mtd: rawnand: gpmi: fix controller timings setting

stable inclusion
from stable-v5.10.110
commit d99e7feaed4c715e7ac974866905b6919cfda8cd
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d99e7feaed4c715e7ac974866905b6919cfda8cd

--------------------------------

[ Upstream commit 2970bf5a ]

Set the controller registers according to the real clock rate. The
controller registers configuration (setup, hold, timeout, ... cycles)
depends on the clock rate of the GPMI. Using the real rate instead of
the ideal one, avoids that this inaccuracy (required_rate - real_rate)
affects the registers setting.

This patch has been tested on two custom boards with i.MX28 and i.MX6
SOCs:
- i.MX28:
  required rate 100MHz, real rate 99.3MHz
- i.MX6
  required rate 100MHz, real rate 99MHz

Fixes: b1206122 ("mtd: rawnand: gpmi: use core timings instead of an empirical derivation")
Co-developed-by: NMichael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: NMichael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: NDario Binacchi <dario.binacchi@amarulasolutions.com>
Tested-by: NSascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220118095434.35081-3-dario.binacchi@amarulasolutions.comSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c

@@ -646,6 +646,7 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 				     const struct nand_sdr_timings *sdr)
 {
 	struct gpmi_nfc_hardware_timing *hw = &this->hw;
+	struct resources *r = &this->resources;
 	unsigned int dll_threshold_ps = this->devdata->max_chain_delay;
 	unsigned int period_ps, reference_period_ps;
 	unsigned int data_setup_cycles, data_hold_cycles, addr_setup_cycles;
@@ -669,6 +670,8 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 		wrn_dly_sel = BV_GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY;
 	}
 
+	hw->clk_rate = clk_round_rate(r->clock[0], hw->clk_rate);
+
 	/* SDR core timings are given in picoseconds */
 	period_ps = div_u64((u64)NSEC_PER_SEC * 1000, hw->clk_rate);