admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

serial: sc16is7xx: add comments for lock requirements

Browse Source 
Indicate why lock needs to be asserted when accessing
MSR register, as this is not immediately obvious when looking at this
register in the device datasheet.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20251027142957.1032073-15-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hugo Villeneuve
2025-10-27 10:29:56 -04:00
committed by Greg Kroah-Hartman
parent bee8828a76
commit 42405cb77f
1 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/tty/serial/sc16is7xx.c
View File

@@ -499,10 +499,10 @@ EXPORT_SYMBOL_GPL(sc16is762_devtype);
static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
{
switch (reg) {
case SC16IS7XX_RHR_REG:
case SC16IS7XX_IIR_REG:
case SC16IS7XX_LSR_REG:
case SC16IS7XX_MSR_REG:
case SC16IS7XX_RHR_REG: /* Shared address space with THR & DLL */
case SC16IS7XX_IIR_REG: /* Shared address space with FCR & EFR */
case SC16IS7XX_LSR_REG: /* Shared address space with XON2 */
case SC16IS7XX_MSR_REG: /* Shared address space with TCR & XOFF1 */
case SC16IS7XX_SPR_REG: /* Shared address space with TLR & XOFF2 */
case SC16IS7XX_TXLVL_REG:
case SC16IS7XX_RXLVL_REG:
@@ -711,6 +711,7 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
unsigned long flags;
unsigned int status, changed;
/* Lock required as MSR address is shared with TCR and XOFF1. */
lockdep_assert_held_once(&one->lock);
status = sc16is7xx_get_hwmctrl(port);