[PATCH v3 0/2] i2c: exynos5: Add support for Exynos8895 SoC

[PATCH v3 0/2] i2c: exynos5: Add support for Exynos8895 SoC

[Ivaylo Ivanov]

Hey folks,

This series adds HSI2C support for Exynos8895 to i2c-exynos5. HSI2C
buses here are mostly available implemented in USIv1 blocks, with 5
available externally - hsi2c_0 to 4. hsi2c_0 is available for PMIC
(although I've never seen it used) and it uses BUSC clocks, which are
still not implemented in the current clock driver, so I've decided to
leave it out for now.

In the next few patchsets support for USIv1 will be added to the
exynos-usi driver and with that the rest of the I2C buses will be made
available in the device tree.

Kind regards,
Ivo

Changes in v3:
 - Added a r-b tag from Krzysztof Kozlowski.
 - Changed the temp calculation for better clarity while also fixing
   an oversight (I2C_TYPE_EXYNOS8895 shouldn't -= t_ftl_cycle).
 - Changed the driver patch commit message as suggested.

Changes in v2:
 - Dropped nested-if in the binding, keeping in mind we'll always
   provide only a single clock.

Ivaylo Ivanov (2):
  dt-bindings: i2c: exynos5: Add samsung,exynos8895-hsi2c compatible
  i2c: exynos5: Add support for Exynos8895 SoC

 .../devicetree/bindings/i2c/i2c-exynos5.yaml  |  1 +
 drivers/i2c/busses/i2c-exynos5.c              | 35 ++++++++++++++++---
 2 files changed, 32 insertions(+), 4 deletions(-)

-- 
2.43.0

[PATCH v3 1/2] dt-bindings: i2c: exynos5: Add samsung,exynos8895-hsi2c compatible

[Ivaylo Ivanov]

Add samsung,exynos8895-hsi2c dedicated compatible for representing
I2C of Exynos8895 SoC. Since there are I2C buses that aren't implemented
as a part of USIv1 blocks, they only require a single clock.

Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 Documentation/devicetree/bindings/i2c/i2c-exynos5.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.yaml b/Documentation/devicetree/bindings/i2c/i2c-exynos5.yaml
index cc8bba553..70cc2ee9e 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-exynos5.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.yaml
@@ -25,6 +25,7 @@ properties:
           - samsung,exynos5250-hsi2c    # Exynos5250 and Exynos5420
           - samsung,exynos5260-hsi2c    # Exynos5260
           - samsung,exynos7-hsi2c       # Exynos7
+          - samsung,exynos8895-hsi2c
           - samsung,exynosautov9-hsi2c
       - items:
           - enum:
-- 
2.43.0

[PATCH v3 2/2] i2c: exynos5: Add support for Exynos8895 SoC

[Ivaylo Ivanov]

Exynos8895 functioning logic mostly follows I2C_TYPE_EXYNOS7, but timing
and temp calculations are slightly different 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 | 35 ++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index e33001508..6cdd957ea 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_EXYNOS7)
-		temp -= t_ftl_cycle;
+	if (i2c->variant->hw == I2C_TYPE_EXYNOS8895)
+		temp = clkin / op_clk - (t_ftl_cycle + 3) * 2;
+	else if (i2c->variant->hw == I2C_TYPE_EXYNOS7)
+		temp = clkin / op_clk - 8 - t_ftl_cycle;
+	else
+		temp = clkin / op_clk - 8 - (t_ftl_cycle * 2);
 	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

Re: [PATCH v3 0/2] i2c: exynos5: Add support for Exynos8895 SoC

[Andi Shyti]

Hi Ivaylo,

> Ivaylo Ivanov (2):
>   dt-bindings: i2c: exynos5: Add samsung,exynos8895-hsi2c compatible
>   i2c: exynos5: Add support for Exynos8895 SoC

merged to i2c/i2c-host.

Thanks,
Andi