From nobody Mon Feb 9 10:30:42 2026 Received: from bg1.exmail.qq.com (bg1.exmail.qq.com [114.132.65.219]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C348D352FA3; Sat, 7 Feb 2026 15:10:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.132.65.219 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770477049; cv=none; b=LD6sNMUJn0X5HQiU5mAxbgrw4NGNTbWh6FK9kAdS+OAebUsa7ymxjluFnYIzf2R+Dz3xB3ApCO2IdMxZHOOMkTH+6PEcyStIORUDsKiF+bFJSGPDKpS76dsAcTtR+0Nff8hybX13rTRnJs3x94VK/IPogPOq/dh/qqsS3VS91Rg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770477049; c=relaxed/simple; bh=fObZ2VADvmnq2ga4fUiik6dtloWq4BE/WX/lsKHQ3Sk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=dMde17zfHNwsNXnN9oVJelg7MDyuK9VK9ps2QA10Z/VUmB6+h0MJ5OGsRb2kdZhJc4/ejkD0ZRJs6O9mSyPnA6xOemJyCSYBmS9bJKVTqEDMTmq4IB3Q5r2M1Yx1x3E4hnvaUI7wy5emJwNikWou+8YDU2jmxhd/AufRnBa7h2c= ARC-Authentication-Results: i=1; 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Sat, 07 Feb 2026 23:08:27 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 0 X-BIZMAIL-ID: 18321366254888439668 EX-QQ-RecipientCnt: 9 From: Troy Mitchell Date: Sat, 07 Feb 2026 23:08:21 +0800 Subject: [PATCH v7 1/2] i2c: spacemit: move i2c_xfer_msg() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260207-b4-k3-i2c-pio-v7-1-626942d94d91@linux.spacemit.com> References: <20260207-b4-k3-i2c-pio-v7-0-626942d94d91@linux.spacemit.com> In-Reply-To: <20260207-b4-k3-i2c-pio-v7-0-626942d94d91@linux.spacemit.com> To: Andi Shyti , Yixun Lan Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, Troy Mitchell , Aurelien Jarno , Alex Elder X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1770476904; l=3114; i=troy.mitchell@linux.spacemit.com; s=20250712; h=from:subject:message-id; bh=fObZ2VADvmnq2ga4fUiik6dtloWq4BE/WX/lsKHQ3Sk=; b=bu1J1Kg+2C5ALywRbkZ6pYQAc7dkVxcV7i9gdjhpyGTuFjmHvJDrt/0aEkZ2RD7Q0tKMFTkAd mOVKspNhag1AZ/QvqMbxFXtcJ7DadSIgdE0IGxYFg6pnaGanWw2UuGm X-Developer-Key: i=troy.mitchell@linux.spacemit.com; a=ed25519; pk=zhRP1xE0bftrurqSWI+SzcSdJGIZ0BTTY9Id0ESzqlI= X-QQ-SENDSIZE: 520 Feedback-ID: zesmtpip:linux.spacemit.com:qybglogicsvrgz:qybglogicsvrgz3a-0 X-QQ-XMAILINFO: NEpYz65Zs0E8QCCvLySY/hHdRN5ebyaoUAuKUJWHwYpcQAZzX7O0Ephs XCqaETFFk/5bfF6KWCi3CeIYvkXOT7afK1jiYExDc3uxeQmf6xJ65dSOZfPRb32JsgKxAI2 2P3oTSGXcSnuJVeUY30ZU28DAZ8Uouu/ljbDRSlZg2OGTlv65tNIe6SyS7gU2dMNHEo2//i H/87G1Z21BgYWXSVxwitRvPy+b0N7aIDhFF4dXVnGhW/AwI2MfpvMCqENC88ZYCE3ncD6bE FBh42bu5bj5LE/dkRbelRvA2NPWo5tsGQngTg5HG1e0TfYq8QBe4cH8TThdS+ctIuAK/teQ P++bfoYmO/0rHGb8QjdTxzz5C2Rn84hleTzgF9V8yAfKfnrkKC8LRxfcEQvzLvkqJ821XC0 uh7pja32bRZQeEFWHoJ9sr82bvtsyTWfShj5ZaX77rHN3aBtdHJoHUU74Jaf4jjjwN9/9Qa SlmBFgoA+j17lLAR7EIO6Ubs25z3K0Fsmf4e37XDor+m2gH2+VScaY3WIFpZPOSd8HuQ/6M YUbaE5xzPxmyz8qba/645hhzdPQZA8i5Kmoi/7C0On9yUQPavSkvw8sHjOiScI00Jeskedm YMhg/BGCoRLYAK2IntSSxKcKoOee/iZbpQGhiVLBoxkmOGYfW5dcIvACcAULzO2mx6hF3y9 E2Z/axDTYUOTc9mE53a2r9bOgnaym1zzhRhPplbQdaLJ1iIOKLoTLBUg4aXL2Rm7js9nwP7 ZttRrfyyKWKel0nIz72Ea+cLCcF1sV0bQjlxxbKR7oRH/eLxs82bymiH6lv3zVu6j1aJ2cx dp8Dn8hRj9xuDvcAYRNSMh8Ho0nJOX9w5WqiCAxxklkmexqmCl8nTCXGfH9hYxaEawVM8Hk y5Rrq1uDpAqcPlTQ6XmOORhHV/XRQ0LQ/pd05eyRqN3uaJ3r2OmWbqv1bWavG6gBZTzATsD 324xA476XHL7DCIrlSl25Qw9zUadGujbNs3PcHCF/9GhPb0/uUUuyDnq01q0kIBSfdcNn84 b3t9lcE60ag4A5uRje3d10Mh/MjWW+T/sHP1qifiZccNghFrUzIhc/EwrLKMrhxlM203YFX GhkeudMjM4du0sG8/9UBU9Lu5Jaa9Lykd4L6kOnJrPQZv2NnCoXnjIkq/nFvItlwE4Jazy7 GyhXDTddQcvzv1ymBQqz7kZ32y6sdcaTwUSWLvbA53ljl90= X-QQ-XMRINFO: NyFYKkN4Ny6FuXrnB5Ye7Aabb3ujjtK+gg== X-QQ-RECHKSPAM: 0 The upcoming PIO support requires a wait_pio_xfer() helper, which is invoked from xfer_msg(). Since wait_pio_xfer() depends on err_check(), move the definition of xfer_msg() after err_check() to avoid a forward declaration of err_check(). Reviewed-by: Aurelien Jarno Reviewed-by: Alex Elder Signed-off-by: Troy Mitchell Tested-by: Aurelien Jarno --- Changes in v7: - nothing - Link to v6: https://lore.kernel.org/all/20260108-k1-i2c-atomic-v6-1-41b13= 2b70f68@linux.spacemit.com/ Changes in v6: - fix wrong subject - Link to v5: https://lore.kernel.org/all/20251226-k1-i2c-atomic-v5-1-023c7= 98c5523@linux.spacemit.com/ --- drivers/i2c/busses/i2c-k1.c | 62 ++++++++++++++++++++++-------------------= ---- 1 file changed, 31 insertions(+), 31 deletions(-) diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c index d42c03ef5db5..accef6653b56 100644 --- a/drivers/i2c/busses/i2c-k1.c +++ b/drivers/i2c/busses/i2c-k1.c @@ -304,37 +304,6 @@ static void spacemit_i2c_start(struct spacemit_i2c_dev= *i2c) writel(val, i2c->base + SPACEMIT_ICR); } =20 -static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) -{ - unsigned long time_left; - struct i2c_msg *msg; - - for (i2c->msg_idx =3D 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) { - msg =3D &i2c->msgs[i2c->msg_idx]; - i2c->msg_buf =3D msg->buf; - i2c->unprocessed =3D msg->len; - i2c->status =3D 0; - - reinit_completion(&i2c->complete); - - spacemit_i2c_start(i2c); - - time_left =3D wait_for_completion_timeout(&i2c->complete, - i2c->adapt.timeout); - if (!time_left) { - dev_err(i2c->dev, "msg completion timeout\n"); - spacemit_i2c_conditionally_reset_bus(i2c); - spacemit_i2c_reset(i2c); - return -ETIMEDOUT; - } - - if (i2c->status & SPACEMIT_SR_ERR) - return spacemit_i2c_handle_err(i2c); - } - - return 0; -} - static bool spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c) { if (i2c->msg_idx !=3D i2c->msg_num - 1) @@ -418,6 +387,37 @@ static void spacemit_i2c_err_check(struct spacemit_i2c= _dev *i2c) complete(&i2c->complete); } =20 +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) +{ + unsigned long time_left; + struct i2c_msg *msg; + + for (i2c->msg_idx =3D 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) { + msg =3D &i2c->msgs[i2c->msg_idx]; + i2c->msg_buf =3D msg->buf; + i2c->unprocessed =3D msg->len; + i2c->status =3D 0; + + reinit_completion(&i2c->complete); + + spacemit_i2c_start(i2c); + + time_left =3D wait_for_completion_timeout(&i2c->complete, + i2c->adapt.timeout); + if (!time_left) { + dev_err(i2c->dev, "msg completion timeout\n"); + spacemit_i2c_conditionally_reset_bus(i2c); + spacemit_i2c_reset(i2c); + return -ETIMEDOUT; + } + + if (i2c->status & SPACEMIT_SR_ERR) + return spacemit_i2c_handle_err(i2c); + } + + return 0; +} + static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) { struct spacemit_i2c_dev *i2c =3D devid; --=20 2.53.0 From nobody Mon Feb 9 10:30:42 2026 Received: from smtpbg151.qq.com (smtpbg151.qq.com [18.169.211.239]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 602DB352F9E; Sat, 7 Feb 2026 15:10:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.169.211.239 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260207-b4-k3-i2c-pio-v7-2-626942d94d91@linux.spacemit.com> References: <20260207-b4-k3-i2c-pio-v7-0-626942d94d91@linux.spacemit.com> In-Reply-To: <20260207-b4-k3-i2c-pio-v7-0-626942d94d91@linux.spacemit.com> To: Andi Shyti , Yixun Lan Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, Troy Mitchell , Aurelien Jarno X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1770476904; l=17056; i=troy.mitchell@linux.spacemit.com; s=20250712; h=from:subject:message-id; bh=XfPIQa1n40k4DtDFLExyqh9x4NVudCjNtkjrXUxfOM4=; b=XIY4R0qzj1xusVZzihXzER85wSRM7WzaTl1oVUYJFuG7TIXeEs2LcJkkKrNlcoWI+dTRnAxKZ oGRgFjUtEi3AkwereTE8OP4fTDYRuwKBa4IYZ5pGBiuz5kZSrBdyzJe X-Developer-Key: i=troy.mitchell@linux.spacemit.com; a=ed25519; pk=zhRP1xE0bftrurqSWI+SzcSdJGIZ0BTTY9Id0ESzqlI= X-QQ-SENDSIZE: 520 Feedback-ID: zesmtpip:linux.spacemit.com:qybglogicsvrgz:qybglogicsvrgz3a-0 X-QQ-XMAILINFO: N1fXDe1nQuLqzJzJOUTbdH9h9jBP7c8qePKUzi9lLqp7NJW/cdnK4SDM Ov7xtkjxgUqkJbUCzZVNWEAA//WadqOeRj3d7Yvmx1Ibfteccn8eXQWk30GW0zEH/DnAKKF gq/ars2tRCDRDyafnTWdKbpEmU1mzThCmSRgM4ISdFt3qsbfvC4Ay1Qg5kO1MklkyeXTaBH 4fnUb23QlCFB5SAgCHo3SncwI6jK80TaIWpQRIpSHv8cBx9TQaV0F6mLYn4QaYBdSN5yqhp cu8AIKtjcFiM+FWZs4ELu/qHSP+h+vUN5IMbcQjT+RiH2l8n40WS9g7HPwE62l2K/XDyqiE hRRH3+n9/P4XFQuyeM3TpT2FT36q0NQTH+BQmLWp1YLSArdH1pdCfXUxUkknKDTKEqT8wSm DiW30X40xAeQgjhsmB97XPglHIIPXZUo0qnkYHU9w4BU9g84/2zr9PE5KzJtASzM4/gpv7Q hhlDuU+SC+92LBt719y2Az5MEjejRPsaqlR+hYaQhehI93VCSu7otgfWPhEfkKBZ+bCJDp+ yz4MgqiVG8N+JTGMGifUDweUQ+Fb36cgxHxVe8Ua+CAbcHv8ktFO34bpuPLs1ezckfbsQID igD2VnolVw9FgntHILbxKGAsJCpduRWuWehmTbW27nzqBGoNqZDscOvAM+sNcbfCbg1/Tcu UEEiSlu3gk0jqLtH//eQlDfaZzjkg3UeMAow4B+e2LqPugXaD4PiY7ehwQeUngSS/hzjAar z8KFYIm5AUuL6l5rr/tjFN5HRCl5CTPAZ8vplCfRfPd26gBuuLoRUgOmvwCfpijrPaN/UJ0 Rw+Pr2E6qPh92W+bwq9HkGx/FXsyokDuNGpvJQDSJCIMqxhcVQSe68ZftKM1l12SuU5nqQb kYRMG7GMreDpIIgEB04H6x2YbSEr8DlBL99Nv2AQhpH8YA3rT7jeCYMQfCu1HSMRb+D3Y1J f9V75cUztQmUBrerpSi+nqi+ZoZ/H/EoUMdR1X1+FhordfRmM1xvj9Vwt1uL6McFnrXVWCL 9Li7+DaKm18dIU4b9etg4elYkn8PmagoBIIaTicV+1YxFE23ud4DstSeog39oxHURAz4FB5 RrC4Ti9lZoGjVGGjvy88tkZaDJLKCiT6Y5dadOYSXIIh3ljmgqyhMnbEpvDjlFiidBvgldc cEVaZ3Flqd110OylhwDgu5S1uMrP0pXmIn+fqghV9c46OSvebs5z3IPHOQ== X-QQ-XMRINFO: M/715EihBoGS47X28/vv4NpnfpeBLnr4Qg== X-QQ-RECHKSPAM: 0 This patch introduces I2C PIO functionality for the Spacemit K1 SoC, enabling the use of I2C in atomic context. When i2c xfer_atomic is invoked, use_pio is set accordingly. Since an atomic context is required, all interrupts are disabled when operating in PIO mode. Even with interrupts disabled, the bits in the ISR (Interrupt Status Register) will still be set, so error handling can be performed by polling the relevant status bits in the ISR. Signed-off-by: Troy Mitchell Tested-by: Aurelien Jarno Reviewed-by: Aurelien Jarno --- Changes in v7: - optimize register access in spacemit_i2c_handle_state() by moving readl()= inside the non-idle check - refactor loop logic in spacemit_i2c_wait_pio_xfer() for better readability - simplify spacemit_i2c_delay() to use fsleep() and remove redundant range = arguments - fix multi-line comment style and remove unnecessary blank lin - Link to v6: https://lore.kernel.org/all/20260108-k1-i2c-atomic-v6-2-41b13= 2b70f68@linux.spacemit.com/ Changes in v6: - modify code style - modify and add comments - Link to v5: https://lore.kernel.org/all/20251226-k1-i2c-atomic-v5-2-023c7= 98c5523@linux.spacemit.com/ Changes in v5: - optimize code logic - refactor delay handling into spacemit_i2c_delay() helper - introduce spacemit_i2c_complete() to centralize transfer completion - rework PIO transfer wait logic for clarity and correctness - modify and add some comments - modify commit message - Link to v4: https://lore.kernel.org/all/20251009-k1-i2c-atomic-v4-1-a8936= 7870286@linux.spacemit.com/ Changes in v4: - refactor for better readability: simplify condition check and moving if/e= lse (timeout/ wait_xfer_complete) logic into a function - remove irrelevant changes - remove the status clear call in spacemit_i2c_xfer_common() - sort functions to avoid forward declarations, move unavoidable ones above function definitions - use udelay() in atomic context to avoid sleeping - wait for MSD on the last byte in wait_pio_xfer() - Link to v3: https://lore.kernel.org/r/20250929-k1-i2c-atomic-v3-1-f7e660c= 138b6@linux.spacemit.com Changes in v3: - drop 1-5 patches (have been merged) - modify commit message - use readl_poll_timeout_atomic() in wait_pio_xfer() - use msecs_to_jiffies() when get PIO mode timeout value - factor out transfer state handling into spacemit_i2c_handle_state(). - do not disable/enable the controller IRQ around PIO transfers. - consolidate spacemit_i2c_init() interrupt setup - rename is_pio -> use_pio - rename spacemit_i2c_xfer() -> spacemit_i2c_xfer_common() - rename spacemit_i2c_int_xfer() -> spacemit_i2c_xfer() - rename spacemit_i2c_pio_xfer() -> spacemit_i2c_pio_xfer_atomic() - call spacemit_i2c_err_check() in wait_pio_xfer() when write last byte - Link to v2: https://lore.kernel.org/r/20250925-k1-i2c-atomic-v2-0-46dc133= 11cda@linux.spacemit.com Changes in v2: - add is_pio judgement in irq_handler() - use a fixed timeout value when PIO - use readl_poll_timeout() in spacemit_i2c_wait_bus_idle() when PIO - Link to v1: https://lore.kernel.org/r/20250827-k1-i2c-atomic-v1-0-e59bea0= 2d680@linux.spacemit.com --- drivers/i2c/busses/i2c-k1.c | 300 +++++++++++++++++++++++++++++++++-------= ---- 1 file changed, 228 insertions(+), 72 deletions(-) diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c index accef6653b56..2e2669a7a9b5 100644 --- a/drivers/i2c/busses/i2c-k1.c +++ b/drivers/i2c/busses/i2c-k1.c @@ -97,6 +97,10 @@ =20 #define SPACEMIT_BUS_RESET_CLK_CNT_MAX 9 =20 +#define SPACEMIT_WAIT_TIMEOUT 1000 /* ms */ +#define SPACEMIT_POLL_TIMEOUT 1000 /* us */ +#define SPACEMIT_POLL_INTERVAL 30 /* us */ + enum spacemit_i2c_state { SPACEMIT_STATE_IDLE, SPACEMIT_STATE_START, @@ -125,6 +129,7 @@ struct spacemit_i2c_dev { =20 enum spacemit_i2c_state state; bool read; + bool use_pio; struct completion complete; u32 status; }; @@ -171,6 +176,14 @@ static int spacemit_i2c_handle_err(struct spacemit_i2c= _dev *i2c) return i2c->status & SPACEMIT_SR_ACKNAK ? -ENXIO : -EIO; } =20 +static inline void spacemit_i2c_delay(struct spacemit_i2c_dev *i2c, unsign= ed int us) +{ + if (i2c->use_pio) + udelay(us); + else + fsleep(us); +} + static void spacemit_i2c_conditionally_reset_bus(struct spacemit_i2c_dev *= i2c) { u32 status; @@ -182,7 +195,8 @@ static void spacemit_i2c_conditionally_reset_bus(struct= spacemit_i2c_dev *i2c) return; =20 spacemit_i2c_reset(i2c); - usleep_range(10, 20); + + spacemit_i2c_delay(i2c, 10); =20 for (clk_cnt =3D 0; clk_cnt < SPACEMIT_BUS_RESET_CLK_CNT_MAX; clk_cnt++) { status =3D readl(i2c->base + SPACEMIT_IBMR); @@ -211,9 +225,15 @@ static int spacemit_i2c_wait_bus_idle(struct spacemit_= i2c_dev *i2c) if (!(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB))) return 0; =20 - ret =3D readl_poll_timeout(i2c->base + SPACEMIT_ISR, - val, !(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB)), - 1500, SPACEMIT_I2C_BUS_BUSY_TIMEOUT); + if (i2c->use_pio) + ret =3D readl_poll_timeout_atomic(i2c->base + SPACEMIT_ISR, + val, !(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB)), + 1500, SPACEMIT_I2C_BUS_BUSY_TIMEOUT); + else + ret =3D readl_poll_timeout(i2c->base + SPACEMIT_ISR, + val, !(val & (SPACEMIT_SR_UB | SPACEMIT_SR_IBB)), + 1500, SPACEMIT_I2C_BUS_BUSY_TIMEOUT); + if (ret) spacemit_i2c_reset(i2c); =20 @@ -225,7 +245,7 @@ static void spacemit_i2c_check_bus_release(struct space= mit_i2c_dev *i2c) /* in case bus is not released after transfer completes */ if (readl(i2c->base + SPACEMIT_ISR) & SPACEMIT_SR_EBB) { spacemit_i2c_conditionally_reset_bus(i2c); - usleep_range(90, 150); + spacemit_i2c_delay(i2c, 90); } } =20 @@ -237,25 +257,33 @@ spacemit_i2c_clear_int_status(struct spacemit_i2c_dev= *i2c, u32 mask) =20 static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c) { - u32 val; - - /* - * Unmask interrupt bits for all xfer mode: - * bus error, arbitration loss detected. - * For transaction complete signal, we use master stop - * interrupt, so we don't need to unmask SPACEMIT_CR_TXDONEIE. - */ - val =3D SPACEMIT_CR_BEIE | SPACEMIT_CR_ALDIE; - - /* - * Unmask interrupt bits for interrupt xfer mode: - * When IDBR receives a byte, an interrupt is triggered. - * - * For the tx empty interrupt, it will be enabled in the - * i2c_start function. - * Otherwise, it will cause an erroneous empty interrupt before i2c_start. - */ - val |=3D SPACEMIT_CR_DRFIE; + u32 val =3D 0; + + if (!i2c->use_pio) { + /* + * Enable interrupt bits for all xfer mode: + * bus error, arbitration loss detected. + */ + val |=3D SPACEMIT_CR_BEIE | SPACEMIT_CR_ALDIE; + + /* + * Unmask interrupt bits for interrupt xfer mode: + * When IDBR receives a byte, an interrupt is triggered. + * + * For the tx empty interrupt, it will be enabled in the + * i2c_start(). + * We don't want a TX empty interrupt until we start + * a transfer in i2c_start(). + */ + val |=3D SPACEMIT_CR_DRFIE; + + /* + * Enable master stop interrupt bit. + * For transaction complete signal, we use master stop + * interrupt, so we don't need to unmask SPACEMIT_CR_TXDONEIE. + */ + val |=3D SPACEMIT_CR_MSDIE; + } =20 if (i2c->clock_freq =3D=3D SPACEMIT_I2C_MAX_FAST_MODE_FREQ) val |=3D SPACEMIT_CR_MODE_FAST; @@ -267,7 +295,7 @@ static void spacemit_i2c_init(struct spacemit_i2c_dev *= i2c) val |=3D SPACEMIT_CR_SCLE; =20 /* enable master stop detected */ - val |=3D SPACEMIT_CR_MSDE | SPACEMIT_CR_MSDIE; + val |=3D SPACEMIT_CR_MSDE; =20 writel(val, i2c->base + SPACEMIT_ICR); =20 @@ -300,7 +328,12 @@ static void spacemit_i2c_start(struct spacemit_i2c_dev= *i2c) /* send start pulse */ val =3D readl(i2c->base + SPACEMIT_ICR); val &=3D ~SPACEMIT_CR_STOP; - val |=3D SPACEMIT_CR_START | SPACEMIT_CR_TB | SPACEMIT_CR_DTEIE; + val |=3D SPACEMIT_CR_START | SPACEMIT_CR_TB; + + /* Enable the TX empty interrupt */ + if (!i2c->use_pio) + val |=3D SPACEMIT_CR_DTEIE; + writel(val, i2c->base + SPACEMIT_ICR); } =20 @@ -315,8 +348,23 @@ static bool spacemit_i2c_is_last_msg(struct spacemit_i= 2c_dev *i2c) return !i2c->unprocessed; } =20 +static inline void spacemit_i2c_complete(struct spacemit_i2c_dev *i2c) +{ + /* SPACEMIT_STATE_IDLE avoids triggering the next byte */ + i2c->state =3D SPACEMIT_STATE_IDLE; + + if (i2c->use_pio) + return; + + complete(&i2c->complete); +} + static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c) { + /* If there's no space in the IDBR, we're done */ + if (!(i2c->status & SPACEMIT_SR_ITE)) + return; + /* if transfer completes, SPACEMIT_ISR will handle it */ if (i2c->status & SPACEMIT_SR_MSD) return; @@ -327,16 +375,19 @@ static void spacemit_i2c_handle_write(struct spacemit= _i2c_dev *i2c) return; } =20 - /* SPACEMIT_STATE_IDLE avoids trigger next byte */ - i2c->state =3D SPACEMIT_STATE_IDLE; - complete(&i2c->complete); + spacemit_i2c_complete(i2c); } =20 static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c) { + /* If there's nothing in the IDBR, we're done */ + if (!(i2c->status & SPACEMIT_SR_IRF)) + return; + if (i2c->unprocessed) { *i2c->msg_buf++ =3D readl(i2c->base + SPACEMIT_IDBR); i2c->unprocessed--; + return; } =20 /* if transfer completes, SPACEMIT_ISR will handle it */ @@ -347,9 +398,7 @@ static void spacemit_i2c_handle_read(struct spacemit_i2= c_dev *i2c) if (i2c->unprocessed) return; =20 - /* SPACEMIT_STATE_IDLE avoids trigger next byte */ - i2c->state =3D SPACEMIT_STATE_IDLE; - complete(&i2c->complete); + spacemit_i2c_complete(i2c); } =20 static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c) @@ -383,8 +432,129 @@ static void spacemit_i2c_err_check(struct spacemit_i2= c_dev *i2c) =20 spacemit_i2c_clear_int_status(i2c, SPACEMIT_I2C_INT_STATUS_MASK); =20 - i2c->state =3D SPACEMIT_STATE_IDLE; - complete(&i2c->complete); + spacemit_i2c_complete(i2c); +} + +static void spacemit_i2c_handle_state(struct spacemit_i2c_dev *i2c) +{ + u32 val; + + if (i2c->status & SPACEMIT_SR_ERR) + goto err_out; + + switch (i2c->state) { + case SPACEMIT_STATE_START: + spacemit_i2c_handle_start(i2c); + break; + case SPACEMIT_STATE_READ: + spacemit_i2c_handle_read(i2c); + break; + case SPACEMIT_STATE_WRITE: + spacemit_i2c_handle_write(i2c); + break; + default: + break; + } + + if (i2c->state !=3D SPACEMIT_STATE_IDLE) { + val =3D readl(i2c->base + SPACEMIT_ICR); + val &=3D ~(SPACEMIT_CR_TB | SPACEMIT_CR_ACKNAK | + SPACEMIT_CR_STOP | SPACEMIT_CR_START); + val |=3D SPACEMIT_CR_TB; + if (!i2c->use_pio) + val |=3D SPACEMIT_CR_ALDIE; + + if (spacemit_i2c_is_last_msg(i2c)) { + /* trigger next byte with stop */ + val |=3D SPACEMIT_CR_STOP; + + if (i2c->read) + val |=3D SPACEMIT_CR_ACKNAK; + } + writel(val, i2c->base + SPACEMIT_ICR); + } + +err_out: + spacemit_i2c_err_check(i2c); +} + +/* + * In PIO mode, this function is used as a replacement for + * wait_for_completion_timeout(), whose return value indicates + * the remaining time. + * + * We do not have a meaningful remaining-time value here, so + * return a non-zero value on success to indicate "not timed out". + * Returning 1 ensures callers treating the return value as + * time_left will not incorrectly report a timeout. + */ +static int spacemit_i2c_wait_pio_xfer(struct spacemit_i2c_dev *i2c) +{ + u32 mask, msec =3D jiffies_to_msecs(i2c->adapt.timeout); + ktime_t timeout =3D ktime_add_ms(ktime_get(), msec); + int ret; + + mask =3D SPACEMIT_SR_IRF | SPACEMIT_SR_ITE; + + do { + i2c->status =3D readl(i2c->base + SPACEMIT_ISR); + + spacemit_i2c_clear_int_status(i2c, i2c->status); + + if (i2c->status & mask) + spacemit_i2c_handle_state(i2c); + else + udelay(SPACEMIT_POLL_INTERVAL); + } while (i2c->unprocessed && ktime_compare(ktime_get(), timeout) < 0); + + if (i2c->unprocessed) + return 0; + + if (i2c->read) + return 1; + + /* + * If this is the last byte to write of the current message, + * we have to wait here. Otherwise, control will proceed directly + * to start(), which would overwrite the current data. + */ + ret =3D readl_poll_timeout_atomic(i2c->base + SPACEMIT_ISR, + i2c->status, i2c->status & SPACEMIT_SR_ITE, + SPACEMIT_POLL_INTERVAL, SPACEMIT_POLL_TIMEOUT); + if (ret) + return 0; + + /* + * For writes: in interrupt mode, an ITE (write-empty) interrupt is trigg= ered + * after the last byte, and the MSD-related handling takes place there. + * In PIO mode, however, we need to explicitly call err_check() to emulat= e this + * step, otherwise the next transfer will fail. + */ + if (i2c->msg_idx =3D=3D i2c->msg_num - 1) { + mask =3D SPACEMIT_SR_MSD | SPACEMIT_SR_ERR; + /* + * In some cases, MSD may not arrive immediately; + * wait here to handle that. + */ + ret =3D readl_poll_timeout_atomic(i2c->base + SPACEMIT_ISR, + i2c->status, i2c->status & mask, + SPACEMIT_POLL_INTERVAL, SPACEMIT_POLL_TIMEOUT); + if (ret) + return 0; + + spacemit_i2c_err_check(i2c); + } + + return 1; +} + +static int spacemit_i2c_wait_xfer_complete(struct spacemit_i2c_dev *i2c) +{ + if (i2c->use_pio) + return spacemit_i2c_wait_pio_xfer(i2c); + + return wait_for_completion_timeout(&i2c->complete, + i2c->adapt.timeout); } =20 static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) @@ -402,8 +572,8 @@ static int spacemit_i2c_xfer_msg(struct spacemit_i2c_de= v *i2c) =20 spacemit_i2c_start(i2c); =20 - time_left =3D wait_for_completion_timeout(&i2c->complete, - i2c->adapt.timeout); + time_left =3D spacemit_i2c_wait_xfer_complete(i2c); + if (!time_left) { dev_err(i2c->dev, "msg completion timeout\n"); spacemit_i2c_conditionally_reset_bus(i2c); @@ -421,7 +591,7 @@ static int spacemit_i2c_xfer_msg(struct spacemit_i2c_de= v *i2c) static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) { struct spacemit_i2c_dev *i2c =3D devid; - u32 status, val; + u32 status; =20 status =3D readl(i2c->base + SPACEMIT_ISR); if (!status) @@ -431,41 +601,8 @@ static irqreturn_t spacemit_i2c_irq_handler(int irq, v= oid *devid) =20 spacemit_i2c_clear_int_status(i2c, status); =20 - if (i2c->status & SPACEMIT_SR_ERR) - goto err_out; - - val =3D readl(i2c->base + SPACEMIT_ICR); - val &=3D ~(SPACEMIT_CR_TB | SPACEMIT_CR_ACKNAK | SPACEMIT_CR_STOP | SPACE= MIT_CR_START); + spacemit_i2c_handle_state(i2c); =20 - switch (i2c->state) { - case SPACEMIT_STATE_START: - spacemit_i2c_handle_start(i2c); - break; - case SPACEMIT_STATE_READ: - spacemit_i2c_handle_read(i2c); - break; - case SPACEMIT_STATE_WRITE: - spacemit_i2c_handle_write(i2c); - break; - default: - break; - } - - if (i2c->state !=3D SPACEMIT_STATE_IDLE) { - val |=3D SPACEMIT_CR_TB | SPACEMIT_CR_ALDIE; - - if (spacemit_i2c_is_last_msg(i2c)) { - /* trigger next byte with stop */ - val |=3D SPACEMIT_CR_STOP; - - if (i2c->read) - val |=3D SPACEMIT_CR_ACKNAK; - } - writel(val, i2c->base + SPACEMIT_ICR); - } - -err_out: - spacemit_i2c_err_check(i2c); return IRQ_HANDLED; } =20 @@ -474,6 +611,11 @@ static void spacemit_i2c_calc_timeout(struct spacemit_= i2c_dev *i2c) unsigned long timeout; int idx =3D 0, cnt =3D 0; =20 + if (i2c->use_pio) { + i2c->adapt.timeout =3D msecs_to_jiffies(SPACEMIT_WAIT_TIMEOUT); + return; + } + for (; idx < i2c->msg_num; idx++) cnt +=3D (i2c->msgs + idx)->len + 1; =20 @@ -486,11 +628,14 @@ static void spacemit_i2c_calc_timeout(struct spacemit= _i2c_dev *i2c) i2c->adapt.timeout =3D usecs_to_jiffies(timeout + USEC_PER_SEC / 10) / i2= c->msg_num; } =20 -static int spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg *ms= gs, int num) +static inline int +spacemit_i2c_xfer_common(struct i2c_adapter *adapt, struct i2c_msg *msgs, = int num, bool use_pio) { struct spacemit_i2c_dev *i2c =3D i2c_get_adapdata(adapt); int ret; =20 + i2c->use_pio =3D use_pio; + i2c->msgs =3D msgs; i2c->msg_num =3D num; =20 @@ -518,6 +663,16 @@ static int spacemit_i2c_xfer(struct i2c_adapter *adapt= , struct i2c_msg *msgs, in return ret < 0 ? ret : num; } =20 +static int spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg *ms= gs, int num) +{ + return spacemit_i2c_xfer_common(adapt, msgs, num, false); +} + +static int spacemit_i2c_pio_xfer_atomic(struct i2c_adapter *adapt, struct = i2c_msg *msgs, int num) +{ + return spacemit_i2c_xfer_common(adapt, msgs, num, true); +} + static u32 spacemit_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); @@ -525,6 +680,7 @@ static u32 spacemit_i2c_func(struct i2c_adapter *adap) =20 static const struct i2c_algorithm spacemit_i2c_algo =3D { .xfer =3D spacemit_i2c_xfer, + .xfer_atomic =3D spacemit_i2c_pio_xfer_atomic, .functionality =3D spacemit_i2c_func, }; =20 --=20 2.53.0