460 lines
13 KiB
C
460 lines
13 KiB
C
/*
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* CAN bus driver for the Freescale MPC5xxx embedded CPU.
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*
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* Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>,
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* Varma Electronics Oy
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* Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
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* Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the version 2 of the GNU General Public License
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* as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/netdevice.h>
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#include <linux/can/dev.h>
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#include <linux/of_platform.h>
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#include <sysdev/fsl_soc.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <asm/mpc52xx.h>
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#include "mscan.h"
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#define DRV_NAME "mpc5xxx_can"
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struct mpc5xxx_can_data {
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unsigned int type;
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u32 (*get_clock)(struct platform_device *ofdev, const char *clock_name,
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int *mscan_clksrc);
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void (*put_clock)(struct platform_device *ofdev);
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};
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#ifdef CONFIG_PPC_MPC52xx
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static struct of_device_id mpc52xx_cdm_ids[] = {
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{ .compatible = "fsl,mpc5200-cdm", },
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{}
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};
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static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
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const char *clock_name, int *mscan_clksrc)
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{
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unsigned int pvr;
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struct mpc52xx_cdm __iomem *cdm;
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struct device_node *np_cdm;
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unsigned int freq;
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u32 val;
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pvr = mfspr(SPRN_PVR);
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/*
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* Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
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* (IP_CLK) can be selected as MSCAN clock source. According to
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* the MPC5200 user's manual, the oscillator clock is the better
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* choice as it has less jitter. For this reason, it is selected
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* by default. Unfortunately, it can not be selected for the old
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* MPC5200 Rev. A chips due to a hardware bug (check errata).
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*/
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if (clock_name && strcmp(clock_name, "ip") == 0)
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*mscan_clksrc = MSCAN_CLKSRC_BUS;
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else
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*mscan_clksrc = MSCAN_CLKSRC_XTAL;
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freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node);
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if (!freq)
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return 0;
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if (*mscan_clksrc == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
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return freq;
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/* Determine SYS_XTAL_IN frequency from the clock domain settings */
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np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids);
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if (!np_cdm) {
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dev_err(&ofdev->dev, "can't get clock node!\n");
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return 0;
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}
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cdm = of_iomap(np_cdm, 0);
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if (in_8(&cdm->ipb_clk_sel) & 0x1)
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freq *= 2;
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val = in_be32(&cdm->rstcfg);
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freq *= (val & (1 << 5)) ? 8 : 4;
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freq /= (val & (1 << 6)) ? 12 : 16;
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of_node_put(np_cdm);
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iounmap(cdm);
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return freq;
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}
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#else /* !CONFIG_PPC_MPC52xx */
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static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
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const char *clock_name, int *mscan_clksrc)
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{
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return 0;
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}
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#endif /* CONFIG_PPC_MPC52xx */
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#ifdef CONFIG_PPC_MPC512x
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static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
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const char *clock_source, int *mscan_clksrc)
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{
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struct device_node *np;
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u32 clockdiv;
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enum {
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CLK_FROM_AUTO,
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CLK_FROM_IPS,
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CLK_FROM_SYS,
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CLK_FROM_REF,
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} clk_from;
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struct clk *clk_in, *clk_can;
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unsigned long freq_calc;
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struct mscan_priv *priv;
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struct clk *clk_ipg;
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/* the caller passed in the clock source spec that was read from
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* the device tree, get the optional clock divider as well
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*/
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np = ofdev->dev.of_node;
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clockdiv = 1;
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of_property_read_u32(np, "fsl,mscan-clock-divider", &clockdiv);
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dev_dbg(&ofdev->dev, "device tree specs: clk src[%s] div[%d]\n",
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clock_source ? clock_source : "<NULL>", clockdiv);
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/* when clock-source is 'ip', the CANCTL1[CLKSRC] bit needs to
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* get set, and the 'ips' clock is the input to the MSCAN
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* component
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*
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* for clock-source values of 'ref' or 'sys' the CANCTL1[CLKSRC]
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* bit needs to get cleared, an optional clock-divider may have
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* been specified (the default value is 1), the appropriate
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* MSCAN related MCLK is the input to the MSCAN component
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*
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* in the absence of a clock-source spec, first an optimal clock
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* gets determined based on the 'sys' clock, if that fails the
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* 'ref' clock is used
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*/
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clk_from = CLK_FROM_AUTO;
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if (clock_source) {
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/* interpret the device tree's spec for the clock source */
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if (!strcmp(clock_source, "ip"))
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clk_from = CLK_FROM_IPS;
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else if (!strcmp(clock_source, "sys"))
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clk_from = CLK_FROM_SYS;
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else if (!strcmp(clock_source, "ref"))
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clk_from = CLK_FROM_REF;
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else
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goto err_invalid;
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dev_dbg(&ofdev->dev, "got a clk source spec[%d]\n", clk_from);
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}
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if (clk_from == CLK_FROM_AUTO) {
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/* no spec so far, try the 'sys' clock; round to the
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* next MHz and see if we can get a multiple of 16MHz
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*/
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dev_dbg(&ofdev->dev, "no clk source spec, trying SYS\n");
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clk_in = devm_clk_get(&ofdev->dev, "sys");
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if (IS_ERR(clk_in))
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goto err_notavail;
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freq_calc = clk_get_rate(clk_in);
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freq_calc += 499999;
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freq_calc /= 1000000;
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freq_calc *= 1000000;
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if ((freq_calc % 16000000) == 0) {
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clk_from = CLK_FROM_SYS;
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clockdiv = freq_calc / 16000000;
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dev_dbg(&ofdev->dev,
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"clk fit, sys[%lu] div[%d] freq[%lu]\n",
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freq_calc, clockdiv, freq_calc / clockdiv);
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}
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}
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if (clk_from == CLK_FROM_AUTO) {
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/* no spec so far, use the 'ref' clock */
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dev_dbg(&ofdev->dev, "no clk source spec, trying REF\n");
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clk_in = devm_clk_get(&ofdev->dev, "ref");
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if (IS_ERR(clk_in))
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goto err_notavail;
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clk_from = CLK_FROM_REF;
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freq_calc = clk_get_rate(clk_in);
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dev_dbg(&ofdev->dev,
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"clk fit, ref[%lu] (no div) freq[%lu]\n",
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freq_calc, freq_calc);
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}
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/* select IPS or MCLK as the MSCAN input (returned to the caller),
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* setup the MCLK mux source and rate if applicable, apply the
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* optionally specified or derived above divider, and determine
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* the actual resulting clock rate to return to the caller
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*/
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switch (clk_from) {
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case CLK_FROM_IPS:
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clk_can = devm_clk_get(&ofdev->dev, "ips");
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if (IS_ERR(clk_can))
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goto err_notavail;
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priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
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priv->clk_can = clk_can;
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freq_calc = clk_get_rate(clk_can);
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*mscan_clksrc = MSCAN_CLKSRC_IPS;
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dev_dbg(&ofdev->dev, "clk from IPS, clksrc[%d] freq[%lu]\n",
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*mscan_clksrc, freq_calc);
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break;
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case CLK_FROM_SYS:
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case CLK_FROM_REF:
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clk_can = devm_clk_get(&ofdev->dev, "mclk");
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if (IS_ERR(clk_can))
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goto err_notavail;
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priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
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priv->clk_can = clk_can;
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if (clk_from == CLK_FROM_SYS)
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clk_in = devm_clk_get(&ofdev->dev, "sys");
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if (clk_from == CLK_FROM_REF)
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clk_in = devm_clk_get(&ofdev->dev, "ref");
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if (IS_ERR(clk_in))
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goto err_notavail;
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clk_set_parent(clk_can, clk_in);
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freq_calc = clk_get_rate(clk_in);
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freq_calc /= clockdiv;
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clk_set_rate(clk_can, freq_calc);
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freq_calc = clk_get_rate(clk_can);
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*mscan_clksrc = MSCAN_CLKSRC_BUS;
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dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n",
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*mscan_clksrc, freq_calc);
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break;
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default:
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goto err_invalid;
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}
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/* the above clk_can item is used for the bitrate, access to
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* the peripheral's register set needs the clk_ipg item
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*/
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clk_ipg = devm_clk_get(&ofdev->dev, "ipg");
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if (IS_ERR(clk_ipg))
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goto err_notavail_ipg;
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if (clk_prepare_enable(clk_ipg))
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goto err_notavail_ipg;
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priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
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priv->clk_ipg = clk_ipg;
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/* return the determined clock source rate */
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return freq_calc;
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err_invalid:
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dev_err(&ofdev->dev, "invalid clock source specification\n");
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/* clock source rate could not get determined */
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return 0;
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err_notavail:
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dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n");
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/* clock source rate could not get determined */
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return 0;
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err_notavail_ipg:
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dev_err(&ofdev->dev, "cannot acquire or setup register clock\n");
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/* clock source rate could not get determined */
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return 0;
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}
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static void mpc512x_can_put_clock(struct platform_device *ofdev)
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{
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struct mscan_priv *priv;
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priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
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if (priv->clk_ipg)
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clk_disable_unprepare(priv->clk_ipg);
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}
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#else /* !CONFIG_PPC_MPC512x */
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static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
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const char *clock_name, int *mscan_clksrc)
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{
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return 0;
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}
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#define mpc512x_can_put_clock NULL
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#endif /* CONFIG_PPC_MPC512x */
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static const struct of_device_id mpc5xxx_can_table[];
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static int mpc5xxx_can_probe(struct platform_device *ofdev)
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{
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const struct of_device_id *match;
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const struct mpc5xxx_can_data *data;
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struct device_node *np = ofdev->dev.of_node;
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struct net_device *dev;
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struct mscan_priv *priv;
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void __iomem *base;
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const char *clock_name = NULL;
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int irq, mscan_clksrc = 0;
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int err = -ENOMEM;
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match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
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if (!match)
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return -EINVAL;
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data = match->data;
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base = of_iomap(np, 0);
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if (!base) {
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dev_err(&ofdev->dev, "couldn't ioremap\n");
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return err;
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}
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irq = irq_of_parse_and_map(np, 0);
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if (!irq) {
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dev_err(&ofdev->dev, "no irq found\n");
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err = -ENODEV;
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goto exit_unmap_mem;
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}
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dev = alloc_mscandev();
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if (!dev)
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goto exit_dispose_irq;
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platform_set_drvdata(ofdev, dev);
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SET_NETDEV_DEV(dev, &ofdev->dev);
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priv = netdev_priv(dev);
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priv->reg_base = base;
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dev->irq = irq;
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clock_name = of_get_property(np, "fsl,mscan-clock-source", NULL);
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BUG_ON(!data);
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priv->type = data->type;
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priv->can.clock.freq = data->get_clock(ofdev, clock_name,
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&mscan_clksrc);
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if (!priv->can.clock.freq) {
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dev_err(&ofdev->dev, "couldn't get MSCAN clock properties\n");
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goto exit_free_mscan;
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}
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err = register_mscandev(dev, mscan_clksrc);
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if (err) {
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dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
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DRV_NAME, err);
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goto exit_free_mscan;
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}
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dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n",
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priv->reg_base, dev->irq, priv->can.clock.freq);
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return 0;
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exit_free_mscan:
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free_candev(dev);
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exit_dispose_irq:
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irq_dispose_mapping(irq);
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exit_unmap_mem:
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iounmap(base);
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return err;
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}
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static int mpc5xxx_can_remove(struct platform_device *ofdev)
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{
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const struct of_device_id *match;
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const struct mpc5xxx_can_data *data;
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struct net_device *dev = platform_get_drvdata(ofdev);
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struct mscan_priv *priv = netdev_priv(dev);
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match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
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data = match ? match->data : NULL;
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unregister_mscandev(dev);
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if (data && data->put_clock)
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data->put_clock(ofdev);
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iounmap(priv->reg_base);
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irq_dispose_mapping(dev->irq);
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free_candev(dev);
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return 0;
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}
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#ifdef CONFIG_PM
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static struct mscan_regs saved_regs;
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static int mpc5xxx_can_suspend(struct platform_device *ofdev, pm_message_t state)
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{
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struct net_device *dev = platform_get_drvdata(ofdev);
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struct mscan_priv *priv = netdev_priv(dev);
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struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
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_memcpy_fromio(&saved_regs, regs, sizeof(*regs));
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return 0;
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}
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static int mpc5xxx_can_resume(struct platform_device *ofdev)
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{
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struct net_device *dev = platform_get_drvdata(ofdev);
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struct mscan_priv *priv = netdev_priv(dev);
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struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
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regs->canctl0 |= MSCAN_INITRQ;
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while (!(regs->canctl1 & MSCAN_INITAK))
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udelay(10);
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regs->canctl1 = saved_regs.canctl1;
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regs->canbtr0 = saved_regs.canbtr0;
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regs->canbtr1 = saved_regs.canbtr1;
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regs->canidac = saved_regs.canidac;
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/* restore masks, buffers etc. */
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_memcpy_toio(®s->canidar1_0, (void *)&saved_regs.canidar1_0,
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sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0));
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regs->canctl0 &= ~MSCAN_INITRQ;
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regs->cantbsel = saved_regs.cantbsel;
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regs->canrier = saved_regs.canrier;
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regs->cantier = saved_regs.cantier;
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regs->canctl0 = saved_regs.canctl0;
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return 0;
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}
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#endif
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static const struct mpc5xxx_can_data mpc5200_can_data = {
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.type = MSCAN_TYPE_MPC5200,
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.get_clock = mpc52xx_can_get_clock,
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/* .put_clock not applicable */
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};
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static const struct mpc5xxx_can_data mpc5121_can_data = {
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.type = MSCAN_TYPE_MPC5121,
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.get_clock = mpc512x_can_get_clock,
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.put_clock = mpc512x_can_put_clock,
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};
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static const struct of_device_id mpc5xxx_can_table[] = {
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{ .compatible = "fsl,mpc5200-mscan", .data = &mpc5200_can_data, },
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/* Note that only MPC5121 Rev. 2 (and later) is supported */
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{ .compatible = "fsl,mpc5121-mscan", .data = &mpc5121_can_data, },
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{},
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};
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MODULE_DEVICE_TABLE(of, mpc5xxx_can_table);
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static struct platform_driver mpc5xxx_can_driver = {
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.driver = {
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.name = "mpc5xxx_can",
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.owner = THIS_MODULE,
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.of_match_table = mpc5xxx_can_table,
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},
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.probe = mpc5xxx_can_probe,
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.remove = mpc5xxx_can_remove,
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#ifdef CONFIG_PM
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.suspend = mpc5xxx_can_suspend,
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.resume = mpc5xxx_can_resume,
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#endif
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};
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module_platform_driver(mpc5xxx_can_driver);
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MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
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MODULE_DESCRIPTION("Freescale MPC5xxx CAN driver");
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MODULE_LICENSE("GPL v2");
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