adp-mipi.c

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/component.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include <drm/drm_bridge.h>
#include <drm/drm_mipi_dsi.h>

#define DSI_GEN_HDR 0x6c
#define DSI_GEN_PLD_DATA 0x70

#define DSI_CMD_PKT_STATUS 0x74

#define GEN_PLD_R_EMPTY BIT(4)
#define GEN_PLD_W_FULL BIT(3)
#define GEN_PLD_W_EMPTY BIT(2)
#define GEN_CMD_FULL BIT(1)
#define GEN_CMD_EMPTY BIT(0)
#define GEN_RD_CMD_BUSY BIT(6)
#define CMD_PKT_STATUS_TIMEOUT_US 20000

struct adp_mipi_drv_private {
	struct mipi_dsi_host dsi;
	struct drm_bridge bridge;
	struct drm_bridge *next_bridge;
	void __iomem *mipi;
};

#define mipi_to_adp(x) container_of(x, struct adp_mipi_drv_private, dsi)

static int adp_dsi_gen_pkt_hdr_write(struct adp_mipi_drv_private *adp, u32 hdr_val)
{
	int ret;
	u32 val, mask;

	ret = readl_poll_timeout(adp->mipi + DSI_CMD_PKT_STATUS,
				 val, !(val & GEN_CMD_FULL), 1000,
				 CMD_PKT_STATUS_TIMEOUT_US);
	if (ret) {
		dev_err(adp->dsi.dev, "failed to get available command FIFO\n");
		return ret;
	}

	writel(hdr_val, adp->mipi + DSI_GEN_HDR);

	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
	ret = readl_poll_timeout(adp->mipi + DSI_CMD_PKT_STATUS,
				 val, (val & mask) == mask,
				 1000, CMD_PKT_STATUS_TIMEOUT_US);
	if (ret) {
		dev_err(adp->dsi.dev, "failed to write command FIFO\n");
		return ret;
	}

	return 0;
}

static int adp_dsi_write(struct adp_mipi_drv_private *adp,
			 const struct mipi_dsi_packet *packet)
{
	const u8 *tx_buf = packet->payload;
	int len = packet->payload_length, pld_data_bytes = sizeof(u32), ret;
	__le32 word;
	u32 val;

	while (len) {
		if (len < pld_data_bytes) {
			word = 0;
			memcpy(&word, tx_buf, len);
			writel(le32_to_cpu(word), adp->mipi + DSI_GEN_PLD_DATA);
			len = 0;
		} else {
			memcpy(&word, tx_buf, pld_data_bytes);
			writel(le32_to_cpu(word), adp->mipi + DSI_GEN_PLD_DATA);
			tx_buf += pld_data_bytes;
			len -= pld_data_bytes;
		}

		ret = readl_poll_timeout(adp->mipi + DSI_CMD_PKT_STATUS,
					 val, !(val & GEN_PLD_W_FULL), 1000,
					 CMD_PKT_STATUS_TIMEOUT_US);
		if (ret) {
			dev_err(adp->dsi.dev,
				"failed to get available write payload FIFO\n");
			return ret;
		}
	}

	word = 0;
	memcpy(&word, packet->header, sizeof(packet->header));
	return adp_dsi_gen_pkt_hdr_write(adp, le32_to_cpu(word));
}

static int adp_dsi_read(struct adp_mipi_drv_private *adp,
			const struct mipi_dsi_msg *msg)
{
	int i, j, ret, len = msg->rx_len;
	u8 *buf = msg->rx_buf;
	u32 val;

	/* Wait end of the read operation */
	ret = readl_poll_timeout(adp->mipi + DSI_CMD_PKT_STATUS,
				 val, !(val & GEN_RD_CMD_BUSY),
				 1000, CMD_PKT_STATUS_TIMEOUT_US);
	if (ret) {
		dev_err(adp->dsi.dev, "Timeout during read operation\n");
		return ret;
	}

	for (i = 0; i < len; i += 4) {
		/* Read fifo must not be empty before all bytes are read */
		ret = readl_poll_timeout(adp->mipi + DSI_CMD_PKT_STATUS,
					 val, !(val & GEN_PLD_R_EMPTY),
					 1000, CMD_PKT_STATUS_TIMEOUT_US);
		if (ret) {
			dev_err(adp->dsi.dev, "Read payload FIFO is empty\n");
			return ret;
		}

		val = readl(adp->mipi + DSI_GEN_PLD_DATA);
		for (j = 0; j < 4 && j + i < len; j++)
			buf[i + j] = val >> (8 * j);
	}

	return ret;
}

static ssize_t adp_dsi_host_transfer(struct mipi_dsi_host *host,
				     const struct mipi_dsi_msg *msg)
{
	struct adp_mipi_drv_private *adp = mipi_to_adp(host);
	struct mipi_dsi_packet packet;
	int ret, nb_bytes;

	ret = mipi_dsi_create_packet(&packet, msg);
	if (ret) {
		dev_err(adp->dsi.dev, "failed to create packet: %d\n", ret);
		return ret;
	}

	ret = adp_dsi_write(adp, &packet);
	if (ret)
		return ret;

	if (msg->rx_buf && msg->rx_len) {
		ret = adp_dsi_read(adp, msg);
		if (ret)
			return ret;
		nb_bytes = msg->rx_len;
	} else {
		nb_bytes = packet.size;
	}

	return nb_bytes;
}

static int adp_dsi_bind(struct device *dev, struct device *master, void *data)
{
	return 0;
}

static void adp_dsi_unbind(struct device *dev, struct device *master, void *data)
{
}

static const struct component_ops adp_dsi_component_ops = {
	.bind	= adp_dsi_bind,
	.unbind	= adp_dsi_unbind,
};

static int adp_dsi_host_attach(struct mipi_dsi_host *host,
			       struct mipi_dsi_device *dev)
{
	struct adp_mipi_drv_private *adp = mipi_to_adp(host);
	struct drm_bridge *next;
	int ret;

	next = devm_drm_of_get_bridge(adp->dsi.dev, adp->dsi.dev->of_node, 1, 0);
	if (IS_ERR(next))
		return PTR_ERR(next);

	adp->next_bridge = next;

	drm_bridge_add(&adp->bridge);

	ret = component_add(host->dev, &adp_dsi_component_ops);
	if (ret) {
		pr_err("failed to add dsi_host component: %d\n", ret);
		drm_bridge_remove(&adp->bridge);
		return ret;
	}

	return 0;
}

static int adp_dsi_host_detach(struct mipi_dsi_host *host,
			       struct mipi_dsi_device *dev)
{
	struct adp_mipi_drv_private *adp = mipi_to_adp(host);

	component_del(host->dev, &adp_dsi_component_ops);
	drm_bridge_remove(&adp->bridge);
	return 0;
}

static const struct mipi_dsi_host_ops adp_dsi_host_ops = {
	.transfer = adp_dsi_host_transfer,
	.attach = adp_dsi_host_attach,
	.detach = adp_dsi_host_detach,
};

static int adp_dsi_bridge_attach(struct drm_bridge *bridge,
				 struct drm_encoder *encoder,
				 enum drm_bridge_attach_flags flags)
{
	struct adp_mipi_drv_private *adp =
		container_of(bridge, struct adp_mipi_drv_private, bridge);

	return drm_bridge_attach(encoder, adp->next_bridge, bridge, flags);
}

static const struct drm_bridge_funcs adp_dsi_bridge_funcs = {
	.attach	= adp_dsi_bridge_attach,
};

static int adp_mipi_probe(struct platform_device *pdev)
{
	struct adp_mipi_drv_private *adp;

	adp = devm_drm_bridge_alloc(&pdev->dev, struct adp_mipi_drv_private,
				    bridge, &adp_dsi_bridge_funcs);
	if (IS_ERR(adp))
		return PTR_ERR(adp);

	adp->mipi = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(adp->mipi)) {
		dev_err(&pdev->dev, "failed to map mipi mmio");
		return PTR_ERR(adp->mipi);
	}

	adp->dsi.dev = &pdev->dev;
	adp->dsi.ops = &adp_dsi_host_ops;
	adp->bridge.of_node = pdev->dev.of_node;
	adp->bridge.type = DRM_MODE_CONNECTOR_DSI;
	dev_set_drvdata(&pdev->dev, adp);
	return mipi_dsi_host_register(&adp->dsi);
}

static void adp_mipi_remove(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct adp_mipi_drv_private *adp = dev_get_drvdata(dev);

	mipi_dsi_host_unregister(&adp->dsi);
}

static const struct of_device_id adp_mipi_of_match[] = {
	{ .compatible = "apple,h7-display-pipe-mipi", },
	{ },
};
MODULE_DEVICE_TABLE(of, adp_mipi_of_match);

static struct platform_driver adp_mipi_platform_driver = {
	.driver = {
		.name = "adp-mipi",
		.of_match_table = adp_mipi_of_match,
	},
	.probe = adp_mipi_probe,
	.remove = adp_mipi_remove,
};

module_platform_driver(adp_mipi_platform_driver);

MODULE_DESCRIPTION("Apple Display Pipe MIPI driver");
MODULE_LICENSE("GPL");