[PATCH v1 3/4] staging: fbtft: ssd1331: send gamma table via fbtft_write_buf_dc()

[Sun Jian <sun.jian.kdev@gmail.com>]

Clang reports a large stack frame in set_gamma() (-Wframe-larger-than=1024)
because write_reg() expands into a large varargs call and triggers
NUMARGS((int[]){...}) stack allocation.

Use fbtft_write_buf_dc() to send the command byte (0xB8) and the gamma
payload as a buffer.

No functional change intended.

Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
---
 drivers/staging/fbtft/fb_ssd1331.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/fbtft/fb_ssd1331.c b/drivers/staging/fbtft/fb_ssd1331.c
index 06b7056d6c71..cbe10f191f5b 100644
--- a/drivers/staging/fbtft/fb_ssd1331.c
+++ b/drivers/staging/fbtft/fb_ssd1331.c
@@ -130,37 +130,38 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
  */
 static int set_gamma(struct fbtft_par *par, u32 *curves)
 {
-	unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
+	u8 data[GAMMA_LEN];
+	u8 cmd = 0xB8;
 	int i, acc = 0;
+	int ret;
 
-	for (i = 0; i < 63; i++) {
+	for (i = 0; i < GAMMA_LEN; i++) {
 		if (i > 0 && curves[i] < 2) {
 			dev_err(par->info->device,
 				"Illegal value in Grayscale Lookup Table at index %d. Must be greater than 1\n",
 				i);
 			return -EINVAL;
 		}
+
 		acc += curves[i];
-		tmp[i] = acc;
+
 		if (acc > 180) {
 			dev_err(par->info->device,
 				"Illegal value(s) in Grayscale Lookup Table. At index=%d, the accumulated value has exceeded 180\n",
 				i);
 			return -EINVAL;
 		}
+
+		data[i] = acc;
 	}
 
-	write_reg(par, 0xB8,
-		  tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6],
-		  tmp[7], tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13],
-		  tmp[14], tmp[15], tmp[16], tmp[17], tmp[18], tmp[19], tmp[20],
-		  tmp[21], tmp[22], tmp[23], tmp[24], tmp[25], tmp[26],	tmp[27],
-		  tmp[28], tmp[29], tmp[30], tmp[31], tmp[32], tmp[33], tmp[34],
-		  tmp[35], tmp[36], tmp[37], tmp[38], tmp[39], tmp[40], tmp[41],
-		  tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47], tmp[48],
-		  tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55],
-		  tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61],
-		  tmp[62]);
+	ret = fbtft_write_buf_dc(par, &cmd, 1, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = fbtft_write_buf_dc(par, data, sizeof(data), 1);
+	if (ret < 0)
+		return ret;
 
 	return 0;
 }
-- 
2.43.0