linux-kernel - [PATCH v2 09/12] i2c: riic: Add support for fast mode plus

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Date: Tue, 25 Jun 2024 15:13:55 +0300
From: Claudiu <claudiu.beznea@...on.dev>
To: chris.brandt@...esas.com,
	andi.shyti@...nel.org,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	geert+renesas@...der.be,
	magnus.damm@...il.com,
	mturquette@...libre.com,
	sboyd@...nel.org,
	p.zabel@...gutronix.de,
	wsa+renesas@...g-engineering.com
Cc: linux-renesas-soc@...r.kernel.org,
	linux-i2c@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org,
	claudiu.beznea@...on.dev,
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: [PATCH v2 09/12] i2c: riic: Add support for fast mode plus

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

Fast mode plus is available on most of the IP variants that RIIC driver
is working with. The exception is (according to HW manuals of the SoCs
where this IP is available) the Renesas RZ/A1H. For this, patch
introduces the struct riic_of_data::fast_mode_plus.

Fast mode plus was tested on RZ/G3S, RZ/G2{L,UL,LC}, RZ/Five by
instantiating the RIIC frequency to 1MHz and issuing i2c reads on the
fast mode plus capable devices (and the i2c clock frequency was checked on
RZ/G3S).

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---

Changes in v2:
- dropped code that handles the renesas,riic-no-fast-mode-plus
- updated commit description

 drivers/i2c/busses/i2c-riic.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index 8ffbead95492..c07317f95e82 100644
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -63,6 +63,8 @@
 #define ICMR3_ACKWP	0x10
 #define ICMR3_ACKBT	0x08
 
+#define ICFER_FMPE	0x80
+
 #define ICIER_TIE	0x80
 #define ICIER_TEIE	0x40
 #define ICIER_RIE	0x20
@@ -80,6 +82,7 @@ enum riic_reg_list {
 	RIIC_ICCR2,
 	RIIC_ICMR1,
 	RIIC_ICMR3,
+	RIIC_ICFER,
 	RIIC_ICSER,
 	RIIC_ICIER,
 	RIIC_ICSR2,
@@ -92,6 +95,7 @@ enum riic_reg_list {
 
 struct riic_of_data {
 	const u8 *regs;
+	bool fast_mode_plus;
 };
 
 struct riic_dev {
@@ -315,11 +319,13 @@ static int riic_init_hw(struct riic_dev *riic)
 	int total_ticks, cks, brl, brh;
 	struct i2c_timings *t = &riic->i2c_t;
 	struct device *dev = riic->adapter.dev.parent;
+	const struct riic_of_data *info = riic->info;
 
-	if (t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) {
-		dev_err(dev,
-			"unsupported bus speed (%dHz). %d max\n",
-			t->bus_freq_hz, I2C_MAX_FAST_MODE_FREQ);
+	if ((!info->fast_mode_plus && t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) ||
+	    (info->fast_mode_plus && t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ)) {
+		dev_err(dev, "unsupported bus speed (%dHz). %d max\n", t->bus_freq_hz,
+			info->fast_mode_plus ? I2C_MAX_FAST_MODE_PLUS_FREQ :
+			I2C_MAX_FAST_MODE_FREQ);
 		return -EINVAL;
 	}
 
@@ -407,6 +413,9 @@ static int riic_init_hw(struct riic_dev *riic)
 	riic_writeb(riic, 0, RIIC_ICSER);
 	riic_writeb(riic, ICMR3_ACKWP | ICMR3_RDRFS, RIIC_ICMR3);
 
+	if (info->fast_mode_plus && t->bus_freq_hz == I2C_MAX_FAST_MODE_PLUS_FREQ)
+		riic_clear_set_bit(riic, 0, ICFER_FMPE, RIIC_ICFER);
+
 	riic_clear_set_bit(riic, ICCR1_IICRST, 0, RIIC_ICCR1);
 
 	pm_runtime_mark_last_busy(dev);
@@ -536,6 +545,7 @@ static const u8 riic_rz_a_regs[RIIC_REG_END] = {
 	[RIIC_ICCR2] = 0x04,
 	[RIIC_ICMR1] = 0x08,
 	[RIIC_ICMR3] = 0x10,
+	[RIIC_ICFER] = 0x14,
 	[RIIC_ICSER] = 0x18,
 	[RIIC_ICIER] = 0x1c,
 	[RIIC_ICSR2] = 0x24,
@@ -549,11 +559,17 @@ static const struct riic_of_data riic_rz_a_info = {
 	.regs = riic_rz_a_regs,
 };
 
+static const struct riic_of_data riic_rz_g2_info = {
+	.regs = riic_rz_a_regs,
+	.fast_mode_plus = true,
+};
+
 static const u8 riic_rz_v2h_regs[RIIC_REG_END] = {
 	[RIIC_ICCR1] = 0x00,
 	[RIIC_ICCR2] = 0x01,
 	[RIIC_ICMR1] = 0x02,
 	[RIIC_ICMR3] = 0x04,
+	[RIIC_ICFER] = 0x05,
 	[RIIC_ICSER] = 0x06,
 	[RIIC_ICIER] = 0x07,
 	[RIIC_ICSR2] = 0x09,
@@ -565,6 +581,7 @@ static const u8 riic_rz_v2h_regs[RIIC_REG_END] = {
 
 static const struct riic_of_data riic_rz_v2h_info = {
 	.regs = riic_rz_v2h_regs,
+	.fast_mode_plus = true,
 };
 
 static int riic_i2c_suspend(struct device *dev)
@@ -613,6 +630,9 @@ static const struct dev_pm_ops riic_i2c_pm_ops = {
 
 static const struct of_device_id riic_i2c_dt_ids[] = {
 	{ .compatible = "renesas,riic-rz", .data = &riic_rz_a_info },
+	{ .compatible = "renesas,riic-r9a07g043", .data =  &riic_rz_g2_info, },
+	{ .compatible = "renesas,riic-r9a07g044", .data =  &riic_rz_g2_info, },
+	{ .compatible = "renesas,riic-r9a07g054", .data =  &riic_rz_g2_info, },
 	{ .compatible = "renesas,riic-r9a09g057", .data = &riic_rz_v2h_info },
 	{ /* Sentinel */ },
 };
-- 
2.39.2