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Message-ID: <20220123074029.GA79722@mail.google.com>
Date: Sun, 23 Jan 2022 20:40:29 +1300
From: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@...il.com>
To: gregkh@...uxfoundation.org, paulo.miguel.almeida.rodenas@...il.com,
realwakka@...il.com
Cc: linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] staging: pi433: add debugfs interface
This adds debugfs interface that can be used for debugging possible
hardware/software issues.
It currently exposes the following debugfs entries for each SPI device
probed:
/sys/kernel/debug/pi433/<DEVICE>/regs
...
The 'regs' file contains all rf69 uC registers values that are useful
for troubleshooting misconfigurations between 2 devices. It contains one
register per line so it should be easy to use normal filtering tools to
find the registers of interest if needed.
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@...il.com>
---
Meta-comments:
- I'm not entirely sure if I'm allowed to add additional dependencies to Kconfig
the way I did or if I should surround debugfs routines with
#ifdef CONFIG_DEBUG_FS. I saw both approaches couldn't put my finger on which
one is the 'right' way here. I'm taking suggestions :)
- I saw that in some other drivers there is a tendency to have debugfs routines
in a separate file such as debugfs.c and in that way this allows for smaller
files (which I do like) and Makefile that build files based on selected
configs such as:
pi433-$(CONFIG_DEBUG_FS) += debugfs.o
The only way I could achieve such thing would be if I moved pi433_device struct
to pi433_if.h but I wanted to double check if reviewers would agree with this
approach first.
---
drivers/staging/pi433/Kconfig | 2 +-
drivers/staging/pi433/pi433_if.c | 82 ++++++++++++++++++++++++++++++++
drivers/staging/pi433/rf69.c | 2 +-
drivers/staging/pi433/rf69.h | 1 +
4 files changed, 85 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/pi433/Kconfig b/drivers/staging/pi433/Kconfig
index dd9e4709d1a8..9a8b7ef3e670 100644
--- a/drivers/staging/pi433/Kconfig
+++ b/drivers/staging/pi433/Kconfig
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
config PI433
tristate "Pi433 - a 433MHz radio module for Raspberry Pi"
- depends on SPI
+ depends on SPI && DEBUG_FS
help
This option allows you to enable support for the radio module Pi433.
diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index 17ff51f6a9da..e3a0d78385c0 100644
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -41,6 +41,9 @@
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#endif
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
#include "pi433_if.h"
#include "rf69.h"
@@ -56,6 +59,8 @@ static DEFINE_MUTEX(minor_lock); /* Protect idr accesses */
static struct class *pi433_class; /* mainly for udev to create /dev/pi433 */
+static struct dentry *dbgfs_root_entry;
+
/*
* tx config is instance specific
* so with each open a new tx config struct is needed
@@ -103,6 +108,9 @@ struct pi433_device {
bool rx_active;
bool tx_active;
bool interrupt_rx_allowed;
+
+ /* debug fs */
+ struct dentry *entry;
};
struct pi433_instance {
@@ -1102,6 +1110,72 @@ static const struct file_operations pi433_fops = {
.llseek = no_llseek,
};
+static int pi433_debugfs_regs_show(struct seq_file *m, void *p)
+{
+ struct pi433_device *dev;
+ u8 reg_data[114];
+ size_t i;
+ char *fmt = "0x%02x, 0x%02x\n";
+
+ // obtain pi433_device reference
+ dev = m->private;
+
+ // acquire locks to avoid race conditions
+ mutex_lock(&dev->tx_fifo_lock);
+ mutex_lock(&dev->rx_lock);
+
+ // wait for on-going operations to finish
+ if (dev->tx_active)
+ wait_event_interruptible(dev->rx_wait_queue, !dev->tx_active);
+
+ if (dev->rx_active)
+ wait_event_interruptible(dev->tx_wait_queue, !dev->rx_active);
+
+ // read contiguous regs
+ // skip FIFO register (0x0) otherwise this can affect some of uC ops
+ for (i = 1; i < 0x50; i++)
+ reg_data[i] = rf69_read_reg(dev->spi, i);
+
+ // read non-contiguous regs
+ reg_data[REG_TESTLNA] = rf69_read_reg(dev->spi, REG_TESTLNA);
+ reg_data[REG_TESTPA1] = rf69_read_reg(dev->spi, REG_TESTPA1);
+ reg_data[REG_TESTPA2] = rf69_read_reg(dev->spi, REG_TESTPA2);
+ reg_data[REG_TESTDAGC] = rf69_read_reg(dev->spi, REG_TESTDAGC);
+ reg_data[REG_TESTAFC] = rf69_read_reg(dev->spi, REG_TESTAFC);
+
+ seq_puts(m, "# reg, val\n");
+
+ // print contiguous regs
+ for (i = 1; i < 0x50; i++)
+ seq_printf(m, fmt, i, reg_data[i]);
+
+ // print non-contiguous regs
+ seq_printf(m, fmt, REG_TESTLNA, reg_data[REG_TESTLNA]);
+ seq_printf(m, fmt, REG_TESTPA1, reg_data[REG_TESTPA1]);
+ seq_printf(m, fmt, REG_TESTPA2, reg_data[REG_TESTPA2]);
+ seq_printf(m, fmt, REG_TESTDAGC, reg_data[REG_TESTDAGC]);
+ seq_printf(m, fmt, REG_TESTAFC, reg_data[REG_TESTAFC]);
+
+ // release locks
+ mutex_unlock(&dev->tx_fifo_lock);
+ mutex_unlock(&dev->rx_lock);
+
+ return 0;
+}
+
+static ssize_t pi433_debugfs_regs_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, pi433_debugfs_regs_show, inode->i_private);
+}
+
+static const struct file_operations debugfs_fops = {
+ .llseek = seq_lseek,
+ .open = pi433_debugfs_regs_open,
+ .owner = THIS_MODULE,
+ .read = seq_read,
+ .release = single_release
+};
+
/*-------------------------------------------------------------------------*/
static int pi433_probe(struct spi_device *spi)
@@ -1256,6 +1330,10 @@ static int pi433_probe(struct spi_device *spi)
/* spi setup */
spi_set_drvdata(spi, device);
+ /* debugfs setup */
+ device->entry = debugfs_create_dir(dev_name(device->dev), dbgfs_root_entry);
+ debugfs_create_file("regs", 0400, device->entry, device, &debugfs_fops);
+
return 0;
del_cdev:
@@ -1353,6 +1431,8 @@ static int __init pi433_init(void)
return PTR_ERR(pi433_class);
}
+ dbgfs_root_entry = debugfs_create_dir("pi433", NULL);
+
status = spi_register_driver(&pi433_spi_driver);
if (status < 0) {
class_destroy(pi433_class);
@@ -1370,6 +1450,8 @@ static void __exit pi433_exit(void)
spi_unregister_driver(&pi433_spi_driver);
class_destroy(pi433_class);
unregister_chrdev(MAJOR(pi433_dev), pi433_spi_driver.driver.name);
+ debugfs_remove_recursive(dbgfs_root_entry);
+
}
module_exit(pi433_exit);
diff --git a/drivers/staging/pi433/rf69.c b/drivers/staging/pi433/rf69.c
index d60514a840c2..b1a3382f4042 100644
--- a/drivers/staging/pi433/rf69.c
+++ b/drivers/staging/pi433/rf69.c
@@ -24,7 +24,7 @@
/*-------------------------------------------------------------------------*/
-static u8 rf69_read_reg(struct spi_device *spi, u8 addr)
+u8 rf69_read_reg(struct spi_device *spi, u8 addr)
{
int retval;
diff --git a/drivers/staging/pi433/rf69.h b/drivers/staging/pi433/rf69.h
index c25942f142a6..3ff5609ecf2e 100644
--- a/drivers/staging/pi433/rf69.h
+++ b/drivers/staging/pi433/rf69.h
@@ -17,6 +17,7 @@
#define FIFO_SIZE 66 /* bytes */
#define FIFO_THRESHOLD 15 /* bytes */
+u8 rf69_read_reg(struct spi_device *spi, u8 addr);
int rf69_get_version(struct spi_device *spi);
int rf69_set_mode(struct spi_device *spi, enum mode mode);
int rf69_set_data_mode(struct spi_device *spi, u8 data_mode);
--
2.25.4
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