[v6] Fixes and improvements for RS485

[PATCH v6 6/7] serial: omap: do not override settings for RS485 support

Posted by Lino Sanfilippo 2 years ago

The drivers RS485 support is deactivated if there is no RTS GPIO available.
This is done by nullifying the ports rs485_supported struct. After that
however the settings in serial_omap_rs485_supported are assigned to the
same structure unconditionally, which results in an unintended reactivation
of RS485 support.

Fix this by moving the assignment to the beginning of
serial_omap_probe_rs485() and thus before uart_get_rs485_mode() gets
called.

Also replace the assignment of rs485_config() to have the complete RS485
setup in one function.

Fixes: e2752ae3cfc9 ("serial: omap: Disallow RS-485 if rts-gpio is not specified")
Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
---
 drivers/tty/serial/omap-serial.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index ad4c1c5d0a7f..b563c109caa9 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1497,6 +1497,9 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
 	if (!np)
 		return 0;
 
+	up->port.rs485_config = serial_omap_config_rs485;
+	up->port.rs485_supported = serial_omap_rs485_supported;
+
 	ret = uart_get_rs485_mode(&up->port);
 	if (ret)
 		return ret;
@@ -1604,17 +1607,11 @@ static int serial_omap_probe(struct platform_device *pdev)
 		dev_info(up->port.dev, "no wakeirq for uart%d\n",
 			 up->port.line);
 
-	ret = serial_omap_probe_rs485(up, &pdev->dev);
-	if (ret < 0)
-		goto err_rs485;
-
 	sprintf(up->name, "OMAP UART%d", up->port.line);
 	up->port.mapbase = mem->start;
 	up->port.membase = base;
 	up->port.flags = omap_up_info->flags;
 	up->port.uartclk = omap_up_info->uartclk;
-	up->port.rs485_config = serial_omap_config_rs485;
-	up->port.rs485_supported = serial_omap_rs485_supported;
 	if (!up->port.uartclk) {
 		up->port.uartclk = DEFAULT_CLK_SPEED;
 		dev_warn(&pdev->dev,
@@ -1622,6 +1619,10 @@ static int serial_omap_probe(struct platform_device *pdev)
 			 DEFAULT_CLK_SPEED);
 	}
 
+	ret = serial_omap_probe_rs485(up, &pdev->dev);
+	if (ret < 0)
+		goto err_rs485;
+
 	up->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
 	up->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
 	cpu_latency_qos_add_request(&up->pm_qos_request, up->latency);
-- 
2.43.0

Re: [PATCH v6 6/7] serial: omap: do not override settings for RS485 support

Posted by kernel test robot 2 years ago

Hi Lino,

kernel test robot noticed the following build errors:

[auto build test ERROR on ceb6a6f023fd3e8b07761ed900352ef574010bcb]

url:    https://github.com/intel-lab-lkp/linux/commits/Lino-Sanfilippo/serial-Do-not-hold-the-port-lock-when-setting-rx-during-tx-GPIO/20231225-193833
base:   ceb6a6f023fd3e8b07761ed900352ef574010bcb
patch link:    https://lore.kernel.org/r/20231225113524.8800-7-l.sanfilippo%40kunbus.com
patch subject: [PATCH v6 6/7] serial: omap: do not override settings for RS485 support
config: powerpc-allmodconfig (https://download.01.org/0day-ci/archive/20231226/202312260719.mI12i497-lkp@intel.com/config)
compiler: clang version 18.0.0git (https://github.com/llvm/llvm-project d3ef86708241a3bee902615c190dead1638c4e09)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231226/202312260719.mI12i497-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312260719.mI12i497-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/tty/serial/omap-serial.c:1501:29: error: use of undeclared identifier 'serial_omap_rs485_supported'
    1501 |         up->port.rs485_supported = serial_omap_rs485_supported;
         |                                    ^
   1 error generated.


vim +/serial_omap_rs485_supported +1501 drivers/tty/serial/omap-serial.c

  1485	
  1486	static int serial_omap_probe_rs485(struct uart_omap_port *up,
  1487					   struct device *dev)
  1488	{
  1489		struct serial_rs485 *rs485conf = &up->port.rs485;
  1490		struct device_node *np = dev->of_node;
  1491		enum gpiod_flags gflags;
  1492		int ret;
  1493	
  1494		rs485conf->flags = 0;
  1495		up->rts_gpiod = NULL;
  1496	
  1497		if (!np)
  1498			return 0;
  1499	
  1500		up->port.rs485_config = serial_omap_config_rs485;
> 1501		up->port.rs485_supported = serial_omap_rs485_supported;
  1502	
  1503		ret = uart_get_rs485_mode(&up->port);
  1504		if (ret)
  1505			return ret;
  1506	
  1507		if (of_property_read_bool(np, "rs485-rts-active-high")) {
  1508			rs485conf->flags |= SER_RS485_RTS_ON_SEND;
  1509			rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
  1510		} else {
  1511			rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
  1512			rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
  1513		}
  1514	
  1515		/* check for tx enable gpio */
  1516		gflags = rs485conf->flags & SER_RS485_RTS_AFTER_SEND ?
  1517			GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
  1518		up->rts_gpiod = devm_gpiod_get_optional(dev, "rts", gflags);
  1519		if (IS_ERR(up->rts_gpiod)) {
  1520			ret = PTR_ERR(up->rts_gpiod);
  1521		        if (ret == -EPROBE_DEFER)
  1522				return ret;
  1523	
  1524			up->rts_gpiod = NULL;
  1525			up->port.rs485_supported = (const struct serial_rs485) { };
  1526			if (rs485conf->flags & SER_RS485_ENABLED) {
  1527				dev_err(dev, "disabling RS-485 (rts-gpio missing in device tree)\n");
  1528				memset(rs485conf, 0, sizeof(*rs485conf));
  1529			}
  1530		} else {
  1531			gpiod_set_consumer_name(up->rts_gpiod, "omap-serial");
  1532		}
  1533	
  1534		return 0;
  1535	}
  1536	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v6 6/7] serial: omap: do not override settings for RS485 support

Posted by kernel test robot 2 years ago

Hi Lino,

kernel test robot noticed the following build errors:

[auto build test ERROR on ceb6a6f023fd3e8b07761ed900352ef574010bcb]

url:    https://github.com/intel-lab-lkp/linux/commits/Lino-Sanfilippo/serial-Do-not-hold-the-port-lock-when-setting-rx-during-tx-GPIO/20231225-193833
base:   ceb6a6f023fd3e8b07761ed900352ef574010bcb
patch link:    https://lore.kernel.org/r/20231225113524.8800-7-l.sanfilippo%40kunbus.com
patch subject: [PATCH v6 6/7] serial: omap: do not override settings for RS485 support
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20231226/202312260601.aT9SYjjo-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231226/202312260601.aT9SYjjo-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312260601.aT9SYjjo-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   drivers/tty/serial/omap-serial.c: In function 'serial_omap_probe_rs485':
>> drivers/tty/serial/omap-serial.c:1501:36: error: 'serial_omap_rs485_supported' undeclared (first use in this function); did you mean 'serial_omap_request_port'?
    1501 |         up->port.rs485_supported = serial_omap_rs485_supported;
         |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                                    serial_omap_request_port
   drivers/tty/serial/omap-serial.c:1501:36: note: each undeclared identifier is reported only once for each function it appears in
   drivers/tty/serial/omap-serial.c: At top level:
>> drivers/tty/serial/omap-serial.c:1537:34: warning: 'serial_omap_rs485_supported' defined but not used [-Wunused-const-variable=]
    1537 | static const struct serial_rs485 serial_omap_rs485_supported = {
         |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +1501 drivers/tty/serial/omap-serial.c

  1485	
  1486	static int serial_omap_probe_rs485(struct uart_omap_port *up,
  1487					   struct device *dev)
  1488	{
  1489		struct serial_rs485 *rs485conf = &up->port.rs485;
  1490		struct device_node *np = dev->of_node;
  1491		enum gpiod_flags gflags;
  1492		int ret;
  1493	
  1494		rs485conf->flags = 0;
  1495		up->rts_gpiod = NULL;
  1496	
  1497		if (!np)
  1498			return 0;
  1499	
  1500		up->port.rs485_config = serial_omap_config_rs485;
> 1501		up->port.rs485_supported = serial_omap_rs485_supported;
  1502	
  1503		ret = uart_get_rs485_mode(&up->port);
  1504		if (ret)
  1505			return ret;
  1506	
  1507		if (of_property_read_bool(np, "rs485-rts-active-high")) {
  1508			rs485conf->flags |= SER_RS485_RTS_ON_SEND;
  1509			rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
  1510		} else {
  1511			rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
  1512			rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
  1513		}
  1514	
  1515		/* check for tx enable gpio */
  1516		gflags = rs485conf->flags & SER_RS485_RTS_AFTER_SEND ?
  1517			GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
  1518		up->rts_gpiod = devm_gpiod_get_optional(dev, "rts", gflags);
  1519		if (IS_ERR(up->rts_gpiod)) {
  1520			ret = PTR_ERR(up->rts_gpiod);
  1521		        if (ret == -EPROBE_DEFER)
  1522				return ret;
  1523	
  1524			up->rts_gpiod = NULL;
  1525			up->port.rs485_supported = (const struct serial_rs485) { };
  1526			if (rs485conf->flags & SER_RS485_ENABLED) {
  1527				dev_err(dev, "disabling RS-485 (rts-gpio missing in device tree)\n");
  1528				memset(rs485conf, 0, sizeof(*rs485conf));
  1529			}
  1530		} else {
  1531			gpiod_set_consumer_name(up->rts_gpiod, "omap-serial");
  1532		}
  1533	
  1534		return 0;
  1535	}
  1536	
> 1537	static const struct serial_rs485 serial_omap_rs485_supported = {
  1538		.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
  1539			 SER_RS485_RX_DURING_TX,
  1540		.delay_rts_before_send = 1,
  1541		.delay_rts_after_send = 1,
  1542	};
  1543	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v6 1/7] serial: Do not hold the port lock when setting rx-during-tx GPIO
[PATCH v6 2/7] serial: core: set missing supported flag for RX during TX GPIO
[PATCH v6 3/7] serial: core: fix sanitizing check for RTS settings
[PATCH v6 4/7] serial: core: make sure RS485 cannot be enabled when it is not supported
[PATCH v6 5/7] serial: core, imx: do not set RS485 enabled if it is not supported
[PATCH v6 6/7] serial: omap: do not override settings for RS485 support
[PATCH v6 7/7] serial: 8250_exar: Set missing rs485_supported flag