Re: [RFC net-next 08/15] net: lora: sx1276: Add debugfs

Jiri Pirko
2018-07-02T16:28:31Z

Sun, Jul 01, 2018 at 01:07:57PM CEST, afaerber@suse.de wrote:
>Allow some interactive inspection at runtime via debugfs.
>
>Signed-off-by: Andreas Färber <afaerber@suse.de>
>---
> drivers/net/lora/sx1276.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 132 insertions(+)
>
>diff --git a/drivers/net/lora/sx1276.c b/drivers/net/lora/sx1276.c
>index d6732111247a..1072019cfcc1 100644
>--- a/drivers/net/lora/sx1276.c
>+++ b/drivers/net/lora/sx1276.c
>@@ -5,6 +5,7 @@
> * Copyright (c) 2016-2018 Andreas Färber
> */
>
>+#include <linux/debugfs.h>
> #include <linux/delay.h>
> #include <linux/lora.h>
> #include <linux/module.h>
>@@ -61,6 +62,8 @@ struct sx1276_priv {
>
> struct workqueue_struct *wq;
> struct work_struct tx_work;
>+
>+ struct dentry *debugfs;
> };
>
> static int sx1276_read_single(struct spi_device *spi, u8 reg, u8 *val)
>@@ -416,6 +419,128 @@ static const struct net_device_ops sx1276_netdev_ops = {
> .ndo_start_xmit = sx1276_loradev_start_xmit,
> };
>
>+static ssize_t sx1276_freq_read(struct file *file, char __user *user_buf,
>+ size_t count, loff_t *ppos)
>+{
>+ struct net_device *netdev = file->private_data;
>+ struct sx1276_priv *priv = netdev_priv(netdev);
>+ struct spi_device *spi = priv->spi;
>+ ssize_t size;
>+ char *buf;
>+ int ret;
>+ u8 msb, mid, lsb;
>+ u32 freq_xosc;
>+ unsigned long long frf;
>+
>+ ret = of_property_read_u32(spi->dev.of_node, "clock-frequency", &freq_xosc);
>+ if (ret)
>+ return 0;
>+
>+ mutex_lock(&priv->spi_lock);
>+
>+ ret = sx1276_read_single(spi, REG_FRF_MSB, &msb);
>+ if (!ret)
>+ ret = sx1276_read_single(spi, REG_FRF_MID, &mid);
>+ if (!ret)
>+ ret = sx1276_read_single(spi, REG_FRF_LSB, &lsb);
>+
>+ mutex_unlock(&priv->spi_lock);
>+
>+ if (ret)
>+ return 0;
>+
>+ frf = freq_xosc;
>+ frf *= ((ulong)msb << 16) | ((ulong)mid << 8) | lsb;
>+ frf /= (1 << 19);
>+
>+ buf = kasprintf(GFP_KERNEL, "%llu\n", frf);
>+ if (!buf)
>+ return 0;
>+
>+ size = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
>+ kfree(buf);
>+
>+ return size;
>+}
>+
>+static const struct file_operations sx1276_freq_fops = {
>+ .owner = THIS_MODULE,
>+ .open = simple_open,
>+ .read = sx1276_freq_read,
>+};
>+
>+static ssize_t sx1276_state_read(struct file *file, char __user *user_buf,
>+ size_t count, loff_t *ppos)
>+{
>+ struct net_device *netdev = file->private_data;
>+ struct sx1276_priv *priv = netdev_priv(netdev);
>+ struct spi_device *spi = priv->spi;
>+ ssize_t size;
>+ char *buf;
>+ int len = 0;
>+ int ret;
>+ u8 val;
>+ bool lora_mode = true;
>+ const int max_len = 4096;
>+
>+ buf = kzalloc(max_len, GFP_KERNEL);
>+ if (!buf)
>+ return 0;
>+
>+ mutex_lock(&priv->spi_lock);
>+
>+ ret = sx1276_read_single(spi, REG_OPMODE, &val);
>+ if (!ret) {
>+ len += snprintf(buf + len, max_len - len, "RegOpMode = 0x%02x\n", val);
>+ lora_mode = (val & REG_OPMODE_LONG_RANGE_MODE) != 0;
>+ }
>+
>+ ret = sx1276_read_single(spi, REG_FRF_MSB, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegFrMsb = 0x%02x\n", val);
>+ ret = sx1276_read_single(spi, REG_FRF_MID, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegFrMid = 0x%02x\n", val);
>+ ret = sx1276_read_single(spi, REG_FRF_LSB, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegFrLsb = 0x%02x\n", val);
>+
>+ ret = sx1276_read_single(spi, REG_PA_CONFIG, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegPaConfig = 0x%02x\n", val);
>+
>+ if (lora_mode) {
>+ ret = sx1276_read_single(spi, LORA_REG_IRQ_FLAGS_MASK, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegIrqFlagsMask = 0x%02x\n", val);
>+
>+ ret = sx1276_read_single(spi, LORA_REG_IRQ_FLAGS, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegIrqFlags = 0x%02x\n", val);
>+
>+ ret = sx1276_read_single(spi, LORA_REG_SYNC_WORD, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegSyncWord = 0x%02x\n", val);
>+ }
>+
>+ ret = sx1276_read_single(spi, REG_PA_DAC, &val);
>+ if (!ret)
>+ len += snprintf(buf + len, max_len - len, "RegPaDac = 0x%02x\n", val);
>+
>+ mutex_unlock(&priv->spi_lock);
>+
>+ size = simple_read_from_buffer(user_buf, count, ppos, buf, len);
>+ kfree(buf);
>+
>+ return size;
>+}
>+
>+static const struct file_operations sx1276_state_fops = {
>+ .owner = THIS_MODULE,
>+ .open = simple_open,
>+ .read = sx1276_state_read,
>+};
>+
> static int sx1276_probe(struct spi_device *spi)
> {
> struct net_device *netdev;
>@@ -566,6 +691,10 @@ static int sx1276_probe(struct spi_device *spi)
> return ret;
> }
>
>+ priv->debugfs = debugfs_create_dir(dev_name(&spi->dev), NULL);
>+ debugfs_create_file("state", S_IRUGO, priv->debugfs, netdev, &sx1276_state_fops);
>+ debugfs_create_file("frequency", S_IRUGO, priv->debugfs, netdev, &sx1276_freq_fops);

Hmm. These look like useful information not only for debugging. I think
it would be worth to expose these via some standard uapi. Like generic
netlink, similar to nl80211

>+
> dev_info(&spi->dev, "SX1276 module probed (SX%d)", model);
>
> return 0;
>@@ -574,6 +703,9 @@ static int sx1276_probe(struct spi_device *spi)
> static int sx1276_remove(struct spi_device *spi)
> {
> struct net_device *netdev = spi_get_drvdata(spi);
>+ struct sx1276_priv *priv = netdev_priv(netdev);
>+
>+ debugfs_remove_recursive(priv->debugfs);
>
> unregister_loradev(netdev);
> free_loradev(netdev);
>--
>2.16.4
>