[PATCH 09/12] i2c: riic: Add support for fast mode plus

Claudiu
2024-06-21T11:23:36Z

From: Claudiu Beznea <claudiu.beznea.uj@bp.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. Along with it,
according to the RZ/G3S HW manual, chapter 47.5.15 I2C Bus Interface Access
Timing, note 7, Tfmin cannot meet the specification in fast-mode plus for
the RIIC ch2 and ch3.

Due to these limitations:
- the struct riic_of_data::fast_mode_plus was introduced to address the
Renesas RZ/A1H use case
- the renesas,riic-no-fast-mode-plus was introduced to address the Renesas
RZ/G3S limitation.

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@bp.renesas.com>
---
drivers/i2c/busses/i2c-riic.c | 36 +++++++++++++++++++++++++++++++----
1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index 46070f323810..d246143a1037 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 {
@@ -107,6 +111,7 @@ struct riic_dev {
struct clk *clk;
struct reset_control *rstc;
struct i2c_timings i2c_t;
+ bool fast_mode_plus;
};

struct riic_irq_desc {
@@ -316,10 +321,11 @@ static int riic_init_hw(struct riic_dev *riic)
struct i2c_timings *t = &riic->i2c_t;
struct device *dev = riic->adapter.dev.parent;

- 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 ((!riic->fast_mode_plus && t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ) ||
+ (riic->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,
+ riic->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 (riic->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);
@@ -487,6 +496,14 @@ static int riic_i2c_probe(struct platform_device *pdev)
init_completion(&riic->msg_done);

i2c_parse_fw_timings(dev, &riic->i2c_t, true);
+ if (riic->info->fast_mode_plus) {
+ /*
+ * On the same SoC it may happen to have IP variants that support
+ * fast mode plus as well as IP variants that doesn't support it.
+ */
+ riic->fast_mode_plus = !of_property_read_bool(dev->of_node,
+ "renesas,riic-no-fast-mode-plus");
+ }

pm_runtime_set_autosuspend_delay(dev, 0);
pm_runtime_use_autosuspend(dev);
@@ -535,6 +552,7 @@ 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,
@@ -548,11 +566,17 @@ 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,
@@ -564,6 +588,7 @@ 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)
@@ -610,6 +635,9 @@ 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