f_pos += count; + ret = count; +out: + mutex_unlock(&sensehat_display->rw_mtx); + 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, +}; + +static int sensehat_display_probe(struct platform_device *pdev) +{ + int ret; + + struct sensehat_display *sensehat_display = + devm_kmalloc(&pdev->dev, sizeof(*sensehat_display), GFP_KERNEL); + if (!sensehat_display) + return -ENOMEM; + + sensehat_display->pdev = pdev; + + dev_set_drvdata(&pdev->dev, sensehat_display); + + sensehat_display->regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (!sensehat_display->regmap) { + dev_err(&pdev->dev, + "unable to get sensehat regmap"); + return -ENODEV; + } + + memset(sensehat_display->vmem, 0, VMEM_SIZE); + + mutex_init(&sensehat_display->rw_mtx); + + ret = sensehat_update_display(sensehat_display); + if (ret < 0) { + dev_err(&pdev->dev, + "Could not communicate with sensehat"); + return ret; + } + + 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."); + return ret; + } + + dev_info(&pdev->dev, + "8x8 LED matrix display registered with minor number %i", + sensehat_display->mdev.minor); + + return 0; +} + +static int sensehat_display_remove(struct platform_device *pdev) +{ + struct sensehat_display *sensehat_display = dev_get_drvdata(&pdev->dev); + + misc_deregister(&sensehat_display->mdev); + return 0; +} + +static const struct of_device_id sensehat_display_device_id[] = { + { .compatible = "raspberrypi,sensehat-display" }, + {}, +}; +MODULE_DEVICE_TABLE(of, sensehat_display_device_id); + +static struct platform_driver sensehat_display_driver = { + .probe = sensehat_display_probe, + .remove = sensehat_display_remove, + .driver = { + .name = "sensehat-display", + .of_match_table = sensehat_display_device_id, + }, +}; + +module_platform_driver(sensehat_display_driver); + +MODULE_DESCRIPTION("Raspberry Pi Sense HAT 8x8 LED matrix display driver"); +MODULE_AUTHOR("Charles Mirabile <cmirabil@redhat.com>"); +MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>"); +MODULE_LICENSE("GPL"); -- 2.31.1
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