• SSM2518

• CN0296

• EVAL-SSM2518Z
• PMOD-AMP3

The I2C address of the SSM2518 depends on the setting of the ADDR pin

static struct i2c_board_info __initdata bfin_i2c_board_info[] = {
 
	[--snip--]
	{
		I2C_BOARD_INFO("ssm2518", 0x34),
	},
	[--snip--]
}

static int __init stamp_init(void)
{
	[--snip--]
	i2c_register_board_info(0, bfin_i2c_board_info,
				ARRAY_SIZE(bfin_i2c_board_info));
	[--snip--]
 
	return 0;
}
arch_initcall(board_init);

i2s: i2c@41600000 {
	compatible = "...;
	...

	#size-cells = <0>;
	#address-cells = <1>;
            
	ssm2518: ssm2518@34 {
		compatible = "adi,ssm2518";
		reg = <0x34>;
		gpios = <&gpio 5 0>;
	};
};

The codec driver registers one DAI named “ssm2518-hifi”.

The CODECs system clock can be configured for various input rates. When configuring the codec system clock use SSM2518_SYSCLK for the clock id.

The following list contains the supported system clock rates and their resulting sample-rates.

To configure the devices sysclk the snd_soc_codec_set_sysclk() function can be used. It needs to be called at least once before playback starts. The clk_id parameter must always be SSM2518_SYSCLK and the dir parameter must always be SND_SOC_CLOCK_IN. The freq can be set to any of the frequencies above. The system clock can either be taken from the external MCLK or the BCLK. In case the system clock is taken from the BCLK the BCLK needs to be applied to the MCLK pin and the BLCK can be left unconnected. To use the MCLK as the system clock source the source parameter should to be set to SSM2518_SYSCLK_SRC_MCLK, to use the BCLK it should be set to SSM2518_SYSCLK_SRC_BCLK

#define SSM2518_SYSCLK 0 
 
enum ssm2518_sysclk_src {
    SSM2518_SYSCLK_SRC_MCLK = 0,
    SSM2518_SYSCLK_SRC_BCLK = 1,
};

If you want to use the SSM2518 in TDM mode you can configure it using snd_soc_dai_set_tdm_slot() from you ASoC board driver.

The following restrictions apply to the parameters of snd_soc_dai_set_tdm_slot().

• tx_mask must have exactly two bits set. The most upper bit will be the slot of right channel, the most lower bit will be the slot left channel. E.g. 0x3 means the left channel will be at slot 0 and the right channel will be at slot 1 in the TDM stream.
• rx_mask must be 0.
• slots must be either 1, 2, 4, 8 or 16
• width must be either 16, 24, 32

Example:

static int ssm2518_link_init(struct snd_soc_pcm_runtime *rtd)
{
    int ret;
 
    ret = snd_soc_dai_set_tdm_slot(rtd->codec_dai, 0x0c, 0x00, 8, 32);
    if (ret < 0)
        return ret;
 
    return 0;
}
 
static struct snd_soc_dai_link ssm2518_dai_link = {
    ...,
    .init = ssm2518_link_init,
};

#include "../codecs/ssm2518.h"
 
static int pmod_amp3_init(struct snd_soc_pcm_runtime *rtd)
{
    return snd_soc_codec_set_sysclk(rtd->codec, SSM2518_SYSCLK,
                SSM2518_SYSCLK_SRC_MCLK, 12288000, SND_SOC_CLOCK_IN);
}
 
static const struct snd_soc_dapm_widget pmod_amp3_widgets[] = {
    SND_SOC_DAPM_SPK("Speaker Out", NULL),
};
 
static const struct snd_soc_dapm_route pmod_amp3_routes[] = {
    { "Speaker Out", NULL, "OUTL" },
    { "Speaker Out", NULL, "OUTR" },
};
 
static struct snd_soc_dai_link pmod_amp3_dai_link = {
    .name = "ssm2518",
    .stream_name = "ssm2518",
    .codec_dai_name = "ssm2518-hifi",
    .dai_fmt = SND_SOC_DAIFMT_I2S |
            SND_SOC_DAIFMT_NB_NF |
            SND_SOC_DAIFMT_CBS_CFS,
    .init = pmod_amp3_init,
};
 
static struct snd_soc_card pmod_amp3_card = {
    .name = "PMOD AMP3 SSM2518",
    .owner = THIS_MODULE,
    .dai_link = &pmod_amp3_dai_link,
    .num_links = 1,
    .dapm_widgets = pmod_amp3_widgets,
    .num_dapm_widgets = ARRAY_SIZE(pmod_amp3_widgets),
    .dapm_routes = pmod_amp3_routes,
    .num_dapm_routes = ARRAY_SIZE(pmod_amp3_routes),
    .fully_routed = true,
};