Contributors: 5
Author Tokens Token Proportion Commits Commit Proportion
Niklas Söderlund 2138 99.77% 2 28.57%
Uwe Kleine-König 2 0.09% 2 28.57%
Ihor Matushchak 1 0.05% 1 14.29%
Rikard Falkeborn 1 0.05% 1 14.29%
Laurent Pinchart 1 0.05% 1 14.29%
Total 2143 7 


// SPDX-License-Identifier: GPL-2.0
/*
 * Maxim MAX96712 Quad GMSL2 Deserializer Driver
 *
 * Copyright (C) 2021 Renesas Electronics Corporation
 * Copyright (C) 2021 Niklas Söderlund
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of_graph.h>
#include <linux/regmap.h>

#include <media/v4l2-ctrls.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>

#define MAX96712_ID 0x20

#define MAX96712_DPLL_FREQ 1000

enum max96712_pattern {
	MAX96712_PATTERN_CHECKERBOARD = 0,
	MAX96712_PATTERN_GRADIENT,
};

struct max96712_priv {
	struct i2c_client *client;
	struct regmap *regmap;
	struct gpio_desc *gpiod_pwdn;

	bool cphy;
	struct v4l2_mbus_config_mipi_csi2 mipi;

	struct v4l2_subdev sd;
	struct v4l2_ctrl_handler ctrl_handler;
	struct media_pad pads[1];

	enum max96712_pattern pattern;
};

static int max96712_read(struct max96712_priv *priv, int reg)
{
	int ret, val;

	ret = regmap_read(priv->regmap, reg, &val);
	if (ret) {
		dev_err(&priv->client->dev, "read 0x%04x failed\n", reg);
		return ret;
	}

	return val;
}

static int max96712_write(struct max96712_priv *priv, unsigned int reg, u8 val)
{
	int ret;

	ret = regmap_write(priv->regmap, reg, val);
	if (ret)
		dev_err(&priv->client->dev, "write 0x%04x failed\n", reg);

	return ret;
}

static int max96712_update_bits(struct max96712_priv *priv, unsigned int reg,
				u8 mask, u8 val)
{
	int ret;

	ret = regmap_update_bits(priv->regmap, reg, mask, val);
	if (ret)
		dev_err(&priv->client->dev, "update 0x%04x failed\n", reg);

	return ret;
}

static int max96712_write_bulk(struct max96712_priv *priv, unsigned int reg,
			       const void *val, size_t val_count)
{
	int ret;

	ret = regmap_bulk_write(priv->regmap, reg, val, val_count);
	if (ret)
		dev_err(&priv->client->dev, "bulk write 0x%04x failed\n", reg);

	return ret;
}

static int max96712_write_bulk_value(struct max96712_priv *priv,
				     unsigned int reg, unsigned int val,
				     size_t val_count)
{
	unsigned int i;
	u8 values[4];

	for (i = 1; i <= val_count; i++)
		values[i - 1] = (val >> ((val_count - i) * 8)) & 0xff;

	return max96712_write_bulk(priv, reg, &values, val_count);
}

static void max96712_reset(struct max96712_priv *priv)
{
	max96712_update_bits(priv, 0x13, 0x40, 0x40);
	msleep(20);
}

static void max96712_mipi_enable(struct max96712_priv *priv, bool enable)
{
	if (enable) {
		max96712_update_bits(priv, 0x40b, 0x02, 0x02);
		max96712_update_bits(priv, 0x8a0, 0x80, 0x80);
	} else {
		max96712_update_bits(priv, 0x8a0, 0x80, 0x00);
		max96712_update_bits(priv, 0x40b, 0x02, 0x00);
	}
}

static void max96712_mipi_configure(struct max96712_priv *priv)
{
	unsigned int i;
	u8 phy5 = 0;

	max96712_mipi_enable(priv, false);

	/* Select 2x4 mode. */
	max96712_write(priv, 0x8a0, 0x04);

	/* TODO: Add support for 2-lane and 1-lane configurations. */
	if (priv->cphy) {
		/* Configure a 3-lane C-PHY using PHY0 and PHY1. */
		max96712_write(priv, 0x94a, 0xa0);

		/* Configure C-PHY timings. */
		max96712_write(priv, 0x8ad, 0x3f);
		max96712_write(priv, 0x8ae, 0x7d);
	} else {
		/* Configure a 4-lane D-PHY using PHY0 and PHY1. */
		max96712_write(priv, 0x94a, 0xc0);
	}

	/* Configure lane mapping for PHY0 and PHY1. */
	/* TODO: Add support for lane swapping. */
	max96712_write(priv, 0x8a3, 0xe4);

	/* Configure lane polarity for PHY0 and PHY1. */
	for (i = 0; i < priv->mipi.num_data_lanes + 1; i++)
		if (priv->mipi.lane_polarities[i])
			phy5 |= BIT(i == 0 ? 5 : i < 3 ? i - 1 : i);
	max96712_write(priv, 0x8a5, phy5);

	/* Set link frequency for PHY0 and PHY1. */
	max96712_update_bits(priv, 0x415, 0x3f,
			     ((MAX96712_DPLL_FREQ / 100) & 0x1f) | BIT(5));
	max96712_update_bits(priv, 0x418, 0x3f,
			     ((MAX96712_DPLL_FREQ / 100) & 0x1f) | BIT(5));

	/* Enable PHY0 and PHY1 */
	max96712_update_bits(priv, 0x8a2, 0xf0, 0x30);
}

static void max96712_pattern_enable(struct max96712_priv *priv, bool enable)
{
	const u32 h_active = 1920;
	const u32 h_fp = 88;
	const u32 h_sw = 44;
	const u32 h_bp = 148;
	const u32 h_tot = h_active + h_fp + h_sw + h_bp;

	const u32 v_active = 1080;
	const u32 v_fp = 4;
	const u32 v_sw = 5;
	const u32 v_bp = 36;
	const u32 v_tot = v_active + v_fp + v_sw + v_bp;

	if (!enable) {
		max96712_write(priv, 0x1051, 0x00);
		return;
	}

	/* PCLK 75MHz. */
	max96712_write(priv, 0x0009, 0x01);

	/* Configure Video Timing Generator for 1920x1080 @ 30 fps. */
	max96712_write_bulk_value(priv, 0x1052, 0, 3);
	max96712_write_bulk_value(priv, 0x1055, v_sw * h_tot, 3);
	max96712_write_bulk_value(priv, 0x1058,
				  (v_active + v_fp + + v_bp) * h_tot, 3);
	max96712_write_bulk_value(priv, 0x105b, 0, 3);
	max96712_write_bulk_value(priv, 0x105e, h_sw, 2);
	max96712_write_bulk_value(priv, 0x1060, h_active + h_fp + h_bp, 2);
	max96712_write_bulk_value(priv, 0x1062, v_tot, 2);
	max96712_write_bulk_value(priv, 0x1064,
				  h_tot * (v_sw + v_bp) + (h_sw + h_bp), 3);
	max96712_write_bulk_value(priv, 0x1067, h_active, 2);
	max96712_write_bulk_value(priv, 0x1069, h_fp + h_sw + h_bp, 2);
	max96712_write_bulk_value(priv, 0x106b, v_active, 2);

	/* Generate VS, HS and DE in free-running mode. */
	max96712_write(priv, 0x1050, 0xfb);

	/* Configure Video Pattern Generator. */
	if (priv->pattern == MAX96712_PATTERN_CHECKERBOARD) {
		/* Set checkerboard pattern size. */
		max96712_write(priv, 0x1074, 0x3c);
		max96712_write(priv, 0x1075, 0x3c);
		max96712_write(priv, 0x1076, 0x3c);

		/* Set checkerboard pattern colors. */
		max96712_write_bulk_value(priv, 0x106e, 0xfecc00, 3);
		max96712_write_bulk_value(priv, 0x1071, 0x006aa7, 3);

		/* Generate checkerboard pattern. */
		max96712_write(priv, 0x1051, 0x10);
	} else {
		/* Set gradient increment. */
		max96712_write(priv, 0x106d, 0x10);

		/* Generate gradient pattern. */
		max96712_write(priv, 0x1051, 0x20);
	}
}

static int max96712_s_stream(struct v4l2_subdev *sd, int enable)
{
	struct max96712_priv *priv = v4l2_get_subdevdata(sd);

	if (enable) {
		max96712_pattern_enable(priv, true);
		max96712_mipi_enable(priv, true);
	} else {
		max96712_mipi_enable(priv, false);
		max96712_pattern_enable(priv, false);
	}

	return 0;
}

static const struct v4l2_subdev_video_ops max96712_video_ops = {
	.s_stream = max96712_s_stream,
};

static int max96712_get_pad_format(struct v4l2_subdev *sd,
				   struct v4l2_subdev_state *sd_state,
				   struct v4l2_subdev_format *format)
{
	format->format.width = 1920;
	format->format.height = 1080;
	format->format.code = MEDIA_BUS_FMT_RGB888_1X24;
	format->format.field = V4L2_FIELD_NONE;

	return 0;
}

static const struct v4l2_subdev_pad_ops max96712_pad_ops = {
	.get_fmt = max96712_get_pad_format,
	.set_fmt = max96712_get_pad_format,
};

static const struct v4l2_subdev_ops max96712_subdev_ops = {
	.video = &max96712_video_ops,
	.pad = &max96712_pad_ops,
};

static const char * const max96712_test_pattern[] = {
	"Checkerboard",
	"Gradient",
};

static int max96712_s_ctrl(struct v4l2_ctrl *ctrl)
{
	struct max96712_priv *priv =
		container_of(ctrl->handler, struct max96712_priv, ctrl_handler);

	switch (ctrl->id) {
	case V4L2_CID_TEST_PATTERN:
		priv->pattern = ctrl->val ?
			MAX96712_PATTERN_GRADIENT :
			MAX96712_PATTERN_CHECKERBOARD;
		break;
	}
	return 0;
}

static const struct v4l2_ctrl_ops max96712_ctrl_ops = {
	.s_ctrl = max96712_s_ctrl,
};

static int max96712_v4l2_register(struct max96712_priv *priv)
{
	long pixel_rate;
	int ret;

	v4l2_i2c_subdev_init(&priv->sd, priv->client, &max96712_subdev_ops);
	priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
	priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;

	v4l2_ctrl_handler_init(&priv->ctrl_handler, 2);

	/*
	 * TODO: Once V4L2_CID_LINK_FREQ is changed from a menu control to an
	 * INT64 control it should be used here instead of V4L2_CID_PIXEL_RATE.
	 */
	pixel_rate = MAX96712_DPLL_FREQ / priv->mipi.num_data_lanes * 1000000;
	v4l2_ctrl_new_std(&priv->ctrl_handler, NULL, V4L2_CID_PIXEL_RATE,
			  pixel_rate, pixel_rate, 1, pixel_rate);

	v4l2_ctrl_new_std_menu_items(&priv->ctrl_handler, &max96712_ctrl_ops,
				     V4L2_CID_TEST_PATTERN,
				     ARRAY_SIZE(max96712_test_pattern) - 1,
				     0, 0, max96712_test_pattern);

	priv->sd.ctrl_handler = &priv->ctrl_handler;
	ret = priv->ctrl_handler.error;
	if (ret)
		goto error;

	priv->pads[0].flags = MEDIA_PAD_FL_SOURCE;
	ret = media_entity_pads_init(&priv->sd.entity, 1, priv->pads);
	if (ret)
		goto error;

	v4l2_set_subdevdata(&priv->sd, priv);

	ret = v4l2_async_register_subdev(&priv->sd);
	if (ret < 0) {
		dev_err(&priv->client->dev, "Unable to register subdevice\n");
		goto error;
	}

	return 0;
error:
	v4l2_ctrl_handler_free(&priv->ctrl_handler);

	return ret;
}

static int max96712_parse_dt(struct max96712_priv *priv)
{
	struct fwnode_handle *ep;
	struct v4l2_fwnode_endpoint v4l2_ep = {
		.bus_type = V4L2_MBUS_UNKNOWN,
	};
	unsigned int supported_lanes;
	int ret;

	ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(&priv->client->dev), 4,
					     0, 0);
	if (!ep) {
		dev_err(&priv->client->dev, "Not connected to subdevice\n");
		return -EINVAL;
	}

	ret = v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
	fwnode_handle_put(ep);
	if (ret) {
		dev_err(&priv->client->dev, "Could not parse v4l2 endpoint\n");
		return -EINVAL;
	}

	switch (v4l2_ep.bus_type) {
	case V4L2_MBUS_CSI2_DPHY:
		supported_lanes = 4;
		priv->cphy = false;
		break;
	case V4L2_MBUS_CSI2_CPHY:
		supported_lanes = 3;
		priv->cphy = true;
		break;
	default:
		dev_err(&priv->client->dev, "Unsupported bus-type %u\n",
			v4l2_ep.bus_type);
		return -EINVAL;
	}

	if (v4l2_ep.bus.mipi_csi2.num_data_lanes != supported_lanes) {
		dev_err(&priv->client->dev, "Only %u data lanes supported\n",
			supported_lanes);
		return -EINVAL;
	}

	priv->mipi = v4l2_ep.bus.mipi_csi2;

	return 0;
}

static const struct regmap_config max96712_i2c_regmap = {
	.reg_bits = 16,
	.val_bits = 8,
	.max_register = 0x1f00,
};

static int max96712_probe(struct i2c_client *client)
{
	struct max96712_priv *priv;
	int ret;

	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->client = client;
	i2c_set_clientdata(client, priv);

	priv->regmap = devm_regmap_init_i2c(client, &max96712_i2c_regmap);
	if (IS_ERR(priv->regmap))
		return PTR_ERR(priv->regmap);

	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
						   GPIOD_OUT_HIGH);
	if (IS_ERR(priv->gpiod_pwdn))
		return PTR_ERR(priv->gpiod_pwdn);

	gpiod_set_consumer_name(priv->gpiod_pwdn, "max96712-pwdn");
	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);

	if (priv->gpiod_pwdn)
		usleep_range(4000, 5000);

	if (max96712_read(priv, 0x4a) != MAX96712_ID)
		return -ENODEV;

	max96712_reset(priv);

	ret = max96712_parse_dt(priv);
	if (ret)
		return ret;

	max96712_mipi_configure(priv);

	return max96712_v4l2_register(priv);
}

static void max96712_remove(struct i2c_client *client)
{
	struct max96712_priv *priv = i2c_get_clientdata(client);

	v4l2_async_unregister_subdev(&priv->sd);

	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
}

static const struct of_device_id max96712_of_table[] = {
	{ .compatible = "maxim,max96712" },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, max96712_of_table);

static struct i2c_driver max96712_i2c_driver = {
	.driver	= {
		.name = "max96712",
		.of_match_table	= of_match_ptr(max96712_of_table),
	},
	.probe = max96712_probe,
	.remove = max96712_remove,
};

module_i2c_driver(max96712_i2c_driver);

MODULE_DESCRIPTION("Maxim MAX96712 Quad GMSL2 Deserializer Driver");
MODULE_AUTHOR("Niklas Söderlund <niklas.soderlund@ragnatech.se>");
MODULE_LICENSE("GPL");