[PATCH v2 1/5] i2c: mt7621: rework cmd/wait OPs to support atomic afer variant
From: Christian Marangi <ansuelsmth@gmail.com>
Date: 2025-07-21 18:07:29
Also in:
linux-devicetree, linux-i2c, linux-mediatek, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, mediatek mt7621/28/88 i2c driver, the rest · Maintainers:
Andi Shyti, Stefan Roese, Linus Torvalds
It was reported the need for atomic operation on some Airoha SoC that makes use of I2C bus. Rework the cmd/wait OPs to suppor the xfer_atomic variant. To support this it's mainlin needed to do the readl poll in atomic context. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- drivers/i2c/busses/i2c-mt7621.c | 59 ++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 19 deletions(-)
diff --git a/drivers/i2c/busses/i2c-mt7621.c b/drivers/i2c/busses/i2c-mt7621.c
index 2103f21f9ddd..c0e13f9af3e5 100644
--- a/drivers/i2c/busses/i2c-mt7621.c
+++ b/drivers/i2c/busses/i2c-mt7621.c@@ -67,14 +67,19 @@ struct mtk_i2c { struct clk *clk; }; -static int mtk_i2c_wait_idle(struct mtk_i2c *i2c) +static int mtk_i2c_wait_idle(struct mtk_i2c *i2c, bool atomic) { int ret; u32 val; - ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG, - val, !(val & SM0CTL1_TRI), - 10, TIMEOUT_MS * 1000); + if (atomic) + ret = readl_relaxed_poll_timeout_atomic(i2c->base + REG_SM0CTL1_REG, + val, !(val & SM0CTL1_TRI), + 10, TIMEOUT_MS * 1000); + else + ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG, + val, !(val & SM0CTL1_TRI), + 10, TIMEOUT_MS * 1000); if (ret) dev_dbg(i2c->dev, "idle err(%d)\n", ret);
@@ -117,27 +122,28 @@ static int mtk_i2c_check_ack(struct mtk_i2c *i2c, u32 expected) return ((ack & ack_expected) == ack_expected) ? 0 : -ENXIO; } -static int mtk_i2c_start(struct mtk_i2c *i2c) +static int mtk_i2c_start(struct mtk_i2c *i2c, bool atomic) { iowrite32(SM0CTL1_START | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG); - return mtk_i2c_wait_idle(i2c); + return mtk_i2c_wait_idle(i2c, atomic); } -static int mtk_i2c_stop(struct mtk_i2c *i2c) +static int mtk_i2c_stop(struct mtk_i2c *i2c, bool atomic) { iowrite32(SM0CTL1_STOP | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG); - return mtk_i2c_wait_idle(i2c); + return mtk_i2c_wait_idle(i2c, atomic); } -static int mtk_i2c_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len) +static int mtk_i2c_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len, + bool atomic) { iowrite32(cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len), i2c->base + REG_SM0CTL1_REG); - return mtk_i2c_wait_idle(i2c); + return mtk_i2c_wait_idle(i2c, atomic); } -static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, - int num) +static int mtk_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num, bool atomic) { struct mtk_i2c *i2c; struct i2c_msg *pmsg;
@@ -152,12 +158,12 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, pmsg = &msgs[i]; /* wait hardware idle */ - ret = mtk_i2c_wait_idle(i2c); + ret = mtk_i2c_wait_idle(i2c, atomic); if (ret) goto err_timeout; /* start sequence */ - ret = mtk_i2c_start(i2c); + ret = mtk_i2c_start(i2c, atomic); if (ret) goto err_timeout;
@@ -169,14 +175,16 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, if (pmsg->flags & I2C_M_RD) addr |= 1; iowrite32(addr, i2c->base + REG_SM0D0_REG); - ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 2); + ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 2, + atomic); if (ret) goto err_timeout; } else { /* 7 bits address */ addr = i2c_8bit_addr_from_msg(pmsg); iowrite32(addr, i2c->base + REG_SM0D0_REG); - ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 1); + ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 1, + atomic); if (ret) goto err_timeout; }
@@ -202,7 +210,7 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, cmd = SM0CTL1_WRITE; } - ret = mtk_i2c_cmd(i2c, cmd, page_len); + ret = mtk_i2c_cmd(i2c, cmd, page_len, atomic); if (ret) goto err_timeout;
@@ -222,7 +230,7 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, } } - ret = mtk_i2c_stop(i2c); + ret = mtk_i2c_stop(i2c, atomic); if (ret) goto err_timeout;
@@ -230,7 +238,7 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, return i; err_ack: - ret = mtk_i2c_stop(i2c); + ret = mtk_i2c_stop(i2c, atomic); if (ret) goto err_timeout; return -ENXIO;
@@ -241,6 +249,18 @@ static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, return ret; } +static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + return mtk_i2c_xfer_common(adap, msgs, num, false); +} + +static int mtk_i2c_xfer_atomic(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + return mtk_i2c_xfer_common(adap, msgs, num, true); +} + static u32 mtk_i2c_func(struct i2c_adapter *a) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
@@ -248,6 +268,7 @@ static u32 mtk_i2c_func(struct i2c_adapter *a) static const struct i2c_algorithm mtk_i2c_algo = { .xfer = mtk_i2c_xfer, + .xfer_atomic = mtk_i2c_xfer_atomic, .functionality = mtk_i2c_func, };
--
2.50.0