iio: dac: adi-axi-dac: extend features

Extend AXI-DAC backend with new features required to interface
to the ad3552r DAC. Mainly, a new compatible string is added to
support the ad3552r-axi DAC IP, very similar to the generic DAC
IP but with some customizations to work with the ad3552r.

Then, a series of generic functions has been added to match with
ad3552r needs. Function names has been kept generic as much as
possible, to allow re-utilization from other frontend drivers.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241028-wip-bl-ad3552r-axi-v0-iio-testing-v9-4-f6960b4f9719@kernel-space.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: spectrum70

drivers/iio/dac/adi-axi-dac.c

@@ -46,9 +46,28 @@
 #define AXI_DAC_CNTRL_1_REG			0x0044
 #define   AXI_DAC_CNTRL_1_SYNC			BIT(0)
 #define AXI_DAC_CNTRL_2_REG			0x0048
+#define   AXI_DAC_CNTRL_2_SDR_DDR_N		BIT(16)
+#define   AXI_DAC_CNTRL_2_SYMB_8B		BIT(14)
 #define   ADI_DAC_CNTRL_2_R1_MODE		BIT(5)
+#define   AXI_DAC_CNTRL_2_UNSIGNED_DATA		BIT(4)
+#define AXI_DAC_STATUS_1_REG			0x0054
+#define AXI_DAC_STATUS_2_REG			0x0058
 #define AXI_DAC_DRP_STATUS_REG			0x0074
 #define   AXI_DAC_DRP_STATUS_DRP_LOCKED		BIT(17)
+#define AXI_DAC_CUSTOM_RD_REG			0x0080
+#define AXI_DAC_CUSTOM_WR_REG			0x0084
+#define   AXI_DAC_CUSTOM_WR_DATA_8		GENMASK(23, 16)
+#define   AXI_DAC_CUSTOM_WR_DATA_16		GENMASK(23, 8)
+#define AXI_DAC_UI_STATUS_REG			0x0088
+#define   AXI_DAC_UI_STATUS_IF_BUSY		BIT(4)
+#define AXI_DAC_CUSTOM_CTRL_REG			0x008C
+#define   AXI_DAC_CUSTOM_CTRL_ADDRESS		GENMASK(31, 24)
+#define   AXI_DAC_CUSTOM_CTRL_SYNCED_TRANSFER	BIT(2)
+#define   AXI_DAC_CUSTOM_CTRL_STREAM		BIT(1)
+#define   AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA	BIT(0)
+
+#define AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE	(AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA | \
+						 AXI_DAC_CUSTOM_CTRL_STREAM)
 
 /* DAC Channel controls */
 #define AXI_DAC_CHAN_CNTRL_1_REG(c)		(0x0400 + (c) * 0x40)
@@ -63,12 +82,21 @@
 #define AXI_DAC_CHAN_CNTRL_7_REG(c)		(0x0418 + (c) * 0x40)
 #define   AXI_DAC_CHAN_CNTRL_7_DATA_SEL		GENMASK(3, 0)
 
+#define AXI_DAC_RD_ADDR(x)			(BIT(7) | (x))
+
 /* 360 degrees in rad */
 #define AXI_DAC_2_PI_MEGA			6283190
 
 enum {
 	AXI_DAC_DATA_INTERNAL_TONE,
 	AXI_DAC_DATA_DMA = 2,
+	AXI_DAC_DATA_INTERNAL_RAMP_16BIT = 11,
+};
+
+struct axi_dac_info {
+	unsigned int version;
+	const struct iio_backend_info *backend_info;
+	bool has_dac_clk;
 };
 
 struct axi_dac_state {
@@ -79,9 +107,11 @@ struct axi_dac_state {
 	 * data/variables.
 	 */
 	struct mutex lock;
+	const struct axi_dac_info *info;
 	u64 dac_clk;
 	u32 reg_config;
 	bool int_tone;
+	int dac_clk_rate;
 };
 
 static int axi_dac_enable(struct iio_backend *back)
@@ -471,6 +501,11 @@ static int axi_dac_data_source_set(struct iio_backend *back, unsigned int chan,
 					  AXI_DAC_CHAN_CNTRL_7_REG(chan),
 					  AXI_DAC_CHAN_CNTRL_7_DATA_SEL,
 					  AXI_DAC_DATA_DMA);
+	case IIO_BACKEND_INTERNAL_RAMP_16BIT:
+		return regmap_update_bits(st->regmap,
+					  AXI_DAC_CHAN_CNTRL_7_REG(chan),
+					  AXI_DAC_CHAN_CNTRL_7_DATA_SEL,
+					  AXI_DAC_DATA_INTERNAL_RAMP_16BIT);
 	default:
 		return -EINVAL;
 	}
@@ -528,6 +563,154 @@ static int axi_dac_reg_access(struct iio_backend *back, unsigned int reg,
 	return regmap_write(st->regmap, reg, writeval);
 }
 
+static int axi_dac_ddr_enable(struct iio_backend *back)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	return regmap_clear_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
+				 AXI_DAC_CNTRL_2_SDR_DDR_N);
+}
+
+static int axi_dac_ddr_disable(struct iio_backend *back)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	return regmap_set_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
+			       AXI_DAC_CNTRL_2_SDR_DDR_N);
+}
+
+static int axi_dac_data_stream_enable(struct iio_backend *back)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	return regmap_set_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+			       AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE);
+}
+
+static int axi_dac_data_stream_disable(struct iio_backend *back)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	return regmap_clear_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+				 AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE);
+}
+
+static int axi_dac_data_transfer_addr(struct iio_backend *back, u32 address)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	if (address > FIELD_MAX(AXI_DAC_CUSTOM_CTRL_ADDRESS))
+		return -EINVAL;
+
+	/*
+	 * Sample register address, when the DAC is configured, or stream
+	 * start address when the FSM is in stream state.
+	 */
+	return regmap_update_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+				  AXI_DAC_CUSTOM_CTRL_ADDRESS,
+				  FIELD_PREP(AXI_DAC_CUSTOM_CTRL_ADDRESS,
+				  address));
+}
+
+static int axi_dac_data_format_set(struct iio_backend *back, unsigned int ch,
+				   const struct iio_backend_data_fmt *data)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	switch (data->type) {
+	case IIO_BACKEND_DATA_UNSIGNED:
+		return regmap_clear_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
+					 AXI_DAC_CNTRL_2_UNSIGNED_DATA);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int __axi_dac_bus_reg_write(struct iio_backend *back, u32 reg,
+				 u32 val, size_t data_size)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+	int ret;
+	u32 ival;
+
+	/*
+	 * Both AXI_DAC_CNTRL_2_REG and AXI_DAC_CUSTOM_WR_REG need to know
+	 * the data size. So keeping data size control here only,
+	 * since data size is mandatory for the current transfer.
+	 * DDR state handled separately by specific backend calls,
+	 * generally all raw register writes are SDR.
+	 */
+	if (data_size == sizeof(u16))
+		ival = FIELD_PREP(AXI_DAC_CUSTOM_WR_DATA_16, val);
+	else
+		ival = FIELD_PREP(AXI_DAC_CUSTOM_WR_DATA_8, val);
+
+	ret = regmap_write(st->regmap, AXI_DAC_CUSTOM_WR_REG, ival);
+	if (ret)
+		return ret;
+
+	if (data_size == sizeof(u8))
+		ret = regmap_set_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
+				      AXI_DAC_CNTRL_2_SYMB_8B);
+	else
+		ret = regmap_clear_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
+					AXI_DAC_CNTRL_2_SYMB_8B);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+				 AXI_DAC_CUSTOM_CTRL_ADDRESS,
+				 FIELD_PREP(AXI_DAC_CUSTOM_CTRL_ADDRESS, reg));
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+				 AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA,
+				 AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA);
+	if (ret)
+		return ret;
+
+	ret = regmap_read_poll_timeout(st->regmap,
+				AXI_DAC_UI_STATUS_REG, ival,
+				FIELD_GET(AXI_DAC_UI_STATUS_IF_BUSY, ival) == 0,
+				10, 100 * KILO);
+	if (ret == -ETIMEDOUT)
+		dev_err(st->dev, "AXI read timeout\n");
+
+	/* Cleaning always AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA */
+	return regmap_clear_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
+				 AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA);
+}
+
+static int axi_dac_bus_reg_write(struct iio_backend *back, u32 reg,
+					u32 val, size_t data_size)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+
+	guard(mutex)(&st->lock);
+	return __axi_dac_bus_reg_write(back, reg, val, data_size);
+}
+
+static int axi_dac_bus_reg_read(struct iio_backend *back, u32 reg, u32 *val,
+				size_t data_size)
+{
+	struct axi_dac_state *st = iio_backend_get_priv(back);
+	int ret;
+
+	guard(mutex)(&st->lock);
+
+	/*
+	 * SPI, we write with read flag, then we read just at the AXI
+	 * io address space to get data read.
+	 */
+	ret = __axi_dac_bus_reg_write(back, AXI_DAC_RD_ADDR(reg), 0,
+				      data_size);
+	if (ret)
+		return ret;
+
+	return regmap_read(st->regmap, AXI_DAC_CUSTOM_RD_REG, val);
+}
+
 static const struct iio_backend_ops axi_dac_generic_ops = {
 	.enable = axi_dac_enable,
 	.disable = axi_dac_disable,
@@ -541,11 +724,30 @@ static const struct iio_backend_ops axi_dac_generic_ops = {
 	.debugfs_reg_access = iio_backend_debugfs_ptr(axi_dac_reg_access),
 };
 
+static const struct iio_backend_ops axi_ad3552r_ops = {
+	.enable = axi_dac_enable,
+	.disable = axi_dac_disable,
+	.request_buffer = axi_dac_request_buffer,
+	.free_buffer = axi_dac_free_buffer,
+	.data_source_set = axi_dac_data_source_set,
+	.ddr_enable = axi_dac_ddr_enable,
+	.ddr_disable = axi_dac_ddr_disable,
+	.data_stream_enable = axi_dac_data_stream_enable,
+	.data_stream_disable = axi_dac_data_stream_disable,
+	.data_format_set = axi_dac_data_format_set,
+	.data_transfer_addr = axi_dac_data_transfer_addr,
+};
+
 static const struct iio_backend_info axi_dac_generic = {
 	.name = "axi-dac",
 	.ops = &axi_dac_generic_ops,
 };
 
+static const struct iio_backend_info axi_ad3552r = {
+	.name = "axi-ad3552r",
+	.ops = &axi_ad3552r_ops,
+};
+
 static const struct regmap_config axi_dac_regmap_config = {
 	.val_bits = 32,
 	.reg_bits = 32,
@@ -555,7 +757,6 @@ static const struct regmap_config axi_dac_regmap_config = {
 
 static int axi_dac_probe(struct platform_device *pdev)
 {
-	const unsigned int *expected_ver;
 	struct axi_dac_state *st;
 	void __iomem *base;
 	unsigned int ver;
@@ -566,14 +767,29 @@ static int axi_dac_probe(struct platform_device *pdev)
 	if (!st)
 		return -ENOMEM;
 
-	expected_ver = device_get_match_data(&pdev->dev);
-	if (!expected_ver)
+	st->info = device_get_match_data(&pdev->dev);
+	if (!st->info)
 		return -ENODEV;
+	clk = devm_clk_get_enabled(&pdev->dev, "s_axi_aclk");
+	if (IS_ERR(clk)) {
+		/* Backward compat., old fdt versions without clock-names. */
+		clk = devm_clk_get_enabled(&pdev->dev, NULL);
+		if (IS_ERR(clk))
+			return dev_err_probe(&pdev->dev, PTR_ERR(clk),
+					"failed to get clock\n");
+	}
+
+	if (st->info->has_dac_clk) {
+		struct clk *dac_clk;
 
-	clk = devm_clk_get_enabled(&pdev->dev, NULL);
-	if (IS_ERR(clk))
-		return dev_err_probe(&pdev->dev, PTR_ERR(clk),
-				     "failed to get clock\n");
+		dac_clk = devm_clk_get_enabled(&pdev->dev, "dac_clk");
+		if (IS_ERR(dac_clk))
+			return dev_err_probe(&pdev->dev, PTR_ERR(dac_clk),
+					     "failed to get dac_clk clock\n");
+
+		/* We only care about the streaming mode rate */
+		st->dac_clk_rate = clk_get_rate(dac_clk) / 2;
+	}
 
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
@@ -598,12 +814,13 @@ static int axi_dac_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	if (ADI_AXI_PCORE_VER_MAJOR(ver) != ADI_AXI_PCORE_VER_MAJOR(*expected_ver)) {
+	if (ADI_AXI_PCORE_VER_MAJOR(ver) !=
+		ADI_AXI_PCORE_VER_MAJOR(st->info->version)) {
 		dev_err(&pdev->dev,
 			"Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
-			ADI_AXI_PCORE_VER_MAJOR(*expected_ver),
-			ADI_AXI_PCORE_VER_MINOR(*expected_ver),
-			ADI_AXI_PCORE_VER_PATCH(*expected_ver),
+			ADI_AXI_PCORE_VER_MAJOR(st->info->version),
+			ADI_AXI_PCORE_VER_MINOR(st->info->version),
+			ADI_AXI_PCORE_VER_PATCH(st->info->version),
 			ADI_AXI_PCORE_VER_MAJOR(ver),
 			ADI_AXI_PCORE_VER_MINOR(ver),
 			ADI_AXI_PCORE_VER_PATCH(ver));
@@ -629,7 +846,8 @@ static int axi_dac_probe(struct platform_device *pdev)
 		return ret;
 
 	mutex_init(&st->lock);
-	ret = devm_iio_backend_register(&pdev->dev, &axi_dac_generic, st);
+
+	ret = devm_iio_backend_register(&pdev->dev, st->info->backend_info, st);
 	if (ret)
 		return dev_err_probe(&pdev->dev, ret,
 				     "failed to register iio backend\n");
@@ -642,10 +860,20 @@ static int axi_dac_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static unsigned int axi_dac_9_1_b_info = ADI_AXI_PCORE_VER(9, 1, 'b');
+static const struct axi_dac_info dac_generic = {
+	.version = ADI_AXI_PCORE_VER(9, 1, 'b'),
+	.backend_info = &axi_dac_generic,
+};
+
+static const struct axi_dac_info dac_ad3552r = {
+	.version = ADI_AXI_PCORE_VER(9, 1, 'b'),
+	.backend_info = &axi_ad3552r,
+	.has_dac_clk = true,
+};
 
 static const struct of_device_id axi_dac_of_match[] = {
-	{ .compatible = "adi,axi-dac-9.1.b", .data = &axi_dac_9_1_b_info },
+	{ .compatible = "adi,axi-dac-9.1.b", .data = &dac_generic },
+	{ .compatible = "adi,axi-ad3552r", .data = &dac_ad3552r },
 	{}
 };
 MODULE_DEVICE_TABLE(of, axi_dac_of_match);