this driver relies on exposing a char device to userspace to tx
messages. Every message can be sent using different trasmitter settings
such so the tx_cfg must be written before sending any messages.
Failing to do so will cause the message to fail silently depending on
printk/dynamic_debug settings which makes it hard to troubleshoot.
This patch add a control variable that will get initialized once tx_cfg
is set for the fd used when interacting with the char device.
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@xxxxxxxxx>
---
changelog:
v2: changed message and remove redudant assignments pointed out during
code review. (Req: Dan Carpenter, Sidong Yang)
v1: https://lore.kernel.org/lkml/20220108222652.GA11883@xxxxxxxxxxxxxxx/
patch dependency:
- This patch needs the patch below to be applied first as both tweak the
same file.
https://lore.kernel.org/lkml/20220108212728.GA7784@xxxxxxxxxxxxxxx/
---
drivers/staging/pi433/pi433_if.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index 051c9052aeeb..f9f86e2c44a9 100644
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -108,6 +108,9 @@ struct pi433_device {
struct pi433_instance {
struct pi433_device *device;
struct pi433_tx_cfg tx_cfg;
+
+ /* control flags */
+ bool tx_cfg_initialized;
};
/*-------------------------------------------------------------------------*/
@@ -823,6 +826,16 @@ pi433_write(struct file *filp, const char __user *buf,
if (count > MAX_MSG_SIZE)
return -EMSGSIZE;
+ /*
+ * check if tx_cfg has been initialized otherwise we won't be able to
+ * config the RF trasmitter correctly due to invalid settings
+ */
+ if (!instance->tx_cfg_initialized) {
+ dev_notice_once(device->dev,
+ "write: failed due to unconfigured tx_cfg (see PI433_IOC_WR_TX_CFG)");
+ return -EINVAL;
+ }
+
/*
* write the following sequence into fifo:
* - tx_cfg
@@ -897,6 +910,7 @@ pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return -EFAULT;
mutex_lock(&device->tx_fifo_lock);
memcpy(&instance->tx_cfg, &tx_cfg, sizeof(struct pi433_tx_cfg));
+ instance->tx_cfg_initialized = true;
mutex_unlock(&device->tx_fifo_lock);
break;
case PI433_IOC_RD_RX_CFG:
@@ -949,8 +963,6 @@ static int pi433_open(struct inode *inode, struct file *filp)
/* setup instance data*/
instance->device = device;
- instance->tx_cfg.bit_rate = 4711;
- // TODO: fill instance->tx_cfg;
/* instance data as context */
filp->private_data = instance;
--
2.25.4
