linux-kernel - [PATCH 4/6] i2c: exynos5: Add support for ExynosAutoV9 SoC

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Message-Id: <20211201190455.31646-5-semen.protsenko@linaro.org>
Date:   Wed,  1 Dec 2021 21:04:53 +0200
From:   Sam Protsenko <semen.protsenko@...aro.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Jaewon Kim <jaewon02.kim@...sung.com>,
        Chanho Park <chanho61.park@...sung.com>,
        David Virag <virag.david003@...il.com>,
        Youngmin Nam <youngmin.nam@...sung.com>,
        Wolfram Sang <wsa@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org
Subject: [PATCH 4/6] i2c: exynos5: Add support for ExynosAutoV9 SoC

From: Jaewon Kim <jaewon02.kim@...sung.com>

ExynosAutoV9 functioning logic mostly follows I2C_TYPE_EXYNOS7, but
timing calculation and configuration procedure is changed: e.g. only
timing_s3 has to be set now.

Another change of HSI2C controller in ExynosAutoV9 SoC is that it's now
a part of USIv2 IP-core. No changes is needed for I2C driver though, as
all USI related configuration is done in USI driver.

Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
---
 drivers/i2c/busses/i2c-exynos5.c | 62 +++++++++++++++++++++++++++-----
 1 file changed, 53 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index c2e4bab11366..5198e71e8dab 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -169,6 +169,7 @@
 enum i2c_type_exynos {
 	I2C_TYPE_EXYNOS5,
 	I2C_TYPE_EXYNOS7,
+	I2C_TYPE_EXYNOSAUTOV9,
 };
 
 struct exynos5_i2c {
@@ -230,6 +231,11 @@ static const struct exynos_hsi2c_variant exynos7_hsi2c_data = {
 	.hw		= I2C_TYPE_EXYNOS7,
 };
 
+static const struct exynos_hsi2c_variant exynosautov9_hsi2c_data = {
+	.fifo_depth	= 64,
+	.hw		= I2C_TYPE_EXYNOSAUTOV9,
+};
+
 static const struct of_device_id exynos5_i2c_match[] = {
 	{
 		.compatible = "samsung,exynos5-hsi2c",
@@ -243,6 +249,9 @@ static const struct of_device_id exynos5_i2c_match[] = {
 	}, {
 		.compatible = "samsung,exynos7-hsi2c",
 		.data = &exynos7_hsi2c_data
+	}, {
+		.compatible = "samsung,exynosautov9-hsi2c",
+		.data = &exynosautov9_hsi2c_data
 	}, {},
 };
 MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
@@ -281,6 +290,31 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
 		i2c->op_clock;
 	int div, clk_cycle, temp;
 
+	/*
+	 * In case of HSI2C controllers in ExynosAutoV9:
+	 *
+	 * FSCL = IPCLK / ((CLK_DIV + 1) * 16)
+	 * T_SCL_LOW = IPCLK * (CLK_DIV + 1) * (N + M)
+	 *   [N : number of 0's in the TSCL_H_HS]
+	 *   [M : number of 0's in the TSCL_L_HS]
+	 * T_SCL_HIGH = IPCLK * (CLK_DIV + 1) * (N + M)
+	 *   [N : number of 1's in the TSCL_H_HS]
+	 *   [M : number of 1's in the TSCL_L_HS]
+	 *
+	 * Result of (N + M) is always 8.
+	 * In general case, we don't need to control timing_s1 and timing_s2.
+	 */
+	if (i2c->variant->hw == I2C_TYPE_EXYNOSAUTOV9) {
+		div = ((clkin / (16 * i2c->op_clock)) - 1);
+		i2c_timing_s3 = div << 16;
+		if (hs_timings)
+			writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3);
+		else
+			writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3);
+
+		return 0;
+	}
+
 	/*
 	 * In case of HSI2C controller in Exynos5 series
 	 * FPCLK / FI2C =
@@ -422,7 +456,10 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
 	writel(int_status, i2c->regs + HSI2C_INT_STATUS);
 
 	/* handle interrupt related to the transfer status */
-	if (i2c->variant->hw == I2C_TYPE_EXYNOS7) {
+	switch (i2c->variant->hw) {
+	case I2C_TYPE_EXYNOSAUTOV9:
+		fallthrough;
+	case I2C_TYPE_EXYNOS7:
 		if (int_status & HSI2C_INT_TRANS_DONE) {
 			i2c->trans_done = 1;
 			i2c->state = 0;
@@ -443,7 +480,12 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
 			i2c->state = -ETIMEDOUT;
 			goto stop;
 		}
-	} else if (int_status & HSI2C_INT_I2C) {
+
+		break;
+	case I2C_TYPE_EXYNOS5:
+		if (!(int_status & HSI2C_INT_I2C))
+			break;
+
 		trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
 		if (trans_status & HSI2C_NO_DEV_ACK) {
 			dev_dbg(i2c->dev, "No ACK from device\n");
@@ -465,6 +507,8 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
 			i2c->trans_done = 1;
 			i2c->state = 0;
 		}
+
+		break;
 	}
 
 	if ((i2c->msg->flags & I2C_M_RD) && (int_status &
@@ -569,13 +613,13 @@ static void exynos5_i2c_bus_check(struct exynos5_i2c *i2c)
 {
 	unsigned long timeout;
 
-	if (i2c->variant->hw != I2C_TYPE_EXYNOS7)
+	if (i2c->variant->hw == I2C_TYPE_EXYNOS5)
 		return;
 
 	/*
-	 * HSI2C_MASTER_ST_LOSE state in EXYNOS7 variant before transaction
-	 * indicates that bus is stuck (SDA is low). In such case bus recovery
-	 * can be performed.
+	 * HSI2C_MASTER_ST_LOSE state (in Exynos7 and ExynosAutoV9 variants)
+	 * before transaction indicates that bus is stuck (SDA is low).
+	 * In such case bus recovery can be performed.
 	 */
 	timeout = jiffies + msecs_to_jiffies(100);
 	for (;;) {
@@ -611,10 +655,10 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
 	unsigned long flags;
 	unsigned short trig_lvl;
 
-	if (i2c->variant->hw == I2C_TYPE_EXYNOS7)
-		int_en |= HSI2C_INT_I2C_TRANS;
-	else
+	if (i2c->variant->hw == I2C_TYPE_EXYNOS5)
 		int_en |= HSI2C_INT_I2C;
+	else
+		int_en |= HSI2C_INT_I2C_TRANS;
 
 	i2c_ctl = readl(i2c->regs + HSI2C_CTL);
 	i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
-- 
2.30.2