On 2018/10/19 4:39, Boris Brezillon wrote:
On Thu, 18 Oct 2018 13:09:05 +0800
Jianxin Pan <jianxin.pan@xxxxxxxxxxx> wrote:
+static int meson_nfc_calc_set_timing(struct meson_nfc *nfc,
+ const struct nand_sdr_timings *timings)
+{
+ struct nand_timing *timing = &nfc->timing;
+ int div, bt_min, bt_max, bus_timing;
+ int ret;
+
+ div = DIV_ROUND_UP((timings->tRC_min / 1000), NFC_CLK_CYCLE);
+ ret = clk_set_rate(nfc->device_clk, 1000000000 / div);
+ if (ret) {
+ dev_err(nfc->dev, "failed to set nand clock rate\n");
+ return ret;
+ }
+
+ timing->twb = DIV_ROUND_UP(PSEC_TO_NSEC(timings->tWB_max),
+ div * NFC_CLK_CYCLE);
+ timing->tadl = DIV_ROUND_UP(PSEC_TO_NSEC(timings->tADL_min),
+ div * NFC_CLK_CYCLE);
+ timing->twhr = DIV_ROUND_UP(PSEC_TO_NSEC(timings->tWHR_min),
+ div * NFC_CLK_CYCLE);
+
+ bt_min = (timings->tREA_max + NFC_DEFAULT_DELAY) / div;
+ bt_max = (NFC_DEFAULT_DELAY + timings->tRHOH_min
+ + timings->tRC_min / 2) / div;
+
+ bt_min = DIV_ROUND_UP(bt_min, 1000);
+ bt_max = DIV_ROUND_UP(bt_max, 1000);
+
+ if (bt_max < bt_min)
+ return -EINVAL;
+
+ bus_timing = (bt_min + bt_max) / 2 + 1;
+
+ writel((1 << 21), nfc->reg_base + NFC_REG_CFG);
+ writel((NFC_CLK_CYCLE - 1) | (bus_timing << 5),
+ nfc->reg_base + NFC_REG_CFG);
+
+ writel((1 << 31), nfc->reg_base + NFC_REG_CMD);
+
+ return 0;
+}
+
+static int
+meson_nfc_setup_data_interface(struct nand_chip *nand, int csline,
+ const struct nand_data_interface *conf)
+{
+ struct meson_nfc *nfc = nand_get_controller_data(nand);
+ const struct nand_sdr_timings *timings;
+
+ timings = nand_get_sdr_timings(conf);
+ if (IS_ERR(timings))
+ return -ENOTSUPP;
+
+ if (csline == NAND_DATA_IFACE_CHECK_ONLY)
+ return 0;
Hm, before saying you supporting the requested timing, you should make
sure they are actually supported. I'd recommend splitting this in 2
steps:
1/ calc timings
2/ store the timings in the chip priv struct so that they can be
applied next time ->select_chip() is called.
ok, i will try to split.
+
+ meson_nfc_calc_set_timing(nfc, timings);
> You should not set the timing from ->setup_data_interface(), just
calculate them, make sure they are supported and store the state in the
private chip struct. Applying those timings should be done in
->select_chip(), so that you can support 2 chips with different timings.
em, i will fix it.
+ return 0;
+}
.
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