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i2c driver develpment with diolan DLN-2 / ACPI?
by Martin Kepplinger April 30, 2016

April 30, 2016

Hi roberta or anyone who uses a diolan i2c/spi bridge device, I try to do get the kernel driver for the connected chip loaded, but I'm having some trouble getting it right. Cables are connected to the device (i2c), and the (mainline) kernel driver for the diolan DLN-2 device is compiled and loaded on plugin. I don't use any of their (userspace) software. Now I get a new i2c bus and can manually instanciate my driver root@laptop:/sys/bus/i2c/devices/i2c-7# echo mma8452 0x1c > new_device and the driver loads. (Now for development, later maybe for merging) I added acpi support, I guess I'd need it, but ACPI_HANDLE(&client->dev) isn't true (during probe) hence we don't continue. I append my adding-acpi-patch below. How do you do it? Do *you* manually instantiate your i2c-driver during development with your diolan device or should it somehow even get loaded automatically? thanks so much for any help, martin --- a/drivers/iio/accel/mma8452.c +++ b/drivers/iio/accel/mma8452.c @@ -33,6 +33,7 @@ #include <linux/of_device.h> #include <linux/of_irq.h> #include <linux/pm_runtime.h> +#include <linux/acpi.h> #define MMA8452_STATUS 0x00 #define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0)) @@ -1434,6 +1435,19 @@ static const struct of_device_id mma8452_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, mma8452_dt_ids); +static const char *mma8452_match_acpi_device(struct device *dev, int *data) +{ + const struct acpi_device_id *id; + + id = acpi_match_device(dev->driver->acpi_match_table, dev); + if (!id) + return NULL; + + *data = (int)id->driver_data; + + return dev_name(dev); +} + static int mma8452_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -1441,21 +1455,35 @@ static int mma8452_probe(struct i2c_client *client, struct iio_dev *indio_dev; int ret; const struct of_device_id *match; + const char *name = NULL; + int dev_id = 0; - match = of_match_device(mma8452_dt_ids, &client->dev); - if (!match) { - dev_err(&client->dev, "unknown device model\n"); - return -ENODEV; - } +pr_info("mma probe running!!\n"); indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); data->client = client; + + match = of_match_device(mma8452_dt_ids, &client->dev); + if (match) { + if (id) + name = id->name; + data->chip_info = match->data; + } else if (ACPI_HANDLE(&client->dev)) { + name = mma8452_match_acpi_device(&client->dev, &dev_id); + pr_info("mma acpi ok. found id %d\n", dev_id); + /* TODO chip_info setting*/ + data->chip_info = &mma_chip_info_table[dev_id]; + } else { + dev_err(&client->dev, "unknown device model\n"); + return -ENODEV; + } + mutex_init(&data->lock); - data->chip_info = match->data; ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I); if (ret < 0) @@ -1475,11 +1503,10 @@ static int mma8452_probe(struct i2c_client *client, } dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n", - match->compatible, data->chip_info->chip_id); + name, data->chip_info->chip_id); - i2c_set_clientdata(client, indio_dev); indio_dev->info = &mma8452_info; - indio_dev->name = id->name; + indio_dev->name = name; indio_dev->dev.parent = &client->dev; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = data->chip_info->channels; @@ -1669,6 +1696,17 @@ static const struct dev_pm_ops mma8452_pm_ops = { mma8452_runtime_resume, NULL) }; +static const struct acpi_device_id mma8452_acpi_match[] = { + { "MMA8451", mma8451 }, + { "MMA8452", mma8452 }, + { "MMA8453", mma8453 }, + { "MMA8652", mma8652 }, + { "MMA8653", mma8653 }, + { "FXLS8471", fxls8471 }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, mma8452_acpi_match); + static const struct i2c_device_id mma8452_id[] = { { "mma8451", mma8451 }, { "mma8452", mma8452 }, @@ -1684,6 +1722,7 @@ static struct i2c_driver mma8452_driver = { .driver = { .name = "mma8452", .of_match_table = of_match_ptr(mma8452_dt_ids), + .acpi_match_table = ACPI_PTR(mma8452_acpi_match), .pm = &mma8452_pm_ops, }, .probe = mma8452_probe, -- 2.1.4

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unable to find function definition
by Nijam Haider April 28, 2016

April 28, 2016

i was going through the code leds-gpio.c. i found a function "platform_gpio_blink_set" declared under private data of "gpio_led_data",and was trying to get through this function. But hardly i can find any link to definition for the same anywhere. Regards Nijam

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Re: strange dtc errors after adding sram node
by Stefan Wahren April 27, 2016

April 27, 2016

Hi Arnd, Am 25.04.2016 um 15:06 schrieb Arnd Bergmann: > On Monday 25 April 2016 08:04:53 Stefan Wahren wrote: >> >> i've found reason for these errors. I missed to adjust the affected dts >> files which refer to the ahb node. > > Makes sense. Maybe you can just remove the address and 'reg' property from > the ahb node? is this a proposal for a patch set? Does it apply to all top-level nodes like apb? > That should solve the dtc problem and make the contents > more like what we have elsewhere. Does it refer to a specific patch / discussion or something? Regards Stefan > > Arnd >

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Re: unable to find function definition
by nizam haider April 27, 2016

April 27, 2016

Thank you all for replies. sure these are helping a lot. On Wed 27 Apr, 2016 8:35 am Jay Aurabind, <jay.aurabind(a)gmail.com> wrote: > On 27 April 2016 at 07:05, John de la Garza <john(a)jjdev.com> wrote: > > On Tue, Apr 26, 2016 at 02:00:02PM +0530, Jay Aurabind wrote: > >> On 20 April 2016 at 12:56, Cihangir Akturk <cakturk(a)gmail.com> wrote: > >> > On Wed, Apr 20, 2016 at 06:17:38AM +0000, Nijam Haider wrote: > >> >> i was going through the code leds-gpio.c. > >> >> i found a function "platform_gpio_blink_set" declared under private > data of > >> >> "gpio_led_data",and was trying to get through this function. But > hardly i can > >> >> find any link to definition for the same anywhere. > >> > > >> > Hi, > >> > > >> > That is a function pointer, so you should search assignments to > >> > that pointer. That way you can find the real function you are > >> > looking for. > >> > >> I've spotted such usages in a lot of places, outside the kernel as > >> well. Just wanted know if there is a smarted way of finding the > >> assignments, like some tools or any other tips which people could use > >> to make life easier ? > > > > I've been able to print the address of the functions (once it has > > been assigned), then check the System.map for the function name. > > Thank you all for the smart answers! > > -- > > Thanks and Regards, > Aurabindo J >

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Contributing to Kernel Networking stack
by Shraddha kamat April 26, 2016

April 26, 2016

I have strong desire to contribute to kernel networking stack. What is the most effective way to do some pretty significant changes (bug fixes, feature addition) in less time. All you kernel gurus please guide me. I have read UTLK pretty well (I don't say I understood it all, but for ex. I know where which locking mechanism is used, what is mem barrier and how it is implemented etc.) Regards, Shraddha

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Fw: new message
by bear.yogi＠gmx.de April 26, 2016

April 26, 2016

Hello! You have a new message, please read <http://arshemusicshop.com/rolling.php?vs> bear.yogi(a)gmx.de

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Question about cc:stable and git send-email
by Ricardo Ribalda Delgado April 25, 2016

April 25, 2016

Hello I was trying to do The right thing (TM) with a patch for a regression. I did my homework and found which commit introduced the error using git blame and also found out when that commit was introduced using git describe. I added the tags: Fixes: XXXXXXX (XXXX) CC: stable(a)vger.kernel.org # 4.4.x- But when I do git send email, it automatically adds # and 4.4.x- as recipients, failing to send the mail. What am I doing wrong? Thanks! -- Ricardo Ribalda

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Re: strange dtc errors after adding sram node
by Stefan Wahren April 25, 2016

April 25, 2016

Hi Jörg, Am 23.04.2016 um 12:33 schrieb Jörg Krause: > Hi Stefan, > > On Sa, 2016-04-23 at 10:18 +0200, Jörg Krause wrote: >> Hi Stefan, >> >> On Sa, 2016-04-23 at 09:46 +0200, Stefan Wahren wrote: >>> Hi, >>> >>> i want to add an sram node to arch/arm/boot/dts/imx28.dtsi. >>> According >>> to >>> the reference manual [1] the On-Chip RAM is connected to AHB, >>> start >>> address 0 and has a size of 128 KB. >>> >>> So i modified the imx28.dtsi based on the patch below. >>> Unfortunately >>> the >>> dtc give me some strang errors: >>> >>> ERROR (duplicate_label): Duplicate label 'mac0' on >>> /ahb@80080000/ethernet@800f0000 and /ahb@00000000/ethernet@800f0000 >>> ERROR: Input tree has errors, aborting (use -f to force output) >>> >>> What's wrong with my patch or does it reveal another issue? >>> >>> Regards >>> Stefan >>> >>> [1] - http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM >>> .p >>> df >>> i.MX28 Applications Processor Reference Manual, Rev. 2, 08/2013 >>> Chapter 4.1 Memory Map Overview >>> >>> -------------------------->8--------------------------------------- >>> --- a/arch/arm/boot/dts/imx28.dtsi >>> +++ b/arch/arm/boot/dts/imx28.dtsi >>> @@ -1311,13 +1311,18 @@ >>> }; >>> }; >>> >>> - ahb@80080000 { >>> + ahb@00000000 { >>> compatible = "simple-bus"; >>> #address-cells = <1>; >>> #size-cells = <1>; >>> - reg = <0x80080000 0x80000>; >>> + reg = <0x00000000 0x20000>, <0x80080000 0x80000>; >>> ranges; >>> >>> + ocram: sram@00000000 { >>> + compatible = "mmio-sram"; >>> + reg = <0x00000000 0x20000>; >>> + }; >>> + >>> usb0: usb@80080000 { >>> compatible = "fsl,imx28-usb", "fsl,imx27- >>> usb"; >>> reg = <0x80080000 0x10000>; >> >> Follwing the address map for the i.MX28 (p. 125ff) the AHB is mapped >> to >> different start addresses: >> >> Bus MNEMONIC START ADDRESS >> -------------------------------------- >> AHB OCRAM 0x00000000 >> AHB USBCTRL0 0x80080000 >> AHB OCROM 0xC0000000 >> >> So instead of replacing ahb@80080000 by ahb@00000000 a new node >> should >> be created. However, I am not sure if this is really necessary, I >> haven't seen it for all device trees using "mmio-sram". > > Sorry, for not looking carefully enough at your patch. Haven't seen you > adjusted the 'reg' property. I tried with an additional ahb@00000000 no > de and this did work. > > So, there is really something odd here... i've found reason for these errors. I missed to adjust the affected dts files which refer to the ahb node. Stefan > > Best regards > Jörg Krause >

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network driver & phy framework
by Ran Shalit April 24, 2016

April 24, 2016

Hello, I write a network driver, and I try to understand how to communicate with phy. I see several methods, but did not found documentation on the differences, and when to use each of these methods: 1. using generic phy - a. I think we use it when we don't know the exaxt phy (?), though I'm not sure of that. b. use mii_if_info struct to register the read/write API between mii & phy. mii.mdio_read = custom_mdio_read_mii; mii.mdio_write = custom_mdio_write_mii; c. ethtool is used with mii_if_info and the registered functions 2. using external phy. a. I think we use it when we don't know the exaxt phy (?), though I'm not sure of that. b. use mii_bus to register the read/write API between mii & phy. mii.read = custom_mdio_read_mii; mii.write = custom_mdio_write_mii; c. not sure how ethtool is used in this case (?)... 3. using internal phy (?) - not sure how ethtool is used in this case (?)... Thanks for any feedback, Ran

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strange dtc errors after adding sram node
by Stefan Wahren April 23, 2016

April 23, 2016

Hi, i want to add an sram node to arch/arm/boot/dts/imx28.dtsi. According to the reference manual [1] the On-Chip RAM is connected to AHB, start address 0 and has a size of 128 KB. So i modified the imx28.dtsi based on the patch below. Unfortunately the dtc give me some strang errors: ERROR (duplicate_label): Duplicate label 'mac0' on /ahb@80080000/ethernet@800f0000 and /ahb@00000000/ethernet@800f0000 ERROR: Input tree has errors, aborting (use -f to force output) What's wrong with my patch or does it reveal another issue? Regards Stefan [1] - http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf i.MX28 Applications Processor Reference Manual, Rev. 2, 08/2013 Chapter 4.1 Memory Map Overview -------------------------->8--------------------------------------- --- a/arch/arm/boot/dts/imx28.dtsi +++ b/arch/arm/boot/dts/imx28.dtsi @@ -1311,13 +1311,18 @@ }; }; - ahb@80080000 { + ahb@00000000 { compatible = "simple-bus"; #address-cells = <1>; #size-cells = <1>; - reg = <0x80080000 0x80000>; + reg = <0x00000000 0x20000>, <0x80080000 0x80000>; ranges; + ocram: sram@00000000 { + compatible = "mmio-sram"; + reg = <0x00000000 0x20000>; + }; + usb0: usb@80080000 { compatible = "fsl,imx28-usb", "fsl,imx27-usb"; reg = <0x80080000 0x10000>;

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