Add support for Allo Boss DAC add-on board for Raspberry Pi. (#1924)

Signed-off-by: Baswaraj K <[email protected]>
Reviewed-by: Deepak <[email protected]>
Reviewed-by: BabuSubashChandar <[email protected]>

Author: babuenir

arch/arm/boot/dts/overlays/Makefile

@@ -7,6 +7,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	ads1115.dtbo \
 	ads7846.dtbo \
 	akkordion-iqdacplus.dtbo \
+	allo-boss-dac-pcm512x-audio.dtbo \
 	allo-piano-dac-pcm512x-audio.dtbo \
 	allo-piano-dac-plus-pcm512x-audio.dtbo \
 	at86rf233.dtbo \

arch/arm/boot/dts/overlays/README

@@ -263,6 +263,30 @@ Params: 24db_digital_gain       Allow gain to be applied via the PCM512x codec
                                 that does not result in clipping/distortion!)
 
 
+Name:   allo-boss-dac-pcm512x-audio
+Info:   Configures the Allo Boss DAC audio cards.
+Load:   dtoverlay=allo-boss-dac-pcm512x-audio,<param>
+Params: 24db_digital_gain       Allow gain to be applied via the PCM512x codec
+                                Digital volume control. Enable with
+                                "dtoverlay=allo-boss-dac-pcm512x-audio,
+                                24db_digital_gain"
+                                (The default behaviour is that the Digital
+                                volume control is limited to a maximum of
+                                0dB. ie. it can attenuate but not provide
+                                gain. For most users, this will be desired
+                                as it will prevent clipping. By appending
+                                the 24db_digital_gain parameter, the Digital
+                                volume control will allow up to 24dB of
+                                gain. If this parameter is enabled, it is the
+                                responsibility of the user to ensure that
+                                the Digital volume control is set to a value
+                                that does not result in clipping/distortion!)
+        slave                   Force Boss DAC into slave mode, using Pi a
+                                master for bit clock and frame clock. Enable
+                                with "dtoverlay=allo-boss-dac-pcm512x-audio,
+                                slave"
+
+
 Name:   allo-piano-dac-pcm512x-audio
 Info:   Configures the Allo Piano DAC (2.0/2.1) audio cards.
         (NB. This initial support is for 2.0 channel audio ONLY! ie. stereo.

arch/arm/boot/dts/overlays/allo-boss-dac-pcm512x-audio-overlay.dts

@@ -0,0 +1,58 @@
+/*
+ * Definitions for Allo Boss DAC board
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2708";
+
+	fragment@0 {
+		target-path = "/clocks";
+		__overlay__ {
+			boss_osc: boss_osc {
+				compatible = "allo,dac-clk";
+				#clock-cells = <0>;
+			};
+		};
+	};
+
+	fragment@1 {
+		target = <&i2s>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@2 {
+		target = <&i2c1>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "okay";
+
+			pcm5122@4d {
+				#sound-dai-cells = <0>;
+				compatible = "ti,pcm5122";
+				clocks = <&boss_osc>;
+				reg = <0x4d>;
+				status = "okay";
+			};
+		};
+	};
+
+	fragment@3 {
+		target = <&sound>;
+		boss_dac: __overlay__ {
+			compatible = "allo,boss-dac";
+			i2s-controller = <&i2s>;
+			status = "okay";
+		};
+	};
+
+	__overrides__ {
+		24db_digital_gain = <&boss_dac>,"allo,24db_digital_gain?";
+		slave = <&boss_dac>,"allo,slave?";
+	};
+};

drivers/clk/Makefile

@@ -17,6 +17,7 @@ endif
 
 # hardware specific clock types
 # please keep this section sorted lexicographically by file path name
+obj-$(CONFIG_SND_BCM2708_SOC_ALLO_BOSS_DAC)	+= clk-allo-dac-45Mhz.o
 obj-$(CONFIG_MACH_ASM9260)		+= clk-asm9260.o
 obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
 obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o

drivers/clk/clk-allo-dac-45Mhz.c

@@ -0,0 +1,161 @@
+/*
+ * Clock Driver for Allo DAC
+ *
+ * Author:	Baswaraj K <[email protected]>
+ *		Copyright 2016
+ *		based on code by Stuart MacLean
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+/* Clock rate of CLK44EN attached to GPIO6 pin */
+#define CLK_44EN_RATE 45158400UL
+/* Clock rate of CLK48EN attached to GPIO3 pin */
+#define CLK_48EN_RATE 49152000UL
+
+/**
+ * struct allo_dac_clk - Common struct to the Allo DAC
+ * @hw: clk_hw for the common clk framework
+ * @mode: 0 => CLK44EN, 1 => CLK48EN
+ */
+struct clk_allo_hw {
+	struct clk_hw hw;
+	uint8_t mode;
+};
+
+#define to_allo_clk(_hw) container_of(_hw, struct clk_allo_hw, hw)
+
+static const struct of_device_id clk_allo_dac_dt_ids[] = {
+	{ .compatible = "allo,dac-clk",},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, clk_allo_dac_dt_ids);
+
+static unsigned long clk_allo_dac_recalc_rate(struct clk_hw *hw,
+	unsigned long parent_rate)
+{
+	return (to_allo_clk(hw)->mode == 0) ? CLK_44EN_RATE :
+		CLK_48EN_RATE;
+}
+
+static long clk_allo_dac_round_rate(struct clk_hw *hw,
+	unsigned long rate, unsigned long *parent_rate)
+{
+	long actual_rate;
+
+	if (rate <= CLK_44EN_RATE) {
+		actual_rate = (long)CLK_44EN_RATE;
+	} else if (rate >= CLK_48EN_RATE) {
+		actual_rate = (long)CLK_48EN_RATE;
+	} else {
+		long diff44Rate = (long)(rate - CLK_44EN_RATE);
+		long diff48Rate = (long)(CLK_48EN_RATE - rate);
+
+		if (diff44Rate < diff48Rate)
+			actual_rate = (long)CLK_44EN_RATE;
+		else
+			actual_rate = (long)CLK_48EN_RATE;
+	}
+	return actual_rate;
+}
+
+
+static int clk_allo_dac_set_rate(struct clk_hw *hw,
+	unsigned long rate, unsigned long parent_rate)
+{
+	unsigned long actual_rate;
+	struct clk_allo_hw *clk = to_allo_clk(hw);
+
+	actual_rate = (unsigned long)clk_allo_dac_round_rate(hw, rate,
+		&parent_rate);
+	clk->mode = (actual_rate == CLK_44EN_RATE) ? 0 : 1;
+	return 0;
+}
+
+
+const struct clk_ops clk_allo_dac_rate_ops = {
+	.recalc_rate = clk_allo_dac_recalc_rate,
+	.round_rate = clk_allo_dac_round_rate,
+	.set_rate = clk_allo_dac_set_rate,
+};
+
+static int clk_allo_dac_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct clk_allo_hw *proclk;
+	struct clk *clk;
+	struct device *dev;
+	struct clk_init_data init;
+
+	dev = &pdev->dev;
+
+	proclk = kzalloc(sizeof(struct clk_allo_hw), GFP_KERNEL);
+	if (!proclk)
+		return -ENOMEM;
+
+	init.name = "clk-allo-dac";
+	init.ops = &clk_allo_dac_rate_ops;
+	init.flags = CLK_IS_ROOT | CLK_IS_BASIC;
+	init.parent_names = NULL;
+	init.num_parents = 0;
+
+	proclk->mode = 0;
+	proclk->hw.init = &init;
+
+	clk = devm_clk_register(dev, &proclk->hw);
+	if (!IS_ERR(clk)) {
+		ret = of_clk_add_provider(dev->of_node, of_clk_src_simple_get,
+			clk);
+	} else {
+		dev_err(dev, "Fail to register clock driver\n");
+		kfree(proclk);
+		ret = PTR_ERR(clk);
+	}
+	return ret;
+}
+
+static int clk_allo_dac_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+	return 0;
+}
+
+static struct platform_driver clk_allo_dac_driver = {
+	.probe = clk_allo_dac_probe,
+	.remove = clk_allo_dac_remove,
+	.driver = {
+		.name = "clk-allo-dac",
+		.of_match_table = clk_allo_dac_dt_ids,
+	},
+};
+
+static int __init clk_allo_dac_init(void)
+{
+	return platform_driver_register(&clk_allo_dac_driver);
+}
+core_initcall(clk_allo_dac_init);
+
+static void __exit clk_allo_dac_exit(void)
+{
+	platform_driver_unregister(&clk_allo_dac_driver);
+}
+module_exit(clk_allo_dac_exit);
+
+MODULE_DESCRIPTION("Allo DAC clock driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:clk-allo-dac");

sound/soc/bcm/Kconfig

@@ -176,6 +176,14 @@ config SND_BCM2708_SOC_FE_PI_AUDIO
 	help
 	  Say Y or M if you want to add support for Fe-Pi-Audio.
 
+config SND_BCM2708_SOC_ALLO_BOSS_DAC
+	tristate "Support for allo Boss DAC"
+	depends on SND_BCM2708_SOC_I2S || SND_BCM2835_SOC_I2S
+	select SND_SOC_PCM512x_I2C
+	help
+	  Say Y or M if you want to add support for allo Boss DAC.
+
+
 config SND_PISOUND
 	tristate "Support for Blokas Labs pisound"
 	depends on SND_BCM2708_SOC_I2S || SND_BCM2835_SOC_I2S

sound/soc/bcm/Makefile

@@ -31,6 +31,7 @@ snd-soc-audioinjector-octo-soundcard-objs := audioinjector-octo-soundcard.o
 snd-soc-digidac1-soundcard-objs := digidac1-soundcard.o
 snd-soc-dionaudio-loco-objs := dionaudio_loco.o
 snd-soc-dionaudio-loco-v2-objs := dionaudio_loco-v2.o
+snd-soc-allo-boss-dac-objs := allo-boss-dac.o
 snd-soc-allo-piano-dac-objs := allo-piano-dac.o
 snd-soc-allo-piano-dac-plus-objs := allo-piano-dac-plus.o
 snd-soc-pisound-objs := pisound.o
@@ -56,6 +57,7 @@ obj-$(CONFIG_SND_AUDIOINJECTOR_OCTO_SOUNDCARD) += snd-soc-audioinjector-octo-sou
 obj-$(CONFIG_SND_DIGIDAC1_SOUNDCARD) += snd-soc-digidac1-soundcard.o
 obj-$(CONFIG_SND_BCM2708_SOC_DIONAUDIO_LOCO) += snd-soc-dionaudio-loco.o
 obj-$(CONFIG_SND_BCM2708_SOC_DIONAUDIO_LOCO_V2) += snd-soc-dionaudio-loco-v2.o
+obj-$(CONFIG_SND_BCM2708_SOC_ALLO_BOSS_DAC) += snd-soc-allo-boss-dac.o
 obj-$(CONFIG_SND_BCM2708_SOC_ALLO_PIANO_DAC) += snd-soc-allo-piano-dac.o
 obj-$(CONFIG_SND_BCM2708_SOC_ALLO_PIANO_DAC_PLUS) += snd-soc-allo-piano-dac-plus.o
 obj-$(CONFIG_SND_PISOUND) += snd-soc-pisound.o