1 files changed, 306 insertions, 0 deletions
diff --git a/drivers/auxdisplay/img-ascii-lcd.c b/drivers/auxdisplay/img-ascii-lcd.c
new file mode 100644
index 000000000..fa23e415f
--- /dev/null
+++ b/drivers/auxdisplay/img-ascii-lcd.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "line-display.h"
+
+struct img_ascii_lcd_ctx;
+
+/**
+ * struct img_ascii_lcd_config - Configuration information about an LCD model
+ * @num_chars: the number of characters the LCD can display
+ * @external_regmap: true if registers are in a system controller, else false
+ * @update: function called to update the LCD
+ */
+struct img_ascii_lcd_config {
+	unsigned int num_chars;
+	bool external_regmap;
+	void (*update)(struct linedisp *linedisp);
+};
+
+/**
+ * struct img_ascii_lcd_ctx - Private data structure
+ * @base: the base address of the LCD registers
+ * @regmap: the regmap through which LCD registers are accessed
+ * @offset: the offset within regmap to the start of the LCD registers
+ * @cfg: pointer to the LCD model configuration
+ * @linedisp: line display structure
+ * @curr: the string currently displayed on the LCD
+ */
+struct img_ascii_lcd_ctx {
+	union {
+		void __iomem *base;
+		struct regmap *regmap;
+	};
+	u32 offset;
+	const struct img_ascii_lcd_config *cfg;
+	struct linedisp linedisp;
+	char curr[] __aligned(8);
+};
+
+/*
+ * MIPS Boston development board
+ */
+
+static void boston_update(struct linedisp *linedisp)
+{
+	struct img_ascii_lcd_ctx *ctx =
+		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
+	ulong val;
+
+#if BITS_PER_LONG == 64
+	val = *((u64 *)&ctx->curr[0]);
+	__raw_writeq(val, ctx->base);
+#elif BITS_PER_LONG == 32
+	val = *((u32 *)&ctx->curr[0]);
+	__raw_writel(val, ctx->base);
+	val = *((u32 *)&ctx->curr[4]);
+	__raw_writel(val, ctx->base + 4);
+#else
+# error Not 32 or 64 bit
+#endif
+}
+
+static struct img_ascii_lcd_config boston_config = {
+	.num_chars = 8,
+	.update = boston_update,
+};
+
+/*
+ * MIPS Malta development board
+ */
+
+static void malta_update(struct linedisp *linedisp)
+{
+	struct img_ascii_lcd_ctx *ctx =
+		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
+	unsigned int i;
+	int err = 0;
+
+	for (i = 0; i < linedisp->num_chars; i++) {
+		err = regmap_write(ctx->regmap,
+				   ctx->offset + (i * 8), ctx->curr[i]);
+		if (err)
+			break;
+	}
+
+	if (unlikely(err))
+		pr_err_ratelimited("Failed to update LCD display: %d\n", err);
+}
+
+static struct img_ascii_lcd_config malta_config = {
+	.num_chars = 8,
+	.external_regmap = true,
+	.update = malta_update,
+};
+
+/*
+ * MIPS SEAD3 development board
+ */
+
+enum {
+	SEAD3_REG_LCD_CTRL		= 0x00,
+#define SEAD3_REG_LCD_CTRL_SETDRAM	BIT(7)
+	SEAD3_REG_LCD_DATA		= 0x08,
+	SEAD3_REG_CPLD_STATUS		= 0x10,
+#define SEAD3_REG_CPLD_STATUS_BUSY	BIT(0)
+	SEAD3_REG_CPLD_DATA		= 0x18,
+#define SEAD3_REG_CPLD_DATA_BUSY	BIT(7)
+};
+
+static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx)
+{
+	unsigned int status;
+	int err;
+
+	do {
+		err = regmap_read(ctx->regmap,
+				  ctx->offset + SEAD3_REG_CPLD_STATUS,
+				  &status);
+		if (err)
+			return err;
+	} while (status & SEAD3_REG_CPLD_STATUS_BUSY);
+
+	return 0;
+
+}
+
+static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx)
+{
+	unsigned int cpld_data;
+	int err;
+
+	err = sead3_wait_sm_idle(ctx);
+	if (err)
+		return err;
+
+	do {
+		err = regmap_read(ctx->regmap,
+				  ctx->offset + SEAD3_REG_LCD_CTRL,
+				  &cpld_data);
+		if (err)
+			return err;
+
+		err = sead3_wait_sm_idle(ctx);
+		if (err)
+			return err;
+
+		err = regmap_read(ctx->regmap,
+				  ctx->offset + SEAD3_REG_CPLD_DATA,
+				  &cpld_data);
+		if (err)
+			return err;
+	} while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY);
+
+	return 0;
+}
+
+static void sead3_update(struct linedisp *linedisp)
+{
+	struct img_ascii_lcd_ctx *ctx =
+		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
+	unsigned int i;
+	int err = 0;
+
+	for (i = 0; i < linedisp->num_chars; i++) {
+		err = sead3_wait_lcd_idle(ctx);
+		if (err)
+			break;
+
+		err = regmap_write(ctx->regmap,
+				   ctx->offset + SEAD3_REG_LCD_CTRL,
+				   SEAD3_REG_LCD_CTRL_SETDRAM | i);
+		if (err)
+			break;
+
+		err = sead3_wait_lcd_idle(ctx);
+		if (err)
+			break;
+
+		err = regmap_write(ctx->regmap,
+				   ctx->offset + SEAD3_REG_LCD_DATA,
+				   ctx->curr[i]);
+		if (err)
+			break;
+	}
+
+	if (unlikely(err))
+		pr_err_ratelimited("Failed to update LCD display: %d\n", err);
+}
+
+static struct img_ascii_lcd_config sead3_config = {
+	.num_chars = 16,
+	.external_regmap = true,
+	.update = sead3_update,
+};
+
+static const struct of_device_id img_ascii_lcd_matches[] = {
+	{ .compatible = "img,boston-lcd", .data = &boston_config },
+	{ .compatible = "mti,malta-lcd", .data = &malta_config },
+	{ .compatible = "mti,sead3-lcd", .data = &sead3_config },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches);
+
+/**
+ * img_ascii_lcd_probe() - probe an LCD display device
+ * @pdev: the LCD platform device
+ *
+ * Probe an LCD display device, ensuring that we have the required resources in
+ * order to access the LCD & setting up private data as well as sysfs files.
+ *
+ * Return: 0 on success, else -ERRNO
+ */
+static int img_ascii_lcd_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	const struct img_ascii_lcd_config *cfg;
+	struct device *dev = &pdev->dev;
+	struct img_ascii_lcd_ctx *ctx;
+	int err;
+
+	match = of_match_device(img_ascii_lcd_matches, dev);
+	if (!match)
+		return -ENODEV;
+
+	cfg = match->data;
+	ctx = devm_kzalloc(dev, sizeof(*ctx) + cfg->num_chars, GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	if (cfg->external_regmap) {
+		ctx->regmap = syscon_node_to_regmap(dev->parent->of_node);
+		if (IS_ERR(ctx->regmap))
+			return PTR_ERR(ctx->regmap);
+
+		if (of_property_read_u32(dev->of_node, "offset", &ctx->offset))
+			return -EINVAL;
+	} else {
+		ctx->base = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(ctx->base))
+			return PTR_ERR(ctx->base);
+	}
+
+	err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, ctx->curr,
+				cfg->update);
+	if (err)
+		return err;
+
+	/* for backwards compatibility */
+	err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj,
+						   &ctx->linedisp.dev.kobj,
+						   "message", NULL);
+	if (err)
+		goto err_unregister;
+
+	platform_set_drvdata(pdev, ctx);
+	return 0;
+
+err_unregister:
+	linedisp_unregister(&ctx->linedisp);
+	return err;
+}
+
+/**
+ * img_ascii_lcd_remove() - remove an LCD display device
+ * @pdev: the LCD platform device
+ *
+ * Remove an LCD display device, freeing private resources & ensuring that the
+ * driver stops using the LCD display registers.
+ *
+ * Return: 0
+ */
+static int img_ascii_lcd_remove(struct platform_device *pdev)
+{
+	struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
+
+	sysfs_remove_link(&pdev->dev.kobj, "message");
+	linedisp_unregister(&ctx->linedisp);
+	return 0;
+}
+
+static struct platform_driver img_ascii_lcd_driver = {
+	.driver = {
+		.name		= "img-ascii-lcd",
+		.of_match_table	= img_ascii_lcd_matches,
+	},
+	.probe	= img_ascii_lcd_probe,
+	.remove	= img_ascii_lcd_remove,
+};
+module_platform_driver(img_ascii_lcd_driver);
+
+MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display");
+MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
+MODULE_LICENSE("GPL");