cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

mipi.c (14985B)


      1/*
      2 * Copyright (C) 2013 NVIDIA Corporation
      3 *
      4 * Permission to use, copy, modify, distribute, and sell this software and its
      5 * documentation for any purpose is hereby granted without fee, provided that
      6 * the above copyright notice appear in all copies and that both that copyright
      7 * notice and this permission notice appear in supporting documentation, and
      8 * that the name of the copyright holders not be used in advertising or
      9 * publicity pertaining to distribution of the software without specific,
     10 * written prior permission.  The copyright holders make no representations
     11 * about the suitability of this software for any purpose.  It is provided "as
     12 * is" without express or implied warranty.
     13 *
     14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
     15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
     16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
     17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
     18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
     19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
     20 * OF THIS SOFTWARE.
     21 */
     22
     23#include <linux/clk.h>
     24#include <linux/host1x.h>
     25#include <linux/io.h>
     26#include <linux/iopoll.h>
     27#include <linux/of_platform.h>
     28#include <linux/platform_device.h>
     29#include <linux/slab.h>
     30
     31#include "dev.h"
     32
     33#define MIPI_CAL_CTRL			0x00
     34#define MIPI_CAL_CTRL_NOISE_FILTER(x)	(((x) & 0xf) << 26)
     35#define MIPI_CAL_CTRL_PRESCALE(x)	(((x) & 0x3) << 24)
     36#define MIPI_CAL_CTRL_CLKEN_OVR		(1 << 4)
     37#define MIPI_CAL_CTRL_START		(1 << 0)
     38
     39#define MIPI_CAL_AUTOCAL_CTRL		0x01
     40
     41#define MIPI_CAL_STATUS			0x02
     42#define MIPI_CAL_STATUS_DONE		(1 << 16)
     43#define MIPI_CAL_STATUS_ACTIVE		(1 <<  0)
     44
     45#define MIPI_CAL_CONFIG_CSIA		0x05
     46#define MIPI_CAL_CONFIG_CSIB		0x06
     47#define MIPI_CAL_CONFIG_CSIC		0x07
     48#define MIPI_CAL_CONFIG_CSID		0x08
     49#define MIPI_CAL_CONFIG_CSIE		0x09
     50#define MIPI_CAL_CONFIG_CSIF		0x0a
     51#define MIPI_CAL_CONFIG_DSIA		0x0e
     52#define MIPI_CAL_CONFIG_DSIB		0x0f
     53#define MIPI_CAL_CONFIG_DSIC		0x10
     54#define MIPI_CAL_CONFIG_DSID		0x11
     55
     56#define MIPI_CAL_CONFIG_DSIA_CLK	0x19
     57#define MIPI_CAL_CONFIG_DSIB_CLK	0x1a
     58#define MIPI_CAL_CONFIG_CSIAB_CLK	0x1b
     59#define MIPI_CAL_CONFIG_DSIC_CLK	0x1c
     60#define MIPI_CAL_CONFIG_CSICD_CLK	0x1c
     61#define MIPI_CAL_CONFIG_DSID_CLK	0x1d
     62#define MIPI_CAL_CONFIG_CSIE_CLK	0x1d
     63
     64/* for data and clock lanes */
     65#define MIPI_CAL_CONFIG_SELECT		(1 << 21)
     66
     67/* for data lanes */
     68#define MIPI_CAL_CONFIG_HSPDOS(x)	(((x) & 0x1f) << 16)
     69#define MIPI_CAL_CONFIG_HSPUOS(x)	(((x) & 0x1f) <<  8)
     70#define MIPI_CAL_CONFIG_TERMOS(x)	(((x) & 0x1f) <<  0)
     71
     72/* for clock lanes */
     73#define MIPI_CAL_CONFIG_HSCLKPDOSD(x)	(((x) & 0x1f) <<  8)
     74#define MIPI_CAL_CONFIG_HSCLKPUOSD(x)	(((x) & 0x1f) <<  0)
     75
     76#define MIPI_CAL_BIAS_PAD_CFG0		0x16
     77#define MIPI_CAL_BIAS_PAD_PDVCLAMP	(1 << 1)
     78#define MIPI_CAL_BIAS_PAD_E_VCLAMP_REF	(1 << 0)
     79
     80#define MIPI_CAL_BIAS_PAD_CFG1		0x17
     81#define MIPI_CAL_BIAS_PAD_DRV_DN_REF(x) (((x) & 0x7) << 16)
     82#define MIPI_CAL_BIAS_PAD_DRV_UP_REF(x) (((x) & 0x7) << 8)
     83
     84#define MIPI_CAL_BIAS_PAD_CFG2		0x18
     85#define MIPI_CAL_BIAS_PAD_VCLAMP(x)	(((x) & 0x7) << 16)
     86#define MIPI_CAL_BIAS_PAD_VAUXP(x)	(((x) & 0x7) << 4)
     87#define MIPI_CAL_BIAS_PAD_PDVREG	(1 << 1)
     88
     89struct tegra_mipi_pad {
     90	unsigned long data;
     91	unsigned long clk;
     92};
     93
     94struct tegra_mipi_soc {
     95	bool has_clk_lane;
     96	const struct tegra_mipi_pad *pads;
     97	unsigned int num_pads;
     98
     99	bool clock_enable_override;
    100	bool needs_vclamp_ref;
    101
    102	/* bias pad configuration settings */
    103	u8 pad_drive_down_ref;
    104	u8 pad_drive_up_ref;
    105
    106	u8 pad_vclamp_level;
    107	u8 pad_vauxp_level;
    108
    109	/* calibration settings for data lanes */
    110	u8 hspdos;
    111	u8 hspuos;
    112	u8 termos;
    113
    114	/* calibration settings for clock lanes */
    115	u8 hsclkpdos;
    116	u8 hsclkpuos;
    117};
    118
    119struct tegra_mipi {
    120	const struct tegra_mipi_soc *soc;
    121	struct device *dev;
    122	void __iomem *regs;
    123	struct mutex lock;
    124	struct clk *clk;
    125
    126	unsigned long usage_count;
    127};
    128
    129struct tegra_mipi_device {
    130	struct platform_device *pdev;
    131	struct tegra_mipi *mipi;
    132	struct device *device;
    133	unsigned long pads;
    134};
    135
    136static inline u32 tegra_mipi_readl(struct tegra_mipi *mipi,
    137				   unsigned long offset)
    138{
    139	return readl(mipi->regs + (offset << 2));
    140}
    141
    142static inline void tegra_mipi_writel(struct tegra_mipi *mipi, u32 value,
    143				     unsigned long offset)
    144{
    145	writel(value, mipi->regs + (offset << 2));
    146}
    147
    148static int tegra_mipi_power_up(struct tegra_mipi *mipi)
    149{
    150	u32 value;
    151	int err;
    152
    153	err = clk_enable(mipi->clk);
    154	if (err < 0)
    155		return err;
    156
    157	value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG0);
    158	value &= ~MIPI_CAL_BIAS_PAD_PDVCLAMP;
    159
    160	if (mipi->soc->needs_vclamp_ref)
    161		value |= MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
    162
    163	tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
    164
    165	value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG2);
    166	value &= ~MIPI_CAL_BIAS_PAD_PDVREG;
    167	tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
    168
    169	clk_disable(mipi->clk);
    170
    171	return 0;
    172}
    173
    174static int tegra_mipi_power_down(struct tegra_mipi *mipi)
    175{
    176	u32 value;
    177	int err;
    178
    179	err = clk_enable(mipi->clk);
    180	if (err < 0)
    181		return err;
    182
    183	/*
    184	 * The MIPI_CAL_BIAS_PAD_PDVREG controls a voltage regulator that
    185	 * supplies the DSI pads. This must be kept enabled until none of the
    186	 * DSI lanes are used anymore.
    187	 */
    188	value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG2);
    189	value |= MIPI_CAL_BIAS_PAD_PDVREG;
    190	tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
    191
    192	/*
    193	 * MIPI_CAL_BIAS_PAD_PDVCLAMP and MIPI_CAL_BIAS_PAD_E_VCLAMP_REF
    194	 * control a regulator that supplies current to the pre-driver logic.
    195	 * Powering down this regulator causes DSI to fail, so it must remain
    196	 * powered on until none of the DSI lanes are used anymore.
    197	 */
    198	value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG0);
    199
    200	if (mipi->soc->needs_vclamp_ref)
    201		value &= ~MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
    202
    203	value |= MIPI_CAL_BIAS_PAD_PDVCLAMP;
    204	tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
    205
    206	return 0;
    207}
    208
    209struct tegra_mipi_device *tegra_mipi_request(struct device *device,
    210					     struct device_node *np)
    211{
    212	struct tegra_mipi_device *dev;
    213	struct of_phandle_args args;
    214	int err;
    215
    216	err = of_parse_phandle_with_args(np, "nvidia,mipi-calibrate",
    217					 "#nvidia,mipi-calibrate-cells", 0,
    218					 &args);
    219	if (err < 0)
    220		return ERR_PTR(err);
    221
    222	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
    223	if (!dev) {
    224		err = -ENOMEM;
    225		goto out;
    226	}
    227
    228	dev->pdev = of_find_device_by_node(args.np);
    229	if (!dev->pdev) {
    230		err = -ENODEV;
    231		goto free;
    232	}
    233
    234	dev->mipi = platform_get_drvdata(dev->pdev);
    235	if (!dev->mipi) {
    236		err = -EPROBE_DEFER;
    237		goto put;
    238	}
    239
    240	of_node_put(args.np);
    241
    242	dev->pads = args.args[0];
    243	dev->device = device;
    244
    245	return dev;
    246
    247put:
    248	platform_device_put(dev->pdev);
    249free:
    250	kfree(dev);
    251out:
    252	of_node_put(args.np);
    253	return ERR_PTR(err);
    254}
    255EXPORT_SYMBOL(tegra_mipi_request);
    256
    257void tegra_mipi_free(struct tegra_mipi_device *device)
    258{
    259	platform_device_put(device->pdev);
    260	kfree(device);
    261}
    262EXPORT_SYMBOL(tegra_mipi_free);
    263
    264int tegra_mipi_enable(struct tegra_mipi_device *dev)
    265{
    266	int err = 0;
    267
    268	mutex_lock(&dev->mipi->lock);
    269
    270	if (dev->mipi->usage_count++ == 0)
    271		err = tegra_mipi_power_up(dev->mipi);
    272
    273	mutex_unlock(&dev->mipi->lock);
    274
    275	return err;
    276
    277}
    278EXPORT_SYMBOL(tegra_mipi_enable);
    279
    280int tegra_mipi_disable(struct tegra_mipi_device *dev)
    281{
    282	int err = 0;
    283
    284	mutex_lock(&dev->mipi->lock);
    285
    286	if (--dev->mipi->usage_count == 0)
    287		err = tegra_mipi_power_down(dev->mipi);
    288
    289	mutex_unlock(&dev->mipi->lock);
    290
    291	return err;
    292
    293}
    294EXPORT_SYMBOL(tegra_mipi_disable);
    295
    296int tegra_mipi_finish_calibration(struct tegra_mipi_device *device)
    297{
    298	struct tegra_mipi *mipi = device->mipi;
    299	void __iomem *status_reg = mipi->regs + (MIPI_CAL_STATUS << 2);
    300	u32 value;
    301	int err;
    302
    303	err = readl_relaxed_poll_timeout(status_reg, value,
    304					 !(value & MIPI_CAL_STATUS_ACTIVE) &&
    305					 (value & MIPI_CAL_STATUS_DONE), 50,
    306					 250000);
    307	mutex_unlock(&device->mipi->lock);
    308	clk_disable(device->mipi->clk);
    309
    310	return err;
    311}
    312EXPORT_SYMBOL(tegra_mipi_finish_calibration);
    313
    314int tegra_mipi_start_calibration(struct tegra_mipi_device *device)
    315{
    316	const struct tegra_mipi_soc *soc = device->mipi->soc;
    317	unsigned int i;
    318	u32 value;
    319	int err;
    320
    321	err = clk_enable(device->mipi->clk);
    322	if (err < 0)
    323		return err;
    324
    325	mutex_lock(&device->mipi->lock);
    326
    327	value = MIPI_CAL_BIAS_PAD_DRV_DN_REF(soc->pad_drive_down_ref) |
    328		MIPI_CAL_BIAS_PAD_DRV_UP_REF(soc->pad_drive_up_ref);
    329	tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG1);
    330
    331	value = tegra_mipi_readl(device->mipi, MIPI_CAL_BIAS_PAD_CFG2);
    332	value &= ~MIPI_CAL_BIAS_PAD_VCLAMP(0x7);
    333	value &= ~MIPI_CAL_BIAS_PAD_VAUXP(0x7);
    334	value |= MIPI_CAL_BIAS_PAD_VCLAMP(soc->pad_vclamp_level);
    335	value |= MIPI_CAL_BIAS_PAD_VAUXP(soc->pad_vauxp_level);
    336	tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
    337
    338	for (i = 0; i < soc->num_pads; i++) {
    339		u32 clk = 0, data = 0;
    340
    341		if (device->pads & BIT(i)) {
    342			data = MIPI_CAL_CONFIG_SELECT |
    343			       MIPI_CAL_CONFIG_HSPDOS(soc->hspdos) |
    344			       MIPI_CAL_CONFIG_HSPUOS(soc->hspuos) |
    345			       MIPI_CAL_CONFIG_TERMOS(soc->termos);
    346			clk = MIPI_CAL_CONFIG_SELECT |
    347			      MIPI_CAL_CONFIG_HSCLKPDOSD(soc->hsclkpdos) |
    348			      MIPI_CAL_CONFIG_HSCLKPUOSD(soc->hsclkpuos);
    349		}
    350
    351		tegra_mipi_writel(device->mipi, data, soc->pads[i].data);
    352
    353		if (soc->has_clk_lane && soc->pads[i].clk != 0)
    354			tegra_mipi_writel(device->mipi, clk, soc->pads[i].clk);
    355	}
    356
    357	value = tegra_mipi_readl(device->mipi, MIPI_CAL_CTRL);
    358	value &= ~MIPI_CAL_CTRL_NOISE_FILTER(0xf);
    359	value &= ~MIPI_CAL_CTRL_PRESCALE(0x3);
    360	value |= MIPI_CAL_CTRL_NOISE_FILTER(0xa);
    361	value |= MIPI_CAL_CTRL_PRESCALE(0x2);
    362
    363	if (!soc->clock_enable_override)
    364		value &= ~MIPI_CAL_CTRL_CLKEN_OVR;
    365	else
    366		value |= MIPI_CAL_CTRL_CLKEN_OVR;
    367
    368	tegra_mipi_writel(device->mipi, value, MIPI_CAL_CTRL);
    369
    370	/* clear any pending status bits */
    371	value = tegra_mipi_readl(device->mipi, MIPI_CAL_STATUS);
    372	tegra_mipi_writel(device->mipi, value, MIPI_CAL_STATUS);
    373
    374	value = tegra_mipi_readl(device->mipi, MIPI_CAL_CTRL);
    375	value |= MIPI_CAL_CTRL_START;
    376	tegra_mipi_writel(device->mipi, value, MIPI_CAL_CTRL);
    377
    378	/*
    379	 * Wait for min 72uS to let calibration logic finish calibration
    380	 * sequence codes before waiting for pads idle state to apply the
    381	 * results.
    382	 */
    383	usleep_range(75, 80);
    384
    385	return 0;
    386}
    387EXPORT_SYMBOL(tegra_mipi_start_calibration);
    388
    389static const struct tegra_mipi_pad tegra114_mipi_pads[] = {
    390	{ .data = MIPI_CAL_CONFIG_CSIA },
    391	{ .data = MIPI_CAL_CONFIG_CSIB },
    392	{ .data = MIPI_CAL_CONFIG_CSIC },
    393	{ .data = MIPI_CAL_CONFIG_CSID },
    394	{ .data = MIPI_CAL_CONFIG_CSIE },
    395	{ .data = MIPI_CAL_CONFIG_DSIA },
    396	{ .data = MIPI_CAL_CONFIG_DSIB },
    397	{ .data = MIPI_CAL_CONFIG_DSIC },
    398	{ .data = MIPI_CAL_CONFIG_DSID },
    399};
    400
    401static const struct tegra_mipi_soc tegra114_mipi_soc = {
    402	.has_clk_lane = false,
    403	.pads = tegra114_mipi_pads,
    404	.num_pads = ARRAY_SIZE(tegra114_mipi_pads),
    405	.clock_enable_override = true,
    406	.needs_vclamp_ref = true,
    407	.pad_drive_down_ref = 0x2,
    408	.pad_drive_up_ref = 0x0,
    409	.pad_vclamp_level = 0x0,
    410	.pad_vauxp_level = 0x0,
    411	.hspdos = 0x0,
    412	.hspuos = 0x4,
    413	.termos = 0x5,
    414	.hsclkpdos = 0x0,
    415	.hsclkpuos = 0x4,
    416};
    417
    418static const struct tegra_mipi_pad tegra124_mipi_pads[] = {
    419	{ .data = MIPI_CAL_CONFIG_CSIA, .clk = MIPI_CAL_CONFIG_CSIAB_CLK },
    420	{ .data = MIPI_CAL_CONFIG_CSIB, .clk = MIPI_CAL_CONFIG_CSIAB_CLK },
    421	{ .data = MIPI_CAL_CONFIG_CSIC, .clk = MIPI_CAL_CONFIG_CSICD_CLK },
    422	{ .data = MIPI_CAL_CONFIG_CSID, .clk = MIPI_CAL_CONFIG_CSICD_CLK },
    423	{ .data = MIPI_CAL_CONFIG_CSIE, .clk = MIPI_CAL_CONFIG_CSIE_CLK  },
    424	{ .data = MIPI_CAL_CONFIG_DSIA, .clk = MIPI_CAL_CONFIG_DSIA_CLK  },
    425	{ .data = MIPI_CAL_CONFIG_DSIB, .clk = MIPI_CAL_CONFIG_DSIB_CLK  },
    426};
    427
    428static const struct tegra_mipi_soc tegra124_mipi_soc = {
    429	.has_clk_lane = true,
    430	.pads = tegra124_mipi_pads,
    431	.num_pads = ARRAY_SIZE(tegra124_mipi_pads),
    432	.clock_enable_override = true,
    433	.needs_vclamp_ref = true,
    434	.pad_drive_down_ref = 0x2,
    435	.pad_drive_up_ref = 0x0,
    436	.pad_vclamp_level = 0x0,
    437	.pad_vauxp_level = 0x0,
    438	.hspdos = 0x0,
    439	.hspuos = 0x0,
    440	.termos = 0x0,
    441	.hsclkpdos = 0x1,
    442	.hsclkpuos = 0x2,
    443};
    444
    445static const struct tegra_mipi_soc tegra132_mipi_soc = {
    446	.has_clk_lane = true,
    447	.pads = tegra124_mipi_pads,
    448	.num_pads = ARRAY_SIZE(tegra124_mipi_pads),
    449	.clock_enable_override = false,
    450	.needs_vclamp_ref = false,
    451	.pad_drive_down_ref = 0x0,
    452	.pad_drive_up_ref = 0x3,
    453	.pad_vclamp_level = 0x0,
    454	.pad_vauxp_level = 0x0,
    455	.hspdos = 0x0,
    456	.hspuos = 0x0,
    457	.termos = 0x0,
    458	.hsclkpdos = 0x3,
    459	.hsclkpuos = 0x2,
    460};
    461
    462static const struct tegra_mipi_pad tegra210_mipi_pads[] = {
    463	{ .data = MIPI_CAL_CONFIG_CSIA, .clk = 0 },
    464	{ .data = MIPI_CAL_CONFIG_CSIB, .clk = 0 },
    465	{ .data = MIPI_CAL_CONFIG_CSIC, .clk = 0 },
    466	{ .data = MIPI_CAL_CONFIG_CSID, .clk = 0 },
    467	{ .data = MIPI_CAL_CONFIG_CSIE, .clk = 0 },
    468	{ .data = MIPI_CAL_CONFIG_CSIF, .clk = 0 },
    469	{ .data = MIPI_CAL_CONFIG_DSIA, .clk = MIPI_CAL_CONFIG_DSIA_CLK },
    470	{ .data = MIPI_CAL_CONFIG_DSIB, .clk = MIPI_CAL_CONFIG_DSIB_CLK },
    471	{ .data = MIPI_CAL_CONFIG_DSIC, .clk = MIPI_CAL_CONFIG_DSIC_CLK },
    472	{ .data = MIPI_CAL_CONFIG_DSID, .clk = MIPI_CAL_CONFIG_DSID_CLK },
    473};
    474
    475static const struct tegra_mipi_soc tegra210_mipi_soc = {
    476	.has_clk_lane = true,
    477	.pads = tegra210_mipi_pads,
    478	.num_pads = ARRAY_SIZE(tegra210_mipi_pads),
    479	.clock_enable_override = true,
    480	.needs_vclamp_ref = false,
    481	.pad_drive_down_ref = 0x0,
    482	.pad_drive_up_ref = 0x3,
    483	.pad_vclamp_level = 0x1,
    484	.pad_vauxp_level = 0x1,
    485	.hspdos = 0x0,
    486	.hspuos = 0x2,
    487	.termos = 0x0,
    488	.hsclkpdos = 0x0,
    489	.hsclkpuos = 0x2,
    490};
    491
    492static const struct of_device_id tegra_mipi_of_match[] = {
    493	{ .compatible = "nvidia,tegra114-mipi", .data = &tegra114_mipi_soc },
    494	{ .compatible = "nvidia,tegra124-mipi", .data = &tegra124_mipi_soc },
    495	{ .compatible = "nvidia,tegra132-mipi", .data = &tegra132_mipi_soc },
    496	{ .compatible = "nvidia,tegra210-mipi", .data = &tegra210_mipi_soc },
    497	{ },
    498};
    499
    500static int tegra_mipi_probe(struct platform_device *pdev)
    501{
    502	const struct of_device_id *match;
    503	struct tegra_mipi *mipi;
    504	struct resource *res;
    505	int err;
    506
    507	match = of_match_node(tegra_mipi_of_match, pdev->dev.of_node);
    508	if (!match)
    509		return -ENODEV;
    510
    511	mipi = devm_kzalloc(&pdev->dev, sizeof(*mipi), GFP_KERNEL);
    512	if (!mipi)
    513		return -ENOMEM;
    514
    515	mipi->soc = match->data;
    516	mipi->dev = &pdev->dev;
    517
    518	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    519	mipi->regs = devm_ioremap_resource(&pdev->dev, res);
    520	if (IS_ERR(mipi->regs))
    521		return PTR_ERR(mipi->regs);
    522
    523	mutex_init(&mipi->lock);
    524
    525	mipi->clk = devm_clk_get(&pdev->dev, NULL);
    526	if (IS_ERR(mipi->clk)) {
    527		dev_err(&pdev->dev, "failed to get clock\n");
    528		return PTR_ERR(mipi->clk);
    529	}
    530
    531	err = clk_prepare(mipi->clk);
    532	if (err < 0)
    533		return err;
    534
    535	platform_set_drvdata(pdev, mipi);
    536
    537	return 0;
    538}
    539
    540static int tegra_mipi_remove(struct platform_device *pdev)
    541{
    542	struct tegra_mipi *mipi = platform_get_drvdata(pdev);
    543
    544	clk_unprepare(mipi->clk);
    545
    546	return 0;
    547}
    548
    549struct platform_driver tegra_mipi_driver = {
    550	.driver = {
    551		.name = "tegra-mipi",
    552		.of_match_table = tegra_mipi_of_match,
    553	},
    554	.probe = tegra_mipi_probe,
    555	.remove = tegra_mipi_remove,
    556};