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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: Andy Shevchenko <andy@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Robin van der Gracht <robin@protonic.nl>,
	Paul Burton <paulburton@kernel.org>
Subject: [PATCH v3 2/9] auxdisplay: linedisp: Allocate buffer for the string
Date: Mon, 19 Feb 2024 18:58:01 +0200
Message-ID: <20240219170337.2161754-3-andriy.shevchenko@linux.intel.com>
In-Reply-To: <20240219170337.2161754-1-andriy.shevchenko@linux.intel.com>
References: <20240219170337.2161754-1-andriy.shevchenko@linux.intel.com>
Precedence: bulk
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Always allocate a buffer for the currently displayed characters.
It makes the line display API simpler.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/auxdisplay/ht16k33.c       |  8 +++-----
 drivers/auxdisplay/img-ascii-lcd.c | 17 +++++++----------
 drivers/auxdisplay/line-display.c  | 11 +++++++----
 drivers/auxdisplay/line-display.h  |  3 +--
 4 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 32d3afd29177..19805f39a257 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -92,7 +92,6 @@ struct ht16k33_seg {
 		struct seg14_conversion_map seg14;
 	} map;
 	unsigned int map_size;
-	char curr[4];
 };
 
 struct ht16k33_priv {
@@ -457,7 +456,7 @@ static void ht16k33_seg7_update(struct work_struct *work)
 	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,
 						 work.work);
 	struct ht16k33_seg *seg = &priv->seg;
-	char *s = seg->curr;
+	char *s = seg->linedisp.buf;
 	uint8_t buf[9];
 
 	buf[0] = map_to_seg7(&seg->map.seg7, *s++);
@@ -478,7 +477,7 @@ static void ht16k33_seg14_update(struct work_struct *work)
 	struct ht16k33_priv *priv = container_of(work, struct ht16k33_priv,
 						 work.work);
 	struct ht16k33_seg *seg = &priv->seg;
-	char *s = seg->curr;
+	char *s = seg->linedisp.buf;
 	uint8_t buf[8];
 
 	put_unaligned_le16(map_to_seg14(&seg->map.seg14, *s++), buf);
@@ -700,8 +699,7 @@ static int ht16k33_seg_probe(struct device *dev, struct ht16k33_priv *priv,
 	if (err)
 		return err;
 
-	err = linedisp_register(&seg->linedisp, dev, 4, seg->curr,
-				&ht16k33_linedisp_ops);
+	err = linedisp_register(&seg->linedisp, dev, 4, &ht16k33_linedisp_ops);
 	if (err)
 		goto err_remove_map_file;
 
diff --git a/drivers/auxdisplay/img-ascii-lcd.c b/drivers/auxdisplay/img-ascii-lcd.c
index ecfb1c05bf55..925c4cd101e9 100644
--- a/drivers/auxdisplay/img-ascii-lcd.c
+++ b/drivers/auxdisplay/img-ascii-lcd.c
@@ -37,7 +37,6 @@ struct img_ascii_lcd_config {
  * @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
- * @curr: the string currently displayed on the LCD
  */
 struct img_ascii_lcd_ctx {
 	struct linedisp linedisp;
@@ -47,7 +46,6 @@ struct img_ascii_lcd_ctx {
 	};
 	u32 offset;
 	const struct img_ascii_lcd_config *cfg;
-	char curr[] __aligned(8);
 };
 
 /*
@@ -61,12 +59,12 @@ static void boston_update(struct linedisp *linedisp)
 	ulong val;
 
 #if BITS_PER_LONG == 64
-	val = *((u64 *)&ctx->curr[0]);
+	val = *((u64 *)&linedisp->buf[0]);
 	__raw_writeq(val, ctx->base);
 #elif BITS_PER_LONG == 32
-	val = *((u32 *)&ctx->curr[0]);
+	val = *((u32 *)&linedisp->buf[0]);
 	__raw_writel(val, ctx->base);
-	val = *((u32 *)&ctx->curr[4]);
+	val = *((u32 *)&linedisp->buf[4]);
 	__raw_writel(val, ctx->base + 4);
 #else
 # error Not 32 or 64 bit
@@ -93,7 +91,7 @@ static void malta_update(struct linedisp *linedisp)
 
 	for (i = 0; i < linedisp->num_chars; i++) {
 		err = regmap_write(ctx->regmap,
-				   ctx->offset + (i * 8), ctx->curr[i]);
+				   ctx->offset + (i * 8), linedisp->buf[i]);
 		if (err)
 			break;
 	}
@@ -195,7 +193,7 @@ static void sead3_update(struct linedisp *linedisp)
 
 		err = regmap_write(ctx->regmap,
 				   ctx->offset + SEAD3_REG_LCD_DATA,
-				   ctx->curr[i]);
+				   linedisp->buf[i]);
 		if (err)
 			break;
 	}
@@ -236,7 +234,7 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
 	struct img_ascii_lcd_ctx *ctx;
 	int err;
 
-	ctx = devm_kzalloc(dev, sizeof(*ctx) + cfg->num_chars, GFP_KERNEL);
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;
 
@@ -253,8 +251,7 @@ static int img_ascii_lcd_probe(struct platform_device *pdev)
 			return PTR_ERR(ctx->base);
 	}
 
-	err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, ctx->curr,
-				&cfg->ops);
+	err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, &cfg->ops);
 	if (err)
 		return err;
 
diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c
index 13be7c2f6bc3..e2b546210f8d 100644
--- a/drivers/auxdisplay/line-display.c
+++ b/drivers/auxdisplay/line-display.c
@@ -265,6 +265,7 @@ static void linedisp_release(struct device *dev)
 
 	kfree(linedisp->map);
 	kfree(linedisp->message);
+	kfree(linedisp->buf);
 	ida_free(&linedisp_id, linedisp->id);
 }
 
@@ -316,14 +317,12 @@ static int linedisp_init_map(struct linedisp *linedisp)
  * @linedisp: pointer to character line display structure
  * @parent: parent device
  * @num_chars: the number of characters that can be displayed
- * @buf: pointer to a buffer that can hold @num_chars characters
  * @ops: character line display operations
  *
  * Return: zero on success, else a negative error code.
  */
 int linedisp_register(struct linedisp *linedisp, struct device *parent,
-		      unsigned int num_chars, char *buf,
-		      const struct linedisp_ops *ops)
+		      unsigned int num_chars, const struct linedisp_ops *ops)
 {
 	int err;
 
@@ -331,7 +330,6 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent,
 	linedisp->dev.parent = parent;
 	linedisp->dev.type = &linedisp_type;
 	linedisp->ops = ops;
-	linedisp->buf = buf;
 	linedisp->num_chars = num_chars;
 	linedisp->scroll_rate = DEFAULT_SCROLL_RATE;
 
@@ -343,6 +341,11 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent,
 	device_initialize(&linedisp->dev);
 	dev_set_name(&linedisp->dev, "linedisp.%u", linedisp->id);
 
+	err = -ENOMEM;
+	linedisp->buf = kzalloc(linedisp->num_chars, GFP_KERNEL);
+	if (!linedisp->buf)
+		goto out_put_device;
+
 	/* initialise a character mapping, if required */
 	err = linedisp_init_map(linedisp);
 	if (err)
diff --git a/drivers/auxdisplay/line-display.h b/drivers/auxdisplay/line-display.h
index 4e310b0e611e..4348d7a2f69a 100644
--- a/drivers/auxdisplay/line-display.h
+++ b/drivers/auxdisplay/line-display.h
@@ -82,8 +82,7 @@ struct linedisp {
 };
 
 int linedisp_register(struct linedisp *linedisp, struct device *parent,
-		      unsigned int num_chars, char *buf,
-		      const struct linedisp_ops *ops);
+		      unsigned int num_chars, const struct linedisp_ops *ops);
 void linedisp_unregister(struct linedisp *linedisp);
 
 #endif /* LINEDISP_H */
-- 
2.43.0.rc1.1.gbec44491f096