media: platform: meson: Add Amlogic Meson G12A AO CEC Controller driver

The Amlogic G12A SoC embeds a second CEC controller with a totally
different design.

The two controller can work in the same time since the CEC line can
be set to two different pins on the two controllers.

This second CEC controller is documented as "AO-CEC-B", thus the
registers will be named "CECB_" to differentiate with the other
AO-CEC driver.

Unlike the other AO-CEC controller, this one takes the Oscillator
clock as input and embeds a dual-divider to provide a precise
32768Hz clock for communication. This is handled by registering
a clock in the driver.

Unlike the other AO-CEC controller, this controller supports setting
up to 15 logical addresses and supports the signal_free_time settings
in the transmit function.

Unfortunately, this controller does not support "monitor" mode.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/Kconfig

@@ -578,6 +578,22 @@ config VIDEO_MESON_AO_CEC
 	  generic CEC framework interface.
 	  CEC bus is present in the HDMI connector and enables communication
 
+config VIDEO_MESON_G12A_AO_CEC
+	tristate "Amlogic Meson G12A AO CEC driver"
+	depends on ARCH_MESON || COMPILE_TEST
+	depends on COMMON_CLK && OF
+	select REGMAP
+	select REGMAP_MMIO
+	select CEC_CORE
+	select CEC_NOTIFIER
+	---help---
+	  This is a driver for Amlogic Meson G12A SoCs AO CEC interface.
+	  This driver if for the new AO-CEC module found in G12A SoCs,
+	  usually named AO_CEC_B in documentation.
+	  It uses the generic CEC framework interface.
+	  CEC bus is present in the HDMI connector and enables communication
+	  between compatible devices.
+
 config CEC_GPIO
 	tristate "Generic GPIO-based CEC driver"
 	depends on PREEMPT || COMPILE_TEST

drivers/media/platform/meson/Makefile

 obj-$(CONFIG_VIDEO_MESON_AO_CEC)	+= ao-cec.o
+obj-$(CONFIG_VIDEO_MESON_G12A_AO_CEC)	+= ao-cec-g12a.o

drivers/media/platform/meson/ao-cec-g12a.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Amlogic Meson AO CEC G12A Controller
+ *
+ * Copyright (C) 2017 Amlogic, Inc. All rights reserved
+ * Copyright (C) 2019 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <media/cec.h>
+#include <media/cec-notifier.h>
+#include <linux/clk-provider.h>
+
+/* CEC Registers */
+
+#define CECB_CLK_CNTL_REG0		0x00
+
+#define CECB_CLK_CNTL_N1		GENMASK(11, 0)
+#define CECB_CLK_CNTL_N2		GENMASK(23, 12)
+#define CECB_CLK_CNTL_DUAL_EN		BIT(28)
+#define CECB_CLK_CNTL_OUTPUT_EN		BIT(30)
+#define CECB_CLK_CNTL_INPUT_EN		BIT(31)
+
+#define CECB_CLK_CNTL_REG1		0x04
+
+#define CECB_CLK_CNTL_M1		GENMASK(11, 0)
+#define CECB_CLK_CNTL_M2		GENMASK(23, 12)
+#define CECB_CLK_CNTL_BYPASS_EN		BIT(24)
+
+/*
+ * [14:12] Filter_del. For glitch-filtering CEC line, ignore signal
+ *       change pulse width < filter_del * T(filter_tick) * 3.
+ * [9:8] Filter_tick_sel: Select which periodical pulse for
+ *       glitch-filtering CEC line signal.
+ *  - 0=Use T(xtal)*3 = 125ns;
+ *  - 1=Use once-per-1us pulse;
+ *  - 2=Use once-per-10us pulse;
+ *  - 3=Use once-per-100us pulse.
+ * [3]   Sysclk_en. 0=Disable system clock; 1=Enable system clock.
+ * [2:1] cntl_clk
+ *  - 0 = Disable clk (Power-off mode)
+ *  - 1 = Enable gated clock (Normal mode)
+ *  - 2 = Enable free-run clk (Debug mode)
+ * [0] SW_RESET 1=Apply reset; 0=No reset.
+ */
+#define CECB_GEN_CNTL_REG		0x08
+
+#define CECB_GEN_CNTL_RESET		BIT(0)
+#define CECB_GEN_CNTL_CLK_DISABLE	0
+#define CECB_GEN_CNTL_CLK_ENABLE	1
+#define CECB_GEN_CNTL_CLK_ENABLE_DBG	2
+#define CECB_GEN_CNTL_CLK_CTRL_MASK	GENMASK(2, 1)
+#define CECB_GEN_CNTL_SYS_CLK_EN	BIT(3)
+#define CECB_GEN_CNTL_FILTER_TICK_125NS	0
+#define CECB_GEN_CNTL_FILTER_TICK_1US	1
+#define CECB_GEN_CNTL_FILTER_TICK_10US	2
+#define CECB_GEN_CNTL_FILTER_TICK_100US	3
+#define CECB_GEN_CNTL_FILTER_TICK_SEL	GENMASK(9, 8)
+#define CECB_GEN_CNTL_FILTER_DEL	GENMASK(14, 12)
+
+/*
+ * [7:0] cec_reg_addr
+ * [15:8] cec_reg_wrdata
+ * [16] cec_reg_wr
+ *  - 0 = Read
+ *  - 1 = Write
+ * [31:24] cec_reg_rddata
+ */
+#define CECB_RW_REG			0x0c
+
+#define CECB_RW_ADDR			GENMASK(7, 0)
+#define CECB_RW_WR_DATA			GENMASK(15, 8)
+#define CECB_RW_WRITE_EN		BIT(16)
+#define CECB_RW_BUS_BUSY		BIT(23)
+#define CECB_RW_RD_DATA			GENMASK(31, 24)
+
+/*
+ * [0] DONE Interrupt
+ * [1] End Of Message Interrupt
+ * [2] Not Acknowlegde Interrupt
+ * [3] Arbitration Loss Interrupt
+ * [4] Initiator Error Interrupt
+ * [5] Follower Error Interrupt
+ * [6] Wake-Up Interrupt
+ */
+#define CECB_INTR_MASKN_REG		0x10
+#define CECB_INTR_CLR_REG		0x14
+#define CECB_INTR_STAT_REG		0x18
+
+#define CECB_INTR_DONE			BIT(0)
+#define CECB_INTR_EOM			BIT(1)
+#define CECB_INTR_NACK			BIT(2)
+#define CECB_INTR_ARB_LOSS		BIT(3)
+#define CECB_INTR_INITIATOR_ERR		BIT(4)
+#define CECB_INTR_FOLLOWER_ERR		BIT(5)
+#define CECB_INTR_WAKE_UP		BIT(6)
+
+/* CEC Commands */
+
+#define CECB_CTRL		0x00
+
+#define CECB_CTRL_SEND		BIT(0)
+#define CECB_CTRL_TYPE		GENMASK(2, 1)
+#define CECB_CTRL_TYPE_RETRY	0
+#define CECB_CTRL_TYPE_NEW	1
+#define CECB_CTRL_TYPE_NEXT	2
+
+#define CECB_CTRL2		0x01
+#define CECB_INTR_MASK		0x02
+#define CECB_LADD_LOW		0x05
+#define CECB_LADD_HIGH		0x06
+#define CECB_TX_CNT		0x07
+#define CECB_RX_CNT		0x08
+#define CECB_STAT0		0x09
+#define CECB_TX_DATA00		0x10
+#define CECB_TX_DATA01		0x11
+#define CECB_TX_DATA02		0x12
+#define CECB_TX_DATA03		0x13
+#define CECB_TX_DATA04		0x14
+#define CECB_TX_DATA05		0x15
+#define CECB_TX_DATA06		0x16
+#define CECB_TX_DATA07		0x17
+#define CECB_TX_DATA08		0x18
+#define CECB_TX_DATA09		0x19
+#define CECB_TX_DATA10		0x1A
+#define CECB_TX_DATA11		0x1B
+#define CECB_TX_DATA12		0x1C
+#define CECB_TX_DATA13		0x1D
+#define CECB_TX_DATA14		0x1E
+#define CECB_TX_DATA15		0x1F
+#define CECB_RX_DATA00		0x20
+#define CECB_RX_DATA01		0x21
+#define CECB_RX_DATA02		0x22
+#define CECB_RX_DATA03		0x23
+#define CECB_RX_DATA04		0x24
+#define CECB_RX_DATA05		0x25
+#define CECB_RX_DATA06		0x26
+#define CECB_RX_DATA07		0x27
+#define CECB_RX_DATA08		0x28
+#define CECB_RX_DATA09		0x29
+#define CECB_RX_DATA10		0x2A
+#define CECB_RX_DATA11		0x2B
+#define CECB_RX_DATA12		0x2C
+#define CECB_RX_DATA13		0x2D
+#define CECB_RX_DATA14		0x2E
+#define CECB_RX_DATA15		0x2F
+#define CECB_LOCK_BUF		0x30
+
+#define CECB_LOCK_BUF_EN	BIT(0)
+
+#define CECB_WAKEUPCTRL		0x31
+
+struct meson_ao_cec_g12a_device {
+	struct platform_device		*pdev;
+	struct regmap			*regmap;
+	struct regmap			*regmap_cec;
+	spinlock_t			cec_reg_lock;
+	struct cec_notifier		*notify;
+	struct cec_adapter		*adap;
+	struct cec_msg			rx_msg;
+	struct clk			*oscin;
+	struct clk			*core;
+};
+
+static const struct regmap_config meson_ao_cec_g12a_regmap_conf = {
+	.reg_bits = 8,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = CECB_INTR_STAT_REG,
+};
+
+/*
+ * The AO-CECB embeds a dual/divider to generate a more precise
+ * 32,768KHz clock for CEC core clock.
+ *                      ______   ______
+ *                     |      | |      |
+ *         ______      | Div1 |-| Cnt1 |       ______
+ *        |      |    /|______| |______|\     |      |
+ * Xtal-->| Gate |---|  ______   ______  X-X--| Gate |-->
+ *        |______| |  \|      | |      |/  |  |______|
+ *                 |   | Div2 |-| Cnt2 |   |
+ *                 |   |______| |______|   |
+ *                 |_______________________|
+ *
+ * The dividing can be switched to single or dual, with a counter
+ * for each divider to set when the switching is done.
+ * The entire dividing mechanism can be also bypassed.
+ */
+
+struct meson_ao_cec_g12a_dualdiv_clk {
+	struct clk_hw hw;
+	struct regmap *regmap;
+};
+
+#define hw_to_meson_ao_cec_g12a_dualdiv_clk(_hw)			\
+	container_of(_hw, struct meson_ao_cec_g12a_dualdiv_clk, hw)	\
+
+static unsigned long
+meson_ao_cec_g12a_dualdiv_clk_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct meson_ao_cec_g12a_dualdiv_clk *dualdiv_clk =
+		hw_to_meson_ao_cec_g12a_dualdiv_clk(hw);
+	unsigned long n1;
+	u32 reg0, reg1;
+
+	regmap_read(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0, &reg0);
+	regmap_read(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0, &reg1);
+
+	if (reg1 & CECB_CLK_CNTL_BYPASS_EN)
+		return parent_rate;
+
+	if (reg0 & CECB_CLK_CNTL_DUAL_EN) {
+		unsigned long n2, m1, m2, f1, f2, p1, p2;
+
+		n1 = FIELD_GET(CECB_CLK_CNTL_N1, reg0) + 1;
+		n2 = FIELD_GET(CECB_CLK_CNTL_N2, reg0) + 1;
+
+		m1 = FIELD_GET(CECB_CLK_CNTL_M1, reg1) + 1;
+		m2 = FIELD_GET(CECB_CLK_CNTL_M1, reg1) + 1;
+
+		f1 = DIV_ROUND_CLOSEST(parent_rate, n1);
+		f2 = DIV_ROUND_CLOSEST(parent_rate, n2);
+
+		p1 = DIV_ROUND_CLOSEST(100000000 * m1, f1 * (m1 + m2));
+		p2 = DIV_ROUND_CLOSEST(100000000 * m2, f2 * (m1 + m2));
+
+		return DIV_ROUND_UP(100000000, p1 + p2);
+	}
+
+	n1 = FIELD_GET(CECB_CLK_CNTL_N1, reg0) + 1;
+
+	return DIV_ROUND_CLOSEST(parent_rate, n1);
+}
+
+static int meson_ao_cec_g12a_dualdiv_clk_enable(struct clk_hw *hw)
+{
+	struct meson_ao_cec_g12a_dualdiv_clk *dualdiv_clk =
+		hw_to_meson_ao_cec_g12a_dualdiv_clk(hw);
+
+
+	/* Disable Input & Output */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_INPUT_EN | CECB_CLK_CNTL_OUTPUT_EN,
+			   0);
+
+	/* Set N1 & N2 */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_N1,
+			   FIELD_PREP(CECB_CLK_CNTL_N1, 733 - 1));
+
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_N2,
+			   FIELD_PREP(CECB_CLK_CNTL_N2, 732 - 1));
+
+	/* Set M1 & M2 */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG1,
+			   CECB_CLK_CNTL_M1,
+			   FIELD_PREP(CECB_CLK_CNTL_M1, 8 - 1));
+
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG1,
+			   CECB_CLK_CNTL_M2,
+			   FIELD_PREP(CECB_CLK_CNTL_M2, 11 - 1));
+
+	/* Enable Dual divisor */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_DUAL_EN, CECB_CLK_CNTL_DUAL_EN);
+
+	/* Disable divisor bypass */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG1,
+			   CECB_CLK_CNTL_BYPASS_EN, 0);
+
+	/* Enable Input & Output */
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_INPUT_EN | CECB_CLK_CNTL_OUTPUT_EN,
+			   CECB_CLK_CNTL_INPUT_EN | CECB_CLK_CNTL_OUTPUT_EN);
+
+	return 0;
+}
+
+static void meson_ao_cec_g12a_dualdiv_clk_disable(struct clk_hw *hw)
+{
+	struct meson_ao_cec_g12a_dualdiv_clk *dualdiv_clk =
+		hw_to_meson_ao_cec_g12a_dualdiv_clk(hw);
+
+	regmap_update_bits(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0,
+			   CECB_CLK_CNTL_INPUT_EN | CECB_CLK_CNTL_OUTPUT_EN,
+			   0);
+}
+
+static int meson_ao_cec_g12a_dualdiv_clk_is_enabled(struct clk_hw *hw)
+{
+	struct meson_ao_cec_g12a_dualdiv_clk *dualdiv_clk =
+		hw_to_meson_ao_cec_g12a_dualdiv_clk(hw);
+	int val;
+
+	regmap_read(dualdiv_clk->regmap, CECB_CLK_CNTL_REG0, &val);
+
+	return !!(val & (CECB_CLK_CNTL_INPUT_EN | CECB_CLK_CNTL_OUTPUT_EN));
+}
+
+static const struct clk_ops meson_ao_cec_g12a_dualdiv_clk_ops = {
+	.recalc_rate	= meson_ao_cec_g12a_dualdiv_clk_recalc_rate,
+	.is_enabled	= meson_ao_cec_g12a_dualdiv_clk_is_enabled,
+	.enable		= meson_ao_cec_g12a_dualdiv_clk_enable,
+	.disable	= meson_ao_cec_g12a_dualdiv_clk_disable,
+};
+
+static int meson_ao_cec_g12a_setup_clk(struct meson_ao_cec_g12a_device *ao_cec)
+{
+	struct meson_ao_cec_g12a_dualdiv_clk *dualdiv_clk;
+	struct device *dev = &ao_cec->pdev->dev;
+	struct clk_init_data init;
+	const char *parent_name;
+	struct clk *clk;
+	char *name;
+
+	dualdiv_clk = devm_kzalloc(dev, sizeof(*dualdiv_clk), GFP_KERNEL);
+	if (!dualdiv_clk)
+		return -ENOMEM;
+
+	name = kasprintf(GFP_KERNEL, "%s#dualdiv_clk", dev_name(dev));
+	if (!name)
+		return -ENOMEM;
+
+	parent_name = __clk_get_name(ao_cec->oscin);
+
+	init.name = name;
+	init.ops = &meson_ao_cec_g12a_dualdiv_clk_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	dualdiv_clk->regmap = ao_cec->regmap;
+	dualdiv_clk->hw.init = &init;
+
+	clk = devm_clk_register(dev, &dualdiv_clk->hw);
+	kfree(name);
+	if (IS_ERR(clk)) {
+		dev_err(dev, "failed to register clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ao_cec->core = clk;
+
+	return 0;
+}
+
+static int meson_ao_cec_g12a_read(void *context, unsigned int addr,
+				  unsigned int *data)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = context;
+	u32 reg = FIELD_PREP(CECB_RW_ADDR, addr);
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&ao_cec->cec_reg_lock, flags);
+
+	ret = regmap_write(ao_cec->regmap, CECB_RW_REG, reg);
+	if (ret)
+		goto read_out;
+
+	ret = regmap_read_poll_timeout(ao_cec->regmap, CECB_RW_REG, reg,
+				       !(reg & CECB_RW_BUS_BUSY),
+				       5, 1000);
+	if (ret)
+		goto read_out;
+
+	ret = regmap_read(ao_cec->regmap, CECB_RW_REG, &reg);
+
+	*data = FIELD_GET(CECB_RW_RD_DATA, reg);
+
+read_out:
+	spin_unlock_irqrestore(&ao_cec->cec_reg_lock, flags);
+
+	return ret;
+}
+
+static int meson_ao_cec_g12a_write(void *context, unsigned int addr,
+				   unsigned int data)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = context;
+	unsigned long flags;
+	u32 reg = FIELD_PREP(CECB_RW_ADDR, addr) |
+		  FIELD_PREP(CECB_RW_WR_DATA, data) |
+		  CECB_RW_WRITE_EN;
+	int ret = 0;
+
+	spin_lock_irqsave(&ao_cec->cec_reg_lock, flags);
+
+	ret = regmap_write(ao_cec->regmap, CECB_RW_REG, reg);
+
+	spin_unlock_irqrestore(&ao_cec->cec_reg_lock, flags);
+
+	return ret;
+}
+
+static const struct regmap_config meson_ao_cec_g12a_cec_regmap_conf = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.reg_read = meson_ao_cec_g12a_read,
+	.reg_write = meson_ao_cec_g12a_write,
+	.max_register = 0xffff,
+	.fast_io = true,
+};
+
+static inline void
+meson_ao_cec_g12a_irq_setup(struct meson_ao_cec_g12a_device *ao_cec,
+			    bool enable)
+{
+	u32 cfg = CECB_INTR_DONE | CECB_INTR_EOM | CECB_INTR_NACK |
+		  CECB_INTR_ARB_LOSS | CECB_INTR_INITIATOR_ERR |
+		  CECB_INTR_FOLLOWER_ERR;
+
+	regmap_write(ao_cec->regmap, CECB_INTR_MASKN_REG,
+		     enable ? cfg : 0);
+}
+
+static void meson_ao_cec_g12a_irq_rx(struct meson_ao_cec_g12a_device *ao_cec)
+{
+	int i, ret = 0;
+	u32 val;
+
+	ret = regmap_read(ao_cec->regmap_cec, CECB_RX_CNT, &val);
+
+	ao_cec->rx_msg.len = val;
+	if (ao_cec->rx_msg.len > CEC_MAX_MSG_SIZE)
+		ao_cec->rx_msg.len = CEC_MAX_MSG_SIZE;
+
+	for (i = 0; i < ao_cec->rx_msg.len; i++) {
+		ret |= regmap_read(ao_cec->regmap_cec,
+				   CECB_RX_DATA00 + i, &val);
+
+		ao_cec->rx_msg.msg[i] = val & 0xff;
+	}
+
+	ret |= regmap_write(ao_cec->regmap_cec, CECB_LOCK_BUF, 0);
+	if (ret)
+		return;
+
+	cec_received_msg(ao_cec->adap, &ao_cec->rx_msg);
+}
+
+static irqreturn_t meson_ao_cec_g12a_irq(int irq, void *data)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = data;
+	u32 stat;
+
+	regmap_read(ao_cec->regmap, CECB_INTR_STAT_REG, &stat);
+	if (stat)
+		return IRQ_WAKE_THREAD;
+
+	return IRQ_NONE;
+}
+
+static irqreturn_t meson_ao_cec_g12a_irq_thread(int irq, void *data)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = data;
+	u32 stat;
+
+	regmap_read(ao_cec->regmap, CECB_INTR_STAT_REG, &stat);
+	regmap_write(ao_cec->regmap, CECB_INTR_CLR_REG, stat);
+
+	if (stat & CECB_INTR_DONE)
+		cec_transmit_attempt_done(ao_cec->adap, CEC_TX_STATUS_OK);
+
+	if (stat & CECB_INTR_EOM)
+		meson_ao_cec_g12a_irq_rx(ao_cec);
+
+	if (stat & CECB_INTR_NACK)
+		cec_transmit_attempt_done(ao_cec->adap, CEC_TX_STATUS_NACK);
+
+	if (stat & CECB_INTR_ARB_LOSS) {
+		regmap_write(ao_cec->regmap_cec, CECB_TX_CNT, 0);
+		regmap_update_bits(ao_cec->regmap_cec, CECB_CTRL,
+				   CECB_CTRL_SEND | CECB_CTRL_TYPE, 0);
+		cec_transmit_attempt_done(ao_cec->adap, CEC_TX_STATUS_ARB_LOST);
+	}
+
+	/* Initiator reports an error on the CEC bus */
+	if (stat & CECB_INTR_INITIATOR_ERR)
+		cec_transmit_attempt_done(ao_cec->adap, CEC_TX_STATUS_ERROR);
+
+	/* Follower reports a receive error, just reset RX buffer */
+	if (stat & CECB_INTR_FOLLOWER_ERR)
+		regmap_write(ao_cec->regmap_cec, CECB_LOCK_BUF, 0);
+
+	return IRQ_HANDLED;
+}
+
+static int
+meson_ao_cec_g12a_set_log_addr(struct cec_adapter *adap, u8 logical_addr)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = adap->priv;
+	int ret = 0;
+
+	if (logical_addr == CEC_LOG_ADDR_INVALID) {
+		/* Assume this will allways succeed */
+		regmap_write(ao_cec->regmap_cec, CECB_LADD_LOW, 0);
+		regmap_write(ao_cec->regmap_cec, CECB_LADD_HIGH, 0);
+
+		return 0;
+	} else if (logical_addr < 8) {
+		ret = regmap_update_bits(ao_cec->regmap_cec, CECB_LADD_LOW,
+					 BIT(logical_addr),
+					 BIT(logical_addr));
+	} else {
+		ret = regmap_update_bits(ao_cec->regmap_cec, CECB_LADD_HIGH,
+					 BIT(logical_addr - 8),
+					 BIT(logical_addr - 8));
+	}
+
+	/* Always set Broadcast/Unregistered 15 address */
+	ret |= regmap_update_bits(ao_cec->regmap_cec, CECB_LADD_HIGH,
+				  BIT(CEC_LOG_ADDR_UNREGISTERED - 8),
+				  BIT(CEC_LOG_ADDR_UNREGISTERED - 8));
+
+	return ret ? -EIO : 0;
+}
+
+static int meson_ao_cec_g12a_transmit(struct cec_adapter *adap, u8 attempts,
+				 u32 signal_free_time, struct cec_msg *msg)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = adap->priv;
+	unsigned int type;
+	int ret = 0;
+	u32 val;
+	int i;
+
+	/* Check if RX is in progress */
+	ret = regmap_read(ao_cec->regmap_cec, CECB_LOCK_BUF, &val);
+	if (ret)
+		return ret;
+	if (val & CECB_LOCK_BUF_EN)
+		return -EBUSY;
+
+	/* Check if TX Busy */
+	ret = regmap_read(ao_cec->regmap_cec, CECB_CTRL, &val);
+	if (ret)
+		return ret;
+	if (val & CECB_CTRL_SEND)
+		return -EBUSY;
+
+	switch (signal_free_time) {
+	case CEC_SIGNAL_FREE_TIME_RETRY:
+		type = CECB_CTRL_TYPE_RETRY;
+		break;
+	case CEC_SIGNAL_FREE_TIME_NEXT_XFER:
+		type = CECB_CTRL_TYPE_NEXT;
+		break;
+	case CEC_SIGNAL_FREE_TIME_NEW_INITIATOR:
+	default:
+		type = CECB_CTRL_TYPE_NEW;
+		break;
+	}
+
+	for (i = 0; i < msg->len; i++)
+		ret |= regmap_write(ao_cec->regmap_cec, CECB_TX_DATA00 + i,
+				    msg->msg[i]);
+
+	ret |= regmap_write(ao_cec->regmap_cec, CECB_TX_CNT, msg->len);
+	if (ret)
+		return -EIO;
+
+	ret = regmap_update_bits(ao_cec->regmap_cec, CECB_CTRL,
+				 CECB_CTRL_SEND |
+				 CECB_CTRL_TYPE,
+				 CECB_CTRL_SEND |
+				 FIELD_PREP(CECB_CTRL_TYPE, type));
+
+	return ret;
+}
+
+static int meson_ao_cec_g12a_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = adap->priv;
+
+	meson_ao_cec_g12a_irq_setup(ao_cec, false);
+
+	regmap_update_bits(ao_cec->regmap, CECB_GEN_CNTL_REG,
+			   CECB_GEN_CNTL_RESET, CECB_GEN_CNTL_RESET);
+
+	if (!enable)
+		return 0;
+
+	/* Setup Filter */
+	regmap_update_bits(ao_cec->regmap, CECB_GEN_CNTL_REG,
+			   CECB_GEN_CNTL_FILTER_TICK_SEL |
+			   CECB_GEN_CNTL_FILTER_DEL,
+			   FIELD_PREP(CECB_GEN_CNTL_FILTER_TICK_SEL,
+				      CECB_GEN_CNTL_FILTER_TICK_1US) |
+			   FIELD_PREP(CECB_GEN_CNTL_FILTER_DEL, 7));
+
+	/* Enable System Clock */
+	regmap_update_bits(ao_cec->regmap, CECB_GEN_CNTL_REG,
+			   CECB_GEN_CNTL_SYS_CLK_EN,
+			   CECB_GEN_CNTL_SYS_CLK_EN);
+
+	/* Enable gated clock (Normal mode). */
+	regmap_update_bits(ao_cec->regmap, CECB_GEN_CNTL_REG,
+			   CECB_GEN_CNTL_CLK_CTRL_MASK,
+			    FIELD_PREP(CECB_GEN_CNTL_CLK_CTRL_MASK,
+				       CECB_GEN_CNTL_CLK_ENABLE));
+
+	/* Release Reset */
+	regmap_update_bits(ao_cec->regmap, CECB_GEN_CNTL_REG,
+			   CECB_GEN_CNTL_RESET, 0);
+
+	meson_ao_cec_g12a_irq_setup(ao_cec, true);
+
+	return 0;
+}
+
+static const struct cec_adap_ops meson_ao_cec_g12a_ops = {
+	.adap_enable = meson_ao_cec_g12a_adap_enable,
+	.adap_log_addr = meson_ao_cec_g12a_set_log_addr,
+	.adap_transmit = meson_ao_cec_g12a_transmit,
+};
+
+static int meson_ao_cec_g12a_probe(struct platform_device *pdev)
+{
+	struct meson_ao_cec_g12a_device *ao_cec;
+	struct device *hdmi_dev;
+	struct resource *res;
+	void __iomem *base;
+	int ret, irq;
+
+	hdmi_dev = cec_notifier_parse_hdmi_phandle(&pdev->dev);
+	if (IS_ERR(hdmi_dev))
+		return PTR_ERR(hdmi_dev);
+
+	ao_cec = devm_kzalloc(&pdev->dev, sizeof(*ao_cec), GFP_KERNEL);
+	if (!ao_cec)
+		return -ENOMEM;
+
+	spin_lock_init(&ao_cec->cec_reg_lock);
+	ao_cec->pdev = pdev;
+
+	ao_cec->notify = cec_notifier_get(hdmi_dev);
+	if (!ao_cec->notify)
+		return -ENOMEM;
+
+	ao_cec->adap = cec_allocate_adapter(&meson_ao_cec_g12a_ops, ao_cec,
+					    "meson_g12a_ao_cec",
+					    CEC_CAP_DEFAULTS,
+					    CEC_MAX_LOG_ADDRS);
+	if (IS_ERR(ao_cec->adap)) {
+		ret = PTR_ERR(ao_cec->adap);
+		goto out_probe_notify;
+	}
+
+	ao_cec->adap->owner = THIS_MODULE;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base)) {
+		ret = PTR_ERR(base);
+		goto out_probe_adapter;
+	}
+
+	ao_cec->regmap = devm_regmap_init_mmio(&pdev->dev, base,
+					       &meson_ao_cec_g12a_regmap_conf);
+	if (IS_ERR(ao_cec->regmap)) {
+		ret = PTR_ERR(ao_cec->regmap);
+		goto out_probe_adapter;
+	}
+
+	ao_cec->regmap_cec = devm_regmap_init(&pdev->dev, NULL, ao_cec,
+					   &meson_ao_cec_g12a_cec_regmap_conf);
+	if (IS_ERR(ao_cec->regmap_cec)) {
+		ret = PTR_ERR(ao_cec->regmap_cec);
+		goto out_probe_adapter;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_threaded_irq(&pdev->dev, irq,
+					meson_ao_cec_g12a_irq,
+					meson_ao_cec_g12a_irq_thread,
+					0, NULL, ao_cec);
+	if (ret) {
+		dev_err(&pdev->dev, "irq request failed\n");
+		goto out_probe_adapter;
+	}
+
+	ao_cec->oscin = devm_clk_get(&pdev->dev, "oscin");
+	if (IS_ERR(ao_cec->oscin)) {
+		dev_err(&pdev->dev, "oscin clock request failed\n");
+		ret = PTR_ERR(ao_cec->oscin);
+		goto out_probe_adapter;
+	}
+
+	ret = meson_ao_cec_g12a_setup_clk(ao_cec);
+	if (ret)
+		goto out_probe_adapter;
+
+	ret = clk_prepare_enable(ao_cec->core);
+	if (ret) {
+		dev_err(&pdev->dev, "core clock enable failed\n");
+		goto out_probe_adapter;
+	}
+
+	device_reset_optional(&pdev->dev);
+
+	platform_set_drvdata(pdev, ao_cec);
+
+	ret = cec_register_adapter(ao_cec->adap, &pdev->dev);
+	if (ret < 0) {
+		cec_notifier_put(ao_cec->notify);
+		goto out_probe_core_clk;
+	}
+
+	/* Setup Hardware */
+	regmap_write(ao_cec->regmap, CECB_GEN_CNTL_REG, CECB_GEN_CNTL_RESET);
+
+	cec_register_cec_notifier(ao_cec->adap, ao_cec->notify);
+
+	return 0;
+
+out_probe_core_clk:
+	clk_disable_unprepare(ao_cec->core);
+
+out_probe_adapter:
+	cec_delete_adapter(ao_cec->adap);
+
+out_probe_notify:
+	cec_notifier_put(ao_cec->notify);
+
+	dev_err(&pdev->dev, "CEC controller registration failed\n");
+
+	return ret;
+}
+
+static int meson_ao_cec_g12a_remove(struct platform_device *pdev)
+{
+	struct meson_ao_cec_g12a_device *ao_cec = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(ao_cec->core);
+
+	cec_unregister_adapter(ao_cec->adap);
+
+	cec_notifier_put(ao_cec->notify);
+
+	return 0;
+}
+
+static const struct of_device_id meson_ao_cec_g12a_of_match[] = {
+	{ .compatible = "amlogic,meson-g12a-ao-cec", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_ao_cec_g12a_of_match);
+
+static struct platform_driver meson_ao_cec_g12a_driver = {
+	.probe   = meson_ao_cec_g12a_probe,
+	.remove  = meson_ao_cec_g12a_remove,
+	.driver  = {
+		.name = "meson-ao-cec-g12a",
+		.of_match_table = of_match_ptr(meson_ao_cec_g12a_of_match),
+	},
+};
+
+module_platform_driver(meson_ao_cec_g12a_driver);
+
+MODULE_DESCRIPTION("Meson AO CEC G12A Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("GPL");