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RobertCNelsonRobertCNelson
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merge: Rpmsg gpiodrv
fixes: beagleboard/linux#247 Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
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‎patch.sh

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Original file line numberDiff line numberDiff line change
@@ -617,6 +617,7 @@ drivers () {
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dir 'drivers/uio_pruss_shmem'
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dir 'drivers/greybus'
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dir 'RPi'
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dir 'gsoc'
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dir 'fixes'
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}
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‎patches/defconfig

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@@ -5493,6 +5493,7 @@ CONFIG_RPMSG=y
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CONFIG_RPMSG_VIRTIO=m
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CONFIG_RPMSG_RPC=m
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CONFIG_RPMSG_PRU=m
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CONFIG_CONFIG_RPMSG_GPIOHIP_INTERFACE=m
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#
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# Rpmsg virtual device drivers

‎patches/gsoc/0001-Added-driver-to-use-rpmsg-with-gpiochip-interface.Re.patch

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@@ -0,0 +1,278 @@
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From 50ad0fc3083890661113180aa3a849958d0c0787 Mon Sep 17 00:00:00 2001
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From: deebot <deepankar.maithani@stud.th-deg.de>
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Date: Sun, 23 Aug 2020 13:40:44 +0200
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Subject: [PATCH] - Added driver to use rpmsg with gpiochip interface.Requires
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PRU firmware Please follow instructions to load PRU firmware
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https://github.com/deebot/Beaglebone-BidirectionBus/blob/dev/bidirec_299/README.md
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- Added rule to compile rpmsg-gpio driver in Make and Kconfig
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---
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drivers/rpmsg/Kconfig | 12 ++
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drivers/rpmsg/Makefile | 2 +
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drivers/rpmsg/rpmsg_gpio.c | 222 +++++++++++++++++++++++++++++++++++++
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3 files changed, 236 insertions(+)
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create mode 100644 drivers/rpmsg/rpmsg_gpio.c
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diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
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index c41d8157b079..ef2c47c017bb 100644
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--- a/drivers/rpmsg/Kconfig
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+++ b/drivers/rpmsg/Kconfig
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@@ -81,4 +81,16 @@ config RPMSG_PRU
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If unsure, say N.
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+config CONFIG_RPMSG_GPIOHIP_INTERFACE
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+ tristate "A rpmsg driver with gpiochip interface"
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+ default m
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+ depends on RPMSG_VIRTIO
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+ depends on REMOTEPROC
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+ help
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+ This driver provides provides gpiochip inteface which can be accessed
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+ in userspace using libgpiod. You would see a char dev interface in
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+ "/dev" using this driver. Follow the README from the following
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+ repo for more info.
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+ https://github.com/deebot/Beaglebone-BidirectionBus
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+
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endmenu
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diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
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index 6666c8d6327e..3b93ea58ae36 100644
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--- a/drivers/rpmsg/Makefile
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+++ b/drivers/rpmsg/Makefile
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@@ -9,4 +9,6 @@ obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
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obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
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obj-$(CONFIG_RPMSG_RPC) += rpmsg-rpc.o
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+obj-$(CONFIG_RPMSG_GPIOCHIP_INTERFACE) += rpmsg_gpio.o
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rpmsg-rpc-y := rpmsg_rpc.o rpmsg_rpc_sysfs.o rpmsg_rpc_dmabuf.o
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+
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diff --git a/drivers/rpmsg/rpmsg_gpio.c b/drivers/rpmsg/rpmsg_gpio.c
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new file mode 100644
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index 000000000000..92fd7e517c3c
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--- /dev/null
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+++ b/drivers/rpmsg/rpmsg_gpio.c
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@@ -0,0 +1,222 @@
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+/*
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+ * PRU Remote Processor Messaging Driver with gpiochip interface
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+ * copyright (c) 2020 Deepankar Maithani
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+ * Codes examples from Lab no 5 from TI and has been used as boiler plate for rpmsg communication
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+ * https://processors.wiki.ti.com/index.php/PRU_Training:_Hands-on_Labs
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+ *
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+ * For learn more about the complete project visit:
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+ * https://github.com/deebot/Beaglebone-BidirectionBus/tree/dev
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+ * Steps to test the driver.
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+ * https://github.com/deebot/Beaglebone-BidirectionBus/blob/dev/bidirec_299/README.md
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+ *
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+ * This software is licensed under the terms of the GNU General Public
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+ * License version 2, as published by the Free Software Foundation, and
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+ * may be copied, distributed, and modified under those terms.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ */
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+#include <linux/kernel.h>
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+#include <linux/module.h>
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+#include <linux/slab.h>
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+#include <linux/gpio.h>
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+#include <linux/of.h>
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+#include <linux/rpmsg.h>
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+#include <linux/fs.h>
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+#include <linux/init.h>
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+#include <linux/kfifo.h>
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+#include <linux/uaccess.h>
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+#include <linux/poll.h>
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+#include <linux/rpmsg/virtio_rpmsg.h>
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+#include <linux/stat.h>
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+#include <linux/bitops.h>
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+#define PRU_MAX_DEVICES (16)
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+/* Matches the definition in virtio_rpmsg_bus.c */
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+#define RPMSG_BUF_SIZE (512)
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+#define MAX_FIFO_MSG (32)
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+#define FIFO_MSG_SIZE RPMSG_BUF_SIZE
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+#define GPIO_NUM 9
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+static DEFINE_MUTEX(rpmsg_pru_lock);
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+static char rpmsg_pru_buf[RPMSG_BUF_SIZE];
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+static struct gpio_chip chip;
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+struct rpmsg_pru_dev {
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+ struct rpmsg_device *rpdev;
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+ struct device *dev;
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+ bool locked;
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+ dev_t devt;
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+ struct kfifo msg_fifo;
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+ u32 msg_len[MAX_FIFO_MSG];
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+ int msg_idx_rd;
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+ int msg_idx_wr;
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+ wait_queue_head_t wait_list;
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+ uint32_t gpio_state;
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+ long input_state;
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+
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+};
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+
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+struct rpmsg_pru_dev *prudev;
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+/*Reads the lines which are set as input*/
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+static int mygpio_get_value(struct gpio_chip *gc, unsigned offset)
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+{
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+ uint32_t value;
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+ struct rpmsg_device *rpdev = container_of(gc->parent,
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+ struct rpmsg_device, dev);
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+ unsigned int mask = BIT(offset % 8);
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+ prudev = dev_get_drvdata(&rpdev->dev);
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+
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+ value = (prudev->input_state & mask)>>offset;
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+ return value;
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+}
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+/* Writes to the lines and creates the gpio_state which is then sent as RPmsg */
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+static void mygpio_set_value(struct gpio_chip *gc, unsigned offset, int val)
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+{
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+ int ret;
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+ struct rpmsg_device *rpdev = container_of(gc->parent, struct rpmsg_device, dev);
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+ pr_info("set_value function triggered");
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+ pr_info("The bit number %d is set to value: %d", offset, val);
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+
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+ prudev = dev_get_drvdata(&rpdev->dev);
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+ if (val == 0) {
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+ prudev->gpio_state &= ~(1<<offset);
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+ } else {
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+ prudev->gpio_state |= (1<<offset);
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+ }
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+ if (offset == GPIO_NUM-1) {
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+ /* copy the gpiostate in rpmsg buffer which will be sent over to PRU*/
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+ memcpy((void *)&rpmsg_pru_buf, (void *)&(prudev->gpio_state),
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+ sizeof(&(prudev->gpio_state)));
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+ pr_info("A check for checking gpio_state: %d",
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+ prudev->gpio_state);
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+ /* This line actually sends the data to the other side*/
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+ ret = rpmsg_send(rpdev->ept, (void *)rpmsg_pru_buf, 2);
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+ if (ret)
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+ dev_err(gc->parent, "rpmsg_send failed: %d\n", ret);
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+ }
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+
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+}
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+
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+/*sets the pin to output. Will be called when user sets one
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+ * of the gpiochip line as output which can be done manually
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+ * in sysfs or using libgpiod */
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+
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+static int mygpio_direction_output(struct gpio_chip *gc,
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+ unsigned offset, int val)
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+{
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+ pr_info("Direction of GPIO set to: out\n");
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+ return 0;
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+}
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+/*Runs When direction of a line is set as output*/
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+static int mygpio_direction_input(struct gpio_chip *gc,
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+ unsigned offset)
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+{
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+
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+ pr_info("Direction of GPIO set to: in \n");
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+ return 0;
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+}
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+/*This function gets called every time
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+ *an rpmsg_channel is created with a name that matches the .name
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+ *attribute of the rpmsg_driver_sample_id_table. It sets up suitable memory
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+ *and the gpiochip interface that can be seen in /sys/class/gpio and /dev.
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+ */
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+static int mygpio_rpmsg_pru_probe (struct rpmsg_device *rpdev)
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+{
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+ int ret;
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+ struct rpmsg_pru_dev *prudev;
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+ prudev = devm_kzalloc(&rpdev->dev, sizeof(*prudev), GFP_KERNEL);
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+ if (!prudev)
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+ return -ENOMEM;
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+ prudev->rpdev = rpdev;
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+ ret = kfifo_alloc(&prudev->msg_fifo, MAX_FIFO_MSG * FIFO_MSG_SIZE,
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+ GFP_KERNEL);
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+ if (ret) {
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+ dev_err(&rpdev->dev, "Unable to allocate fifo for the rpmsg_pru device\n");
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+ return -ENOMEM;
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+ }
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+ init_waitqueue_head(&prudev->wait_list);
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+ dev_set_drvdata(&rpdev->dev, prudev);
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+ chip.label = rpdev->desc;
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+ chip.base = -1;
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+ chip.parent = &rpdev->dev;
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+ chip.owner = THIS_MODULE;
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+ chip.ngpio = GPIO_NUM;
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+ chip.can_sleep = 1;
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+ chip.get = mygpio_get_value;
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+ chip.set = mygpio_set_value;
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+ chip.direction_output = mygpio_direction_output;
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+ chip.direction_input = mygpio_direction_input;
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+ return gpiochip_add(&chip);
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+}
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+/* Callback function which gets called whenever a new rpmsg is received
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+ * The data received from the PRU is converted into long and then assigned to
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+ * input_state
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+ * @msg_fifo: kernel fifo used to buffer the messages between userspace and PRU
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+ * @msg_len: array storing the lengths of each message in the kernel fifo
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+ * @msg_idx_rd: kernel fifo read index
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+ * @msg_idx_wr: kernel fifo write index
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+ * */
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+static int mygpio_rpmsg_pru_cb(struct rpmsg_device *rpdev, void *data, int len,
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+ void *priv, u32 src)
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+{ int ret;
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+ u32 length;
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+ struct rpmsg_pru_dev *prudev;
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+
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+ prudev = dev_get_drvdata(&rpdev->dev);
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+
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+ if (kfifo_avail(&prudev->msg_fifo) < len) {
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+ dev_err(&rpdev->dev, "Not enough space on the FIFO\n");
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+ return -ENOSPC;
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+ }
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+
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+ if ((prudev->msg_idx_wr + 1) % MAX_FIFO_MSG ==
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+ prudev->msg_idx_rd) {
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+ dev_err(&rpdev->dev, "Message length table is full\n");
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+ return -ENOSPC;
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+ }
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+ /* adds the data received into a fifo*/
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+ length = kfifo_in(&prudev->msg_fifo, data, len);
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+ prudev->msg_len[prudev->msg_idx_wr] = length;
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+ prudev->msg_idx_wr = (prudev->msg_idx_wr + 1) % MAX_FIFO_MSG;
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+
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+ wake_up_interruptible(&prudev->wait_list);
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+ ret = kstrtol((char *) data, 10, &prudev->input_state);
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+ if (ret) {
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+ return ret;
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+ }
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+ pr_info("The shift register port state is: %ld", prudev->input_state);
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+ return 0;
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+}
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+static void mygpio_rpmsg_pru_remove(struct rpmsg_device *rpdev)
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+{
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+ struct rpmsg_pru_dev *prudev;
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+ prudev = dev_get_drvdata(&rpdev->dev);
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+
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+ kfifo_free(&prudev->msg_fifo);
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+ gpiochip_remove(&chip);
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+
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+}
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+/*
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+ * Matches this tag:If you change .name
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+ * PRU firmware should also be updated with same channel name
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+ */
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+static const struct rpmsg_device_id rpmsg_driver_pru_id_table[] = {
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+ { .name = "rpmsg-pru-gpio" },
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+ { },
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+};
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+MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_pru_id_table);
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+
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+static struct rpmsg_driver rpmsg_pru_driver = {
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+ .drv.name = KBUILD_MODNAME,
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+ .id_table = rpmsg_driver_pru_id_table,
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+ .probe = mygpio_rpmsg_pru_probe,
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+ .callback = mygpio_rpmsg_pru_cb,
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+ .remove = mygpio_rpmsg_pru_remove,
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+};
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+
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+module_rpmsg_driver(rpmsg_pru_driver);
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+MODULE_AUTHOR("DeepankarMaithani <deepankar19910@gmail.com>");
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+MODULE_DESCRIPTION("A driver to send rpmsg data using sysfs and chardev interface");
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+MODULE_VERSION("0.1");
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+MODULE_LICENSE("GPL");
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+
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--
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2.28.0
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‎version.sh

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@@ -39,7 +39,7 @@ KERNEL_REL=4.19
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KERNEL_TAG=${KERNEL_REL}.94
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kernel_rt=".94-rt39"
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#Kernel Build
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BUILD=${build_prefix}50
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BUILD=${build_prefix}50.1
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#v5.X-rcX + upto SHA
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#prev_KERNEL_SHA=""

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