target/linux/bcm27xx/patches-6.1/950-1226-i2c-designware-Look-for-CNT-values-in-DT.patch

   1 From 0a09088e24c013ef608b1bb79501ef890cefc767 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 19 Dec 2023 11:16:25 +0000
   4 Subject: [PATCH] i2c: designware: Look for *CNT values in DT
   5
   6 The i2c-designware driver supports reading precise timing values from
   7 ACPI, but the Device Tree support relies on a combination of standard
   8 rise and fall times and hard-coded minimum timings. The result of this
   9 is that it is difficult to get optimum timings, particularly given that
  10 the values are bus speed-specific and only one set can be stored in
  11 DT at a time.
  12
  13 Add support for initialisation from DT that is similar to that for
  14 ACPI.
  15
  16 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  17 ---
  18  drivers/i2c/busses/i2c-designware-platdrv.c | 18 ++++++++++++++++++
  19  1 file changed, 18 insertions(+)
  20
  21 --- a/drivers/i2c/busses/i2c-designware-platdrv.c
  22 +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
  23 @@ -132,9 +132,18 @@ static int mscc_twi_set_sda_hold_time(st
  24         return 0;
  25  }
  26
  27 +static void dw_i2c_read_of_cnt(struct device_node *np, const char *name, u16 *pval)
  28 +{
  29 +       u32 val;
  30 +
  31 +       if (!of_property_read_u32(np, name, &val))
  32 +               *pval = (u16)val;
  33 +}
  34 +
  35  static int dw_i2c_of_configure(struct platform_device *pdev)
  36  {
  37         struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
  38 +       struct device_node *np = pdev->dev.of_node;
  39
  40         switch (dev->flags & MODEL_MASK) {
  41         case MODEL_MSCC_OCELOT:
  42 @@ -146,6 +155,15 @@ static int dw_i2c_of_configure(struct pl
  43                 break;
  44         }
  45
  46 +       dw_i2c_read_of_cnt(np, "snps,ss_hcnt", &dev->ss_hcnt);
  47 +       dw_i2c_read_of_cnt(np, "snps,ss_lcnt", &dev->ss_lcnt);
  48 +       dw_i2c_read_of_cnt(np, "snps,fs_hcnt", &dev->fs_hcnt);
  49 +       dw_i2c_read_of_cnt(np, "snps,fs_lcnt", &dev->fs_lcnt);
  50 +       dw_i2c_read_of_cnt(np, "snps,fp_hcnt", &dev->fp_hcnt);
  51 +       dw_i2c_read_of_cnt(np, "snps,fp_lcnt", &dev->fp_lcnt);
  52 +       dw_i2c_read_of_cnt(np, "snps,hs_hcnt", &dev->hs_hcnt);
  53 +       dw_i2c_read_of_cnt(np, "snps,hs_lcnt", &dev->hs_lcnt);
  54 +
  55         return 0;
  56  }
  57