soc: mediatek: pwrap: add common way for setup CS timing extenstion

Multiple platforms would always use their own way handling CS timing
extension on the bus which leads to a little bit code duplication.
Therefore, the patch groups the similar logic to handle CS timing
extension into the common function which allows the following SoCs
have more reusability for configing CS timing.
Signed-off-by: Chenglin Xu <chenglin.xu@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-pmic-wrap.c

@@ -827,23 +827,44 @@ static int pwrap_init_dual_io(struct pmic_wrapper *wrp)
 	return 0;
 }
 
-static int pwrap_mt8135_init_reg_clock(struct pmic_wrapper *wrp)
+/*
+ * pwrap_init_chip_select_ext is used to configure CS extension time for each
+ * phase during data transactions on the pwrap bus.
+ */
+static void pwrap_init_chip_select_ext(struct pmic_wrapper *wrp, u8 hext_write,
+				       u8 hext_read, u8 lext_start,
+				       u8 lext_end)
 {
-	pwrap_writel(wrp, 0x4, PWRAP_CSHEXT);
-	pwrap_writel(wrp, 0x0, PWRAP_CSHEXT_WRITE);
-	pwrap_writel(wrp, 0x4, PWRAP_CSHEXT_READ);
-	pwrap_writel(wrp, 0x0, PWRAP_CSLEXT_START);
-	pwrap_writel(wrp, 0x0, PWRAP_CSLEXT_END);
+	/*
+	 * After finishing a write and read transaction, extends CS high time
+	 * to be at least xT of BUS CLK as hext_write and hext_read specifies
+	 * respectively.
+	 */
+	pwrap_writel(wrp, hext_write, PWRAP_CSHEXT_WRITE);
+	pwrap_writel(wrp, hext_read, PWRAP_CSHEXT_READ);
 
-	return 0;
+	/*
+	 * Extends CS low time after CSL and before CSH command to be at
+	 * least xT of BUS CLK as lext_start and lext_end specifies
+	 * respectively.
+	 */
+	pwrap_writel(wrp, lext_start, PWRAP_CSLEXT_START);
+	pwrap_writel(wrp, lext_end, PWRAP_CSLEXT_END);
 }
 
-static int pwrap_mt8173_init_reg_clock(struct pmic_wrapper *wrp)
+static int pwrap_common_init_reg_clock(struct pmic_wrapper *wrp)
 {
-	pwrap_writel(wrp, 0x0, PWRAP_CSHEXT_WRITE);
-	pwrap_writel(wrp, 0x4, PWRAP_CSHEXT_READ);
-	pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_START);
-	pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_END);
+	switch (wrp->master->type) {
+	case PWRAP_MT8173:
+		pwrap_init_chip_select_ext(wrp, 0, 4, 2, 2);
+		break;
+	case PWRAP_MT8135:
+		pwrap_writel(wrp, 0x4, PWRAP_CSHEXT);
+		pwrap_init_chip_select_ext(wrp, 0, 4, 0, 0);
+		break;
+	default:
+		break;
+	}
 
 	return 0;
 }
@@ -853,20 +874,14 @@ static int pwrap_mt2701_init_reg_clock(struct pmic_wrapper *wrp)
 	switch (wrp->slave->type) {
 	case PMIC_MT6397:
 		pwrap_writel(wrp, 0xc, PWRAP_RDDMY);
-		pwrap_writel(wrp, 0x4, PWRAP_CSHEXT_WRITE);
-		pwrap_writel(wrp, 0x0, PWRAP_CSHEXT_READ);
-		pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_START);
-		pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_END);
+		pwrap_init_chip_select_ext(wrp, 4, 0, 2, 2);
 		break;
 
 	case PMIC_MT6323:
 		pwrap_writel(wrp, 0x8, PWRAP_RDDMY);
 		pwrap_write(wrp, wrp->slave->dew_regs[PWRAP_DEW_RDDMY_NO],
 			    0x8);
-		pwrap_writel(wrp, 0x5, PWRAP_CSHEXT_WRITE);
-		pwrap_writel(wrp, 0x0, PWRAP_CSHEXT_READ);
-		pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_START);
-		pwrap_writel(wrp, 0x2, PWRAP_CSLEXT_END);
+		pwrap_init_chip_select_ext(wrp, 5, 0, 2, 2);
 		break;
 	default:
 		break;
@@ -1235,7 +1250,7 @@ static const struct pmic_wrapper_type pwrap_mt8135 = {
 	.spi_w = PWRAP_MAN_CMD_SPI_WRITE,
 	.wdt_src = PWRAP_WDT_SRC_MASK_ALL,
 	.has_bridge = 1,
-	.init_reg_clock = pwrap_mt8135_init_reg_clock,
+	.init_reg_clock = pwrap_common_init_reg_clock,
 	.init_soc_specific = pwrap_mt8135_init_soc_specific,
 };
 
@@ -1247,7 +1262,7 @@ static const struct pmic_wrapper_type pwrap_mt8173 = {
 	.spi_w = PWRAP_MAN_CMD_SPI_WRITE,
 	.wdt_src = PWRAP_WDT_SRC_MASK_NO_STAUPD,
 	.has_bridge = 0,
-	.init_reg_clock = pwrap_mt8173_init_reg_clock,
+	.init_reg_clock = pwrap_common_init_reg_clock,
 	.init_soc_specific = pwrap_mt8173_init_soc_specific,
 };