[PATCH v2 2/2] i2c: exynos5: Add support for Exynos8895 SoC

[Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>]

Exynos8895 functioning logic mostly follows I2C_TYPE_EXYNOS7, but timing
and temp calculations are slightly changed according to the following
logic:

FPCLK / FI2C = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 2 *
((FLT_CYCLE + 3) - (FLT_CYCLE + 3) % (CLK_DIV + 1))

temp := (FPCLK / FI2C) - (FLT_CYCLE + 3) * 2

Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
---
 drivers/i2c/busses/i2c-exynos5.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index e33001508..8d8ee42ba 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -168,6 +168,7 @@ enum i2c_type_exynos {
 	I2C_TYPE_EXYNOS5,
 	I2C_TYPE_EXYNOS7,
 	I2C_TYPE_EXYNOSAUTOV9,
+	I2C_TYPE_EXYNOS8895,
 };
 
 struct exynos5_i2c {
@@ -240,6 +241,11 @@ static const struct exynos_hsi2c_variant exynosautov9_hsi2c_data = {
 	.hw		= I2C_TYPE_EXYNOSAUTOV9,
 };
 
+static const struct exynos_hsi2c_variant exynos8895_hsi2c_data = {
+	.fifo_depth	= 64,
+	.hw		= I2C_TYPE_EXYNOS8895,
+};
+
 static const struct of_device_id exynos5_i2c_match[] = {
 	{
 		.compatible = "samsung,exynos5-hsi2c",
@@ -256,6 +262,9 @@ static const struct of_device_id exynos5_i2c_match[] = {
 	}, {
 		.compatible = "samsung,exynosautov9-hsi2c",
 		.data = &exynosautov9_hsi2c_data
+	}, {
+		.compatible = "samsung,exynos8895-hsi2c",
+		.data = &exynos8895_hsi2c_data
 	}, {},
 };
 MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
@@ -331,6 +340,14 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
 	 * clk_cycle := TSCLK_L + TSCLK_H
 	 * temp := (CLK_DIV + 1) * (clk_cycle + 2)
 	 *
+	 * In case of HSI2C controllers in Exynos8895
+	 * FPCLK / FI2C =
+	 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) +
+	 * 2 * ((FLT_CYCLE + 3) - (FLT_CYCLE + 3) % (CLK_DIV + 1))
+	 *
+	 * clk_cycle := TSCLK_L + TSCLK_H
+	 * temp := (FPCLK / FI2C) - (FLT_CYCLE + 3) * 2
+	 *
 	 * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510
 	 *
 	 * To split SCL clock into low, high periods appropriately, one
@@ -352,11 +369,19 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
 	 *
 	 */
 	t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
-	temp = clkin / op_clk - 8 - t_ftl_cycle;
+	if (i2c->variant->hw == I2C_TYPE_EXYNOS8895)
+		temp = clkin / op_clk - (t_ftl_cycle + 3) * 2;
+	else
+		temp = clkin / op_clk - 8 - t_ftl_cycle;
 	if (i2c->variant->hw != I2C_TYPE_EXYNOS7)
 		temp -= t_ftl_cycle;
 	div = temp / 512;
-	clk_cycle = temp / (div + 1) - 2;
+
+	if (i2c->variant->hw == I2C_TYPE_EXYNOS8895)
+		clk_cycle = (temp + ((t_ftl_cycle + 3) % (div + 1)) * 2) /
+			    (div + 1) - 2;
+	else
+		clk_cycle = temp / (div + 1) - 2;
 	if (temp < 4 || div >= 256 || clk_cycle < 2) {
 		dev_err(i2c->dev, "%s clock set-up failed\n",
 			hs_timings ? "HS" : "FS");
@@ -491,6 +516,8 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
 	switch (i2c->variant->hw) {
 	case I2C_TYPE_EXYNOSAUTOV9:
 		fallthrough;
+	case I2C_TYPE_EXYNOS8895:
+		fallthrough;
 	case I2C_TYPE_EXYNOS7:
 		if (int_status & HSI2C_INT_TRANS_DONE) {
 			i2c->trans_done = 1;
-- 
2.43.0