[linux.git] / drivers / bus / bt1-apb.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
 *
 * Authors:
 *   Serge Semin <[email protected]>
 *
 * Baikal-T1 APB-bus driver
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/atomic.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/nmi.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/time64.h>
#include <linux/clk.h>
#include <linux/sysfs.h>

#define APB_EHB_ISR			0x00
#define APB_EHB_ISR_PENDING		BIT(0)
#define APB_EHB_ISR_MASK		BIT(1)
#define APB_EHB_ADDR			0x04
#define APB_EHB_TIMEOUT			0x08

#define APB_EHB_TIMEOUT_MIN		0x000003FFU
#define APB_EHB_TIMEOUT_MAX		0xFFFFFFFFU

/*
 * struct bt1_apb - Baikal-T1 APB EHB private data
 * @dev: Pointer to the device structure.
 * @regs: APB EHB registers map.
 * @res: No-device error injection memory region.
 * @irq: Errors IRQ number.
 * @rate: APB-bus reference clock rate.
 * @pclk: APB-reference clock.
 * @prst: APB domain reset line.
 * @count: Number of errors detected.
 */
struct bt1_apb {
	struct device *dev;

	struct regmap *regs;
	void __iomem *res;
	int irq;

	unsigned long rate;
	struct clk *pclk;

	struct reset_control *prst;

	atomic_t count;
};

static const struct regmap_config bt1_apb_regmap_cfg = {
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	.max_register = APB_EHB_TIMEOUT,
	.fast_io = true
};

static inline unsigned long bt1_apb_n_to_timeout_us(struct bt1_apb *apb, u32 n)
{
	u64 timeout = (u64)n * USEC_PER_SEC;

	do_div(timeout, apb->rate);

	return timeout;

}

static inline unsigned long bt1_apb_timeout_to_n_us(struct bt1_apb *apb,
						    unsigned long timeout)
{
	u64 n = (u64)timeout * apb->rate;

	do_div(n, USEC_PER_SEC);

	return n;

}

static irqreturn_t bt1_apb_isr(int irq, void *data)
{
	struct bt1_apb *apb = data;
	u32 addr = 0;

	regmap_read(apb->regs, APB_EHB_ADDR, &addr);

	dev_crit_ratelimited(apb->dev,
		"APB-bus fault %d: Slave access timeout at 0x%08x\n",
		atomic_inc_return(&apb->count),
		addr);

	/*
	 * Print backtrace on each CPU. This might be pointless if the fault
	 * has happened on the same CPU as the IRQ handler is executed or
	 * the other core proceeded further execution despite the error.
	 * But if it's not, by looking at the trace we would get straight to
	 * the cause of the problem.
	 */
	trigger_all_cpu_backtrace();

	regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, 0);

	return IRQ_HANDLED;
}

static void bt1_apb_clear_data(void *data)
{
	struct bt1_apb *apb = data;
	struct platform_device *pdev = to_platform_device(apb->dev);

	platform_set_drvdata(pdev, NULL);
}

static struct bt1_apb *bt1_apb_create_data(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct bt1_apb *apb;
	int ret;

	apb = devm_kzalloc(dev, sizeof(*apb), GFP_KERNEL);
	if (!apb)
		return ERR_PTR(-ENOMEM);

	ret = devm_add_action(dev, bt1_apb_clear_data, apb);
	if (ret) {
		dev_err(dev, "Can't add APB EHB data clear action\n");
		return ERR_PTR(ret);
	}

	apb->dev = dev;
	atomic_set(&apb->count, 0);
	platform_set_drvdata(pdev, apb);

	return apb;
}

static int bt1_apb_request_regs(struct bt1_apb *apb)
{
	struct platform_device *pdev = to_platform_device(apb->dev);
	void __iomem *regs;

	regs = devm_platform_ioremap_resource_byname(pdev, "ehb");
	if (IS_ERR(regs)) {
		dev_err(apb->dev, "Couldn't map APB EHB registers\n");
		return PTR_ERR(regs);
	}

	apb->regs = devm_regmap_init_mmio(apb->dev, regs, &bt1_apb_regmap_cfg);
	if (IS_ERR(apb->regs)) {
		dev_err(apb->dev, "Couldn't create APB EHB regmap\n");
		return PTR_ERR(apb->regs);
	}

	apb->res = devm_platform_ioremap_resource_byname(pdev, "nodev");
	if (IS_ERR(apb->res))
		dev_err(apb->dev, "Couldn't map reserved region\n");

	return PTR_ERR_OR_ZERO(apb->res);
}

static int bt1_apb_request_rst(struct bt1_apb *apb)
{
	int ret;

	apb->prst = devm_reset_control_get_optional_exclusive(apb->dev, "prst");
	if (IS_ERR(apb->prst)) {
		dev_warn(apb->dev, "Couldn't get reset control line\n");
		return PTR_ERR(apb->prst);
	}

	ret = reset_control_deassert(apb->prst);
	if (ret)
		dev_err(apb->dev, "Failed to deassert the reset line\n");

	return ret;
}

static void bt1_apb_disable_clk(void *data)
{
	struct bt1_apb *apb = data;

	clk_disable_unprepare(apb->pclk);
}

static int bt1_apb_request_clk(struct bt1_apb *apb)
{
	int ret;

	apb->pclk = devm_clk_get(apb->dev, "pclk");
	if (IS_ERR(apb->pclk)) {
		dev_err(apb->dev, "Couldn't get APB clock descriptor\n");
		return PTR_ERR(apb->pclk);
	}

	ret = clk_prepare_enable(apb->pclk);
	if (ret) {
		dev_err(apb->dev, "Couldn't enable the APB clock\n");
		return ret;
	}

	ret = devm_add_action_or_reset(apb->dev, bt1_apb_disable_clk, apb);
	if (ret) {
		dev_err(apb->dev, "Can't add APB EHB clocks disable action\n");
		return ret;
	}

	apb->rate = clk_get_rate(apb->pclk);
	if (!apb->rate) {
		dev_err(apb->dev, "Invalid clock rate\n");
		return -EINVAL;
	}

	return 0;
}

static void bt1_apb_clear_irq(void *data)
{
	struct bt1_apb *apb = data;

	regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_MASK, 0);
}

static int bt1_apb_request_irq(struct bt1_apb *apb)
{
	struct platform_device *pdev = to_platform_device(apb->dev);
	int ret;

	apb->irq = platform_get_irq(pdev, 0);
	if (apb->irq < 0)
		return apb->irq;

	ret = devm_request_irq(apb->dev, apb->irq, bt1_apb_isr, IRQF_SHARED,
			       "bt1-apb", apb);
	if (ret) {
		dev_err(apb->dev, "Couldn't request APB EHB IRQ\n");
		return ret;
	}

	ret = devm_add_action(apb->dev, bt1_apb_clear_irq, apb);
	if (ret) {
		dev_err(apb->dev, "Can't add APB EHB IRQs clear action\n");
		return ret;
	}

	/* Unmask IRQ and clear it' pending flag. */
	regmap_update_bits(apb->regs, APB_EHB_ISR,
			   APB_EHB_ISR_PENDING | APB_EHB_ISR_MASK,
			   APB_EHB_ISR_MASK);

	return 0;
}

static ssize_t count_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	struct bt1_apb *apb = dev_get_drvdata(dev);

	return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&apb->count));
}
static DEVICE_ATTR_RO(count);

static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct bt1_apb *apb = dev_get_drvdata(dev);
	unsigned long timeout;
	int ret;
	u32 n;

	ret = regmap_read(apb->regs, APB_EHB_TIMEOUT, &n);
	if (ret)
		return ret;

	timeout = bt1_apb_n_to_timeout_us(apb, n);

	return scnprintf(buf, PAGE_SIZE, "%lu\n", timeout);
}

static ssize_t timeout_store(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf, size_t count)
{
	struct bt1_apb *apb = dev_get_drvdata(dev);
	unsigned long timeout;
	int ret;
	u32 n;

	if (kstrtoul(buf, 0, &timeout) < 0)
		return -EINVAL;

	n = bt1_apb_timeout_to_n_us(apb, timeout);
	n = clamp(n, APB_EHB_TIMEOUT_MIN, APB_EHB_TIMEOUT_MAX);

	ret = regmap_write(apb->regs, APB_EHB_TIMEOUT, n);

	return ret ?: count;
}
static DEVICE_ATTR_RW(timeout);

static ssize_t inject_error_show(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n");
}

static ssize_t inject_error_store(struct device *dev,
				  struct device_attribute *attr,
				  const char *data, size_t count)
{
	struct bt1_apb *apb = dev_get_drvdata(dev);

	/*
	 * Either dummy read from the unmapped address in the APB IO area
	 * or manually set the IRQ status.
	 */
	if (sysfs_streq(data, "nodev"))
		readl(apb->res);
	else if (sysfs_streq(data, "irq"))
		regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING,
				   APB_EHB_ISR_PENDING);
	else
		return -EINVAL;

	return count;
}
static DEVICE_ATTR_RW(inject_error);

static struct attribute *bt1_apb_sysfs_attrs[] = {
	&dev_attr_count.attr,
	&dev_attr_timeout.attr,
	&dev_attr_inject_error.attr,
	NULL
};
ATTRIBUTE_GROUPS(bt1_apb_sysfs);

static void bt1_apb_remove_sysfs(void *data)
{
	struct bt1_apb *apb = data;

	device_remove_groups(apb->dev, bt1_apb_sysfs_groups);
}

static int bt1_apb_init_sysfs(struct bt1_apb *apb)
{
	int ret;

	ret = device_add_groups(apb->dev, bt1_apb_sysfs_groups);
	if (ret) {
		dev_err(apb->dev, "Failed to create EHB APB sysfs nodes\n");
		return ret;
	}

	ret = devm_add_action_or_reset(apb->dev, bt1_apb_remove_sysfs, apb);
	if (ret)
		dev_err(apb->dev, "Can't add APB EHB sysfs remove action\n");

	return ret;
}

static int bt1_apb_probe(struct platform_device *pdev)
{
	struct bt1_apb *apb;
	int ret;

	apb = bt1_apb_create_data(pdev);
	if (IS_ERR(apb))
		return PTR_ERR(apb);

	ret = bt1_apb_request_regs(apb);
	if (ret)
		return ret;

	ret = bt1_apb_request_rst(apb);
	if (ret)
		return ret;

	ret = bt1_apb_request_clk(apb);
	if (ret)
		return ret;

	ret = bt1_apb_request_irq(apb);
	if (ret)
		return ret;

	ret = bt1_apb_init_sysfs(apb);
	if (ret)
		return ret;

	return 0;
}

static const struct of_device_id bt1_apb_of_match[] = {
	{ .compatible = "baikal,bt1-apb" },
	{ }
};
MODULE_DEVICE_TABLE(of, bt1_apb_of_match);

static struct platform_driver bt1_apb_driver = {
	.probe = bt1_apb_probe,
	.driver = {
		.name = "bt1-apb",
		.of_match_table = bt1_apb_of_match
	}
};
module_platform_driver(bt1_apb_driver);

MODULE_AUTHOR("Serge Semin <[email protected]>");
MODULE_DESCRIPTION("Baikal-T1 APB-bus driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
8f93662d SS	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
	4	*
	5	* Authors:
	6	* Serge Semin <[email protected]>
	7	*
	8	* Baikal-T1 APB-bus driver
	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/types.h>
	14	#include <linux/device.h>
	15	#include <linux/atomic.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/interrupt.h>
1c8ceb16	18	#include <linux/io.h>
8f93662d SS	19	#include <linux/nmi.h>
	20	#include <linux/of.h>
	21	#include <linux/regmap.h>
	22	#include <linux/clk.h>
	23	#include <linux/reset.h>
	24	#include <linux/time64.h>
	25	#include <linux/clk.h>
	26	#include <linux/sysfs.h>
	27
	28	#define APB_EHB_ISR 0x00
	29	#define APB_EHB_ISR_PENDING BIT(0)
	30	#define APB_EHB_ISR_MASK BIT(1)
	31	#define APB_EHB_ADDR 0x04
	32	#define APB_EHB_TIMEOUT 0x08
	33
	34	#define APB_EHB_TIMEOUT_MIN 0x000003FFU
	35	#define APB_EHB_TIMEOUT_MAX 0xFFFFFFFFU
	36
	37	/*
	38	* struct bt1_apb - Baikal-T1 APB EHB private data
	39	* @dev: Pointer to the device structure.
	40	* @regs: APB EHB registers map.
	41	* @res: No-device error injection memory region.
	42	* @irq: Errors IRQ number.
	43	* @rate: APB-bus reference clock rate.
	44	* @pclk: APB-reference clock.
	45	* @prst: APB domain reset line.
	46	* @count: Number of errors detected.
	47	*/
	48	struct bt1_apb {
	49	struct device *dev;
	50
	51	struct regmap *regs;
	52	void __iomem *res;
	53	int irq;
	54
	55	unsigned long rate;
	56	struct clk *pclk;
	57
	58	struct reset_control *prst;
	59
	60	atomic_t count;
	61	};
	62
	63	static const struct regmap_config bt1_apb_regmap_cfg = {
	64	.reg_bits = 32,
	65	.val_bits = 32,
	66	.reg_stride = 4,
	67	.max_register = APB_EHB_TIMEOUT,
	68	.fast_io = true
	69	};
	70
	71	static inline unsigned long bt1_apb_n_to_timeout_us(struct bt1_apb *apb, u32 n)
	72	{
	73	u64 timeout = (u64)n * USEC_PER_SEC;
	74
	75	do_div(timeout, apb->rate);
	76
	77	return timeout;
	78
	79	}
	80
	81	static inline unsigned long bt1_apb_timeout_to_n_us(struct bt1_apb *apb,
	82	unsigned long timeout)
83	{
84	u64 n = (u64)timeout * apb->rate;
85
86	do_div(n, USEC_PER_SEC);
87
88	return n;
89
90	}
91
92	static irqreturn_t bt1_apb_isr(int irq, void *data)
93	{
94	struct bt1_apb *apb = data;
95	u32 addr = 0;
96
97	regmap_read(apb->regs, APB_EHB_ADDR, &addr);
98
99	dev_crit_ratelimited(apb->dev,
100	"APB-bus fault %d: Slave access timeout at 0x%08x\n",
101	atomic_inc_return(&apb->count),
102	addr);
103
104	/*
105	* Print backtrace on each CPU. This might be pointless if the fault
106	* has happened on the same CPU as the IRQ handler is executed or
107	* the other core proceeded further execution despite the error.
108	* But if it's not, by looking at the trace we would get straight to
109	* the cause of the problem.
110	*/
111	trigger_all_cpu_backtrace();
112
113	regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, 0);
114
115	return IRQ_HANDLED;
116	}
117
118	static void bt1_apb_clear_data(void *data)
119	{
120	struct bt1_apb *apb = data;
121	struct platform_device *pdev = to_platform_device(apb->dev);
122
123	platform_set_drvdata(pdev, NULL);
124	}
125
126	static struct bt1_apb bt1_apb_create_data(struct platform_device pdev)
127	{
128	struct device *dev = &pdev->dev;
129	struct bt1_apb *apb;
130	int ret;
131
132	apb = devm_kzalloc(dev, sizeof(*apb), GFP_KERNEL);
133	if (!apb)
134	return ERR_PTR(-ENOMEM);
135
136	ret = devm_add_action(dev, bt1_apb_clear_data, apb);
137	if (ret) {
138	dev_err(dev, "Can't add APB EHB data clear action\n");
139	return ERR_PTR(ret);
140	}
141
142	apb->dev = dev;
143	atomic_set(&apb->count, 0);
144	platform_set_drvdata(pdev, apb);
145
146	return apb;
147	}
148
149	static int bt1_apb_request_regs(struct bt1_apb *apb)
150	{
151	struct platform_device *pdev = to_platform_device(apb->dev);
152	void __iomem *regs;
153
154	regs = devm_platform_ioremap_resource_byname(pdev, "ehb");
155	if (IS_ERR(regs)) {
156	dev_err(apb->dev, "Couldn't map APB EHB registers\n");
157	return PTR_ERR(regs);
158	}
159
160	apb->regs = devm_regmap_init_mmio(apb->dev, regs, &bt1_apb_regmap_cfg);
161	if (IS_ERR(apb->regs)) {
162	dev_err(apb->dev, "Couldn't create APB EHB regmap\n");
163	return PTR_ERR(apb->regs);
164	}
165
166	apb->res = devm_platform_ioremap_resource_byname(pdev, "nodev");
75341b3d	167	if (IS_ERR(apb->res))
8f93662d	168	dev_err(apb->dev, "Couldn't map reserved region\n");
8f93662d	169
75341b3d	170	return PTR_ERR_OR_ZERO(apb->res);
8f93662d SS	171	}
	172
	173	static int bt1_apb_request_rst(struct bt1_apb *apb)
	174	{
	175	int ret;
	176
	177	apb->prst = devm_reset_control_get_optional_exclusive(apb->dev, "prst");
	178	if (IS_ERR(apb->prst)) {
	179	dev_warn(apb->dev, "Couldn't get reset control line\n");
	180	return PTR_ERR(apb->prst);
	181	}
	182
	183	ret = reset_control_deassert(apb->prst);
	184	if (ret)
	185	dev_err(apb->dev, "Failed to deassert the reset line\n");
	186
	187	return ret;
	188	}
	189
	190	static void bt1_apb_disable_clk(void *data)
	191	{
	192	struct bt1_apb *apb = data;
	193
	194	clk_disable_unprepare(apb->pclk);
	195	}
	196
	197	static int bt1_apb_request_clk(struct bt1_apb *apb)
	198	{
	199	int ret;
	200
	201	apb->pclk = devm_clk_get(apb->dev, "pclk");
	202	if (IS_ERR(apb->pclk)) {
	203	dev_err(apb->dev, "Couldn't get APB clock descriptor\n");
	204	return PTR_ERR(apb->pclk);
	205	}
	206
	207	ret = clk_prepare_enable(apb->pclk);
	208	if (ret) {
	209	dev_err(apb->dev, "Couldn't enable the APB clock\n");
	210	return ret;
	211	}
	212
	213	ret = devm_add_action_or_reset(apb->dev, bt1_apb_disable_clk, apb);
	214	if (ret) {
	215	dev_err(apb->dev, "Can't add APB EHB clocks disable action\n");
	216	return ret;
	217	}
	218
	219	apb->rate = clk_get_rate(apb->pclk);
	220	if (!apb->rate) {
	221	dev_err(apb->dev, "Invalid clock rate\n");
	222	return -EINVAL;
	223	}
	224
	225	return 0;
	226	}
	227
	228	static void bt1_apb_clear_irq(void *data)
	229	{
	230	struct bt1_apb *apb = data;
	231
	232	regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_MASK, 0);
	233	}
	234
235	static int bt1_apb_request_irq(struct bt1_apb *apb)
236	{
237	struct platform_device *pdev = to_platform_device(apb->dev);
238	int ret;
239
240	apb->irq = platform_get_irq(pdev, 0);
241	if (apb->irq < 0)
242	return apb->irq;
243
244	ret = devm_request_irq(apb->dev, apb->irq, bt1_apb_isr, IRQF_SHARED,
245	"bt1-apb", apb);
246	if (ret) {
247	dev_err(apb->dev, "Couldn't request APB EHB IRQ\n");
248	return ret;
249	}
250
251	ret = devm_add_action(apb->dev, bt1_apb_clear_irq, apb);
252	if (ret) {
253	dev_err(apb->dev, "Can't add APB EHB IRQs clear action\n");
254	return ret;
255	}
256
257	/* Unmask IRQ and clear it' pending flag. */
258	regmap_update_bits(apb->regs, APB_EHB_ISR,
259	APB_EHB_ISR_PENDING \| APB_EHB_ISR_MASK,
260	APB_EHB_ISR_MASK);
261
262	return 0;
263	}
264
265	static ssize_t count_show(struct device dev, struct device_attribute attr,
266	char *buf)
267	{
268	struct bt1_apb *apb = dev_get_drvdata(dev);
269
270	return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&apb->count));
271	}
272	static DEVICE_ATTR_RO(count);
273
274	static ssize_t timeout_show(struct device dev, struct device_attribute attr,
275	char *buf)
276	{
277	struct bt1_apb *apb = dev_get_drvdata(dev);
278	unsigned long timeout;
279	int ret;
280	u32 n;
281
282	ret = regmap_read(apb->regs, APB_EHB_TIMEOUT, &n);
283	if (ret)
284	return ret;
285
286	timeout = bt1_apb_n_to_timeout_us(apb, n);
287
288	return scnprintf(buf, PAGE_SIZE, "%lu\n", timeout);
289	}
290
291	static ssize_t timeout_store(struct device *dev,
292	struct device_attribute *attr,
293	const char *buf, size_t count)
294	{
295	struct bt1_apb *apb = dev_get_drvdata(dev);
296	unsigned long timeout;
297	int ret;
298	u32 n;
299
300	if (kstrtoul(buf, 0, &timeout) < 0)
301	return -EINVAL;
302
303	n = bt1_apb_timeout_to_n_us(apb, timeout);
304	n = clamp(n, APB_EHB_TIMEOUT_MIN, APB_EHB_TIMEOUT_MAX);
305
306	ret = regmap_write(apb->regs, APB_EHB_TIMEOUT, n);
307
308	return ret ?: count;
309	}
310	static DEVICE_ATTR_RW(timeout);
311
b19dc1b7 SS	312	static ssize_t inject_error_show(struct device *dev,
b19dc1b7 SS	313	struct device_attribute attr, char buf)
8f93662d SS	314	{
	315	return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n");
	316	}
	317
	318	static ssize_t inject_error_store(struct device *dev,
b19dc1b7 SS	319	struct device_attribute *attr,
b19dc1b7 SS	320	const char *data, size_t count)
8f93662d SS	321	{
	322	struct bt1_apb *apb = dev_get_drvdata(dev);
	323
	324	/*
	325	* Either dummy read from the unmapped address in the APB IO area
	326	* or manually set the IRQ status.
	327	*/
b7cb430d	328	if (sysfs_streq(data, "nodev"))
8f93662d	329	readl(apb->res);
b7cb430d	330	else if (sysfs_streq(data, "irq"))
8f93662d SS	331	regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING,
	332	APB_EHB_ISR_PENDING);
	333	else
	334	return -EINVAL;
	335
	336	return count;
	337	}
	338	static DEVICE_ATTR_RW(inject_error);
	339
	340	static struct attribute *bt1_apb_sysfs_attrs[] = {
	341	&dev_attr_count.attr,
	342	&dev_attr_timeout.attr,
	343	&dev_attr_inject_error.attr,
	344	NULL
	345	};
	346	ATTRIBUTE_GROUPS(bt1_apb_sysfs);
	347
	348	static void bt1_apb_remove_sysfs(void *data)
	349	{
	350	struct bt1_apb *apb = data;
	351
	352	device_remove_groups(apb->dev, bt1_apb_sysfs_groups);
	353	}
	354
	355	static int bt1_apb_init_sysfs(struct bt1_apb *apb)
	356	{
	357	int ret;
	358
	359	ret = device_add_groups(apb->dev, bt1_apb_sysfs_groups);
	360	if (ret) {
	361	dev_err(apb->dev, "Failed to create EHB APB sysfs nodes\n");
	362	return ret;
	363	}
	364
	365	ret = devm_add_action_or_reset(apb->dev, bt1_apb_remove_sysfs, apb);
	366	if (ret)
	367	dev_err(apb->dev, "Can't add APB EHB sysfs remove action\n");
	368
	369	return ret;
	370	}
	371
	372	static int bt1_apb_probe(struct platform_device *pdev)
	373	{
	374	struct bt1_apb *apb;
	375	int ret;
	376
	377	apb = bt1_apb_create_data(pdev);
	378	if (IS_ERR(apb))
	379	return PTR_ERR(apb);
	380
	381	ret = bt1_apb_request_regs(apb);
	382	if (ret)
	383	return ret;
	384
	385	ret = bt1_apb_request_rst(apb);
	386	if (ret)
	387	return ret;
	388
	389	ret = bt1_apb_request_clk(apb);
	390	if (ret)
	391	return ret;
	392
	393	ret = bt1_apb_request_irq(apb);
	394	if (ret)
395	return ret;
396
397	ret = bt1_apb_init_sysfs(apb);
398	if (ret)
399	return ret;
400
401	return 0;
402	}
403
404	static const struct of_device_id bt1_apb_of_match[] = {
405	{ .compatible = "baikal,bt1-apb" },
406	{ }
407	};
408	MODULE_DEVICE_TABLE(of, bt1_apb_of_match);
409
410	static struct platform_driver bt1_apb_driver = {
411	.probe = bt1_apb_probe,
412	.driver = {
413	.name = "bt1-apb",
414	.of_match_table = bt1_apb_of_match
415	}
416	};
417	module_platform_driver(bt1_apb_driver);
418
419	MODULE_AUTHOR("Serge Semin <[email protected]>");
420	MODULE_DESCRIPTION("Baikal-T1 APB-bus driver");
421	MODULE_LICENSE("GPL v2");