clk: Add ICS8N3QV01 driver

Add a driver for the ICS8N3QV01 Quad-Frequency Programmable VCXO.

Signed-off-by: Mario Six <mario.six@gdsys.cc>

drivers/clk/Kconfig

@@ -89,4 +89,12 @@ source "drivers/clk/exynos/Kconfig"
 source "drivers/clk/at91/Kconfig"
 source "drivers/clk/renesas/Kconfig"
 
+config ICS8N3QV01
+	bool "Enable ICS8N3QV01 VCXO driver"
+	depends on CLK
+	help
+	  Support for the ICS8N3QV01 Quad-Frequency VCXO (Voltage-Controlled
+	  Crystal Oscillator). The output frequency can be programmed via an
+	  I2C interface.
+
 endmenu

drivers/clk/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_CLK_STM32MP1) += clk_stm32mp1.o
 obj-$(CONFIG_CLK_UNIPHIER) += uniphier/
 obj-$(CONFIG_CLK_ZYNQ) += clk_zynq.o
 obj-$(CONFIG_CLK_ZYNQMP) += clk_zynqmp.o
+obj-$(CONFIG_ICS8N3QV01) += ics8n3qv01.o
 obj-$(CONFIG_MACH_PIC32) += clk_pic32.o
 obj-$(CONFIG_SANDBOX) += clk_sandbox.o
 obj-$(CONFIG_SANDBOX) += clk_sandbox_test.o

drivers/clk/ics8n3qv01.c

@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2017
+ * Mario Six,  Guntermann & Drunck GmbH, mario.six@gdsys.cc
+ *
+ * based on the gdsys osd driver, which is
+ *
+ * (C) Copyright 2010
+ * Dirk Eibach,  Guntermann & Drunck GmbH, eibach@gdsys.de
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <clk-uclass.h>
+#include <i2c.h>
+
+const long long ICS8N3QV01_FREF = 114285000;
+const long long ICS8N3QV01_FREF_LL = 114285000LL;
+const long long ICS8N3QV01_F_DEFAULT_0 = 156250000LL;
+const long long ICS8N3QV01_F_DEFAULT_1 = 125000000LL;
+const long long ICS8N3QV01_F_DEFAULT_2 = 100000000LL;
+const long long ICS8N3QV01_F_DEFAULT_3 = 25175000LL;
+
+const uint MAX_FREQ_INDEX = 3;
+
+struct ics8n3qv01_priv {
+	ulong rate;
+};
+
+static int ics8n3qv01_get_fout_calc(struct udevice *dev, uint index,
+				    uint *fout_calc)
+{
+	u64 n, mint, mfrac;
+	u8 reg_a, reg_b, reg_c, reg_d, reg_f;
+	int val[6];
+	int i;
+
+	if (index > MAX_FREQ_INDEX)
+		return -EINVAL;
+
+	for (i = 0; i <= 5; ++i) {
+		u8 tmp = dm_i2c_reg_read(dev, 4 * i + index);
+
+		if (tmp < 0) {
+			debug("%s: Error while reading i2c register %d.\n",
+			      dev->name, 4 * i + index);
+			return tmp;
+		}
+
+		val[i] = tmp;
+	}
+
+	reg_a = val[0]; /* Register 0 + index */
+	reg_b = val[1]; /* Register 4 + index */
+	reg_c = val[2]; /* Register 8 + index */
+	reg_d = val[3]; /* Register 12 + index */
+	reg_f = val[5]; /* Register 20 + index */
+
+	mint = ((reg_a >> 1) & 0x1f) | /* MINTi[4-0]*/
+		(reg_f & 0x20);        /* MINTi[5] */
+	mfrac = ((reg_a & 0x01) << 17) | /* MFRACi[17] */
+		 (reg_b << 9) |          /* MFRACi[16-9] */
+		 (reg_c << 1) |          /* MFRACi[8-1] */
+		 (reg_d >> 7);           /* MFRACi[0] */
+	n = reg_d & 0x7f; /* Ni[6-0] */
+
+	*fout_calc = (mint * ICS8N3QV01_FREF_LL
+		      + mfrac * ICS8N3QV01_FREF_LL / 262144LL
+		      + ICS8N3QV01_FREF_LL / 524288LL
+		      + n / 2)
+		    / n
+		    * 1000000
+		    / (1000000 - 100);
+
+	return 0;
+}
+
+static int ics8n3qv01_calc_parameters(uint fout, uint *_mint, uint *_mfrac,
+				      uint *_n)
+{
+	uint n, foutiic, fvcoiic, mint;
+	u64 mfrac;
+
+	n = (2215000000U + fout / 2) / fout;
+	if (fout < 417000000U)
+		n = 2 * ((2215000000U / 2 + fout / 2) / fout);
+	else
+		n = (2215000000U + fout / 2) / fout;
+
+	if ((n & 1) && n > 5)
+		n -= 1;
+
+	foutiic = fout - (fout / 10000);
+	fvcoiic = foutiic * n;
+
+	mint = fvcoiic / 114285000;
+	if (mint < 17 || mint > 63)
+		return -EINVAL;
+
+	mfrac = ((u64)fvcoiic % 114285000LL) * 262144LL
+		/ 114285000LL;
+
+	*_mint = mint;
+	*_mfrac = mfrac;
+	*_n = n;
+
+	return 0;
+}
+
+static ulong ics8n3qv01_set_rate(struct clk *clk, ulong fout)
+{
+	struct ics8n3qv01_priv *priv = dev_get_priv(clk->dev);
+	uint n, mint, mfrac;
+	uint fout_calc = 0;
+	u64 fout_prog;
+	long long off_ppm;
+	int res, i;
+	u8 reg[6];
+	int tmp;
+	int addr[] = {0, 4, 8, 12, 18, 20};
+
+	priv->rate = fout;
+
+	res = ics8n3qv01_get_fout_calc(clk->dev, 1, &fout_calc);
+
+	if (res) {
+		debug("%s: Error during output frequency calculation.\n",
+		      clk->dev->name);
+		return res;
+	}
+
+	off_ppm = (fout_calc - ICS8N3QV01_F_DEFAULT_1) * 1000000
+		  / ICS8N3QV01_F_DEFAULT_1;
+	printf("%s: PLL is off by %lld ppm\n", clk->dev->name, off_ppm);
+	fout_prog = (u64)fout * (u64)fout_calc
+		    / ICS8N3QV01_F_DEFAULT_1;
+	res = ics8n3qv01_calc_parameters(fout_prog, &mint, &mfrac, &n);
+
+	if (res) {
+		debug("%s: Cannot determine mint parameter.\n",
+		      clk->dev->name);
+		return res;
+	}
+
+	/* Register 0 */
+	tmp = dm_i2c_reg_read(clk->dev, 0) & 0xc0;
+	if (tmp < 0)
+		return tmp;
+	reg[0] = tmp | (mint & 0x1f) << 1;
+	reg[0] |= (mfrac >> 17) & 0x01;
+
+	/* Register 4 */
+	reg[1] = mfrac >> 9;
+
+	/* Register 8 */
+	reg[2] = mfrac >> 1;
+
+	/* Register 12 */
+	reg[3] = mfrac << 7;
+	reg[3] |= n & 0x7f;
+
+	/* Register 18 */
+	tmp = dm_i2c_reg_read(clk->dev, 18) & 0x03;
+	if (tmp < 0)
+		return tmp;
+	reg[4] = tmp | 0x20;
+
+	/* Register 20 */
+	tmp = dm_i2c_reg_read(clk->dev, 20) & 0x1f;
+	if (tmp < 0)
+		return tmp;
+	reg[5] = tmp | (mint & (1 << 5));
+
+	for (i = 0; i <= 5; ++i) {
+		res = dm_i2c_reg_write(clk->dev, addr[i], reg[i]);
+		if (res < 0)
+			return res;
+	}
+
+	return 0;
+}
+
+static int ics8n3qv01_request(struct clk *clock)
+{
+	return 0;
+}
+
+static ulong ics8n3qv01_get_rate(struct clk *clk)
+{
+	struct ics8n3qv01_priv *priv = dev_get_priv(clk->dev);
+
+	return priv->rate;
+}
+
+static int ics8n3qv01_enable(struct clk *clk)
+{
+	return 0;
+}
+
+static int ics8n3qv01_disable(struct clk *clk)
+{
+	return 0;
+}
+
+static const struct clk_ops ics8n3qv01_ops = {
+	.request = ics8n3qv01_request,
+	.get_rate = ics8n3qv01_get_rate,
+	.set_rate = ics8n3qv01_set_rate,
+	.enable = ics8n3qv01_enable,
+	.disable = ics8n3qv01_disable,
+};
+
+static const struct udevice_id ics8n3qv01_ids[] = {
+	{ .compatible = "idt,ics8n3qv01" },
+	{ /* sentinel */ }
+};
+
+int ics8n3qv01_probe(struct udevice *dev)
+{
+	return 0;
+}
+
+U_BOOT_DRIVER(ics8n3qv01) = {
+	.name           = "ics8n3qv01",
+	.id             = UCLASS_CLK,
+	.ops		= &ics8n3qv01_ops,
+	.of_match       = ics8n3qv01_ids,
+	.probe		= ics8n3qv01_probe,
+	.priv_auto_alloc_size	= sizeof(struct ics8n3qv01_priv),
+};