From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [PATCH 1/2] platform/x86: i2c-multi-instantiate: Add flag for passing fwnode Date: Mon, 27 Apr 2020 14:51:23 +0200 Message-ID: References: <20200426104713.216896-1-hdegoede@redhat.com> <20200426104713.216896-2-hdegoede@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Andy Shevchenko Cc: "Rafael J . Wysocki" , Len Brown , Darren Hart , Andy Shevchenko , ACPI Devel Maling List , Platform Driver , Linux Kernel Mailing List List-Id: platform-driver-x86.vger.kernel.org Hi, On 4/26/20 7:59 PM, Andy Shevchenko wrote: > On Sun, Apr 26, 2020 at 1:47 PM Hans de Goede wrote: >> >> In some cases the driver for the i2c_client-s which i2c-multi-instantiate >> instantiates may need access some fields / methods from to the ACPI fwnode >> for which i2c_clients are being instantiated. >> >> An example of this are CPLM3218 ACPI device-s. These contain CPM0 and >> CPM1 packages with various information (e.g. register init values) which >> the driver needs. >> >> Passing the fwnode through the i2c_board_info struct also gives the >> i2c-core access to it, and if we do not pass an IRQ then the i2c-core >> will use the fwnode to get an IRQ, see i2c_acpi_get_irq(). > > I'm wondering, can we rather do it in the same way like we do for > GPIO/APIC case here. > Introduce IRQ_RESOURCE_SHARED (or so) and > > case _SHARED: > irq = i2c_acpi_get_irq(); > ... > > ? I think you are miss-understanding the problem. The problem is not that we want to share the IRQ, the problem is that we want to pass the single IRQ in the resources to only 1 of the instantiated I2C-clients. But if we do not pass an IRQ (we leave it at 0) and we do pass the fwnode then i2c-core-base.c will see that there is an ACPI-node attached to the device and will call i2c_acpi_get_irq(). So the solution is definitely not calling i2c_acpi_get_irq() inside i2c-multi-instantiate.c we want to avoid the i2c_acpi_get_irq(), leaving the other 2 clients for the BSG1160 device without an IRQ and thus avoiding the IRQ mismatch (it is a mismatch because the drivers do not set the shared flag; and that is ok, we do not want to share the IRQ, it is just for the accelerometer AFAIK). Regards, Hans > >> >> This is a problem when there is only an IRQ for 1 of the clients described >> in the ACPI device we are instantiating clients for. If we unconditionally >> pass the fwnode, then i2c_acpi_get_irq() will assign the same IRQ to all >> clients instantiated, leading to kernel-oopses like this (BSG1160 device): >> >> [ 27.340557] genirq: Flags mismatch irq 76. 00002001 (bmc150_magn_event) vs. 00000001 (bmc150_accel_event) >> [ 27.340567] Call Trace: >> ... >> >> So we cannot simply always pass the fwnode. This commit adds a PASS_FWNODE >> flag, which can be used to pass the fwnode in cases where we do not have >> the IRQ problem and the driver for the instantiated client(s) needs access >> to the fwnode. >> >> Signed-off-by: Hans de Goede >> --- >> drivers/platform/x86/i2c-multi-instantiate.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/drivers/platform/x86/i2c-multi-instantiate.c b/drivers/platform/x86/i2c-multi-instantiate.c >> index 6acc8457866e..dcafb1a29d17 100644 >> --- a/drivers/platform/x86/i2c-multi-instantiate.c >> +++ b/drivers/platform/x86/i2c-multi-instantiate.c >> @@ -20,6 +20,8 @@ >> #define IRQ_RESOURCE_GPIO 1 >> #define IRQ_RESOURCE_APIC 2 >> >> +#define PASS_FWNODE BIT(2) >> + >> struct i2c_inst_data { >> const char *type; >> unsigned int flags; >> @@ -93,6 +95,10 @@ static int i2c_multi_inst_probe(struct platform_device *pdev) >> snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), >> inst_data[i].type, i); >> board_info.dev_name = name; >> + >> + if (inst_data[i].flags & PASS_FWNODE) >> + board_info.fwnode = dev->fwnode; >> + >> switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) { >> case IRQ_RESOURCE_GPIO: >> ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx); >> -- >> 2.26.0 >> > >