[PATCH 091/120] MIPS: PS2: GS: Show privileged registers with sysfs

[Fredrik Noring <noring@nocrew.org>]

Reading arbitrary numerical and symbolical privileged GS register bit
fields is supported. For example, the PMODE register can be inspected
with:

    # cat /sys/devices/platform/gs/registers/pmode
    en1 1
    en2 0
    crtmd 1
    mmod circuit1
    amod circuit1
    slbg circuit2
    alp 0

The implementation uses a fair amount of macro expansions. This greatly
simplifies register definitions, which in the case of PMODE is:

    SYSFS_RW_REG(pmode, pmode,
    	SYSFS_DECNUM_FIELD(en1),
    	SYSFS_DECNUM_FIELD(en2),
    	SYSFS_DECNUM_FIELD(crtmd),
    	SYSFS_SYMBOL_FIELD(mmod, circuit1, alp),
    	SYSFS_SYMBOL_FIELD(amod, circuit1, circuit2),
    	SYSFS_SYMBOL_FIELD(slbg, circuit2, bgcolor),
    	SYSFS_DECNUM_FIELD(alp));

It relies on the following enum and struct definitions:

    enum gs_pmode_mmod { gs_mmod_circuit1, gs_mmod_alp };
    enum gs_pmode_amod { gs_amod_circuit1, gs_amod_circuit2 };
    enum gs_pmode_slbg { gs_slbg_circuit2, gs_slbg_bgcolor };
    struct gs_pmode {
    	u64 en1 : 1;		/* Enable read circuit 1 */
    	u64 en2 : 1;		/* Enable read circuit 2 */
    	u64 crtmd : 3;		/* CRT output switching (always 001) */
    	u64 mmod : 1;		/* Alpha blending value */
    	u64 amod : 1;		/* OUT1 alpha output */
    	u64 slbg : 1;		/* Alpha blending method */
    	u64 alp : 8;		/* Fixed alpha (0xff = 1.0) */
    	u64 zero : 1;		/* Must be zero */
    	u64 : 47;
    };

Signed-off-by: Fredrik Noring <noring@nocrew.org>
---
 drivers/ps2/Makefile   |   1 +
 drivers/ps2/gs-sysfs.c | 457 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 458 insertions(+)
 create mode 100644 drivers/ps2/gs-sysfs.c

diff --git a/drivers/ps2/Makefile b/drivers/ps2/Makefile
index 28fb55803199..86ba1d3908dd 100644
--- a/drivers/ps2/Makefile
+++ b/drivers/ps2/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_PS2_GS)		+= gif.o
 obj-$(CONFIG_PS2_GS)		+= gs.o
 obj-$(CONFIG_PS2_GS)		+= gs-irq.o
 obj-$(CONFIG_PS2_GS)		+= gs-registers.o
+obj-$(CONFIG_PS2_GS)		+= gs-sysfs.o
 
 obj-m				+= iop-heap.o
 obj-m				+= iop-irq.o
diff --git a/drivers/ps2/gs-sysfs.c b/drivers/ps2/gs-sysfs.c
new file mode 100644
index 000000000000..2429de3e0094
--- /dev/null
+++ b/drivers/ps2/gs-sysfs.c
@@ -0,0 +1,457 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PlayStation 2 Graphics Synthesizer (GS) sysfs driver
+ *
+ * Copyright (C) 2019 Fredrik Noring
+ *
+ * Reading arbitrary numerical and symbolical privileged GS register
+ * bit fields is supported. For example, the PMODE register can be
+ * inspected with:
+ *
+ *	# cat /sys/devices/platform/gs/registers/pmode
+ *	en1 1
+ *	en2 0
+ *	crtmd 1
+ *	mmod circuit1
+ *	amod circuit1
+ *	slbg circuit2
+ *	alp 0
+ *
+ * The implementation uses a fair amount of macro expansions. This greatly
+ * simplifies register definitions, which in the case of PMODE is:
+ *
+ *	SYSFS_RW_REG(pmode, pmode,
+ *		SYSFS_DECNUM_FIELD(en1),
+ *		SYSFS_DECNUM_FIELD(en2),
+ *		SYSFS_DECNUM_FIELD(crtmd),
+ *		SYSFS_SYMBOL_FIELD(mmod, circuit1, alp),
+ *		SYSFS_SYMBOL_FIELD(amod, circuit1, circuit2),
+ *		SYSFS_SYMBOL_FIELD(slbg, circuit2, bgcolor),
+ *		SYSFS_DECNUM_FIELD(alp));
+ *
+ * It relies on the following enum and struct definitions:
+ *
+ *	enum gs_pmode_mmod { gs_mmod_circuit1, gs_mmod_alp };
+ *	enum gs_pmode_amod { gs_amod_circuit1, gs_amod_circuit2 };
+ *	enum gs_pmode_slbg { gs_slbg_circuit2, gs_slbg_bgcolor };
+ *	struct gs_pmode {
+ *		u64 en1 : 1;		// Enable read circuit 1
+ *		u64 en2 : 1;		// Enable read circuit 2
+ *		u64 crtmd : 3;		// CRT output switching (always 001)
+ *		u64 mmod : 1;		// Alpha blending value
+ *		u64 amod : 1;		// OUT1 alpha output
+ *		u64 slbg : 1;		// Alpha blending method
+ *		u64 alp : 8;		// Fixed alpha (0xff = 1.0)
+ *		u64 zero : 1;		// Must be zero
+ *		u64 : 47;
+ *	};
+ */
+
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include <asm/page.h>
+#include <asm/uaccess.h>
+
+#include <asm/mach-ps2/gs.h>
+#include <asm/mach-ps2/gs-registers.h>
+
+#include <uapi/asm/gs.h>
+
+static struct kobject *registers_kobj;
+
+#define SYSFS_STATEMENT1(prefix_, macro_)				\
+	prefix_##macro_;
+
+#define SYSFS_STATEMENT2(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT1(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT3(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT2(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT4(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT3(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT5(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT4(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT6(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT5(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT7(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT6(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT8(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT7(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT9(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT8(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT10(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT9(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT11(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT10(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT12(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT11(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT13(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT12(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT14(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT13(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT15(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT14(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT16(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT15(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT17(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT16(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT18(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT17(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT19(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT18(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT20(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT19(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT21(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT20(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT22(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT21(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT23(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT22(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT24(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT23(prefix_, __VA_ARGS__)
+
+#define SYSFS_STATEMENT25(prefix_, macro_, ...)				\
+	prefix_##macro_;						\
+	SYSFS_STATEMENT24(prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_DECNUM_FIELD(field_, ...)				\
+	do {								\
+		if (valid)						\
+			n += scnprintf(&buf[n], PAGE_SIZE - n,		\
+				#field_ " %u\n", value.field_);		\
+		else							\
+			n += scnprintf(&buf[n], PAGE_SIZE - n,		\
+				#field_ "\n");				\
+	} while (false)
+
+#define SHOW_SYSFS_HEXNUM_FIELD(field_, ...)				\
+	do {								\
+		if (valid)						\
+			n += scnprintf(&buf[n], PAGE_SIZE - n,		\
+				#field_ " 0x%x\n", value.field_);	\
+		else							\
+			n += scnprintf(&buf[n], PAGE_SIZE - n,		\
+				#field_ "\n");				\
+	} while (false)
+
+#define SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_)		\
+	value.field_ == prefix_##_##value_ ? " " #value_ :
+
+#define SHOW_SYSFS_SYMBOL_STRING1(field_, prefix_, value_)		\
+	SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_) "-"
+
+#define SHOW_SYSFS_SYMBOL_STRING2(field_, prefix_, value_, ...)		\
+	SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_)		\
+	SHOW_SYSFS_SYMBOL_STRING1(field_, prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_SYMBOL_STRING3(field_, prefix_, value_, ...)		\
+	SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_)		\
+	SHOW_SYSFS_SYMBOL_STRING2(field_, prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_SYMBOL_STRING4(field_, prefix_, value_, ...)		\
+	SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_)		\
+	SHOW_SYSFS_SYMBOL_STRING3(field_, prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_SYMBOL_STRING5(field_, prefix_, value_, ...)		\
+	SHOW_SYSFS_SYMBOL_STRING_ENTRY(field_, prefix_, value_)		\
+	SHOW_SYSFS_SYMBOL_STRING4(field_, prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_SYMBOL_STRING(field_, prefix_, ...)			\
+	!valid ? "" :							\
+	CONCATENATE(SHOW_SYSFS_SYMBOL_STRING,				\
+		COUNT_ARGS(__VA_ARGS__))(field_, prefix_, __VA_ARGS__)
+
+#define SHOW_SYSFS_SYMBOL_FIELD(field_, ...)			\
+	n += scnprintf(&buf[n], PAGE_SIZE - n, #field_ "%s\n",		\
+		SHOW_SYSFS_SYMBOL_STRING(field_, gs_##field_, __VA_ARGS__))
+
+#define SHOW_SYSFS_REGISTER(reg, str, ...)				\
+	static ssize_t show_##reg(struct device *device,		\
+		struct device_attribute *attr, char *buf)		\
+	{								\
+		const bool valid = gs_valid_##reg();			\
+		const struct gs_##str value = valid ?			\
+			gs_read_##reg() : (struct gs_##str) { };	\
+		size_t n = 0;						\
+		__VA_ARGS__;						\
+		return n;						\
+	}
+
+#define SYSFS_SHOW(reg, str, ...)					\
+	SHOW_SYSFS_REGISTER(reg, str,					\
+		CONCATENATE(SYSFS_STATEMENT,				\
+			COUNT_ARGS(__VA_ARGS__))(SHOW_, __VA_ARGS__))
+
+#define SYSFS_RO_REG(reg, str, ...)					\
+	SYSFS_SHOW(reg, str, __VA_ARGS__)				\
+	static DEVICE_ATTR(reg, S_IRUGO, show_##reg, NULL)
+
+#define SYSFS_RW_REG(reg, str, ...)					\
+	SYSFS_SHOW(reg, str, __VA_ARGS__)				\
+	static DEVICE_ATTR(reg, S_IRUGO, show_##reg, NULL)
+
+SYSFS_RW_REG(pmode, pmode,
+	SYSFS_DECNUM_FIELD(en1),
+	SYSFS_DECNUM_FIELD(en2),
+	SYSFS_DECNUM_FIELD(crtmd),
+	SYSFS_SYMBOL_FIELD(mmod, circuit1, alp),
+	SYSFS_SYMBOL_FIELD(amod, circuit1, circuit2),
+	SYSFS_SYMBOL_FIELD(slbg, circuit2, bgcolor),
+	SYSFS_DECNUM_FIELD(alp));
+
+SYSFS_RW_REG(smode1, smode1,
+	SYSFS_DECNUM_FIELD(rc),
+	SYSFS_DECNUM_FIELD(lc),
+	SYSFS_DECNUM_FIELD(t1248),
+	SYSFS_DECNUM_FIELD(slck),
+	SYSFS_SYMBOL_FIELD(cmod, vesa, ntsc, pal),
+	SYSFS_DECNUM_FIELD(ex),
+	SYSFS_DECNUM_FIELD(prst),
+	SYSFS_DECNUM_FIELD(sint),
+	SYSFS_DECNUM_FIELD(xpck),
+	SYSFS_DECNUM_FIELD(pck2),
+	SYSFS_DECNUM_FIELD(spml),
+	SYSFS_SYMBOL_FIELD(gcont, rgbyc, ycrcb),
+	SYSFS_DECNUM_FIELD(phs),
+	SYSFS_DECNUM_FIELD(pvs),
+	SYSFS_DECNUM_FIELD(pehs),
+	SYSFS_DECNUM_FIELD(pevs),
+	SYSFS_DECNUM_FIELD(clksel),
+	SYSFS_DECNUM_FIELD(nvck),
+	SYSFS_DECNUM_FIELD(slck2),
+	SYSFS_DECNUM_FIELD(vcksel),
+	SYSFS_DECNUM_FIELD(vhp));
+
+SYSFS_RW_REG(smode2, smode2,
+	SYSFS_SYMBOL_FIELD(intm, progressive, interlace),
+	SYSFS_SYMBOL_FIELD(ffmd, field, frame),
+	SYSFS_SYMBOL_FIELD(dpms, on, standby, suspend, off));
+
+SYSFS_RW_REG(srfsh, srfsh,
+	SYSFS_DECNUM_FIELD(rfsh));
+
+SYSFS_RW_REG(synch1, synch1,
+	SYSFS_DECNUM_FIELD(hfp),
+	SYSFS_DECNUM_FIELD(hbp),
+	SYSFS_DECNUM_FIELD(hseq),
+	SYSFS_DECNUM_FIELD(hsvs),
+	SYSFS_DECNUM_FIELD(hs));
+
+SYSFS_RW_REG(synch2, synch2,
+	SYSFS_DECNUM_FIELD(hf),
+	SYSFS_DECNUM_FIELD(hb));
+
+SYSFS_RW_REG(syncv, syncv,
+	SYSFS_DECNUM_FIELD(vfp),
+	SYSFS_DECNUM_FIELD(vfpe),
+	SYSFS_DECNUM_FIELD(vbp),
+	SYSFS_DECNUM_FIELD(vbpe),
+	SYSFS_DECNUM_FIELD(vdp),
+	SYSFS_DECNUM_FIELD(vs));
+
+SYSFS_RW_REG(dispfb1, dispfb,
+	SYSFS_DECNUM_FIELD(fbp),
+	SYSFS_DECNUM_FIELD(fbw),
+	SYSFS_SYMBOL_FIELD(psm, ct32, ct24, ct16, ct16s, gpu24),
+	SYSFS_DECNUM_FIELD(dbx),
+	SYSFS_DECNUM_FIELD(dby));
+
+SYSFS_RW_REG(display1, display,
+	SYSFS_DECNUM_FIELD(dx),
+	SYSFS_DECNUM_FIELD(dy),
+	SYSFS_DECNUM_FIELD(magh),
+	SYSFS_DECNUM_FIELD(magv),
+	SYSFS_DECNUM_FIELD(dw),
+	SYSFS_DECNUM_FIELD(dh));
+
+SYSFS_RW_REG(dispfb2, dispfb,
+	SYSFS_DECNUM_FIELD(fbp),
+	SYSFS_DECNUM_FIELD(fbw),
+	SYSFS_SYMBOL_FIELD(psm, ct32, ct24, ct16, ct16s),
+	SYSFS_DECNUM_FIELD(dbx),
+	SYSFS_DECNUM_FIELD(dby));
+
+SYSFS_RW_REG(display2, display,
+	SYSFS_DECNUM_FIELD(dx),
+	SYSFS_DECNUM_FIELD(dy),
+	SYSFS_DECNUM_FIELD(magh),
+	SYSFS_DECNUM_FIELD(magv),
+	SYSFS_DECNUM_FIELD(dw),
+	SYSFS_DECNUM_FIELD(dh));
+
+SYSFS_RW_REG(extbuf, extbuf,
+	SYSFS_DECNUM_FIELD(exbp),
+	SYSFS_DECNUM_FIELD(exbw),
+	SYSFS_SYMBOL_FIELD(fbin, out1, out2),
+	SYSFS_SYMBOL_FIELD(wffmd, field, frame),
+	SYSFS_SYMBOL_FIELD(emoda, alpha, y, yhalf, zero),
+	SYSFS_SYMBOL_FIELD(emodc, rgb, y, ycbcr, alpha),
+	SYSFS_DECNUM_FIELD(wdx),
+	SYSFS_DECNUM_FIELD(wdy));
+
+SYSFS_RW_REG(extdata, extdata,
+	SYSFS_DECNUM_FIELD(sx),
+	SYSFS_DECNUM_FIELD(sy),
+	SYSFS_DECNUM_FIELD(smph),
+	SYSFS_DECNUM_FIELD(smpv),
+	SYSFS_DECNUM_FIELD(ww),
+	SYSFS_DECNUM_FIELD(wh));
+
+SYSFS_RW_REG(extwrite, extwrite,
+	SYSFS_SYMBOL_FIELD(write, complete_current, start_next));
+
+SYSFS_RW_REG(bgcolor, bgcolor,
+	SYSFS_DECNUM_FIELD(r),
+	SYSFS_DECNUM_FIELD(g),
+	SYSFS_DECNUM_FIELD(b));
+
+SYSFS_RO_REG(csr, csr,
+	SYSFS_DECNUM_FIELD(signal),
+	SYSFS_DECNUM_FIELD(finish),
+	SYSFS_DECNUM_FIELD(hsint),
+	SYSFS_DECNUM_FIELD(vsint),
+	SYSFS_DECNUM_FIELD(edwint),
+	SYSFS_DECNUM_FIELD(flush),
+	SYSFS_DECNUM_FIELD(reset),
+	SYSFS_DECNUM_FIELD(nfield),
+	SYSFS_SYMBOL_FIELD(field, even, odd),
+	SYSFS_SYMBOL_FIELD(fifo, neither, empty, almost_full),
+	SYSFS_HEXNUM_FIELD(rev),
+	SYSFS_HEXNUM_FIELD(id));
+
+SYSFS_RO_REG(imr, imr,
+	SYSFS_DECNUM_FIELD(sigmsk),
+	SYSFS_DECNUM_FIELD(finishmsk),
+	SYSFS_DECNUM_FIELD(hsmsk),
+	SYSFS_DECNUM_FIELD(vsmsk),
+	SYSFS_DECNUM_FIELD(edwmsk),
+	SYSFS_DECNUM_FIELD(ones));
+
+SYSFS_RO_REG(busdir, busdir,
+	SYSFS_SYMBOL_FIELD(dir, host_to_local, local_to_host));
+
+SYSFS_RW_REG(siglblid, siglblid,
+	SYSFS_DECNUM_FIELD(sigid),
+	SYSFS_DECNUM_FIELD(lblid));
+
+static struct attribute *gs_registers_attributes[] = {
+	&dev_attr_pmode.attr,
+	&dev_attr_smode1.attr,
+	&dev_attr_smode2.attr,
+	&dev_attr_srfsh.attr,
+	&dev_attr_synch1.attr,
+	&dev_attr_synch2.attr,
+	&dev_attr_syncv.attr,
+	&dev_attr_dispfb1.attr,
+	&dev_attr_display1.attr,
+	&dev_attr_dispfb2.attr,
+	&dev_attr_display2.attr,
+	&dev_attr_extbuf.attr,
+	&dev_attr_extdata.attr,
+	&dev_attr_extwrite.attr,
+	&dev_attr_bgcolor.attr,
+	&dev_attr_csr.attr,		/* FIXME: Too lowlevel for sysfs? */
+	&dev_attr_imr.attr,		/* FIXME: Too lowlevel for sysfs? */
+	&dev_attr_busdir.attr,		/* FIXME: Too lowlevel for sysfs? */
+	&dev_attr_siglblid.attr,	/* FIXME: Too lowlevel for sysfs? */
+	NULL
+};
+
+static struct attribute_group gs_registers_attribute_group = {
+	.attrs = gs_registers_attributes
+};
+
+static int __init gs_sysfs_init(void)
+{
+	struct device *gs_dev = gs_device();	/* FIXME: Is this method appropriate? */
+	int err;
+
+	if (!gs_dev) {
+		pr_err("gs-sysfs: Failed to retrieve gs device\n");
+		err = -ENXIO;
+		goto gs_dev_err;
+	}
+
+	registers_kobj = kobject_create_and_add("registers", &gs_dev->kobj);
+	if (!registers_kobj) {
+		pr_err("gs-sysfs: Failed to create and add register kernel object\n");
+		err = -ENOMEM;
+		goto kobj_err;
+	}
+
+	err = sysfs_create_group(registers_kobj, &gs_registers_attribute_group);
+	if (err) {
+		pr_err("gs-sysfs: Failed to create register sysfs group\n");
+		goto group_err;
+	}
+
+	return 0;
+
+group_err:
+	kobject_del(registers_kobj);
+
+kobj_err:
+gs_dev_err:
+	return err;
+}
+
+static void __exit gs_sysfs_exit(void)
+{
+	kobject_del(registers_kobj);
+}
+
+module_init(gs_sysfs_init);
+module_exit(gs_sysfs_exit);
+
+MODULE_DESCRIPTION("PlayStation 2 Graphics Synthesizer sysfs driver");
+MODULE_AUTHOR("Fredrik Noring");
+MODULE_LICENSE("GPL");
-- 
2.21.0