From 0a09088e24c013ef608b1bb79501ef890cefc767 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Tue, 19 Dec 2023 11:16:25 +0000 Subject: [PATCH] i2c: designware: Look for *CNT values in DT The i2c-designware driver supports reading precise timing values from ACPI, but the Device Tree support relies on a combination of standard rise and fall times and hard-coded minimum timings. The result of this is that it is difficult to get optimum timings, particularly given that the values are bus speed-specific and only one set can be stored in DT at a time. Add support for initialisation from DT that is similar to that for ACPI. Signed-off-by: Phil Elwell --- drivers/i2c/busses/i2c-designware-platdrv.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -132,9 +132,18 @@ static int mscc_twi_set_sda_hold_time(st return 0; } +static void dw_i2c_read_of_cnt(struct device_node *np, const char *name, u16 *pval) +{ + u32 val; + + if (!of_property_read_u32(np, name, &val)) + *pval = (u16)val; +} + static int dw_i2c_of_configure(struct platform_device *pdev) { struct dw_i2c_dev *dev = platform_get_drvdata(pdev); + struct device_node *np = pdev->dev.of_node; switch (dev->flags & MODEL_MASK) { case MODEL_MSCC_OCELOT: @@ -146,6 +155,15 @@ static int dw_i2c_of_configure(struct pl break; } + dw_i2c_read_of_cnt(np, "snps,ss_hcnt", &dev->ss_hcnt); + dw_i2c_read_of_cnt(np, "snps,ss_lcnt", &dev->ss_lcnt); + dw_i2c_read_of_cnt(np, "snps,fs_hcnt", &dev->fs_hcnt); + dw_i2c_read_of_cnt(np, "snps,fs_lcnt", &dev->fs_lcnt); + dw_i2c_read_of_cnt(np, "snps,fp_hcnt", &dev->fp_hcnt); + dw_i2c_read_of_cnt(np, "snps,fp_lcnt", &dev->fp_lcnt); + dw_i2c_read_of_cnt(np, "snps,hs_hcnt", &dev->hs_hcnt); + dw_i2c_read_of_cnt(np, "snps,hs_lcnt", &dev->hs_lcnt); + return 0; }