/* linux/drivers/mtd/nand/bf5xx_nand.c * * Copyright 2006-2008 Analog Devices Inc. * http://blackfin.uclinux.org/ * Bryan Wu <bryan.wu@analog.com> * * Blackfin BF5xx on-chip NAND flash controller driver * * Derived from drivers/mtd/nand/s3c2410.c * Copyright (c) 2007 Ben Dooks <ben@simtec.co.uk> * * Derived from drivers/mtd/nand/cafe.c * Copyright © 2006 Red Hat, Inc. * Copyright © 2006 David Woodhouse <dwmw2@infradead.org> * * Changelog: * 12-Jun-2007 Bryan Wu: Initial version * 18-Jul-2007 Bryan Wu: * - ECC_HW and ECC_SW supported * - DMA supported in ECC_HW * - YAFFS tested as rootfs in both ECC_HW and ECC_SW * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/module.h> #include <linux/types.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/ioport.h> #include <linux/platform_device.h> #include <linux/delay.h> #include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/io.h> #include <linux/bitops.h> #include <linux/mtd/mtd.h> #include <linux/mtd/nand.h> #include <linux/mtd/nand_ecc.h> #include <linux/mtd/partitions.h> #include <asm/blackfin.h> #include <asm/dma.h> #include <asm/cacheflush.h> #include <asm/nand.h> #include <asm/portmux.h> #define DRV_NAME "bf5xx-nand" #define DRV_VERSION "1.2" #define DRV_AUTHOR "Bryan Wu <bryan.wu@analog.com>" #define DRV_DESC "BF5xx on-chip NAND FLash Controller Driver" /* NFC_STAT Masks */ #define NBUSY 0x01 /* Not Busy */ #define WB_FULL 0x02 /* Write Buffer Full */ #define PG_WR_STAT 0x04 /* Page Write Pending */ #define PG_RD_STAT 0x08 /* Page Read Pending */ #define WB_EMPTY 0x10 /* Write Buffer Empty */ /* NFC_IRQSTAT Masks */ #define NBUSYIRQ 0x01 /* Not Busy IRQ */ #define WB_OVF 0x02 /* Write Buffer Overflow */ #define WB_EDGE 0x04 /* Write Buffer Edge Detect */ #define RD_RDY 0x08 /* Read Data Ready */ #define WR_DONE 0x10 /* Page Write Done */ /* NFC_RST Masks */ #define ECC_RST 0x01 /* ECC (and NFC counters) Reset */ /* NFC_PGCTL Masks */ #define PG_RD_START 0x01 /* Page Read Start */ #define PG_WR_START 0x02 /* Page Write Start */ #ifdef CONFIG_MTD_NAND_BF5XX_HWECC static int hardware_ecc = 1; #else static int hardware_ecc; #endif static const unsigned short bfin_nfc_pin_req[] = {P_NAND_CE, P_NAND_RB, P_NAND_D0, P_NAND_D1, P_NAND_D2, P_NAND_D3, P_NAND_D4, P_NAND_D5, P_NAND_D6, P_NAND_D7, P_NAND_WE, P_NAND_RE, P_NAND_CLE, P_NAND_ALE, 0}; #ifdef CONFIG_MTD_NAND_BF5XX_BOOTROM_ECC static struct nand_ecclayout bootrom_ecclayout = { .eccbytes = 24, .eccpos = { 0x8 * 0, 0x8 * 0 + 1, 0x8 * 0 + 2, 0x8 * 1, 0x8 * 1 + 1, 0x8 * 1 + 2, 0x8 * 2, 0x8 * 2 + 1, 0x8 * 2 + 2, 0x8 * 3, 0x8 * 3 + 1, 0x8 * 3 + 2, 0x8 * 4, 0x8 * 4 + 1, 0x8 * 4 + 2, 0x8 * 5, 0x8 * 5 + 1, 0x8 * 5 + 2, 0x8 * 6, 0x8 * 6 + 1, 0x8 * 6 + 2, 0x8 * 7, 0x8 * 7 + 1, 0x8 * 7 + 2 }, .oobfree = { { 0x8 * 0 + 3, 5 }, { 0x8 * 1 + 3, 5 }, { 0x8 * 2 + 3, 5 }, { 0x8 * 3 + 3, 5 }, { 0x8 * 4 + 3, 5 }, { 0x8 * 5 + 3, 5 }, { 0x8 * 6 + 3, 5 }, { 0x8 * 7 + 3, 5 }, } }; #endif /* * Data structures for bf5xx nand flash controller driver */ /* bf5xx nand info */ struct bf5xx_nand_info { /* mtd info */ struct nand_hw_control controller; struct mtd_info mtd; struct nand_chip chip; /* platform info */ struct bf5xx_nand_platform *platform; /* device info */ struct device *device; /* DMA stuff */ struct completion dma_completion; }; /* * Conversion functions */ static struct bf5xx_nand_info *mtd_to_nand_info(struct mtd_info *mtd) { return container_of(mtd, struct bf5xx_nand_info, mtd); } static struct bf5xx_nand_info *to_nand_info(struct platform_device *pdev) { return platform_get_drvdata(pdev); } static struct bf5xx_nand_platform *to_nand_plat(struct platform_device *pdev) { return dev_get_platdata(&pdev->dev); } /* * struct nand_chip interface function pointers */ /* * bf5xx_nand_hwcontrol * * Issue command and address cycles to the chip */ static void bf5xx_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl) { if (cmd == NAND_CMD_NONE) return; while (bfin_read_NFC_STAT() & WB_FULL) cpu_relax(); if (ctrl & NAND_CLE) bfin_write_NFC_CMD(cmd); else if (ctrl & NAND_ALE) bfin_write_NFC_ADDR(cmd); SSYNC(); } /* * bf5xx_nand_devready() * * returns 0 if the nand is busy, 1 if it is ready */ static int bf5xx_nand_devready(struct mtd_info *mtd) { unsigned short val = bfin_read_NFC_STAT(); if ((val & NBUSY) == NBUSY) return 1; else return 0; } /* * ECC functions * These allow the bf5xx to use the controller's ECC * generator block to ECC the data as it passes through */ /* * ECC error correction function */ static int bf5xx_nand_correct_data_256(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc) { struct bf5xx_nand_info *info = mtd_to_nand_info(mtd); u32 syndrome[5]; u32 calced, stored; int i; unsigned short failing_bit, failing_byte; u_char data; calced = calc_ecc[0] | (calc_ecc[1] << 8) | (calc_ecc[2] << 16); stored = read_ecc[0] | (read_ecc[1] << 8) | (read_ecc[2] << 16); syndrome[0] = (calced ^ stored); /* * syndrome 0: all zero * No error in data * No action */ if (!syndrome[0] || !calced || !stored) return 0; /* * sysdrome 0: only one bit is one * ECC data was incorrect * No action */ if (hweight32(syndrome[0]) == 1) { dev_err(info->device, "ECC data was incorrect!\n"); return 1; } syndrome[1] = (calced & 0x7FF) ^ (stored & 0x7FF); syndrome[2] = (calced & 0x7FF) ^ ((calced >> 11) & 0x7FF); syndrome[3] = (stored & 0x7FF) ^ ((stored >> 11) & 0x7FF); syndrome[4] = syndrome[2] ^ syndrome[3]; for (i = 0; i < 5; i++) dev_info(info->device, "syndrome[%d] 0x%08x\n", i, syndrome[i]); dev_info(info->device, "calced[0x%08x], stored[0x%08x]\n", calced, stored); /* * sysdrome 0: exactly 11 bits are one, each parity * and parity' pair is 1 & 0 or 0 & 1. * 1-bit correctable error * Correct the error */ if (hweight32(syndrome[0]) == 11 && syndrome[4] == 0x7FF) { dev_info(info->device, "1-bit correctable error, correct it.\n"); dev_info(info->device, "syndrome[1] 0x%08x\n", syndrome[1]); failing_bit = syndrome[1] & 0x7; failing_byte = syndrome[1] >> 0x3; data = *(dat + failing_byte); data = data ^ (0x1 << failing_bit); *(dat + failing_byte) = data; return 0; } /* * sysdrome 0: random data * More than 1-bit error, non-correctable error * Discard data, mark bad block */ dev_err(info->device, "More than 1-bit error, non-correctable error.\n"); dev_err(info->device, "Please discard data, mark bad block\n"); return 1; } static int bf5xx_nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc) { struct nand_chip *chip = mtd->priv; int ret; ret = bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc); /* If ecc size is 512, correct second 256 bytes */ if (chip->ecc.size == 512) { dat += 256; read_ecc += 3; calc_ecc += 3; ret |= bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc); } return ret; } static void bf5xx_nand_enable_hwecc(struct mtd_info *mtd, int mode) { return; } static int bf5xx_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code) { struct bf5xx_nand_info *info = mtd_to_nand_info(mtd); struct nand_chip *chip = mtd->priv; u16 ecc0, ecc1; u32 code[2]; u8 *p; /* first 3 bytes ECC code for 256 page size */ ecc0 = bfin_read_NFC_ECC0(); ecc1 = bfin_read_NFC_ECC1(); code[0] = (ecc0 & 0x7ff) | ((ecc1 & 0x7ff) << 11); dev_dbg(info->device, "returning ecc 0x%08x\n", code[0]); p = (u8 *) code; memcpy(ecc_code, p, 3); /* second 3 bytes ECC code for 512 ecc size */ if (chip->ecc.size == 512) { ecc0 = bfin_read_NFC_ECC2(); ecc1 = bfin_read_NFC_ECC3(); code[1] = (ecc0 & 0x7ff) | ((ecc1 & 0x7ff) << 11); /* second 3 bytes in ecc_code for second 256 * bytes of 512 page size */ p = (u8 *) (code + 1); memcpy((ecc_code + 3), p, 3); dev_dbg(info->device, "returning ecc 0x%08x\n", code[1]); } return 0; } /* * PIO mode for buffer writing and reading */ static void bf5xx_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) { int i; unsigned short val; /* * Data reads are requested by first writing to NFC_DATA_RD * and then reading back from NFC_READ. */ for (i = 0; i < len; i++) { while (bfin_read_NFC_STAT() & WB_FULL) cpu_relax(); /* Contents do not matter */ bfin_write_NFC_DATA_RD(0x0000); SSYNC(); while ((bfin_read_NFC_IRQSTAT() & RD_RDY) != RD_RDY) cpu_relax(); buf[i] = bfin_read_NFC_READ(); val = bfin_read_NFC_IRQSTAT(); val |= RD_RDY; bfin_write_NFC_IRQSTAT(val); SSYNC(); } } static uint8_t bf5xx_nand_read_byte(struct mtd_info *mtd) { uint8_t val; bf5xx_nand_read_buf(mtd, &val, 1); return val; } static void bf5xx_nand_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len) { int i; for (i = 0; i < len; i++) { while (bfin_read_NFC_STAT() & WB_FULL) cpu_relax(); bfin_write_NFC_DATA_WR(buf[i]); SSYNC(); } } static void bf5xx_nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len) { int i; u16 *p = (u16 *) buf; len >>= 1; /* * Data reads are requested by first writing to NFC_DATA_RD * and then reading back from NFC_READ. */ bfin_write_NFC_DATA_RD(0x5555); SSYNC(); for (i = 0; i < len; i++) p[i] = bfin_read_NFC_READ(); } static void bf5xx_nand_write_buf16(struct mtd_info *mtd, const uint8_t *buf, int len) { int i; u16 *p = (u16 *) buf; len >>= 1; for (i = 0; i < len; i++) bfin_write_NFC_DATA_WR(p[i]); SSYNC(); } /* * DMA functions for buffer writing and reading */ static irqreturn_t bf5xx_nand_dma_irq(int irq, void *dev_id) { struct bf5xx_nand_info *info = dev_id; clear_dma_irqstat(CH_NFC); disable_dma(CH_NFC); complete(&info->dma_completion); return IRQ_HANDLED; } static void bf5xx_nand_dma_rw(struct mtd_info *mtd, uint8_t *buf, int is_read) { struct bf5xx_nand_info *info = mtd_to_nand_info(mtd); struct nand_chip *chip = mtd->priv; unsigned short val; dev_dbg(info->device, " mtd->%p, buf->%p, is_read %d\n", mtd, buf, is_read); /* * Before starting a dma transfer, be sure to invalidate/flush * the cache over the address range of your DMA buffer to * prevent cache coherency problems. Otherwise very subtle bugs * can be introduced to your driver. */ if (is_read) invalidate_dcache_range((unsigned int)buf, (unsigned int)(buf + chip->ecc.size)); else flush_dcache_range((unsigned int)buf, (unsigned int)(buf + chip->ecc.size)); /* * This register must be written before each page is * transferred to generate the correct ECC register * values. */ bfin_write_NFC_RST(ECC_RST); SSYNC(); while (bfin_read_NFC_RST() & ECC_RST) cpu_relax(); disable_dma(CH_NFC); clear_dma_irqstat(CH_NFC); /* setup DMA register with Blackfin DMA API */ set_dma_config(CH_NFC, 0x0); set_dma_start_addr(CH_NFC, (unsigned long) buf); /* The DMAs have different size on BF52x and BF54x */ #ifdef CONFIG_BF52x set_dma_x_count(CH_NFC, (chip->ecc.size >> 1)); set_dma_x_modify(CH_NFC, 2); val = DI_EN | WDSIZE_16; #endif #ifdef CONFIG_BF54x set_dma_x_count(CH_NFC, (chip->ecc.size >> 2)); set_dma_x_modify(CH_NFC, 4); val = DI_EN | WDSIZE_32; #endif /* setup write or read operation */ if (is_read) val |= WNR; set_dma_config(CH_NFC, val); enable_dma(CH_NFC); /* Start PAGE read/write operation */ if (is_read) bfin_write_NFC_PGCTL(PG_RD_START); else bfin_write_NFC_PGCTL(PG_WR_START); wait_for_completion(&info->dma_completion); } static void bf5xx_nand_dma_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) { struct bf5xx_nand_info *info = mtd_to_nand_info(mtd); struct nand_chip *chip = mtd->priv; dev_dbg(info->device, "mtd->%p, buf->%p, int %d\n", mtd, buf, len); if (len == chip->ecc.size) bf5xx_nand_dma_rw(mtd, buf, 1); else bf5xx_nand_read_buf(mtd, buf, len); } static void bf5xx_nand_dma_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len) { struct bf5xx_nand_info *info = mtd_to_nand_info(mtd); struct nand_chip *chip = mtd->priv; dev_dbg(info->device, "mtd->%p, buf->%p, len %d\n", mtd, buf, len); if (len == chip->ecc.size) bf5xx_nand_dma_rw(mtd, (uint8_t *)buf, 0); else bf5xx_nand_write_buf(mtd, buf, len); } static int bf5xx_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip, uint8_t *buf, int oob_required, int page) { bf5xx_nand_read_buf(mtd, buf, mtd->writesize); bf5xx_nand_read_buf(mtd, chip->oob_poi, mtd->oobsize); return 0; } static int bf5xx_nand_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip, const uint8_t *buf, int oob_required) { bf5xx_nand_write_buf(mtd, buf, mtd->writesize); bf5xx_nand_write_buf(mtd, chip->oob_poi, mtd->oobsize); return 0; } /* * System initialization functions */ static int bf5xx_nand_dma_init(struct bf5xx_nand_info *info) { int ret; /* Do not use dma */ if (!hardware_ecc) return 0; init_completion(&info->dma_completion); /* Request NFC DMA channel */ ret = request_dma(CH_NFC, "BF5XX NFC driver"); if (ret < 0) { dev_err(info->device, " unable to get DMA channel\n"); return ret; } #ifdef CONFIG_BF54x /* Setup DMAC1 channel mux for NFC which shared with SDH */ bfin_write_DMAC1_PERIMUX(bfin_read_DMAC1_PERIMUX() & ~1); SSYNC(); #endif set_dma_callback(CH_NFC, bf5xx_nand_dma_irq, info); /* Turn off the DMA channel first */ disable_dma(CH_NFC); return 0; } static void bf5xx_nand_dma_remove(struct bf5xx_nand_info *info) { /* Free NFC DMA channel */ if (hardware_ecc) free_dma(CH_NFC); } /* * BF5XX NFC hardware initialization * - pin mux setup * - clear interrupt status */ static int bf5xx_nand_hw_init(struct bf5xx_nand_info *info) { int err = 0; unsigned short val; struct bf5xx_nand_platform *plat = info->platform; /* setup NFC_CTL register */ dev_info(info->device, "data_width=%d, wr_dly=%d, rd_dly=%d\n", (plat->data_width ? 16 : 8), plat->wr_dly, plat->rd_dly); val = (1 << NFC_PG_SIZE_OFFSET) | (plat->data_width << NFC_NWIDTH_OFFSET) | (plat->rd_dly << NFC_RDDLY_OFFSET) | (plat->wr_dly << NFC_WRDLY_OFFSET); dev_dbg(info->device, "NFC_CTL is 0x%04x\n", val); bfin_write_NFC_CTL(val); SSYNC(); /* clear interrupt status */ bfin_write_NFC_IRQMASK(0x0); SSYNC(); val = bfin_read_NFC_IRQSTAT(); bfin_write_NFC_IRQSTAT(val); SSYNC(); /* DMA initialization */ if (bf5xx_nand_dma_init(info)) err = -ENXIO; return err; } /* * Device management interface */ static int bf5xx_nand_add_partition(struct bf5xx_nand_info *info) { struct mtd_info *mtd = &info->mtd; struct mtd_partition *parts = info->platform->partitions; int nr = info->platform->nr_partitions; return mtd_device_register(mtd, parts, nr); } static int bf5xx_nand_remove(struct platform_device *pdev) { struct bf5xx_nand_info *info = to_nand_info(pdev); /* first thing we need to do is release all our mtds * and their partitions, then go through freeing the * resources used */ nand_release(&info->mtd); peripheral_free_list(bfin_nfc_pin_req); bf5xx_nand_dma_remove(info); /* free the common resources */ kfree(info); return 0; } static int bf5xx_nand_scan(struct mtd_info *mtd) { struct nand_chip *chip = mtd->priv; int ret; ret = nand_scan_ident(mtd, 1, NULL); if (ret) return ret; if (hardware_ecc) { /* * for nand with page size > 512B, think it as several sections with 512B */ if (likely(mtd->writesize >= 512)) { chip->ecc.size = 512; chip->ecc.bytes = 6; chip->ecc.strength = 2; } else { chip->ecc.size = 256; chip->ecc.bytes = 3; chip->ecc.strength = 1; bfin_write_NFC_CTL(bfin_read_NFC_CTL() & ~(1 << NFC_PG_SIZE_OFFSET)); SSYNC(); } } return nand_scan_tail(mtd); } /* * bf5xx_nand_probe * * called by device layer when it finds a device matching * one our driver can handled. This code checks to see if * it can allocate all necessary resources then calls the * nand layer to look for devices */ static int bf5xx_nand_probe(struct platform_device *pdev) { struct bf5xx_nand_platform *plat = to_nand_plat(pdev); struct bf5xx_nand_info *info = NULL; struct nand_chip *chip = NULL; struct mtd_info *mtd = NULL; int err = 0; dev_dbg(&pdev->dev, "(%p)\n", pdev); if (!plat) { dev_err(&pdev->dev, "no platform specific information\n"); return -EINVAL; } if (peripheral_request_list(bfin_nfc_pin_req, DRV_NAME)) { dev_err(&pdev->dev, "requesting Peripherals failed\n"); return -EFAULT; } info = kzalloc(sizeof(*info), GFP_KERNEL); if (info == NULL) { err = -ENOMEM; goto out_err_kzalloc; } platform_set_drvdata(pdev, info); spin_lock_init(&info->controller.lock); init_waitqueue_head(&info->controller.wq); info->device = &pdev->dev; info->platform = plat; /* initialise chip data struct */ chip = &info->chip; if (plat->data_width) chip->options |= NAND_BUSWIDTH_16; chip->options |= NAND_CACHEPRG | NAND_SKIP_BBTSCAN; chip->read_buf = (plat->data_width) ? bf5xx_nand_read_buf16 : bf5xx_nand_read_buf; chip->write_buf = (plat->data_width) ? bf5xx_nand_write_buf16 : bf5xx_nand_write_buf; chip->read_byte = bf5xx_nand_read_byte; chip->cmd_ctrl = bf5xx_nand_hwcontrol; chip->dev_ready = bf5xx_nand_devready; chip->priv = &info->mtd; chip->controller = &info->controller; chip->IO_ADDR_R = (void __iomem *) NFC_READ; chip->IO_ADDR_W = (void __iomem *) NFC_DATA_WR; chip->chip_delay = 0; /* initialise mtd info data struct */ mtd = &info->mtd; mtd->priv = chip; mtd->owner = THIS_MODULE; /* initialise the hardware */ err = bf5xx_nand_hw_init(info); if (err) goto out_err_hw_init; /* setup hardware ECC data struct */ if (hardware_ecc) { #ifdef CONFIG_MTD_NAND_BF5XX_BOOTROM_ECC chip->ecc.layout = &bootrom_ecclayout; #endif chip->read_buf = bf5xx_nand_dma_read_buf; chip->write_buf = bf5xx_nand_dma_write_buf; chip->ecc.calculate = bf5xx_nand_calculate_ecc; chip->ecc.correct = bf5xx_nand_correct_data; chip->ecc.mode = NAND_ECC_HW; chip->ecc.hwctl = bf5xx_nand_enable_hwecc; chip->ecc.read_page_raw = bf5xx_nand_read_page_raw; chip->ecc.write_page_raw = bf5xx_nand_write_page_raw; } else { chip->ecc.mode = NAND_ECC_SOFT; } /* scan hardware nand chip and setup mtd info data struct */ if (bf5xx_nand_scan(mtd)) { err = -ENXIO; goto out_err_nand_scan; } #ifdef CONFIG_MTD_NAND_BF5XX_BOOTROM_ECC chip->badblockpos = 63; #endif /* add NAND partition */ bf5xx_nand_add_partition(info); dev_dbg(&pdev->dev, "initialised ok\n"); return 0; out_err_nand_scan: bf5xx_nand_dma_remove(info); out_err_hw_init: kfree(info); out_err_kzalloc: peripheral_free_list(bfin_nfc_pin_req); return err; } /* PM Support */ #ifdef CONFIG_PM static int bf5xx_nand_suspend(struct platform_device *dev, pm_message_t pm) { struct bf5xx_nand_info *info = platform_get_drvdata(dev); return 0; } static int bf5xx_nand_resume(struct platform_device *dev) { struct bf5xx_nand_info *info = platform_get_drvdata(dev); return 0; } #else #define bf5xx_nand_suspend NULL #define bf5xx_nand_resume NULL #endif /* driver device registration */ static struct platform_driver bf5xx_nand_driver = { .probe = bf5xx_nand_probe, .remove = bf5xx_nand_remove, .suspend = bf5xx_nand_suspend, .resume = bf5xx_nand_resume, .driver = { .name = DRV_NAME, .owner = THIS_MODULE, }, }; module_platform_driver(bf5xx_nand_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR(DRV_AUTHOR); MODULE_DESCRIPTION(DRV_DESC); MODULE_ALIAS("platform:" DRV_NAME);