[RFC PATCH 3/3] drivers/mfd: rpisense: Raspberry Pi senseHAT 8x8 LED matrix display driver
Joel Savitz
jsavitz at redhat.com
Fri Aug 6 17:27:22 PDT 2021
This patch implements control of the 8x8 RGB LED matrix display.
Signed-off-by: Charles Mirabile <cmirabil at redhat.com>
Signed-off-by: Mwesigwa Guma <mguma at redhat.com>
Signed-off-by: Joel Savitz <jsavitz at redhat.com>
---
drivers/mfd/Makefile | 1 +
drivers/mfd/rpisense-display.c | 242 +++++++++++++++++++++++++++++++++
2 files changed, 243 insertions(+)
create mode 100644 drivers/mfd/rpisense-display.c
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 71356153ccdc..974518d9801b 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -265,6 +265,7 @@ obj-$(CONFIG_MFD_STMFX) += stmfx.o
obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o
obj-$(CONFIG_MFD_RPISENSE) += rpisense-core.o
obj-$(CONFIG_MFD_RPISENSE) += rpisense-js.o
+obj-$(CONFIG_MFD_RPISENSE) += rpisense-display.o
obj-$(CONFIG_MFD_ACER_A500_EC) += acer-ec-a500.o
obj-$(CONFIG_MFD_QCOM_PM8008) += qcom-pm8008.o
diff --git a/drivers/mfd/rpisense-display.c b/drivers/mfd/rpisense-display.c
new file mode 100644
index 000000000000..10a34fa0eece
--- /dev/null
+++ b/drivers/mfd/rpisense-display.c
@@ -0,0 +1,242 @@
+// 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/mfd/rpisense.h>
+
+#define GAMMA_SIZE sizeof_field(struct rpisense_display, gamma)
+#define VMEM_SIZE sizeof_field(struct rpisense_display, vmem)
+
+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 rpisense_display_fops;
+
+static int rpisense_display_probe(struct platform_device *pdev)
+{
+ int ret;
+
+ struct rpisense *rpisense = dev_get_drvdata(&pdev->dev);
+ struct rpisense_display *rpisense_display = &rpisense->display;
+
+ memcpy(rpisense_display->gamma, gamma_presets[lowlight], GAMMA_SIZE);
+
+ memset(rpisense_display->vmem, 0, VMEM_SIZE);
+
+ mutex_init(&rpisense_display->rw_mtx);
+
+ rpisense_display->mdev = (struct miscdevice) {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "sense-hat",
+ .mode = 0666,
+ .fops = &rpisense_display_fops,
+ };
+
+ ret = misc_register(&rpisense_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",
+ rpisense_display->mdev.minor);
+
+ rpisense_update_display(rpisense);
+ return 0;
+}
+
+static int rpisense_display_remove(struct platform_device *pdev)
+{
+ struct rpisense *rpisense = dev_get_drvdata(&pdev->dev);
+ struct rpisense_display *rpisense_display = &rpisense->display;
+
+ misc_deregister(&rpisense_display->mdev);
+ return 0;
+}
+
+static loff_t rpisense_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
+rpisense_display_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
+{
+ struct rpisense *rpisense = container_of(filp->private_data, struct rpisense, display.mdev);
+ struct rpisense_display *rpisense_display = &rpisense->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(&rpisense_display->rw_mtx))
+ return -ERESTARTSYS;
+ if (copy_to_user(buf, rpisense_display->vmem + *f_pos, count))
+ goto out;
+ *f_pos += count;
+ retval = count;
+out:
+ mutex_unlock(&rpisense_display->rw_mtx);
+ return retval;
+}
+
+static ssize_t
+rpisense_display_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos)
+{
+ struct rpisense *rpisense = container_of(filp->private_data, struct rpisense, display.mdev);
+ struct rpisense_display *rpisense_display = &rpisense->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(&rpisense_display->rw_mtx))
+ return -ERESTARTSYS;
+ memcpy(rpisense_display->vmem + *f_pos, temp, count);
+ rpisense_update_display(rpisense);
+ *f_pos += count;
+ mutex_unlock(&rpisense_display->rw_mtx);
+ return count;
+}
+
+static long rpisense_display_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct rpisense *rpisense = container_of(filp->private_data, struct rpisense, display.mdev);
+ struct rpisense_display *rpisense_display = &rpisense->display;
+ void __user *user_ptr = (void __user *)arg;
+ u8 temp[GAMMA_SIZE];
+ int ret;
+
+ if (mutex_lock_interruptible(&rpisense_display->rw_mtx))
+ return -ERESTARTSYS;
+ switch (cmd) {
+ case SENSEDISP_IOGET_GAMMA:
+ if (copy_to_user(user_ptr, rpisense_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(rpisense_display->gamma, temp, GAMMA_SIZE);
+ rpisense_update_display(rpisense);
+out_unlock:
+ mutex_unlock(&rpisense_display->rw_mtx);
+ return ret;
+}
+
+static const struct file_operations rpisense_display_fops = {
+ .owner = THIS_MODULE,
+ .llseek = rpisense_display_llseek,
+ .read = rpisense_display_read,
+ .write = rpisense_display_write,
+ .unlocked_ioctl = rpisense_display_ioctl,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id rpisense_display_id[] = {
+ { .compatible = "rpi,rpi-sense-fb" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, rpisense_display_id);
+#endif
+
+static struct platform_device_id rpisense_display_device_id[] = {
+ { .name = "rpi-sense-fb" },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, rpisense_display_device_id);
+
+static struct platform_driver rpisense_display_driver = {
+ .probe = rpisense_display_probe,
+ .remove = rpisense_display_remove,
+ .driver = {
+ .name = "rpi-sense-fb",
+ },
+};
+
+module_platform_driver(rpisense_display_driver);
+
+MODULE_DESCRIPTION("Raspberry Pi Sense HAT 8x8 LED matrix display driver");
+MODULE_AUTHOR("Serge Schneider <serge at raspberrypi.org>");
+MODULE_LICENSE("GPL");
+
--
2.27.0
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