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staging: pi433: enforce tx_cfg to be set before any message can be sent

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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@gmail.com>
Link: https://lore.kernel.org/r/20220114221643.GA7843@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paulo Miguel Almeida 2022-01-15 11:16:43 +13:00 committed by Greg Kroah-Hartman
parent 39ddef5681
commit ce514dadc6
1 changed files with 14 additions and 2 deletions
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16
drivers/staging/pi433/pi433_if.c
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@ -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;