1 files changed, 321 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
new file mode 100644
index 000000000..58e9d37e8
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
@@ -0,0 +1,321 @@
+/*
+ * Copyright (C) 2016 Maxime Ripard <maxime.ripard@free-electrons.com>
+ * Copyright (C) 2017 Jonathan Liu <net147@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/i2c.h>
+#include <linux/iopoll.h>
+
+#include "sun4i_hdmi.h"
+
+#define SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK ( \
+	SUN4I_HDMI_DDC_INT_STATUS_ILLEGAL_FIFO_OPERATION | \
+	SUN4I_HDMI_DDC_INT_STATUS_DDC_RX_FIFO_UNDERFLOW | \
+	SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW | \
+	SUN4I_HDMI_DDC_INT_STATUS_ARBITRATION_ERROR | \
+	SUN4I_HDMI_DDC_INT_STATUS_ACK_ERROR | \
+	SUN4I_HDMI_DDC_INT_STATUS_BUS_ERROR \
+)
+
+/* FIFO request bit is set when FIFO level is above RX_THRESHOLD during read */
+#define RX_THRESHOLD SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES_MAX
+
+static int fifo_transfer(struct sun4i_hdmi *hdmi, u8 *buf, int len, bool read)
+{
+	/*
+	 * 1 byte takes 9 clock cycles (8 bits + 1 ACK) = 90 us for 100 kHz
+	 * clock. As clock rate is fixed, just round it up to 100 us.
+	 */
+	const unsigned long byte_time_ns = 100;
+	const u32 mask = SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK |
+			 SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST |
+			 SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE;
+	u32 reg;
+	/*
+	 * If threshold is inclusive, then the FIFO may only have
+	 * RX_THRESHOLD number of bytes, instead of RX_THRESHOLD + 1.
+	 */
+	int read_len = RX_THRESHOLD +
+		(hdmi->variant->ddc_fifo_thres_incl ? 0 : 1);
+
+	/*
+	 * Limit transfer length by FIFO threshold or FIFO size.
+	 * For TX the threshold is for an empty FIFO.
+	 */
+	len = min_t(int, len, read ? read_len : SUN4I_HDMI_DDC_FIFO_SIZE);
+
+	/* Wait until error, FIFO request bit set or transfer complete */
+	if (regmap_field_read_poll_timeout(hdmi->field_ddc_int_status, reg,
+					   reg & mask, len * byte_time_ns,
+					   100000))
+		return -ETIMEDOUT;
+
+	if (reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK)
+		return -EIO;
+
+	if (read)
+		readsb(hdmi->base + hdmi->variant->ddc_fifo_reg, buf, len);
+	else
+		writesb(hdmi->base + hdmi->variant->ddc_fifo_reg, buf, len);
+
+	/* Clear FIFO request bit by forcing a write to that bit */
+	regmap_field_force_write(hdmi->field_ddc_int_status,
+				 SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST);
+
+	return len;
+}
+
+static int xfer_msg(struct sun4i_hdmi *hdmi, struct i2c_msg *msg)
+{
+	int i, len;
+	u32 reg;
+
+	/* Set FIFO direction */
+	if (hdmi->variant->ddc_fifo_has_dir) {
+		reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+		reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
+		reg |= (msg->flags & I2C_M_RD) ?
+		       SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ :
+		       SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE;
+		writel(reg, hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+	}
+
+	/* Clear address register (not cleared by soft reset) */
+	regmap_field_write(hdmi->field_ddc_addr_reg, 0);
+
+	/* Set I2C address */
+	regmap_field_write(hdmi->field_ddc_slave_addr, msg->addr);
+
+	/*
+	 * Set FIFO RX/TX thresholds and clear FIFO
+	 *
+	 * If threshold is inclusive, we can set the TX threshold to
+	 * 0 instead of 1.
+	 */
+	regmap_field_write(hdmi->field_ddc_fifo_tx_thres,
+			   hdmi->variant->ddc_fifo_thres_incl ? 0 : 1);
+	regmap_field_write(hdmi->field_ddc_fifo_rx_thres, RX_THRESHOLD);
+	regmap_field_write(hdmi->field_ddc_fifo_clear, 1);
+	if (regmap_field_read_poll_timeout(hdmi->field_ddc_fifo_clear,
+					   reg, !reg, 100, 2000))
+		return -EIO;
+
+	/* Set transfer length */
+	regmap_field_write(hdmi->field_ddc_byte_count, msg->len);
+
+	/* Set command */
+	regmap_field_write(hdmi->field_ddc_cmd,
+			   msg->flags & I2C_M_RD ?
+			   SUN4I_HDMI_DDC_CMD_IMPLICIT_READ :
+			   SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE);
+
+	/* Clear interrupt status bits by forcing a write */
+	regmap_field_force_write(hdmi->field_ddc_int_status,
+				 SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK |
+				 SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST |
+				 SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE);
+
+	/* Start command */
+	regmap_field_write(hdmi->field_ddc_start, 1);
+
+	/* Transfer bytes */
+	for (i = 0; i < msg->len; i += len) {
+		len = fifo_transfer(hdmi, msg->buf + i, msg->len - i,
+				    msg->flags & I2C_M_RD);
+		if (len <= 0)
+			return len;
+	}
+
+	/* Wait for command to finish */
+	if (regmap_field_read_poll_timeout(hdmi->field_ddc_start,
+					   reg, !reg, 100, 100000))
+		return -EIO;
+
+	/* Check for errors */
+	regmap_field_read(hdmi->field_ddc_int_status, &reg);
+	if ((reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK) ||
+	    !(reg & SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE)) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int sun4i_hdmi_i2c_xfer(struct i2c_adapter *adap,
+			       struct i2c_msg *msgs, int num)
+{
+	struct sun4i_hdmi *hdmi = i2c_get_adapdata(adap);
+	u32 reg;
+	int err, i, ret = num;
+
+	for (i = 0; i < num; i++) {
+		if (!msgs[i].len)
+			return -EINVAL;
+		if (msgs[i].len > SUN4I_HDMI_DDC_BYTE_COUNT_MAX)
+			return -EINVAL;
+	}
+
+	/* DDC clock needs to be enabled for the module to work */
+	clk_prepare_enable(hdmi->ddc_clk);
+	clk_set_rate(hdmi->ddc_clk, 100000);
+
+	/* Reset I2C controller */
+	regmap_field_write(hdmi->field_ddc_en, 1);
+	regmap_field_write(hdmi->field_ddc_reset, 1);
+	if (regmap_field_read_poll_timeout(hdmi->field_ddc_reset,
+					   reg, !reg, 100, 2000)) {
+		clk_disable_unprepare(hdmi->ddc_clk);
+		return -EIO;
+	}
+
+	regmap_field_write(hdmi->field_ddc_sck_en, 1);
+	regmap_field_write(hdmi->field_ddc_sda_en, 1);
+
+	for (i = 0; i < num; i++) {
+		err = xfer_msg(hdmi, &msgs[i]);
+		if (err) {
+			ret = err;
+			break;
+		}
+	}
+
+	clk_disable_unprepare(hdmi->ddc_clk);
+	return ret;
+}
+
+static u32 sun4i_hdmi_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm sun4i_hdmi_i2c_algorithm = {
+	.master_xfer	= sun4i_hdmi_i2c_xfer,
+	.functionality	= sun4i_hdmi_i2c_func,
+};
+
+static int sun4i_hdmi_init_regmap_fields(struct sun4i_hdmi *hdmi)
+{
+	hdmi->field_ddc_en =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_en);
+	if (IS_ERR(hdmi->field_ddc_en))
+		return PTR_ERR(hdmi->field_ddc_en);
+
+	hdmi->field_ddc_start =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_start);
+	if (IS_ERR(hdmi->field_ddc_start))
+		return PTR_ERR(hdmi->field_ddc_start);
+
+	hdmi->field_ddc_reset =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_reset);
+	if (IS_ERR(hdmi->field_ddc_reset))
+		return PTR_ERR(hdmi->field_ddc_reset);
+
+	hdmi->field_ddc_addr_reg =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_addr_reg);
+	if (IS_ERR(hdmi->field_ddc_addr_reg))
+		return PTR_ERR(hdmi->field_ddc_addr_reg);
+
+	hdmi->field_ddc_slave_addr =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_slave_addr);
+	if (IS_ERR(hdmi->field_ddc_slave_addr))
+		return PTR_ERR(hdmi->field_ddc_slave_addr);
+
+	hdmi->field_ddc_int_mask =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_int_mask);
+	if (IS_ERR(hdmi->field_ddc_int_mask))
+		return PTR_ERR(hdmi->field_ddc_int_mask);
+
+	hdmi->field_ddc_int_status =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_int_status);
+	if (IS_ERR(hdmi->field_ddc_int_status))
+		return PTR_ERR(hdmi->field_ddc_int_status);
+
+	hdmi->field_ddc_fifo_clear =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_fifo_clear);
+	if (IS_ERR(hdmi->field_ddc_fifo_clear))
+		return PTR_ERR(hdmi->field_ddc_fifo_clear);
+
+	hdmi->field_ddc_fifo_rx_thres =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_fifo_rx_thres);
+	if (IS_ERR(hdmi->field_ddc_fifo_rx_thres))
+		return PTR_ERR(hdmi->field_ddc_fifo_rx_thres);
+
+	hdmi->field_ddc_fifo_tx_thres =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_fifo_tx_thres);
+	if (IS_ERR(hdmi->field_ddc_fifo_tx_thres))
+		return PTR_ERR(hdmi->field_ddc_fifo_tx_thres);
+
+	hdmi->field_ddc_byte_count =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_byte_count);
+	if (IS_ERR(hdmi->field_ddc_byte_count))
+		return PTR_ERR(hdmi->field_ddc_byte_count);
+
+	hdmi->field_ddc_cmd =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_cmd);
+	if (IS_ERR(hdmi->field_ddc_cmd))
+		return PTR_ERR(hdmi->field_ddc_cmd);
+
+	hdmi->field_ddc_sda_en =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_sda_en);
+	if (IS_ERR(hdmi->field_ddc_sda_en))
+		return PTR_ERR(hdmi->field_ddc_sda_en);
+
+	hdmi->field_ddc_sck_en =
+		devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					hdmi->variant->field_ddc_sck_en);
+	if (IS_ERR(hdmi->field_ddc_sck_en))
+		return PTR_ERR(hdmi->field_ddc_sck_en);
+
+	return 0;
+}
+
+int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi)
+{
+	struct i2c_adapter *adap;
+	int ret = 0;
+
+	ret = sun4i_ddc_create(hdmi, hdmi->ddc_parent_clk);
+	if (ret)
+		return ret;
+
+	ret = sun4i_hdmi_init_regmap_fields(hdmi);
+	if (ret)
+		return ret;
+
+	adap = devm_kzalloc(dev, sizeof(*adap), GFP_KERNEL);
+	if (!adap)
+		return -ENOMEM;
+
+	adap->owner = THIS_MODULE;
+	adap->class = I2C_CLASS_DDC;
+	adap->algo = &sun4i_hdmi_i2c_algorithm;
+	strlcpy(adap->name, "sun4i_hdmi_i2c adapter", sizeof(adap->name));
+	i2c_set_adapdata(adap, hdmi);
+
+	ret = i2c_add_adapter(adap);
+	if (ret)
+		return ret;
+
+	hdmi->i2c = adap;
+
+	return ret;
+}