From nobody Sun Feb 8 07:58:44 2026 Received: from smtpbgbr2.qq.com (smtpbgbr2.qq.com [54.207.22.56]) (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 E4B4D38A735; Thu, 8 Jan 2026 07:54:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=54.207.22.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767858850; cv=none; b=Egqs8nDWHztciRdLap3g/vXkSHc1ZhVc/C0x87WdnaaGaGViSVJJA3bgx09nJqRf2yvH/HzFX612ls0RM4LttK3sKIXDXZUJh2o6DRNkwneLU1GkjPY4VgwCOnwxCiAv4WBNSkrmDeghH/J5iwZOak/Xx/vWKh9JaSfTcE5DOIs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767858850; c=relaxed/simple; bh=tbIGjlDaxXLlK3CGW7YL2KnO3OY9L0q1RD5Ci1tLoMc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JppijklmXvMrbtqb0IsguYksk5afHinSSa1Xl7TeKTdOAHmhIX/cwu/8kZPoK+AZAj3nfnXXK1XlVkJfUyCWDw8K+rJ0EG29s2HtuMMG/gIKip95LsbYcvAoNwIypFW70TQPVr2tAFUvxEx/WNhbry+P9PrYLKcoQmk/rq7x7BQ= ARC-Authentication-Results: i=1; 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Thu, 08 Jan 2026 15:52:17 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 0 X-BIZMAIL-ID: 5555458612639012329 EX-QQ-RecipientCnt: 11 From: Troy Mitchell Date: Thu, 08 Jan 2026 15:52:11 +0800 Subject: [PATCH v6 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: <20260108-k1-i2c-atomic-v6-1-41b132b70f68@linux.spacemit.com> References: <20260108-k1-i2c-atomic-v6-0-41b132b70f68@linux.spacemit.com> In-Reply-To: <20260108-k1-i2c-atomic-v6-0-41b132b70f68@linux.spacemit.com> To: Andi Shyti , Yixun Lan , Alex Elder , Aurelien Jarno , Michael Opdenacker , Troy Mitchell Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, Troy Mitchell X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1767858732; l=2987; i=troy.mitchell@linux.spacemit.com; s=20250710; h=from:subject:message-id; bh=tbIGjlDaxXLlK3CGW7YL2KnO3OY9L0q1RD5Ci1tLoMc=; b=iv/VwVfba0jDgoFizy6ZVeTjzmJ9+RmrC3djzGroqWNBoCPOXZzhHQns5VDd6AZILvSXRWNte nt8twu9OoMPB3dl9G71r4gb3tSN7vXpAHfytLh+hu7OScEUfnXdyV9J X-Developer-Key: i=troy.mitchell@linux.spacemit.com; a=ed25519; pk=lQa7BzLrq8DfZnChqmwJ5qQk8fP2USmY/4xZ2/MSsXc= X-QQ-SENDSIZE: 520 Feedback-ID: esmtpsz:linux.spacemit.com:qybglogicsvrgz:qybglogicsvrgz3a-0 X-QQ-XMAILINFO: NoTnWcAlB075yW1wVq4GDLMNSMnq2O1vkNmA15iSvqoA0z4x7bZuRtQe 2hn4Dc/JrMOA0P1of2hdx/ZvdKnN8N1JHmAO1y8pOgOUv04jWro26e8jSYW8B1Nuuok/4tR gQ6h+kcVHOd9ohy0gK9ycI3MBW1LTpY1/qgQA5oibhrGcsElH7CtR8bIFroXlifnbxUEgKn 8BBLgTSTpVKHSREUJJDgEzhCSjyeuSNUiP0DF/27WbZk5mXA8dU3P489a15nNyNypMYAdeR 2wua+6Z0A0y6RHsL8//8RAsjNWw61yF6Y8ypmgpW1+52Z1TQsDDKbRCYFIdl3399IIVZ4oy xiZ5fbcXP3/fbP9rKUmhyqsLMk3tD4tgbRh0GcCbOPktwv7rKq/hGprBOdZ2WRenqZ3Lmy3 +IZmKck2Yi9wObwucmCaChrYxLiJQHLLqKkSKC8zCJJl2/Y6Wb0Zx3bp49vn4OZeNUg8zxt UMY6fE4pnhbYtq+ZUTlhN3La2FwP6Qs56Wc/85HcCIGK9b48cuQQheWZdBzyj78eYZx5aQ4 cbP0lUXLXoa+iQ9fCnO/UkVOuaWm/M4DpZDJNnjWJMmmjT75gc+mg1W/LBNa3+saLGi9ejZ H/asqZg4xH07W4eDrSJwSI6nwRk9jB8ZrHHfb5H5AeNvnvKLZH6hVdDBZVLpUA987ws/Tym B2SYgWQ3+mPUuRcBKRA8G2ZkFmA0650Q+m7LRf2w9bq0LDH+JF3Fd9TIgdY5OLERHU+Y1jx TGqztGjf6nnN8vXQVAjyZ1u3Wp+NcfFlFCMsp3wtDsurnlHNHB2DDTPO5BmXACxYbZGQwkF x6AJpAvX4dT0SXJ44NspY0loU4n0jvHDwsbEWNYf49Com6uhB103rDdIyZISxSCmeSprKe/ qcsDx+99AJN2h+AXHpdVgcKeVwWM9uecVD1w5nHP0pbma+SBjqHqKYmK4Jrkyl7nvXzG0TZ 7pZ3AJIRo/J7Bel5mEGBM+Rrbo9LwpuBK1G8KZX2qTm3CdZKKKlmOlariS1Ho39YopB4rmF Dh9L2KnYTVSzxfgCn45V8wLrjayCnikLk3naBv+5w9WvGc235RN/oKImnLdZm9oD6zsOmkr dlrVvG7qcuFtF8rOicPAwTLFoB+lXU99HSXrdWX1MPyKco4cy+3MQZCPCBOvH99jw== X-QQ-XMRINFO: Nq+8W0+stu50tPAe92KXseR0ZZmBTk3gLg== 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 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 d42c03ef5db5984ea8e06b3d7eb485b4f899e616..accef6653b56bd3505770328af1= 7e441fad613a7 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 2.52.0 From nobody Sun Feb 8 07:58:44 2026 Received: from smtpbg154.qq.com (smtpbg154.qq.com [15.184.224.54]) (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 00AFE37E2EF; Thu, 8 Jan 2026 07:54:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=15.184.224.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260108-k1-i2c-atomic-v6-2-41b132b70f68@linux.spacemit.com> References: <20260108-k1-i2c-atomic-v6-0-41b132b70f68@linux.spacemit.com> In-Reply-To: <20260108-k1-i2c-atomic-v6-0-41b132b70f68@linux.spacemit.com> To: Andi Shyti , Yixun Lan , Alex Elder , Aurelien Jarno , Michael Opdenacker , Troy Mitchell Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, Troy Mitchell X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1767858732; l=16648; i=troy.mitchell@linux.spacemit.com; s=20250710; h=from:subject:message-id; bh=IBO6wAaU3tufWudymtFJMt5TWu0a1ZS63hImtFBjW6g=; b=kkbf5FuC9fsE1LU2HAlxpdJYR3vX+JNgwX5bHoaqFUKbt9oi7S3t6doq7/P3fMwTcPONt3YMx rDQ6t/0vQKQABBXkbc2Jw5GMQu7GQoaJ1yYEstXj4a+S05+LvKu9Yyk X-Developer-Key: i=troy.mitchell@linux.spacemit.com; a=ed25519; pk=lQa7BzLrq8DfZnChqmwJ5qQk8fP2USmY/4xZ2/MSsXc= X-QQ-SENDSIZE: 520 Feedback-ID: zesmtpsz:linux.spacemit.com:qybglogicsvrgz:qybglogicsvrgz3a-0 X-QQ-XMAILINFO: NzR/OK+xrDmmzMwiH5DPgIFWbqRRuSAdP1fBrvB50j32dbj4pHuc333I gvT+u5upOvY/E4NJdCuSFgJ6/M7t/4kxs4CQSer22cljMIJxU8q9ESHx4683fJBJlY8iW+s DtUJt9e2rgvQrV+aNH3cCAyt3er+h9KpCr0ZiW3ffwwzptcOHIXJZvZJJ1apN1W/rRrIV2a k7428jlqaxbRNBkrrUMNPhWkspFDYii1aYJSQF7jIlAk2IPzDDzo7TKzwPVaHd4wWhDr3YR CtC4H5K4AtQ8D+pIoAIf9uPnk+qnCfZNIGc+191PLw5qlZrFXB9TOCyogejuKXxhV4PJKLs TGeVt0Q37t1kCZlFlDwrBoOjZ9JHUewCvH5bdamWuCxNXz43KLy7ftbBx13jJWfQ6VDE82R Kvsdb4/GLuuNplJdYf/4URLslRfxbSI4UarxSsrm/0dUDa7M1AsXjy28LJC9IIg2M70Izln lq+eshhVA5oLrWqIJG2a9zE99vhh/oBqzA3B762sYhqZ45pWWuGyIugFevcoK+ynCyjzRTH 2IiSxe0UJ28N6nGkUcyXa31rNugjgtKO8rVu0RLC2mx30gP5lYh0iONehC23JkAm6/pILrS q/TPmMgVryXi5Ij4fhGql8/xl8TBjWxSM7QD9VkOHihhDMODyQ/6jEyjU/nfR7KqYgWUXgR gJxin7VdowA6KfHIjvdeES5Nbcav9a4Oro+STX76ClXT/WhPvAM+9YJ+ENOhNGiXWAxjaXg NK9ITes+woL2BN0Be7LpyEDII/HG0o1FGN/ohTtFi24Ip9b+WmaH16HITEt7TN1o51rwL/R YygD6AlVwgQilg9i8fDz9gxCYBLaUGyRVruHFRlkDywkrFEwlNSklP6Tll0lZaPSXcWCrPz LZ6/40OjcdCQiANLip+A+evv9NEVJuZiB0CLCQCPiX/5G52cPTqUH+0hUh/3ML9AOqgIwlp rWTzs3XN+N5/pp2ODuCKii2mwXWHPBp9CwI+4JiWMq18cocO0TS2rzuhmeleUd6s6/Z1Ut8 8MZzfO+5rNpKO9t+/grqaoGN+FmeJ18hOinTYzsPky2VRB+Fg04TQZJblQtAFnZJFLsT07W UKQhIqcTdWtYAkWUsaopMyNVJyTj7/Nj0zJaz5T+GW9W/2sr0JhlhfarVo1iTxG5sGcsCz3 c0uak+diaZAWBbQcMuSFTAIVEKG4Wx6VjVfClzDKOErErRuM383c//KmRQ== X-QQ-XMRINFO: MPJ6Tf5t3I/ylTmHUqvI8+Wpn+Gzalws3A== 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 Reviewed-by: Aurelien Jarno Tested-by: Aurelien Jarno --- 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 | 304 +++++++++++++++++++++++++++++++++-------= ---- 1 file changed, 232 insertions(+), 72 deletions(-) diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c index accef6653b56bd3505770328af17e441fad613a7..427cd8dc6947c1d5fbdd364a351= f7c065ba0b595 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 +176,16 @@ 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, + unsigned int min_us, + unsigned int max_us) +{ + if (i2c->use_pio) + udelay(max_us); + else + usleep_range(min_us, max_us); +} + static void spacemit_i2c_conditionally_reset_bus(struct spacemit_i2c_dev *= i2c) { u32 status; @@ -182,7 +197,8 @@ 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); =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 +227,15 @@ 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 +247,7 @@ 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, 150); } } =20 @@ -237,25 +259,32 @@ 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 +296,7 @@ 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 +329,12 @@ 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 +349,23 @@ 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 +376,19 @@ 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 +399,7 @@ 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 +433,132 @@ 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; + + val =3D readl(i2c->base + SPACEMIT_ICR); + val &=3D ~(SPACEMIT_CR_TB | SPACEMIT_CR_ACKNAK | SPACEMIT_CR_STOP | SPACE= MIT_CR_START); + + 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; + 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)) { + udelay(SPACEMIT_POLL_INTERVAL); + continue; + } + + spacemit_i2c_handle_state(i2c); + } 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 +576,8 @@ 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 +595,7 @@ 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 +605,8 @@ 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); - - 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); - } + spacemit_i2c_handle_state(i2c); =20 -err_out: - spacemit_i2c_err_check(i2c); return IRQ_HANDLED; } =20 @@ -474,6 +615,11 @@ 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 +632,14 @@ 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 +667,16 @@ 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 +684,7 @@ 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 2.52.0