From: Jack Chen Date: Thu, 16 Feb 2023 15:10:57 +0000 (-0500) Subject: i3c: master: dw: stop hardcoding initial speed X-Git-Tag: v6.6.7~3377^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=510d2358c466bf6588034f0d3b2266eed2bc0a51;p=platform%2Fkernel%2Flinux-starfive.git i3c: master: dw: stop hardcoding initial speed Bus-speed could be default(12.5MHz) or defined by users in dts. Dw-i3c-master should not hard-code the initial speed to be I3C_BUS_TYP_I3C_SCL_RATE (12.5MHz) And because of Synopsys's I3C controller limit (hcnt/lcnt register length) and core-clk provided, there is a limit to bus speed, too. For example, when core-clk is 250 MHz, the bus speed cannot be lowered below 1MHz. Tested: tested with an i3c sensor and captured with a logic analyzer. Signed-off-by: Jack Chen Link: https://lore.kernel.org/r/20230216151057.293764-1-zenghuchen@google.com Signed-off-by: Alexandre Belloni --- diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c index 51a8608..48954d3 100644 --- a/drivers/i3c/master/dw-i3c-master.c +++ b/drivers/i3c/master/dw-i3c-master.c @@ -531,7 +531,7 @@ static int dw_i3c_clk_cfg(struct dw_i3c_master *master) if (hcnt < SCL_I3C_TIMING_CNT_MIN) hcnt = SCL_I3C_TIMING_CNT_MIN; - lcnt = DIV_ROUND_UP(core_rate, I3C_BUS_TYP_I3C_SCL_RATE) - hcnt; + lcnt = DIV_ROUND_UP(core_rate, master->base.bus.scl_rate.i3c) - hcnt; if (lcnt < SCL_I3C_TIMING_CNT_MIN) lcnt = SCL_I3C_TIMING_CNT_MIN; @@ -541,7 +541,8 @@ static int dw_i3c_clk_cfg(struct dw_i3c_master *master) if (!(readl(master->regs + DEVICE_CTRL) & DEV_CTRL_I2C_SLAVE_PRESENT)) writel(BUS_I3C_MST_FREE(lcnt), master->regs + BUS_FREE_TIMING); - lcnt = DIV_ROUND_UP(I3C_BUS_TLOW_OD_MIN_NS, core_period); + lcnt = max_t(u8, + DIV_ROUND_UP(I3C_BUS_TLOW_OD_MIN_NS, core_period), lcnt); scl_timing = SCL_I3C_TIMING_HCNT(hcnt) | SCL_I3C_TIMING_LCNT(lcnt); writel(scl_timing, master->regs + SCL_I3C_OD_TIMING);