.. | .. |
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1 | | -/* |
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2 | | - * imx-ssi.c -- ALSA Soc Audio Layer |
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3 | | - * |
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4 | | - * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de> |
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5 | | - * |
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6 | | - * This code is based on code copyrighted by Freescale, |
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7 | | - * Liam Girdwood, Javier Martin and probably others. |
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8 | | - * |
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9 | | - * This program is free software; you can redistribute it and/or modify it |
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10 | | - * under the terms of the GNU General Public License as published by the |
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11 | | - * Free Software Foundation; either version 2 of the License, or (at your |
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12 | | - * option) any later version. |
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13 | | - * |
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14 | | - * |
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15 | | - * The i.MX SSI core has some nasty limitations in AC97 mode. While most |
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16 | | - * sane processor vendors have a FIFO per AC97 slot, the i.MX has only |
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17 | | - * one FIFO which combines all valid receive slots. We cannot even select |
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18 | | - * which slots we want to receive. The WM9712 with which this driver |
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19 | | - * was developed with always sends GPIO status data in slot 12 which |
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20 | | - * we receive in our (PCM-) data stream. The only chance we have is to |
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21 | | - * manually skip this data in the FIQ handler. With sampling rates different |
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22 | | - * from 48000Hz not every frame has valid receive data, so the ratio |
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23 | | - * between pcm data and GPIO status data changes. Our FIQ handler is not |
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24 | | - * able to handle this, hence this driver only works with 48000Hz sampling |
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25 | | - * rate. |
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26 | | - * Reading and writing AC97 registers is another challenge. The core |
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27 | | - * provides us status bits when the read register is updated with *another* |
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28 | | - * value. When we read the same register two times (and the register still |
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29 | | - * contains the same value) these status bits are not set. We work |
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30 | | - * around this by not polling these bits but only wait a fixed delay. |
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31 | | - * |
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32 | | - */ |
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| 1 | +// SPDX-License-Identifier: GPL-2.0+ |
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| 2 | +// |
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| 3 | +// imx-ssi.c -- ALSA Soc Audio Layer |
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| 4 | +// |
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| 5 | +// Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de> |
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| 6 | +// |
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| 7 | +// This code is based on code copyrighted by Freescale, |
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| 8 | +// Liam Girdwood, Javier Martin and probably others. |
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| 9 | +// |
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| 10 | +// The i.MX SSI core has some nasty limitations in AC97 mode. While most |
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| 11 | +// sane processor vendors have a FIFO per AC97 slot, the i.MX has only |
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| 12 | +// one FIFO which combines all valid receive slots. We cannot even select |
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| 13 | +// which slots we want to receive. The WM9712 with which this driver |
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| 14 | +// was developed with always sends GPIO status data in slot 12 which |
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| 15 | +// we receive in our (PCM-) data stream. The only chance we have is to |
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| 16 | +// manually skip this data in the FIQ handler. With sampling rates different |
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| 17 | +// from 48000Hz not every frame has valid receive data, so the ratio |
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| 18 | +// between pcm data and GPIO status data changes. Our FIQ handler is not |
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| 19 | +// able to handle this, hence this driver only works with 48000Hz sampling |
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| 20 | +// rate. |
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| 21 | +// Reading and writing AC97 registers is another challenge. The core |
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| 22 | +// provides us status bits when the read register is updated with *another* |
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| 23 | +// value. When we read the same register two times (and the register still |
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| 24 | +// contains the same value) these status bits are not set. We work |
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| 25 | +// around this by not polling these bits but only wait a fixed delay. |
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33 | 26 | |
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34 | 27 | #include <linux/clk.h> |
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35 | 28 | #include <linux/delay.h> |
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.. | .. |
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380 | 373 | |
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381 | 374 | static struct snd_soc_dai_driver imx_ac97_dai = { |
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382 | 375 | .probe = imx_ssi_dai_probe, |
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383 | | - .bus_control = true, |
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384 | 376 | .playback = { |
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385 | 377 | .stream_name = "AC97 Playback", |
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386 | 378 | .channels_min = 2, |
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.. | .. |
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527 | 519 | } |
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528 | 520 | |
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529 | 521 | ssi->irq = platform_get_irq(pdev, 0); |
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530 | | - if (ssi->irq < 0) { |
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531 | | - dev_err(&pdev->dev, "Failed to get IRQ: %d\n", ssi->irq); |
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| 522 | + if (ssi->irq < 0) |
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532 | 523 | return ssi->irq; |
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533 | | - } |
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534 | 524 | |
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535 | 525 | ssi->clk = devm_clk_get(&pdev->dev, NULL); |
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536 | 526 | if (IS_ERR(ssi->clk)) { |
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