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![Ulrich Hecht](/assets/img/avatar_default.png)
HSCIF has facilities that allow moving the RX sampling point by between -8 and 7 sampling cycles (one sampling cycles equals 1/15 of a bit by default) to improve the error margin in case of slightly mismatched bit rates between sender and receiver. This patch tries to determine if shifting the sampling point can improve the error margin and will enable it if so. Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
177 lines
7.4 KiB
C
177 lines
7.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/bitops.h>
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#include <linux/serial_core.h>
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#include <linux/io.h>
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#include <linux/gpio.h>
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#define SCI_MAJOR 204
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#define SCI_MINOR_START 8
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/*
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* SCI register subset common for all port types.
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* Not all registers will exist on all parts.
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*/
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enum {
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SCSMR, /* Serial Mode Register */
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SCBRR, /* Bit Rate Register */
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SCSCR, /* Serial Control Register */
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SCxSR, /* Serial Status Register */
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SCFCR, /* FIFO Control Register */
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SCFDR, /* FIFO Data Count Register */
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SCxTDR, /* Transmit (FIFO) Data Register */
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SCxRDR, /* Receive (FIFO) Data Register */
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SCLSR, /* Line Status Register */
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SCTFDR, /* Transmit FIFO Data Count Register */
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SCRFDR, /* Receive FIFO Data Count Register */
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SCSPTR, /* Serial Port Register */
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HSSRR, /* Sampling Rate Register */
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SCPCR, /* Serial Port Control Register */
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SCPDR, /* Serial Port Data Register */
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SCDL, /* BRG Frequency Division Register */
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SCCKS, /* BRG Clock Select Register */
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HSRTRGR, /* Rx FIFO Data Count Trigger Register */
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HSTTRGR, /* Tx FIFO Data Count Trigger Register */
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SCIx_NR_REGS,
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};
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/* SCSMR (Serial Mode Register) */
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#define SCSMR_C_A BIT(7) /* Communication Mode */
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#define SCSMR_CSYNC BIT(7) /* - Clocked synchronous mode */
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#define SCSMR_ASYNC 0 /* - Asynchronous mode */
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#define SCSMR_CHR BIT(6) /* 7-bit Character Length */
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#define SCSMR_PE BIT(5) /* Parity Enable */
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#define SCSMR_ODD BIT(4) /* Odd Parity */
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#define SCSMR_STOP BIT(3) /* Stop Bit Length */
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#define SCSMR_CKS 0x0003 /* Clock Select */
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/* Serial Mode Register, SCIFA/SCIFB only bits */
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#define SCSMR_CKEDG BIT(12) /* Transmit/Receive Clock Edge Select */
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#define SCSMR_SRC_MASK 0x0700 /* Sampling Control */
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#define SCSMR_SRC_16 0x0000 /* Sampling rate 1/16 */
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#define SCSMR_SRC_5 0x0100 /* Sampling rate 1/5 */
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#define SCSMR_SRC_7 0x0200 /* Sampling rate 1/7 */
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#define SCSMR_SRC_11 0x0300 /* Sampling rate 1/11 */
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#define SCSMR_SRC_13 0x0400 /* Sampling rate 1/13 */
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#define SCSMR_SRC_17 0x0500 /* Sampling rate 1/17 */
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#define SCSMR_SRC_19 0x0600 /* Sampling rate 1/19 */
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#define SCSMR_SRC_27 0x0700 /* Sampling rate 1/27 */
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/* Serial Control Register, SCIFA/SCIFB only bits */
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#define SCSCR_TDRQE BIT(15) /* Tx Data Transfer Request Enable */
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#define SCSCR_RDRQE BIT(14) /* Rx Data Transfer Request Enable */
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/* Serial Control Register, HSCIF-only bits */
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#define HSSCR_TOT_SHIFT 14
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/* SCxSR (Serial Status Register) on SCI */
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#define SCI_TDRE BIT(7) /* Transmit Data Register Empty */
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#define SCI_RDRF BIT(6) /* Receive Data Register Full */
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#define SCI_ORER BIT(5) /* Overrun Error */
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#define SCI_FER BIT(4) /* Framing Error */
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#define SCI_PER BIT(3) /* Parity Error */
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#define SCI_TEND BIT(2) /* Transmit End */
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#define SCI_RESERVED 0x03 /* All reserved bits */
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#define SCI_DEFAULT_ERROR_MASK (SCI_PER | SCI_FER)
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#define SCI_RDxF_CLEAR (u32)(~(SCI_RESERVED | SCI_RDRF))
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#define SCI_ERROR_CLEAR (u32)(~(SCI_RESERVED | SCI_PER | SCI_FER | SCI_ORER))
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#define SCI_TDxE_CLEAR (u32)(~(SCI_RESERVED | SCI_TEND | SCI_TDRE))
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#define SCI_BREAK_CLEAR (u32)(~(SCI_RESERVED | SCI_PER | SCI_FER | SCI_ORER))
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/* SCxSR (Serial Status Register) on SCIF, SCIFA, SCIFB, HSCIF */
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#define SCIF_ER BIT(7) /* Receive Error */
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#define SCIF_TEND BIT(6) /* Transmission End */
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#define SCIF_TDFE BIT(5) /* Transmit FIFO Data Empty */
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#define SCIF_BRK BIT(4) /* Break Detect */
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#define SCIF_FER BIT(3) /* Framing Error */
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#define SCIF_PER BIT(2) /* Parity Error */
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#define SCIF_RDF BIT(1) /* Receive FIFO Data Full */
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#define SCIF_DR BIT(0) /* Receive Data Ready */
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/* SCIF only (optional) */
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#define SCIF_PERC 0xf000 /* Number of Parity Errors */
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#define SCIF_FERC 0x0f00 /* Number of Framing Errors */
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/*SCIFA/SCIFB and SCIF on SH7705/SH7720/SH7721 only */
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#define SCIFA_ORER BIT(9) /* Overrun Error */
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#define SCIF_DEFAULT_ERROR_MASK (SCIF_PER | SCIF_FER | SCIF_BRK | SCIF_ER)
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#define SCIF_RDxF_CLEAR (u32)(~(SCIF_DR | SCIF_RDF))
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#define SCIF_ERROR_CLEAR (u32)(~(SCIF_PER | SCIF_FER | SCIF_ER))
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#define SCIF_TDxE_CLEAR (u32)(~(SCIF_TDFE))
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#define SCIF_BREAK_CLEAR (u32)(~(SCIF_PER | SCIF_FER | SCIF_BRK))
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/* SCFCR (FIFO Control Register) */
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#define SCFCR_RTRG1 BIT(7) /* Receive FIFO Data Count Trigger */
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#define SCFCR_RTRG0 BIT(6)
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#define SCFCR_TTRG1 BIT(5) /* Transmit FIFO Data Count Trigger */
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#define SCFCR_TTRG0 BIT(4)
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#define SCFCR_MCE BIT(3) /* Modem Control Enable */
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#define SCFCR_TFRST BIT(2) /* Transmit FIFO Data Register Reset */
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#define SCFCR_RFRST BIT(1) /* Receive FIFO Data Register Reset */
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#define SCFCR_LOOP BIT(0) /* Loopback Test */
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/* SCLSR (Line Status Register) on (H)SCIF */
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#define SCLSR_TO BIT(2) /* Timeout */
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#define SCLSR_ORER BIT(0) /* Overrun Error */
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/* SCSPTR (Serial Port Register), optional */
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#define SCSPTR_RTSIO BIT(7) /* Serial Port RTS# Pin Input/Output */
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#define SCSPTR_RTSDT BIT(6) /* Serial Port RTS# Pin Data */
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#define SCSPTR_CTSIO BIT(5) /* Serial Port CTS# Pin Input/Output */
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#define SCSPTR_CTSDT BIT(4) /* Serial Port CTS# Pin Data */
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#define SCSPTR_SCKIO BIT(3) /* Serial Port Clock Pin Input/Output */
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#define SCSPTR_SCKDT BIT(2) /* Serial Port Clock Pin Data */
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#define SCSPTR_SPB2IO BIT(1) /* Serial Port Break Input/Output */
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#define SCSPTR_SPB2DT BIT(0) /* Serial Port Break Data */
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/* HSSRR HSCIF */
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#define HSCIF_SRE BIT(15) /* Sampling Rate Register Enable */
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#define HSCIF_SRDE BIT(14) /* Sampling Point Register Enable */
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#define HSCIF_SRHP_SHIFT 8
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#define HSCIF_SRHP_MASK 0x0f00
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/* SCPCR (Serial Port Control Register), SCIFA/SCIFB only */
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#define SCPCR_RTSC BIT(4) /* Serial Port RTS# Pin / Output Pin */
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#define SCPCR_CTSC BIT(3) /* Serial Port CTS# Pin / Input Pin */
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#define SCPCR_SCKC BIT(2) /* Serial Port SCK Pin / Output Pin */
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#define SCPCR_RXDC BIT(1) /* Serial Port RXD Pin / Input Pin */
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#define SCPCR_TXDC BIT(0) /* Serial Port TXD Pin / Output Pin */
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/* SCPDR (Serial Port Data Register), SCIFA/SCIFB only */
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#define SCPDR_RTSD BIT(4) /* Serial Port RTS# Output Pin Data */
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#define SCPDR_CTSD BIT(3) /* Serial Port CTS# Input Pin Data */
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#define SCPDR_SCKD BIT(2) /* Serial Port SCK Output Pin Data */
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#define SCPDR_RXDD BIT(1) /* Serial Port RXD Input Pin Data */
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#define SCPDR_TXDD BIT(0) /* Serial Port TXD Output Pin Data */
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/*
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* BRG Clock Select Register (Some SCIF and HSCIF)
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* The Baud Rate Generator for external clock can provide a clock source for
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* the sampling clock. It outputs either its frequency divided clock, or the
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* (undivided) (H)SCK external clock.
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*/
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#define SCCKS_CKS BIT(15) /* Select (H)SCK (1) or divided SC_CLK (0) */
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#define SCCKS_XIN BIT(14) /* SC_CLK uses bus clock (1) or SCIF_CLK (0) */
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#define SCxSR_TEND(port) (((port)->type == PORT_SCI) ? SCI_TEND : SCIF_TEND)
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#define SCxSR_RDxF(port) (((port)->type == PORT_SCI) ? SCI_RDRF : SCIF_DR | SCIF_RDF)
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#define SCxSR_TDxE(port) (((port)->type == PORT_SCI) ? SCI_TDRE : SCIF_TDFE)
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#define SCxSR_FER(port) (((port)->type == PORT_SCI) ? SCI_FER : SCIF_FER)
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#define SCxSR_PER(port) (((port)->type == PORT_SCI) ? SCI_PER : SCIF_PER)
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#define SCxSR_BRK(port) (((port)->type == PORT_SCI) ? 0x00 : SCIF_BRK)
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#define SCxSR_ERRORS(port) (to_sci_port(port)->params->error_mask)
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#define SCxSR_RDxF_CLEAR(port) \
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(((port)->type == PORT_SCI) ? SCI_RDxF_CLEAR : SCIF_RDxF_CLEAR)
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#define SCxSR_ERROR_CLEAR(port) \
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(to_sci_port(port)->params->error_clear)
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#define SCxSR_TDxE_CLEAR(port) \
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(((port)->type == PORT_SCI) ? SCI_TDxE_CLEAR : SCIF_TDxE_CLEAR)
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#define SCxSR_BREAK_CLEAR(port) \
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(((port)->type == PORT_SCI) ? SCI_BREAK_CLEAR : SCIF_BREAK_CLEAR)
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