i2c: designware-pci: Add a note about struct dw_scl_sda_cfg usage

Add a note about struct dw_scl_sda_cfg usage to discourage people
of using this structure on new platforms. Instead they should try
hard to put the needed information into firmware descriptions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-designware-pcidrv.c

@@ -38,6 +38,13 @@ enum dw_pci_ctl_id_t {
 	navi_amd,
 };
 
+/*
+ * This is a legacy structure to describe the hardware counters
+ * to configure signal timings on the bus. For Device Tree platforms
+ * one should use the respective properties and for ACPI there is
+ * a set of ACPI methods that provide these counters. No new
+ * platform should use this structure.
+ */
 struct dw_scl_sda_cfg {
 	u16 ss_hcnt;
 	u16 fs_hcnt;