Re: [PATCH v4 6/7] serial: exar: add CTI specific setup code

Parker Newman
2024-04-18T14:22:14Z

On Thu, 18 Apr 2024 16:20:15 +0300 (EEST)
Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> wrote:

> On Wed, 17 Apr 2024, Parker Newman wrote:
>
> > From: Parker Newman <pnewman@connecttech.com>
> >
> > This is a large patch but is only additions. All changes and removals
> > are made in previous patches in this series.
> >
> > - Add CTI board_init and port setup functions for each UART type
> > - Add CTI_EXAR_DEVICE() and CTI_PCI_DEVICE() macros
> > - Add support for reading a word from the Exar EEPROM.
> > - Add support for configuring and setting a single MPIO
> > - Add various helper functions for CTI boards.
> > - Add osc_freq to struct exar8250
> >
> > Signed-off-by: Parker Newman <pnewman@connecttech.com>
> > ---
> > Changes in v3:
> > - Moved all base driver changes and refactoring to preparatory patches
> > - Switched any user space types to kernel types
> > - Switched all uses of pci_xxx print functions to dev_xxx
> > - Added struct device pointer in struct exar8250 to simplify above
> > - Switched osc_freq and port_flag parsing to use GENMASK() and
> > FIELD_GET()/FIELD_PREP()
> > - Renamed board_setup function pointer to board_init
> > - Removed some unneeded checks for priv being NULL
> > - Added various convenience functions instead of relying on bools ex:
> > exar_mpio_set_low()/exar_mpio_set_high() instead of exar_mpio_set()
> > - Renamed some variables and defines for clarity
> > - Numerous minor formatting fixes
> >
> > Changes in v4:
> > - Removed pcidev and dev from struct exar8250
> > - Removed some debug prints
> > - Removed some unneeded checks if PCI vendor was Exar
> > - Changed several functions to take pcidev as arg to avoid adding to priv
> > - Removed _exar_mpio_config(), only needed exar_mpio_config_output()
> > - Removed _cti_set_tristate() and _cti_set_plx_int_enable, same as above
> >
> > drivers/tty/serial/8250/8250_exar.c | 846 ++++++++++++++++++++++++++++
> > 1 file changed, 846 insertions(+)
> >
> > diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
> > index 197f45e306ff..6985aabe13cc 100644
> > --- a/drivers/tty/serial/8250/8250_exar.c
> > +++ b/drivers/tty/serial/8250/8250_exar.c
> > @@ -20,6 +20,7 @@
> > #include <linux/property.h>
> > #include <linux/string.h>
> > #include <linux/types.h>
> > +#include <linux/bitfield.h>
> >
> > #include <linux/serial_8250.h>
> > #include <linux/serial_core.h>
> > @@ -128,6 +129,19 @@
> > #define UART_EXAR_DLD 0x02 /* Divisor Fractional */
> > #define UART_EXAR_DLD_485_POLARITY 0x80 /* RS-485 Enable Signal Polarity */
> >
> > +/* EEPROM registers */
> > +#define UART_EXAR_REGB 0x8e
> > +#define UART_EXAR_REGB_EECK BIT(4)
> > +#define UART_EXAR_REGB_EECS BIT(5)
> > +#define UART_EXAR_REGB_EEDI BIT(6)
> > +#define UART_EXAR_REGB_EEDO BIT(7)
> > +#define UART_EXAR_REGB_EE_ADDR_SIZE 6
> > +#define UART_EXAR_REGB_EE_DATA_SIZE 16
> > +
> > +#define UART_EXAR_XR17C15X_PORT_OFFSET 0x200
> > +#define UART_EXAR_XR17V25X_PORT_OFFSET 0x200
> > +#define UART_EXAR_XR17V35X_PORT_OFFSET 0x400
> > +
> > /*
> > * IOT2040 MPIO wiring semantics:
> > *
> > @@ -163,6 +177,52 @@
> > #define IOT2040_UARTS_ENABLE 0x03
> > #define IOT2040_UARTS_GPIO_HI_MODE 0xF8 /* enable & LED as outputs */
> >
> > +/* CTI EEPROM offsets */
> > +#define CTI_EE_OFF_XR17C15X_OSC_FREQ 0x04 /* 2 words */
> > +#define CTI_EE_OFF_XR17V25X_OSC_FREQ 0x08 /* 2 words */
> > +#define CTI_EE_OFF_XR17C15X_PART_NUM 0x0A /* 4 words */
> > +#define CTI_EE_OFF_XR17V25X_PART_NUM 0x0E /* 4 words */
> > +#define CTI_EE_OFF_XR17C15X_SERIAL_NUM 0x0E /* 1 word */
> > +#define CTI_EE_OFF_XR17V25X_SERIAL_NUM 0x12 /* 1 word */
> > +#define CTI_EE_OFF_XR17V35X_SERIAL_NUM 0x11 /* 2 word */
> > +#define CTI_EE_OFF_XR17V35X_BRD_FLAGS 0x13 /* 1 word */
> > +#define CTI_EE_OFF_XR17V35X_PORT_FLAGS 0x14 /* 1 word */
> > +
> > +#define CTI_EE_MASK_PORT_FLAGS_TYPE GENMASK(7, 0)
> > +#define CTI_EE_MASK_OSC_FREQ_LOWER GENMASK(15, 0)
> > +#define CTI_EE_MASK_OSC_FREQ_UPPER GENMASK(31, 16)
> > +
> > +#define CTI_FPGA_RS485_IO_REG 0x2008
> > +#define CTI_FPGA_CFG_INT_EN_REG 0x48
> > +#define CTI_FPGA_CFG_INT_EN_EXT_BIT BIT(15) /* External int enable bit */
> > +
> > +#define CTI_DEFAULT_PCI_OSC_FREQ 29491200
> > +#define CTI_DEFAULT_PCIE_OSC_FREQ 125000000
> > +#define CTI_DEFAULT_FPGA_OSC_FREQ 33333333
> > +
> > +/*
> > + * CTI Serial port line types. These match the values stored in the first
> > + * nibble of the CTI EEPROM port_flags word.
> > + */
> > +enum cti_port_type {
> > + CTI_PORT_TYPE_NONE = 0,
> > + CTI_PORT_TYPE_RS232, // RS232 ONLY
> > + CTI_PORT_TYPE_RS422_485, // RS422/RS485 ONLY
> > + CTI_PORT_TYPE_RS232_422_485_HW, // RS232/422/485 HW ONLY Switchable
> > + CTI_PORT_TYPE_RS232_422_485_SW, // RS232/422/485 SW ONLY Switchable
> > + CTI_PORT_TYPE_RS232_422_485_4B, // RS232/422/485 HW/SW (4bit ex. BCG004)
> > + CTI_PORT_TYPE_RS232_422_485_2B, // RS232/422/485 HW/SW (2bit ex. BBG008)
> > + CTI_PORT_TYPE_MAX,
> > +};
> > +
> > +#define CTI_PORT_TYPE_VALID(_port_type) \
> > + (((_port_type) > CTI_PORT_TYPE_NONE) && \
> > + ((_port_type) < CTI_PORT_TYPE_MAX))
> > +
> > +#define CTI_PORT_TYPE_RS485(_port_type) \
> > + (((_port_type) > CTI_PORT_TYPE_RS232) && \
> > + ((_port_type) < CTI_PORT_TYPE_MAX))
> > +
> > struct exar8250;
> >
> > struct exar8250_platform {
> > @@ -192,11 +252,201 @@ struct exar8250_board {
> >
> > struct exar8250 {
> > unsigned int nr;
> > + unsigned int osc_freq;
> > struct exar8250_board *board;
> > void __iomem *virt;
> > int line[];
> > };
> >
> > +static inline void exar_write_reg(struct exar8250 *priv,
> > + unsigned int reg, u8 value)
> > +{
> > + writeb(value, priv->virt + reg);
> > +}
> > +
> > +static inline u8 exar_read_reg(struct exar8250 *priv, unsigned int reg)
> > +{
> > + return readb(priv->virt + reg);
> > +}
>
> I tried to understand what is going on with this priv->virt in 8250_exar
> in general and why it exists but I failed. It seems to BAR0 is mapped
> there but also serial8250_pci_setup_port() does map the same BAR and
> sets it up into the usual place in membase.
>

Exar PCI/PCIe UARTs have global configuration registers from 0x80-0x9B.
These registers are for reading the EEPROM, configuring the MPIO, etc.
As these registers are only at 0x80, and not port specific, the driver maps
BAR0 to priv->virt for accessing them.

> > +static inline void exar_ee_select(struct exar8250 *priv)
> > +{
> > + // Set chip select pin high to enable EEPROM reads/writes
> > + exar_write_reg(priv, UART_EXAR_REGB, UART_EXAR_REGB_EECS);
> > + // Min ~500ns delay needed between CS assert and EEPROM access
> > + udelay(1);
> > +}
> > +
> > +static inline void exar_ee_deselect(struct exar8250 *priv)
> > +{
> > + exar_write_reg(priv, UART_EXAR_REGB, 0x00);
> > +}
> > +
> > +static inline void exar_ee_write_bit(struct exar8250 *priv, int bit)
> > +{
> > + u8 value = UART_EXAR_REGB_EECS;
> > +
> > + if (bit)
> > + value |= UART_EXAR_REGB_EEDI;
> > +
> > + // Clock out the bit on the EEPROM interface
> > + exar_write_reg(priv, UART_EXAR_REGB, value);
> > + // 2us delay = ~500khz clock speed
> > + udelay(2);
> > +
> > + value |= UART_EXAR_REGB_EECK;
> > +
> > + exar_write_reg(priv, UART_EXAR_REGB, value);
> > + udelay(2);
> > +}
> > +
> > +static inline u8 exar_ee_read_bit(struct exar8250 *priv)
> > +{
> > + u8 regb;
> > + u8 value = UART_EXAR_REGB_EECS;
> > +
> > + // Clock in the bit on the EEPROM interface
> > + exar_write_reg(priv, UART_EXAR_REGB, value);
> > + // 2us delay = ~500khz clock speed
> > + udelay(2);
> > +
> > + value |= UART_EXAR_REGB_EECK;
> > +
> > + exar_write_reg(priv, UART_EXAR_REGB, value);
> > + udelay(2);
> > +
> > + regb = exar_read_reg(priv, UART_EXAR_REGB);
> > +
> > + return (regb & UART_EXAR_REGB_EEDO ? 1 : 0);
>
> Unnecessary parenthesis.
>
> > +}
> > +
> > +/**
> > + * exar_ee_read() - Read a word from the EEPROM
> > + * @priv: Device's private structure
> > + * @ee_addr: Offset of EEPROM to read word from
> > + *
> > + * Read a single 16bit word from an Exar UART's EEPROM.
> > + *
> > + * Return: EEPROM word
> > + */
> > +static u16 exar_ee_read(struct exar8250 *priv, u8 ee_addr)
> > +{
> > + int i;
> > + u16 data = 0;
> > +
> > + exar_ee_select(priv);
> > +
> > + // Send read command (opcode 110)
> > + exar_ee_write_bit(priv, 1);
> > + exar_ee_write_bit(priv, 1);
> > + exar_ee_write_bit(priv, 0);
> > +
> > + // Send address to read from
> > + for (i = 1 << (UART_EXAR_REGB_EE_ADDR_SIZE - 1); i; i >>= 1)
> > + exar_ee_write_bit(priv, (ee_addr & i));
> > +
> > + // Read data 1 bit at a time
> > + for (i = 0; i <= UART_EXAR_REGB_EE_DATA_SIZE; i++) {
> > + data <<= 1;
> > + data |= exar_ee_read_bit(priv);
> > + }
> > +
> > + exar_ee_deselect(priv);
> > +
> > + return data;
> > +}
> > +
> > +/**
> > + * exar_mpio_config_output() - Configure an Exar MPIO as an output
> > + * @priv: Device's private structure
> > + * @mpio_num: MPIO number/offset to configure
> > + *
> > + * Configure a single MPIO as an output and disable tristate. It is reccomended
> > + * to set the level with exar_mpio_set_high()/exar_mpio_set_low() prior to
> > + * calling this function to ensure default MPIO pin state.
> > + *
> > + * Return: 0 on success, negative error code on failure
> > + */
> > +static int exar_mpio_config_output(struct exar8250 *priv,
> > + unsigned int mpio_num)
> > +{
> > + unsigned int mpio_offset;
> > + u8 sel_reg; // MPIO Select register (input/output)
> > + u8 tri_reg; // MPIO Tristate register
> > + u8 value;
> > +
> > + if (mpio_num < 8) {
> > + sel_reg = UART_EXAR_MPIOSEL_7_0;
> > + tri_reg = UART_EXAR_MPIO3T_7_0;
> > + mpio_offset = mpio_num;
> > + } else if (mpio_num >= 8 && mpio_num < 16) {
> > + sel_reg = UART_EXAR_MPIOSEL_15_8;
> > + tri_reg = UART_EXAR_MPIO3T_15_8;
> > + mpio_offset = mpio_num - 8;
> > + } else {
> > + return -EINVAL;
> > + }
> > +
> > + // Disable MPIO pin tri-state
> > + value = exar_read_reg(priv, tri_reg);
> > + value &= ~BIT(mpio_offset);
> > + exar_write_reg(priv, tri_reg, value);
> > +
> > + value = exar_read_reg(priv, sel_reg);
> > + value &= ~BIT(mpio_offset);
> > + exar_write_reg(priv, sel_reg, value);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * _exar_mpio_set() - Set an Exar MPIO output high or low
> > + * @priv: Device's private structure
> > + * @mpio_num: MPIO number/offset to set
> > + * @high: Set MPIO high if true, low if false
> > + *
> > + * Set a single MPIO high or low. exar_mpio_config_output() must also be called
> > + * to configure the pin as an output.
> > + *
> > + * Return: 0 on success, negative error code on failure
> > + */
> > +static int _exar_mpio_set(struct exar8250 *priv,
> > + unsigned int mpio_num, bool high)
> > +{
> > + unsigned int mpio_offset;
> > + u8 lvl_reg;
> > + u8 value;
> > +
> > + if (mpio_num < 8) {
> > + lvl_reg = UART_EXAR_MPIOLVL_7_0;
> > + mpio_offset = mpio_num;
> > + } else if (mpio_num >= 8 && mpio_num < 16) {
> > + lvl_reg = UART_EXAR_MPIOLVL_15_8;
> > + mpio_offset = mpio_num - 8;
> > + } else {
> > + return -EINVAL;
> > + }
> > +
> > + value = exar_read_reg(priv, lvl_reg);
> > + if (high)
> > + value |= BIT(mpio_offset);
> > + else
> > + value &= ~BIT(mpio_offset);
> > + exar_write_reg(priv, lvl_reg, value);
> > +
> > + return 0;
> > +}
> > +
> > +static int exar_mpio_set_low(struct exar8250 *priv, unsigned int mpio_num)
> > +{
> > + return _exar_mpio_set(priv, mpio_num, false);
> > +}
> > +
> > +static int exar_mpio_set_high(struct exar8250 *priv, unsigned int mpio_num)
> > +{
> > + return _exar_mpio_set(priv, mpio_num, true);
> > +}
> > +
> > static int generic_rs485_config(struct uart_port *port, struct ktermios *termios,
> > struct serial_rs485 *rs485)
> > {
> > @@ -385,6 +635,546 @@ pci_fastcom335_setup(struct exar8250 *priv, struct pci_dev *pcidev,
> > return 0;
> > }
> >
> > +/**
> > + * cti_tristate_disable() - Disable RS485 transciever tristate
> > + * @priv: Device's private structure
> > + * @port_num: Port number to set tristate off
> > + *
> > + * Most RS485 capable cards have a power on tristate jumper/switch that ensures
> > + * the RS422/RS485 transciever does not drive a multi-drop RS485 bus when it is
> > + * not the master. When this jumper is installed the user must set the RS485
> > + * mode to Full or Half duplex to disable tristate prior to using the port.
> > + *
> > + * Some Exar UARTs have an auto-tristate feature while others require setting
> > + * an MPIO to disable the tristate.
> > + *
> > + * Return: 0 on success, negative error code on failure
> > + */
> > +static int cti_tristate_disable(struct exar8250 *priv, unsigned int port_num)
> > +{
> > + int ret;
> > +
> > + ret = exar_mpio_set_high(priv, port_num);
> > + if (ret)
> > + return ret;
> > +
> > + return exar_mpio_config_output(priv, port_num);
> > +}
> > +
> > +/**
> > + * cti_plx_int_enable() - Enable UART interrupts to PLX bridge
> > + * @priv: Device's private structure
> > + *
> > + * Some older CTI cards require MPIO_0 to be set low to enable the
> > + * interupts from the UART to the PLX PCI->PCIe bridge.
> > + *
> > + * Return: 0 on success, negative error code on failure
> > + */
> > +static int cti_plx_int_enable(struct exar8250 *priv)
> > +{
> > + int ret;
> > +
> > + ret = exar_mpio_set_low(priv, 0);
> > + if (ret)
> > + return ret;
> > +
> > + return exar_mpio_config_output(priv, 0);
> > +}
> > +
> > +/**
> > + * cti_read_osc_freq() - Read the UART oscillator frequency from EEPROM
> > + * @priv: Device's private structure
> > + * @eeprom_offset: Offset where the oscillator frequency is stored
> > + *
> > + * CTI XR17x15X and XR17V25X cards have the serial boards oscillator frequency
> > + * stored in the EEPROM. FPGA and XR17V35X based cards use the PCI/PCIe clock.
> > + *
> > + * Return: frequency on success, negative error code on failure
> > + */
> > +static int cti_read_osc_freq(struct exar8250 *priv, u8 eeprom_offset)
> > +{
> > + u16 lower_word;
> > + u16 upper_word;
> > + int osc_freq;
> > +
> > + lower_word = exar_ee_read(priv, eeprom_offset);
> > + // Check if EEPROM word was blank
> > + if (lower_word == 0xFFFF)
> > + return -EIO;
> > +
> > + upper_word = exar_ee_read(priv, (eeprom_offset + 1));
> > + if (upper_word == 0xFFFF)
> > + return -EIO;
> > +
> > + osc_freq = FIELD_PREP(CTI_EE_MASK_OSC_FREQ_LOWER, lower_word) |
> > + FIELD_PREP(CTI_EE_MASK_OSC_FREQ_UPPER, upper_word);
> > +
> > + return osc_freq;
> > +}
> > +
> > +/**
> > + * cti_get_port_type_xr17c15x_xr17v25x() - Get port type of xr17c15x/xr17v25x
> > + * @priv: Device's private structure
> > + * @port_num: Port to get type of
> > + *
> > + * CTI xr17c15x and xr17v25x based cards port types are based on PCI IDs.
> > + *
> > + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> > + */
> > +static enum cti_port_type cti_get_port_type_xr17c15x_xr17v25x(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + unsigned int port_num)
> > +{
> > + enum cti_port_type port_type;
> > +
> > + switch (pcidev->subsystem_device) {
> > + // RS232 only cards
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_232:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_232:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_232:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_232:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_232_NS:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_232:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_232_NS:
> > + port_type = CTI_PORT_TYPE_RS232;
> > + break;
> > + // 1x RS232, 1x RS422/RS485
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_1_1:
> > + port_type = (port_num == 0) ?
> > + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
>
> I'd linesplit and align these differently:
>
> port_type = port_num == 0 ? CTI_PORT_TYPE_RS232 :
> CTI_PORT_TYPE_RS422_485;
>
> > + break;
> > + // 2x RS232, 2x RS422/RS485
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_2:
> > + port_type = (port_num < 2) ?
> > + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> > + break;
> > + // 4x RS232, 4x RS422/RS485
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_SP:
> > + port_type = (port_num < 4) ?
> > + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> > + break;
> > + // RS232/RS422/RS485 HW (jumper) selectable
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_SP_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_SP_OPTO_A:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_SP_OPTO_B:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XPRS:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_A:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_B:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_16_XPRS_A:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_16_XPRS_B:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XPRS_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_OPTO_A:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_OPTO_B:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_LEFT:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_RIGHT:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XP_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_XPRS_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP:
> > + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> > + break;
> > + // RS422/RS485 HW (jumper) selectable
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_485:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_485:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_485:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_485:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_485:
> > + port_type = CTI_PORT_TYPE_RS422_485;
> > + break;
> > + // 6x RS232, 2x RS422/RS485
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_6_2_SP:
> > + port_type = (port_num < 6) ?
> > + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> > + break;
> > + // 2x RS232, 6x RS422/RS485
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_6_SP:
> > + port_type = (port_num < 2) ?
> > + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> > + break;
> > + default:
> > + dev_err(&pcidev->dev, "unknown/unsupported device\n");
> > + port_type = CTI_PORT_TYPE_NONE;
> > + }
> > +
> > + return port_type;
> > +}
> > +
> > +/**
> > + * cti_get_port_type_fpga() - Get the port type of a CTI FPGA card
> > + * @priv: Device's private structure
> > + * @port_num: Port to get type of
> > + *
> > + * FPGA based cards port types are based on PCI IDs.
> > + *
> > + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> > + */
> > +static enum cti_port_type cti_get_port_type_fpga(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + unsigned int port_num)
> > +{
> > + enum cti_port_type port_type;
> > +
> > + switch (pcidev->device) {
> > + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG00X:
> > + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG01X:
> > + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_16:
> > + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> > + break;
> > + default:
> > + dev_err(&pcidev->dev, "unknown/unsupported device\n");
> > + return CTI_PORT_TYPE_NONE;
> > + }
> > +
> > + return port_type;
> > +}
> > +
> > +/**
> > + * cti_get_port_type_xr17v35x() - Read port type from the EEPROM
> > + * @priv: Device's private structure
> > + * @port_num: port offset
> > + *
> > + * CTI XR17V35X based cards have the port types stored in the EEPROM.
> > + * This function reads the port type for a single port.
> > + *
> > + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> > + */
> > +static enum cti_port_type cti_get_port_type_xr17v35x(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + unsigned int port_num)
> > +{
> > + enum cti_port_type port_type;
> > + u16 port_flags;
> > + u8 offset;
> > +
> > + offset = CTI_EE_OFF_XR17V35X_PORT_FLAGS + port_num;
> > + port_flags = exar_ee_read(priv, offset);
> > +
> > + port_type = FIELD_GET(CTI_EE_MASK_PORT_FLAGS_TYPE, port_flags);
> > + if (!CTI_PORT_TYPE_VALID(port_type)) {
> > + /*
> > + * If the port type is missing the card assume it is a
> > + * RS232/RS422/RS485 card to be safe.
> > + *
> > + * There is one known board (BEG013) that only has
> > + * 3 of 4 port types written to the EEPROM so this
> > + * acts as a work around.
> > + */
> > + dev_warn(&pcidev->dev,
> > + "failed to get port %d type from EEPROM\n", port_num);
> > + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> > + }
> > +
> > + return port_type;
> > +}
> > +
> > +static int cti_rs485_config_mpio_tristate(struct uart_port *port,
> > + struct ktermios *termios,
> > + struct serial_rs485 *rs485)
> > +{
> > + struct exar8250 *priv = (struct exar8250 *)port->private_data;
> > + int ret;
> > +
> > + ret = generic_rs485_config(port, termios, rs485);
> > + if (ret)
> > + return ret;
> > +
> > + // Disable power-on RS485 tri-state via MPIO
> > + return cti_tristate_disable(priv, port->port_id);
> > +}
> > +
> > +static int cti_port_setup_common(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + int idx, unsigned int offset,
> > + struct uart_8250_port *port)
> > +{
> > + int ret;
> > +
> > + if (priv->osc_freq == 0)
> > + return -EINVAL;
> > +
> > + port->port.port_id = idx;
> > + port->port.uartclk = priv->osc_freq;
> > +
> > + ret = serial8250_pci_setup_port(pcidev, port, 0, offset, 0);
> > + if (ret) {
> > + dev_err(&pcidev->dev,
> > + "failed to setup pci for port %d err: %d\n", idx, ret);
> > + return ret;
> > + }
> > +
> > + port->port.private_data = (void *)priv;
> > + port->port.pm = exar_pm;
> > + port->port.shutdown = exar_shutdown;
> > +
> > + return 0;
> > +}
> > +
> > +static int cti_port_setup_fpga(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + struct uart_8250_port *port,
> > + int idx)
> > +{
> > + enum cti_port_type port_type;
> > + unsigned int offset;
> > +
> > + port_type = cti_get_port_type_fpga(priv, pcidev, idx);
> > +
> > + // FPGA shares port offests with XR17C15X
> > + offset = idx * UART_EXAR_XR17C15X_PORT_OFFSET;
> > + port->port.type = PORT_XR17D15X;
> > +
> > + port->port.get_divisor = xr17v35x_get_divisor;
> > + port->port.set_divisor = xr17v35x_set_divisor;
> > + port->port.startup = xr17v35x_startup;
> > +
> > + if (CTI_PORT_TYPE_RS485(port_type)) {
> > + port->port.rs485_config = generic_rs485_config;
> > + port->port.rs485_supported = generic_rs485_supported;
> > + }
> > +
> > + return cti_port_setup_common(priv, pcidev, idx, offset, port);
> > +}
> > +
> > +static int cti_port_setup_xr17v35x(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + struct uart_8250_port *port,
> > + int idx)
> > +{
> > + enum cti_port_type port_type;
> > + unsigned int offset;
> > + int ret;
> > +
> > + port_type = cti_get_port_type_xr17v35x(priv, pcidev, idx);
> > +
> > + offset = idx * UART_EXAR_XR17V35X_PORT_OFFSET;
> > + port->port.type = PORT_XR17V35X;
> > +
> > + port->port.get_divisor = xr17v35x_get_divisor;
> > + port->port.set_divisor = xr17v35x_set_divisor;
> > + port->port.startup = xr17v35x_startup;
> > +
> > + switch (port_type) {
> > + case CTI_PORT_TYPE_RS422_485:
> > + case CTI_PORT_TYPE_RS232_422_485_HW:
> > + port->port.rs485_config = cti_rs485_config_mpio_tristate;
> > + port->port.rs485_supported = generic_rs485_supported;
> > + break;
> > + case CTI_PORT_TYPE_RS232_422_485_SW:
> > + case CTI_PORT_TYPE_RS232_422_485_4B:
> > + case CTI_PORT_TYPE_RS232_422_485_2B:
> > + port->port.rs485_config = generic_rs485_config;
> > + port->port.rs485_supported = generic_rs485_supported;
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + ret = cti_port_setup_common(priv, pcidev, idx, offset, port);
> > + if (ret)
> > + return ret;
> > +
> > + exar_write_reg(priv, (offset + UART_EXAR_8XMODE), 0x00);
> > + exar_write_reg(priv, (offset + UART_EXAR_FCTR), UART_FCTR_EXAR_TRGD);
> > + exar_write_reg(priv, (offset + UART_EXAR_TXTRG), 128);
> > + exar_write_reg(priv, (offset + UART_EXAR_RXTRG), 128);
>
> Unnecessary parenthesis.
>
> > + return 0;
> > +}
> > +
> > +static int cti_port_setup_xr17v25x(struct exar8250 *priv,
> > + struct pci_dev *pcidev,
> > + struct uart_8250_port *port,
> > + int idx)
> > +{
> > + enum cti_port_type port_type;
> > + unsigned int offset;
> > + int ret;
> > +
> > + port_type = cti_get_port_type_xr17c15x_xr17v25x(priv, pcidev, idx);
> > +
> > + offset = idx * UART_EXAR_XR17V25X_PORT_OFFSET;
> > + port->port.type = PORT_XR17D15X;
> > +
> > + // XR17V25X supports fractional baudrates
> > + port->port.get_divisor = xr17v35x_get_divisor;
> > + port->port.set_divisor = xr17v35x_set_divisor;
> > + port->port.startup = xr17v35x_startup;
> > +
> > + if (CTI_PORT_TYPE_RS485(port_type)) {
> > + switch (pcidev->subsystem_device) {
> > + // These cards support power on 485 tri-state via MPIO
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_485:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_SP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_6_2_SP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_6_SP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_LEFT:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_RIGHT:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XP_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_XPRS_OPTO:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP:
> > + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_485:
> > + port->port.rs485_config = cti_rs485_config_mpio_tristate;
> > + break;
> > + // Otherwise auto or no power on 485 tri-state support
> > + default:
> > + port->port.rs485_config = generic_rs485_config;
> > + break;
> > + }
> > +
> > + port->port.rs485_supported = generic_rs485_supported;
> > + }
> > +
> > + ret = cti_port_setup_common(priv, pcidev, idx, offset, port);
> > + if (ret)
> > + return ret;
> > +
> > + exar_write_reg(priv, (offset + UART_EXAR_8XMODE), 0x00);
> > + exar_write_reg(priv, (offset + UART_EXAR_FCTR), UART_FCTR_EXAR_TRGD);
> > + exar_write_reg(priv, (offset + UART_EXAR_TXTRG), 32);
> > + exar_write_reg(priv, (offset + UART_EXAR_RXTRG), 32);
>
> Unnecessary parenthesis.
>

I will fix these in my cleanup patches.

> I recommend you add a helper for this as it is repeated twice. Are the
> values 32 and 128 literal or do they have some specific meaning? If the
> latter case, they should be using named defines (this likely applies to
> the existing trigger code in the driver too).
>
>

They are the FIFO trigger levels so they are literally 128 and 32.

These 4 writes come from Exar's out-of-tree driver and are in
pci_xr17v35x_setup() and some other vendor specific functions.

I am not sure why/if these are needed.