From c6b110bc30baf518b2ce4191778de57b3cd04075 Mon Sep 17 00:00:00 2001 From: deraadt Date: Sat, 17 Aug 2024 02:28:45 +0000 Subject: [PATCH] The dwiic_init() routine is used at startup to read various chip registers, make some decisions, and then program other registers. After a resume, it is pointless, and potentially incorrect to read such registers again, which a BIOS or something may not have initialized, and we are better off using the remembered soft-state to init cleanly. So craft a custom block of chip restoration, and do it while the chip is stopped hard. ok kettenis mlarkin --- sys/dev/ic/dwiic.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/sys/dev/ic/dwiic.c b/sys/dev/ic/dwiic.c index ba425226ab4..2ca0dc3ffc9 100644 --- a/sys/dev/ic/dwiic.c +++ b/sys/dev/ic/dwiic.c @@ -1,4 +1,4 @@ -/* $OpenBSD: dwiic.c,v 1.19 2024/08/17 02:24:03 deraadt Exp $ */ +/* $OpenBSD: dwiic.c,v 1.20 2024/08/17 02:28:45 deraadt Exp $ */ /* * Synopsys DesignWare I2C controller * @@ -46,7 +46,30 @@ dwiic_activate(struct device *self, int act) dwiic_read(sc, DW_IC_CLR_INTR); break; case DVACT_RESUME: - dwiic_init(sc); + /* if it became enabled for some reason, force it down */ + dwiic_enable(sc, 0); + + dwiic_write(sc, DW_IC_INTR_MASK, 0); + dwiic_read(sc, DW_IC_CLR_INTR); + + /* write standard-mode SCL timing parameters */ + dwiic_write(sc, DW_IC_SS_SCL_HCNT, sc->ss_hcnt); + dwiic_write(sc, DW_IC_SS_SCL_LCNT, sc->ss_lcnt); + + /* and fast-mode SCL timing parameters */ + dwiic_write(sc, DW_IC_FS_SCL_HCNT, sc->fs_hcnt); + dwiic_write(sc, DW_IC_FS_SCL_LCNT, sc->fs_lcnt); + + /* SDA hold time */ + dwiic_write(sc, DW_IC_SDA_HOLD, sc->sda_hold_time); + + dwiic_write(sc, DW_IC_TX_TL, sc->tx_fifo_depth / 2); + dwiic_write(sc, DW_IC_RX_TL, 0); + + /* configure as i2c master with fast speed */ + sc->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; + dwiic_write(sc, DW_IC_CON, sc->master_cfg); rv = config_activate_children(self, act); break; default: -- 2.20.1