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ASoC: rockchip: i2s-tdm: Delay for reset successfully

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This patch Adds delay after reset deassert to make sure
reset done before do enabling xfer.

Considering the follow situation:

- i2s_mclk for 8K capture [2.048M]
- i2s_hclk for i2s register access [150M]
- pclk_cru for cru register access [100M]

       SW                               HW

i2s reset assert   [pclk_cru]           |
        |                               |
   delay time                           |
        |                       i2s reset assert   [i2s_mclk]
i2s reset deassert [pclk_cru]           |
        |                               |
i2s xfer enable    [i2s_hclk]           |
        |                       i2s reset deassert [i2s_mclk]

Obviously, pclk_cru(10ns per cycle) is much faster than i2s_mclk
(500ns per cycle). so delay should be added after reset deassert
to make sure hw reset done. Otherwise, the race between reset and
enable xfer maybe break i2s data aligned.

Fixes: A 10us delay is enough

       SW                               HW

i2s reset assert   [pclk_cru]           |
        |                               |
   delay 10us                           |
        |                       i2s reset assert   [i2s_mclk]
i2s reset deassert [pclk_cru]           |
        |                               |
   delay 10us                           |
        |                       i2s reset deassert [i2s_mclk]
i2s xfer enable    [i2s_hclk]           |
        |                               |

Change-Id: Id370b0aa13f771053841ce04a554b408e9e3c831
Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
This commit is contained in:
Sugar Zhang
2021-05-31 10:31:20 +08:00
committed by Tao Huang
parent b5fc70f671
commit 03eca20525
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
sound/soc/rockchip/rockchip_i2s_tdm.c
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@@ -216,6 +216,8 @@ static void rockchip_snd_xfer_reset_assert(struct rk_i2s_tdm_dev *i2s_tdm,
local_irq_restore(flags);
break;
}
/* delay for reset assert done */
udelay(10);
}
static void rockchip_snd_xfer_reset_deassert(struct rk_i2s_tdm_dev *i2s_tdm,
@@ -260,6 +262,8 @@ static void rockchip_snd_xfer_reset_deassert(struct rk_i2s_tdm_dev *i2s_tdm,
local_irq_restore(flags);
break;
}
/* delay for reset deassert done */
udelay(10);
}
/*
@@ -289,9 +293,6 @@ static void rockchip_snd_xfer_sync_reset(struct rk_i2s_tdm_dev *i2s_tdm)
rockchip_snd_xfer_reset_assert(i2s_tdm, tx_bank, tx_offset,
rx_bank, rx_offset);
udelay(150);
rockchip_snd_xfer_reset_deassert(i2s_tdm, tx_bank, tx_offset,
rx_bank, rx_offset);
}