diff mbox series

[v4,3/3] serial: sc16is7xx: add support for EXAR XR20M1172 UART

Message ID 20240419124506.1531035-4-rilian.la.te@ya.ru
State Superseded
Headers show
Series add support for EXAR XR20M1172 UART | expand

Commit Message

Konstantin Pugin April 19, 2024, 12:45 p.m. UTC
From: Konstantin Pugin <ria.freelander@gmail.com>

XR20M1172 register set is mostly compatible with SC16IS762, but it has
a support for additional division rates of UART with special DLD register.
So, add handling this register by appropriate devicetree bindings.

Signed-off-by: Konstantin Pugin <ria.freelander@gmail.com>
---
 drivers/tty/serial/Kconfig         | 18 +++++----
 drivers/tty/serial/sc16is7xx.c     | 60 ++++++++++++++++++++++++++++--
 drivers/tty/serial/sc16is7xx_i2c.c |  1 +
 drivers/tty/serial/sc16is7xx_spi.c |  1 +
 4 files changed, 68 insertions(+), 12 deletions(-)

Comments

kernel test robot April 20, 2024, 7:28 a.m. UTC | #1
Hi Konstantin,

kernel test robot noticed the following build errors:

[auto build test ERROR on c6795fbffc4547b40933ec368200bd4926a41b44]

url:    https://github.com/intel-lab-lkp/linux/commits/Konstantin-Pugin/serial-sc16is7xx-announce-support-of-SER_RS485_RTS_ON_SEND/20240420-004819
base:   c6795fbffc4547b40933ec368200bd4926a41b44
patch link:    https://lore.kernel.org/r/20240419124506.1531035-4-rilian.la.te%40ya.ru
patch subject: [PATCH v4 3/3] serial: sc16is7xx: add support for EXAR XR20M1172 UART
config: hexagon-randconfig-001-20240420 (https://download.01.org/0day-ci/archive/20240420/202404201559.2eM6MALu-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 7089c359a3845323f6f30c44a47dd901f2edfe63)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240420/202404201559.2eM6MALu-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/202404201559.2eM6MALu-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/tty/serial/sc16is7xx_spi.c:7:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/tty/serial/sc16is7xx_spi.c:7:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/tty/serial/sc16is7xx_spi.c:7:
   In file included from include/linux/regmap.h:20:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   In file included from drivers/tty/serial/sc16is7xx_spi.c:8:
   In file included from include/linux/spi/spi.h:17:
   In file included from include/linux/scatterlist.h:8:
   In file included from include/linux/mm.h:2208:
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> drivers/tty/serial/sc16is7xx_spi.c:72:34: error: use of undeclared identifier 'xr20m1172_devtype'
      72 |         { "xr20m1172",  (kernel_ulong_t)&xr20m1172_devtype, },
         |                                          ^
   7 warnings and 1 error generated.


vim +/xr20m1172_devtype +72 drivers/tty/serial/sc16is7xx_spi.c

    63	
    64	static const struct spi_device_id sc16is7xx_spi_id_table[] = {
    65		{ "sc16is74x",	(kernel_ulong_t)&sc16is74x_devtype, },
    66		{ "sc16is740",	(kernel_ulong_t)&sc16is74x_devtype, },
    67		{ "sc16is741",	(kernel_ulong_t)&sc16is74x_devtype, },
    68		{ "sc16is750",	(kernel_ulong_t)&sc16is750_devtype, },
    69		{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
    70		{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
    71		{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
  > 72		{ "xr20m1172",	(kernel_ulong_t)&xr20m1172_devtype, },
    73		{ }
    74	};
    75	MODULE_DEVICE_TABLE(spi, sc16is7xx_spi_id_table);
    76
diff mbox series

Patch

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 4fdd7857ef4d..4380bfe7dfff 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1029,15 +1029,17 @@  config SERIAL_SC16IS7XX_CORE
 	select SERIAL_SC16IS7XX_SPI if SPI_MASTER
 	select SERIAL_SC16IS7XX_I2C if I2C
 	help
-	  Core driver for NXP SC16IS7xx UARTs.
+	  Core driver for NXP SC16IS7xx-compatible UARTs.
 	  Supported ICs are:
-
-	    SC16IS740
-	    SC16IS741
-	    SC16IS750
-	    SC16IS752
-	    SC16IS760
-	    SC16IS762
+		NXP:
+	    	SC16IS740
+	    	SC16IS741
+	    	SC16IS750
+	    	SC16IS752
+	    	SC16IS760
+	    	SC16IS762
+		EXAR:
+			XR20M1172
 
 	  The driver supports both I2C and SPI interfaces.
 
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index dfcc804f558f..b2aa2e487c84 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -10,6 +10,7 @@ 
 #undef DEFAULT_SYMBOL_NAMESPACE
 #define DEFAULT_SYMBOL_NAMESPACE SERIAL_NXP_SC16IS7XX
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -68,6 +69,7 @@ 
 /* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
 #define SC16IS7XX_DLL_REG		(0x00) /* Divisor Latch Low */
 #define SC16IS7XX_DLH_REG		(0x01) /* Divisor Latch High */
+#define XR20M117X_DLD_REG		(0x02) /* Divisor Fractional Register */
 
 /* Enhanced Register set: Only if (LCR == 0xBF) */
 #define SC16IS7XX_EFR_REG		(0x02) /* Enhanced Features */
@@ -221,6 +223,20 @@ 
 #define SC16IS7XX_TCR_RX_HALT(words)	((((words) / 4) & 0x0f) << 0)
 #define SC16IS7XX_TCR_RX_RESUME(words)	((((words) / 4) & 0x0f) << 4)
 
+/*
+ * Divisor Fractional Register bits (EXAR extension)
+ * EXAR hardware is mostly compatible with SC16IS7XX, but supports additional feature:
+ * 4x and 8x divisor, instead of default 16x. It has a special register to program it.
+ * Bits 0 to 3 is fractional divisor, it used to set value of last 16 bits of
+ * uartclk * (16 / divisor) / baud, in case of default it will be uartclk / baud.
+ * Bits 4 and 5 used as switches, and should not be set to 1 simultaneously.
+ */
+
+#define XR20M117X_DLD_16X			0
+#define XR20M117X_DLD_DIV_MASK		GENMASK(3, 0)
+#define XR20M117X_DLD_8X			BIT(4)
+#define XR20M117X_DLD_4X			BIT(5)
+
 /*
  * TLR register bits
  * If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
@@ -523,6 +539,13 @@  const struct sc16is7xx_devtype sc16is762_devtype = {
 };
 EXPORT_SYMBOL_GPL(sc16is762_devtype);
 
+static const struct sc16is7xx_devtype xr20m1172_devtype = {
+	.name		= "XR20M1172",
+	.nr_gpio	= 8,
+	.nr_uart	= 2,
+};
+EXPORT_SYMBOL_GPL(sc16is762_devtype);
+
 static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
@@ -555,18 +578,43 @@  static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg)
 	return reg == SC16IS7XX_RHR_REG;
 }
 
+static bool sc16is7xx_has_dld(struct device *dev)
+{
+       struct sc16is7xx_port *s = dev_get_drvdata(dev);
+
+       if (s->devtype == &xr20m1172_devtype)
+               return true;
+       return false;
+}
+
 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
 {
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
-	u8 lcr;
+	unsigned long clk = port->uartclk, div, div16;
+	bool has_dld = sc16is7xx_has_dld(port->dev);
+	u8 dld_mode = XR20M117X_DLD_16X;
 	u8 prescaler = 0;
-	unsigned long clk = port->uartclk, div = clk / 16 / baud;
+	u8 divisor = 16;
+	u8 lcr;
+
+	if (has_dld && DIV_ROUND_CLOSEST(clk, baud) < 16)
+		divisor = rounddown_pow_of_two(DIV_ROUND_CLOSEST(clk, baud));
+
+	div16 = (clk * 16) / divisor / baud;
+	div = div16 / 16;
 
 	if (div >= BIT(16)) {
 		prescaler = SC16IS7XX_MCR_CLKSEL_BIT;
 		div /= 4;
 	}
 
+	/* Count additional divisor for EXAR devices */
+	if (divisor == 8)
+		dld_mode = XR20M117X_DLD_8X;
+	if (divisor == 4)
+		dld_mode = XR20M117X_DLD_4X;
+	dld_mode |= FIELD_PREP(XR20M117X_DLD_DIV_MASK, div16);
+
 	/* Enable enhanced features */
 	sc16is7xx_efr_lock(port);
 	sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
@@ -587,12 +635,14 @@  static int sc16is7xx_set_baud(struct uart_port *port, int baud)
 	regcache_cache_bypass(one->regmap, true);
 	sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
 	sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
+	if (has_dld)
+		sc16is7xx_port_write(port, XR20M117X_DLD_REG, dld_mode);
 	regcache_cache_bypass(one->regmap, false);
 
 	/* Restore LCR and access to general register set */
 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
 
-	return DIV_ROUND_CLOSEST(clk / 16, div);
+	return DIV_ROUND_CLOSEST(clk / divisor, div);
 }
 
 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
@@ -1002,6 +1052,7 @@  static void sc16is7xx_set_termios(struct uart_port *port,
 				  const struct ktermios *old)
 {
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
+	bool has_dld = sc16is7xx_has_dld(port->dev);
 	unsigned int lcr, flow = 0;
 	int baud;
 	unsigned long flags;
@@ -1084,7 +1135,7 @@  static void sc16is7xx_set_termios(struct uart_port *port,
 	/* Get baud rate generator configuration */
 	baud = uart_get_baud_rate(port, termios, old,
 				  port->uartclk / 16 / 4 / 0xffff,
-				  port->uartclk / 16);
+				  port->uartclk / (has_dld ? 4 : 16));
 
 	/* Setup baudrate generator */
 	baud = sc16is7xx_set_baud(port, baud);
@@ -1684,6 +1735,7 @@  void sc16is7xx_remove(struct device *dev)
 EXPORT_SYMBOL_GPL(sc16is7xx_remove);
 
 const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
+	{ .compatible = "exar,xr20m1172",	.data = &xr20m1172_devtype, },
 	{ .compatible = "nxp,sc16is740",	.data = &sc16is74x_devtype, },
 	{ .compatible = "nxp,sc16is741",	.data = &sc16is74x_devtype, },
 	{ .compatible = "nxp,sc16is750",	.data = &sc16is750_devtype, },
diff --git a/drivers/tty/serial/sc16is7xx_i2c.c b/drivers/tty/serial/sc16is7xx_i2c.c
index 3ed47c306d85..839de902821b 100644
--- a/drivers/tty/serial/sc16is7xx_i2c.c
+++ b/drivers/tty/serial/sc16is7xx_i2c.c
@@ -46,6 +46,7 @@  static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
 	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
 	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
 	{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
+	{ "xr20m1172",	(kernel_ulong_t)&xr20m1172_devtype, },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, sc16is7xx_i2c_id_table);
diff --git a/drivers/tty/serial/sc16is7xx_spi.c b/drivers/tty/serial/sc16is7xx_spi.c
index 73df36f8a7fd..2b278282dbd0 100644
--- a/drivers/tty/serial/sc16is7xx_spi.c
+++ b/drivers/tty/serial/sc16is7xx_spi.c
@@ -69,6 +69,7 @@  static const struct spi_device_id sc16is7xx_spi_id_table[] = {
 	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
 	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
 	{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
+	{ "xr20m1172",	(kernel_ulong_t)&xr20m1172_devtype, },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, sc16is7xx_spi_id_table);