From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CDBEE4C6507; Fri, 9 Oct 2026 14:14:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791555253; cv=none; b=njJP+xXPHQ5bVEAV5IixT9+XnAQbB/6vVtLf6JcG2G+X/XW6Nez/2gSMQKNAi8q9Nl8hA/399ZPqn3U5iZnoApDEDKC193sgyXI0lxlUBQC4da3st9Z8LFQOkUlOoRr0UQ34AvecCOGnG11FdmjuR90lwtVSe84f9O4KvMc6xVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791555253; c=relaxed/simple; bh=r3p5mzo5vt22moaJ9g12b4bH2ZFYRKbM5agTH+hc3qk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YtSbfyC8Et23pjtCs+1a0iC96wnmTtJI9lgecCqXeRyRFK8bBWl86jFkAgeHMRVO4dOOR8ZHAeTaj0+dtVIGJkEyLngCKh9y7VQN2Gp6C7hpUKEyab6EDsgOa2tDJ735/kHCR/26UXrJPvgBOTCnF9PZyOX/WOcT52c9aPwCl1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=i4iPyZeH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="i4iPyZeH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 928461F00893; Fri, 9 Oct 2026 14:14:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791555248; bh=i8eKryt6Z+PjpgLF1ak9kJbCGua7hUOqNAEzuscvE+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i4iPyZeH4XhNA1EeDjE492IR9ZV9OsM/QqGDqTz9TEtWl/yTZ+GnE8zdQ0Vo5e6bc ghIbQ89yBmEIE+FfzjIkOwHYvNr84VWIqcGAeMZdf2XScAaM73r18CvsfFWf2keuFB E8RsWm7x14sKc6lW6fl/KpD891Z5XcszFBLve2B0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Heikki Krogerus , Rodrigo Vivi , Sasha Levin Subject: [PATCH 7.2 003/428] drm/xe/i2c: Keep the i2c controller always enabled Date: Fri, 9 Oct 2026 16:05:40 +0200 Message-ID: <20261009140946.097727660@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261009140946.008206689@linuxfoundation.org> References: <20261009140946.008206689@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heikki Krogerus [ Upstream commit 244abef7f280a6a84297bfab5fd2e77147bc419a ] Some platforms make an assumption that the i2c controller's enabled state indicates also the power state of the controller. This can create a problem when the controller is in disabled state, because the hardware may assume incorrectly that it is then also in low-power state. To fix this, the controller is kept enabled by taking over the IC_ENABLE register. The controller has to be disabled when the configuration is updated and when the target address or the slave address are assigned, so disabling it when IC_CON, IC_TAR or IC_SAR registers are programmed, and then re-enabling it again. Fixes: f0e53aadd702 ("drm/xe: Support for I2C attached MCUs") Cc: stable@vger.kernel.org Signed-off-by: Heikki Krogerus Reviewed-by: Rodrigo Vivi Link: https://patch.msgid.link/20260811121008.1493015-4-heikki.krogerus@linux.intel.com Signed-off-by: Rodrigo Vivi (cherry picked from commit 76cc14e2faed1adae20f4ee144ead0e3a7566c49) Signed-off-by: Rodrigo Vivi Signed-off-by: Sasha Levin --- drivers/gpu/drm/xe/xe_i2c.c | 49 ++++++++++++++++++++++++++++++++++++- drivers/gpu/drm/xe/xe_i2c.h | 1 + 2 files changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_i2c.c b/drivers/gpu/drm/xe/xe_i2c.c index 6fce3de272965..b376a9167cc1c 100644 --- a/drivers/gpu/drm/xe/xe_i2c.c +++ b/drivers/gpu/drm/xe/xe_i2c.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -215,11 +216,40 @@ void xe_i2c_irq_postinstall(struct xe_device *xe) xe_mmio_rmw32(mmio, I2C_CONFIG_CMD, PCI_COMMAND_INTX_DISABLE, 0); } +/* See "Disabling DW_apb_i2c" in the DesignWare DW_abp_i2c databook. */ +static void xe_i2c_disable(struct xe_i2c *i2c) +{ + int timeout = 100; + u32 status; + + xe_mmio_rmw32(i2c->mmio, I2C_REG(DW_IC_ENABLE), DW_IC_ENABLE_ENABLE, 0); + + do { + status = xe_mmio_read32(i2c->mmio, I2C_REG(DW_IC_ENABLE_STATUS)); + if (!(status & DW_IC_ENABLE_ENABLE)) + return; + /* Can't sleep here. */ + udelay(25); + } while (timeout--); + + dev_warn(i2c->drm_dev, "timeout in disabling i2c adapter\n"); +} + static int xe_i2c_read(void *context, unsigned int reg, unsigned int *val) { struct xe_i2c *i2c = context; - *val = xe_mmio_read32(i2c->mmio, XE_REG(reg + I2C_MEM_SPACE_OFFSET)); + *val = xe_mmio_read32(i2c->mmio, I2C_REG(reg)); + + switch (reg) { + case DW_IC_ENABLE: + case DW_IC_ENABLE_STATUS: + FIELD_MODIFY(DW_IC_ENABLE_ENABLE, val, + i2c->ic_enable & DW_IC_ENABLE_ENABLE); + break; + default: + break; + } return 0; } @@ -229,6 +259,23 @@ static int xe_i2c_write(void *context, unsigned int reg, unsigned int val) struct xe_i2c *i2c = context; switch (reg) { + case DW_IC_CON: + case DW_IC_TAR: + case DW_IC_SAR: + /* Disable the controller. */ + xe_i2c_disable(i2c); + + /* Write the register. */ + xe_mmio_write32(i2c->mmio, I2C_REG(reg), val); + + /* Enable the controller. */ + xe_mmio_rmw32(i2c->mmio, I2C_REG(DW_IC_ENABLE), 0, DW_IC_ENABLE_ENABLE); + return 0; + case DW_IC_ENABLE: + i2c->ic_enable = val; + /* Other fields can be updated except the enable bit. */ + val |= DW_IC_ENABLE_ENABLE; + break; case DW_IC_SMBUS_INTR_MASK: /* Make sure the Alert is never masked. */ val |= DW_IC_SMBUS_INTR_ALERT; diff --git a/drivers/gpu/drm/xe/xe_i2c.h b/drivers/gpu/drm/xe/xe_i2c.h index b200966b00484..d63adacfefe71 100644 --- a/drivers/gpu/drm/xe/xe_i2c.h +++ b/drivers/gpu/drm/xe/xe_i2c.h @@ -37,6 +37,7 @@ struct xe_i2c { struct platform_device *pdev; struct i2c_adapter *adapter; struct i2c_client *client[XE_I2C_MAX_CLIENTS]; + unsigned int ic_enable; struct notifier_block bus_notifier; struct work_struct work; -- 2.53.0