Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752292AbbH1JNc (ORCPT ); Fri, 28 Aug 2015 05:13:32 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:55833 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751888AbbH1JM2 (ORCPT ); Fri, 28 Aug 2015 05:12:28 -0400 From: Milo Kim To: , CC: Milo Kim , Dmitry Torokhov , Felipe Balbi , Greg Kroah-Hartman , Lee Jones , Rob Herring , Samuel Ortiz , Tony Lindgren , Subject: [RFC 0/4] of: introduce of_dev_get_platdata() Date: Fri, 28 Aug 2015 18:12:04 +0900 Message-ID: <1440753128-3288-1-git-send-email-milo.kim@ti.com> X-Mailer: git-send-email 1.9.5.msysgit.0 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6238 Lines: 197 New function, 'of_dev_get_platdata()' - provides unified handling of getting device platform data - supports DT and non-DT(legacy) cases - removes duplicated code from each driver - keeps driver specific code simple in each driver Issues ------ On loading a driver, the driver tries to get the platform data. * Check conditions prior to parsing the DT You can see various/not general way of checking the platform data. case 1) driver checks whether the platform data is null or not. foo_platform_data *pdata = dev_get_platdata(dev); if (!pdata) { pdata = foo_parse_dt(); if (IS_ERR(pdata)) return PTR_ERR(pdata); } case 2) driver checks whether 'of_node' exists or not. if (dev.of_node) { pdata = foo_parse_dt(); if (IS_ERR(pdata)) return PTR_ERR(pdata); } case 3) check both if (pdata) { copy pdata into driver private data } else if (dev.of_node) { pdata = foo_parse_dt(); } Check conditions are very depend on the driver, but it can be unified. of_dev_get_platdata() provides unified handling. So the driver can reduce if-condition statements. * Memory allocation in each parser In most cases, driver allocates the platform data inside its DT parser. static struct foo_platform_data *foo_parse_dt() { allocates memory for generating platform data. parsing DT properties and copy them into the platform data. } of_dev_get_platdata() allocates the platform data internally. And it calls back to the driver specific parser function. It removes memory allocation code in each driver. * Two types of parser definition Many drivers implement DT parser in two cases, '#ifdef CONFIG_OF' and '#else'. #ifdef CONFIG_OF static struct foo_platform_data *foo_parse_dt() { (snip) } #else static struct foo_platform_data *foo_parse_dt() { return NULL; } #endif of_dev_get_platdata() supports both cases. It removes few lines of code in each driver. What of_dev_get_platdata() does ------------------------------- if CONFIG_OF is not defined, return legacy code, 'dev_get_platdata()'. if platform data exists, just return it. if platform data is null, check the 'of node'. if of_node is null, then return NULL. Otherwise, allocates memory for platform data. Call back to the driver(caller) with allocated platform data and private data if needed. Then, driver will parse the DT internally and handle errors. Examples -------- Following patches are examples. drivers/input/touchscreen/mms114.c drivers/mfd/tps65910.c drivers/usb/musb/ux500.c Driver list ----------- of_dev_get_platdata() can be applied into files below. You may find more if you're interested in this. :) drivers/dma/ste_dma40.c drivers/gpio/gpio-rcar.c drivers/gpu/drm/exynos/exynos_dp_core.c drivers/gpu/drm/exynos/exynos_hdmi.c drivers/hwmon/ntc_thermistor.c drivers/i2c/busses/i2c-s3c2410.c drivers/iio/frequency/adf4350.c drivers/input/keyboard/matrix_keypad.c drivers/input/keyboard/samsung-keypad.c drivers/input/misc/drv260x.c drivers/input/misc/regulator-haptic.c drivers/input/misc/rotary_encoder.c drivers/input/touchscreen/atmel_mxt_ts.c drivers/input/touchscreen/auo-pixcir-ts.c drivers/input/touchscreen/bu21013_ts.c drivers/input/touchscreen/mms114.c drivers/input/touchscreen/pixcir_i2c_ts.c drivers/input/touchscreen/zforce_ts.c drivers/leds/leds-lp5521.c drivers/leds/leds-lp5523.c drivers/leds/leds-lp5562.c drivers/leds/leds-lp55xx-common.c drivers/leds/leds-lp8501.c drivers/leds/leds-mc13783.c drivers/leds/leds-pca963x.c drivers/leds/leds-tca6507.c drivers/mfd/max8997.c drivers/mfd/max8998.c drivers/mfd/sec-core.c drivers/mfd/tps6586x.c drivers/mfd/tps65910.c drivers/misc/lis3lv02d/lis3lv02d.c drivers/mmc/host/davinci_mmc.c drivers/mmc/host/dw_mmc.c drivers/mmc/host/sdhci-s3c.c drivers/mtd/devices/spear_smi.c drivers/mtd/nand/fsmc_nand.c drivers/mtd/nand/lpc32xx_mlc.c drivers/mtd/nand/lpc32xx_slc.c drivers/mtd/nand/sh_flctl.c drivers/net/can/sja1000/sja1000_platform.c drivers/net/ethernet/davicom/dm9000.c drivers/net/ethernet/marvell/mv643xx_eth.c drivers/net/ethernet/renesas/sh_eth.c drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c drivers/power/bq24735-charger.c drivers/power/gpio-charger.c drivers/power/sbs-battery.c drivers/power/tps65090-charger.c drivers/power/twl4030_charger.c drivers/pwm/pwm-lp3943.c drivers/pwm/pwm-samsung.c drivers/spi/spi-sh-msiof.c drivers/spi/spi/spi-s3c64xx.c drivers/thermal/db8500_thermal.c drivers/usb/misc/usb3503.c drivers/usb/musb/omap2430.c drivers/usb/musb/ux500.c drivers/usb/renesas_usbhs/common.c drivers/video/fbdev/simplefb.c drivers/video/backlight/lp855x_bl.c drivers/video/backlight/pwm_bl.c drivers/video/backlight/sky81452-backlight.c drivers/video/backlight/tps65217_bl.c This is the RFC, so I would like to get some feedback prior to patching all drivers. Any comments are welcome. Cc: Dmitry Torokhov Cc: Felipe Balbi Cc: Grant Likely Cc: Greg Kroah-Hartman Cc: Lee Jones Cc: Rob Herring Cc: Samuel Ortiz Cc: Tony Lindgren Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Milo Kim (4): of: introduce of_dev_get_platdata() input: touchscree: mms114: use of_dev_get_platdata() mfd: tps65910: use of_dev_get_platdata() usb: musb: use of_dev_get_platdata() drivers/input/touchscreen/mms114.c | 34 ++++++++------------------ drivers/mfd/tps65910.c | 49 +++++++++++++------------------------- drivers/of/device.c | 46 +++++++++++++++++++++++++++++++++++ drivers/usb/musb/ux500.c | 40 +++++++++++++------------------ include/linux/of_device.h | 12 ++++++++++ 5 files changed, 100 insertions(+), 81 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/