diff mbox

clk: Add axi-clkgen driver

Message ID 1357755120-32735-1-git-send-email-lars@metafoo.de (mailing list archive)
State New, archived
Headers show

Commit Message

Lars-Peter Clausen Jan. 9, 2013, 6:12 p.m. UTC 
This driver adds support for the AXI clkgen pcore to the common clock framework.
The AXI clkgen pcore is a AXI front-end to the MMCM_ADV frequency synthesizer
commonly found in Xilinx FPGAs.

The AXI clkgen pcore is used in Analog Devices' reference designs targeting
Xilinx FPGAs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 .../devicetree/bindings/clock/axi-clkgen.txt       |  22 ++
 drivers/clk/Kconfig                                |   8 +
 drivers/clk/Makefile                               |   1 +
 drivers/clk/clk-axi-clkgen.c                       | 326 +++++++++++++++++++++
 4 files changed, 357 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/axi-clkgen.txt
 create mode 100644 drivers/clk/clk-axi-clkgen.c

Comments

Mike Turquette Jan. 22, 2013, 5:55 p.m. UTC | #1 
Quoting Lars-Peter Clausen (2013-01-09 10:12:00)
<snip>
> +static void axi_clkgen_write(struct axi_clkgen *axi_clkgen,
> +       unsigned int reg, unsigned int val)
> +{
> +       iowrite32(val, axi_clkgen->base + reg);

Silly question: any reason to use this over readl()?  This is more for
my understanding than a real criticism.

> +}
> +
> +static void axi_clkgen_read(struct axi_clkgen *axi_clkgen,
> +       unsigned int reg, unsigned int *val)
> +{
> +       *val = ioread32(axi_clkgen->base + reg);

Same as above, any reason to use this over writel?

<snip>
> +static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
> +       unsigned long parent_rate)
> +{
> +       struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
> +       unsigned int d, m, dout;
> +       unsigned int reg;
> +
> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT1, &reg);
> +       dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_DIV, &reg);
> +       d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_FB1, &reg);
> +       m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
> +
> +       if (d == 0 || dout == 0)
> +               return 0;
> +
> +       return parent_rate / d * m / dout;

Any chance of overflow here?  Maybe do_div should be used?

Regards,
Mike
Josh Cartwright Jan. 22, 2013, 6:08 p.m. UTC | #2 
On Wed, Jan 09, 2013 at 07:12:00PM +0100, Lars-Peter Clausen wrote:
> This driver adds support for the AXI clkgen pcore to the common clock framework.
> The AXI clkgen pcore is a AXI front-end to the MMCM_ADV frequency synthesizer
> commonly found in Xilinx FPGAs.
> 
> The AXI clkgen pcore is used in Analog Devices' reference designs targeting
> Xilinx FPGAs.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> ---
>  .../devicetree/bindings/clock/axi-clkgen.txt       |  22 ++
>  drivers/clk/Kconfig                                |   8 +
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-axi-clkgen.c                       | 326 +++++++++++++++++++++
>  4 files changed, 357 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/axi-clkgen.txt
>  create mode 100644 drivers/clk/clk-axi-clkgen.c
> 
[..]
> diff --git a/drivers/clk/clk-axi-clkgen.c b/drivers/clk/clk-axi-clkgen.c
> new file mode 100644
> index 0000000..e9db225
> --- /dev/null
> +++ b/drivers/clk/clk-axi-clkgen.c
> @@ -0,0 +1,326 @@
> +/*
> + * AXI clkgen driver
> + *
> + * Copyright 2012-2013 Analog Device Inc.
> + *  Author: Lars-Peter Clausen <lars@metafoo.de>
> + *
> + * Licensed under the GPL-2.
> + *
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +
> +#define AXI_CLKGEN_REG_UPDATE_ENABLE	0x04
> +#define AXI_CLKGEN_REG_CLK_OUT1		0x08
> +#define AXI_CLKGEN_REG_CLK_OUT2		0x0c
> +#define AXI_CLKGEN_REG_CLK_DIV		0x10
> +#define AXI_CLKGEN_REG_CLK_FB1		0x14
> +#define AXI_CLKGEN_REG_CLK_FB2		0x18
> +#define AXI_CLKGEN_REG_LOCK1		0x1c
> +#define AXI_CLKGEN_REG_LOCK2		0x20
> +#define AXI_CLKGEN_REG_LOCK3		0x24
> +#define AXI_CLKGEN_REG_FILTER1		0x28
> +#define AXI_CLKGEN_REG_FILTER2		0x2c
> +
> +struct axi_clkgen {
> +	void __iomem *base;
> +	struct clk_hw clk_hw;
> +};
> +
> +static uint32_t axi_clkgen_lookup_filter(unsigned int m)
> +{
> +	switch (m) {
> +	case 0:
> +		return 0x01001990;
> +	case 1:
> +		return 0x01001190;
> +	case 2:
> +		return 0x01009890;
> +	case 3:
> +		return 0x01001890;
> +	case 4:
> +		return 0x01008890;
> +	case 5 ... 8:
> +		return 0x01009090;
> +	case 9 ... 11:
> +		return 0x0100890;

Just checking to ensure this ^ entry is correct, since it looks
different then the others (it may very well be).

   Josh
Lars-Peter Clausen Jan. 23, 2013, 9:57 a.m. UTC | #3 
On 01/22/2013 07:08 PM, Josh Cartwright wrote:
> On Wed, Jan 09, 2013 at 07:12:00PM +0100, Lars-Peter Clausen wrote:
>> This driver adds support for the AXI clkgen pcore to the common clock framework.
>> The AXI clkgen pcore is a AXI front-end to the MMCM_ADV frequency synthesizer
>> commonly found in Xilinx FPGAs.
>>
>> The AXI clkgen pcore is used in Analog Devices' reference designs targeting
>> Xilinx FPGAs.
>>
>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
>> ---
>>  .../devicetree/bindings/clock/axi-clkgen.txt       |  22 ++
>>  drivers/clk/Kconfig                                |   8 +
>>  drivers/clk/Makefile                               |   1 +
>>  drivers/clk/clk-axi-clkgen.c                       | 326 +++++++++++++++++++++
>>  4 files changed, 357 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/clock/axi-clkgen.txt
>>  create mode 100644 drivers/clk/clk-axi-clkgen.c
>>
> [..]
>> diff --git a/drivers/clk/clk-axi-clkgen.c b/drivers/clk/clk-axi-clkgen.c
>> new file mode 100644
>> index 0000000..e9db225
>> --- /dev/null
>> +++ b/drivers/clk/clk-axi-clkgen.c
>> @@ -0,0 +1,326 @@
>> +/*
>> + * AXI clkgen driver
>> + *
>> + * Copyright 2012-2013 Analog Device Inc.
>> + *  Author: Lars-Peter Clausen <lars@metafoo.de>
>> + *
>> + * Licensed under the GPL-2.
>> + *
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/clk.h>
>> +#include <linux/slab.h>
>> +#include <linux/io.h>
>> +#include <linux/of.h>
>> +#include <linux/module.h>
>> +#include <linux/err.h>
>> +
>> +#define AXI_CLKGEN_REG_UPDATE_ENABLE	0x04
>> +#define AXI_CLKGEN_REG_CLK_OUT1		0x08
>> +#define AXI_CLKGEN_REG_CLK_OUT2		0x0c
>> +#define AXI_CLKGEN_REG_CLK_DIV		0x10
>> +#define AXI_CLKGEN_REG_CLK_FB1		0x14
>> +#define AXI_CLKGEN_REG_CLK_FB2		0x18
>> +#define AXI_CLKGEN_REG_LOCK1		0x1c
>> +#define AXI_CLKGEN_REG_LOCK2		0x20
>> +#define AXI_CLKGEN_REG_LOCK3		0x24
>> +#define AXI_CLKGEN_REG_FILTER1		0x28
>> +#define AXI_CLKGEN_REG_FILTER2		0x2c
>> +
>> +struct axi_clkgen {
>> +	void __iomem *base;
>> +	struct clk_hw clk_hw;
>> +};
>> +
>> +static uint32_t axi_clkgen_lookup_filter(unsigned int m)
>> +{
>> +	switch (m) {
>> +	case 0:
>> +		return 0x01001990;
>> +	case 1:
>> +		return 0x01001190;
>> +	case 2:
>> +		return 0x01009890;
>> +	case 3:
>> +		return 0x01001890;
>> +	case 4:
>> +		return 0x01008890;
>> +	case 5 ... 8:
>> +		return 0x01009090;
>> +	case 9 ... 11:
>> +		return 0x0100890;
> 
> Just checking to ensure this ^ entry is correct, since it looks
> different then the others (it may very well be).

Nice catch, it's wrong indeed.

Thanks
- Lars
Lars-Peter Clausen Jan. 23, 2013, 10 a.m. UTC | #4 
On 01/22/2013 06:55 PM, Mike Turquette wrote:
> Quoting Lars-Peter Clausen (2013-01-09 10:12:00)
> <snip>
>> +static void axi_clkgen_write(struct axi_clkgen *axi_clkgen,
>> +       unsigned int reg, unsigned int val)
>> +{
>> +       iowrite32(val, axi_clkgen->base + reg);
> 
> Silly question: any reason to use this over readl()?  This is more for
> my understanding than a real criticism.

I think I read somewhere at some point that ioread{8,16,32} is preferred
over write{b,h,l} in new code.

> 
>> +}
>> +
>> +static void axi_clkgen_read(struct axi_clkgen *axi_clkgen,
>> +       unsigned int reg, unsigned int *val)
>> +{
>> +       *val = ioread32(axi_clkgen->base + reg);
> 
> Same as above, any reason to use this over writel?

Same answer.

> 
> <snip>
>> +static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
>> +       unsigned long parent_rate)
>> +{
>> +       struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
>> +       unsigned int d, m, dout;
>> +       unsigned int reg;
>> +
>> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT1, &reg);
>> +       dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
>> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_DIV, &reg);
>> +       d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
>> +       axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_FB1, &reg);
>> +       m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
>> +
>> +       if (d == 0 || dout == 0)
>> +               return 0;
>> +
>> +       return parent_rate / d * m / dout;
> 
> Any chance of overflow here?  Maybe do_div should be used?

Not if all the parameters are within spec. But since this is on a slowpath I
guess it does not hurt to use do_div.

Will send a v2.

Thanks for the review,
- Lars
Russell King - ARM Linux Jan. 23, 2013, 10:27 a.m. UTC | #5 
On Wed, Jan 23, 2013 at 11:00:56AM +0100, Lars-Peter Clausen wrote:
> I think I read somewhere at some point that ioread{8,16,32} is preferred
> over write{b,h,l} in new code.

But... there's *no* point using ioread*() if you don't only use the
ioremap() interface.

ioread*() is there to allow PC IO and PC MMIO accesses through one
accessor depending on the cookie.  ioremap() only ever returns cookies
for MMIO accesses.
Lars-Peter Clausen Jan. 23, 2013, 10:49 a.m. UTC | #6 
On 01/23/2013 11:27 AM, Russell King - ARM Linux wrote:
> On Wed, Jan 23, 2013 at 11:00:56AM +0100, Lars-Peter Clausen wrote:
>> I think I read somewhere at some point that ioread{8,16,32} is preferred
>> over write{b,h,l} in new code.
> 
> But... there's *no* point using ioread*() if you don't only use the
> ioremap() interface.
> 
> ioread*() is there to allow PC IO and PC MMIO accesses through one
> accessor depending on the cookie.  ioremap() only ever returns cookies
> for MMIO accesses.

So your point is, if you know that it is MMIO memory only ever use readl and
friends?

- Lars
Russell King - ARM Linux Jan. 23, 2013, 10:57 a.m. UTC | #7 
On Wed, Jan 23, 2013 at 11:49:16AM +0100, Lars-Peter Clausen wrote:
> On 01/23/2013 11:27 AM, Russell King - ARM Linux wrote:
> > On Wed, Jan 23, 2013 at 11:00:56AM +0100, Lars-Peter Clausen wrote:
> >> I think I read somewhere at some point that ioread{8,16,32} is preferred
> >> over write{b,h,l} in new code.
> > 
> > But... there's *no* point using ioread*() if you don't only use the
> > ioremap() interface.
> > 
> > ioread*() is there to allow PC IO and PC MMIO accesses through one
> > accessor depending on the cookie.  ioremap() only ever returns cookies
> > for MMIO accesses.
> 
> So your point is, if you know that it is MMIO memory only ever use readl and
> friends?

My point is... if you're going to stick with using ioremap(), then don't
bother with the potential overhead from ioread*() - you don't gain
anything but you have a few extra CPU cycles per access.  You might as
well just stick with read*() which aren't going anywhere anytime soon.

Sure, if you need stuff to work on both IO and MMIO accesses, then use
ioread*() but you'd also need the driver to:
- accept IORESOURCE_IO resource types.
- request these resources in the IO resource tree rather than the MMIO
  resource tree.
- use ioport_map() to "map" these resource types.

So, I don't mind seeing ioread*() in a driver _if_ it also uses IO resources
and handles them correctly, but it's pointless to use this accessor in any
driver which doesn't.
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/clock/axi-clkgen.txt b/Documentation/devicetree/bindings/clock/axi-clkgen.txt
new file mode 100644
index 0000000..028b493
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/axi-clkgen.txt
@@ -0,0 +1,22 @@ 
+Binding for the axi-clkgen clock generator
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be "adi,axi-clkgen".
+- #clock-cells : from common clock binding; Should always be set to 0.
+- reg : Address and length of the axi-clkgen register set.
+- clocks : Phandle and clock specifier for the parent clock.
+
+Optional properties:
+- clock-output-names : From common clock binding.
+
+Example:
+	clock@0xff000000 {
+		compatible = "adi,axi-clkgen";
+		#clock-cells = <0>;
+		reg = <0xff000000 0x1000>;
+		clocks = <&osc 1>;
+	};
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 823f62d..d8cd9ad 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -63,4 +63,12 @@  config CLK_TWL6040
 	  McPDM. McPDM module is using the external bit clock on the McPDM bus
 	  as functional clock.
 
+config COMMON_CLK_AXI_CLKGEN
+	tristate "AXI clkgen driver"
+	depends on ARCH_ZYNQ || MICROBLAZE
+	help
+	---help---
+	  Support for the Analog Device axi-clkgen pcore clock generator for Xilinx
+	  FPGAs. It is commonly used in Analog Devices reference designs.
+
 endmenu
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 2701235..a3df2b3 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -21,6 +21,7 @@  obj-$(CONFIG_ARCH_U8500)	+= ux500/
 obj-$(CONFIG_ARCH_VT8500)	+= clk-vt8500.o
 
 # Chip specific
+obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o
 obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
 obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
 obj-$(CONFIG_CLK_TWL6040)	+= clk-twl6040.o
diff --git a/drivers/clk/clk-axi-clkgen.c b/drivers/clk/clk-axi-clkgen.c
new file mode 100644
index 0000000..e9db225
--- /dev/null
+++ b/drivers/clk/clk-axi-clkgen.c
@@ -0,0 +1,326 @@ 
+/*
+ * AXI clkgen driver
+ *
+ * Copyright 2012-2013 Analog Device Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * Licensed under the GPL-2.
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/err.h>
+
+#define AXI_CLKGEN_REG_UPDATE_ENABLE	0x04
+#define AXI_CLKGEN_REG_CLK_OUT1		0x08
+#define AXI_CLKGEN_REG_CLK_OUT2		0x0c
+#define AXI_CLKGEN_REG_CLK_DIV		0x10
+#define AXI_CLKGEN_REG_CLK_FB1		0x14
+#define AXI_CLKGEN_REG_CLK_FB2		0x18
+#define AXI_CLKGEN_REG_LOCK1		0x1c
+#define AXI_CLKGEN_REG_LOCK2		0x20
+#define AXI_CLKGEN_REG_LOCK3		0x24
+#define AXI_CLKGEN_REG_FILTER1		0x28
+#define AXI_CLKGEN_REG_FILTER2		0x2c
+
+struct axi_clkgen {
+	void __iomem *base;
+	struct clk_hw clk_hw;
+};
+
+static uint32_t axi_clkgen_lookup_filter(unsigned int m)
+{
+	switch (m) {
+	case 0:
+		return 0x01001990;
+	case 1:
+		return 0x01001190;
+	case 2:
+		return 0x01009890;
+	case 3:
+		return 0x01001890;
+	case 4:
+		return 0x01008890;
+	case 5 ... 8:
+		return 0x01009090;
+	case 9 ... 11:
+		return 0x0100890;
+	case 12:
+		return 0x08009090;
+	case 13 ... 22:
+		return 0x01008090;
+	case 23 ... 36:
+		return 0x01008090;
+	case 37 ... 46:
+		return 0x08001090;
+	default:
+		return 0x08008090;
+	}
+}
+
+static const uint32_t axi_clkgen_lock_table[] = {
+	0x060603e8, 0x060603e8, 0x080803e8, 0x0b0b03e8,
+	0x0e0e03e8, 0x111103e8, 0x131303e8, 0x161603e8,
+	0x191903e8, 0x1c1c03e8, 0x1f1f0384, 0x1f1f0339,
+	0x1f1f02ee, 0x1f1f02bc, 0x1f1f028a, 0x1f1f0271,
+	0x1f1f023f, 0x1f1f0226, 0x1f1f020d, 0x1f1f01f4,
+	0x1f1f01db, 0x1f1f01c2, 0x1f1f01a9, 0x1f1f0190,
+	0x1f1f0190, 0x1f1f0177, 0x1f1f015e, 0x1f1f015e,
+	0x1f1f0145, 0x1f1f0145, 0x1f1f012c, 0x1f1f012c,
+	0x1f1f012c, 0x1f1f0113, 0x1f1f0113, 0x1f1f0113,
+};
+
+static uint32_t axi_clkgen_lookup_lock(unsigned int m)
+{
+	if (m < ARRAY_SIZE(axi_clkgen_lock_table))
+		return axi_clkgen_lock_table[m];
+	return 0x1f1f00fa;
+}
+
+static const unsigned int fpfd_min = 10000;
+static const unsigned int fpfd_max = 300000;
+static const unsigned int fvco_min = 600000;
+static const unsigned int fvco_max = 1200000;
+
+static void axi_clkgen_calc_params(unsigned long fin, unsigned long fout,
+	unsigned int *best_d, unsigned int *best_m, unsigned int *best_dout)
+{
+	unsigned long d, d_min, d_max, _d_min, _d_max;
+	unsigned long m, m_min, m_max;
+	unsigned long f, dout, best_f, fvco;
+
+	fin /= 1000;
+	fout /= 1000;
+
+	best_f = UINT_MAX;
+	*best_d = 0;
+	*best_m = 0;
+	*best_dout = 0;
+
+	d_min = max_t(unsigned long, DIV_ROUND_UP(fin, fpfd_max), 1);
+	d_max = min_t(unsigned long, fin / fpfd_min, 80);
+
+	m_min = max_t(unsigned long, DIV_ROUND_UP(fvco_min, fin) * d_min, 1);
+	m_max = min_t(unsigned long, fvco_max * d_max / fin, 64);
+
+	for (m = m_min; m <= m_max; m++) {
+		_d_min = max(d_min, DIV_ROUND_UP(fin * m, fvco_max));
+		_d_max = min(d_max, fin * m / fvco_min);
+
+		for (d = _d_min; d <= _d_max; d++) {
+			fvco = fin * m / d;
+
+			dout = DIV_ROUND_CLOSEST(fvco, fout);
+			dout = clamp_t(unsigned long, dout, 1, 128);
+			f = fvco / dout;
+			if (abs(f - fout) < abs(best_f - fout)) {
+				best_f = f;
+				*best_d = d;
+				*best_m = m;
+				*best_dout = dout;
+				if (best_f == fout)
+					return;
+			}
+		}
+	}
+}
+
+static void axi_clkgen_calc_clk_params(unsigned int divider, unsigned int *low,
+	unsigned int *high, unsigned int *edge, unsigned int *nocount)
+{
+	if (divider == 1)
+		*nocount = 1;
+	else
+		*nocount = 0;
+
+	*high = divider / 2;
+	*edge = divider % 2;
+	*low = divider - *high;
+}
+
+static void axi_clkgen_write(struct axi_clkgen *axi_clkgen,
+	unsigned int reg, unsigned int val)
+{
+	iowrite32(val, axi_clkgen->base + reg);
+}
+
+static void axi_clkgen_read(struct axi_clkgen *axi_clkgen,
+	unsigned int reg, unsigned int *val)
+{
+	*val = ioread32(axi_clkgen->base + reg);
+}
+
+static struct axi_clkgen *clk_hw_to_axi_clkgen(struct clk_hw *clk_hw)
+{
+	return container_of(clk_hw, struct axi_clkgen, clk_hw);
+}
+
+static int axi_clkgen_set_rate(struct clk_hw *clk_hw,
+	unsigned long rate, unsigned long parent_rate)
+{
+	struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
+	unsigned int d, m, dout;
+	unsigned int nocount;
+	unsigned int high;
+	unsigned int edge;
+	unsigned int low;
+	uint32_t filter;
+	uint32_t lock;
+
+	if (parent_rate == 0 || rate == 0)
+		return -EINVAL;
+
+	axi_clkgen_calc_params(parent_rate, rate, &d, &m, &dout);
+
+	if (d == 0 || dout == 0 || m == 0)
+		return -EINVAL;
+
+	filter = axi_clkgen_lookup_filter(m - 1);
+	lock = axi_clkgen_lookup_lock(m - 1);
+
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_UPDATE_ENABLE, 0);
+
+	axi_clkgen_calc_clk_params(dout, &low, &high, &edge, &nocount);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT1,
+		(high << 6) | low);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT2,
+		(edge << 7) | (nocount << 6));
+
+	axi_clkgen_calc_clk_params(d, &low, &high, &edge, &nocount);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_CLK_DIV,
+		(edge << 13) | (nocount << 12) | (high << 6) | low);
+
+	axi_clkgen_calc_clk_params(m, &low, &high, &edge, &nocount);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_CLK_FB1,
+		(high << 6) | low);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_CLK_FB2,
+		(edge << 7) | (nocount << 6));
+
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_LOCK1, lock & 0x3ff);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_LOCK2,
+		(((lock >> 16) & 0x1f) << 10) | 0x1);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_LOCK3,
+		(((lock >> 24) & 0x1f) << 10) | 0x3e9);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_FILTER1, filter >> 16);
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_FILTER2, filter);
+
+	axi_clkgen_write(axi_clkgen, AXI_CLKGEN_REG_UPDATE_ENABLE, 1);
+
+	return 0;
+}
+
+static long axi_clkgen_round_rate(struct clk_hw *hw, unsigned long rate,
+	unsigned long *parent_rate)
+{
+	unsigned int d, m, dout;
+
+	axi_clkgen_calc_params(*parent_rate, rate, &d, &m, &dout);
+
+	if (d == 0 || dout == 0 || m == 0)
+		return -EINVAL;
+
+	return *parent_rate / d * m / dout;
+}
+
+static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
+	unsigned long parent_rate)
+{
+	struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
+	unsigned int d, m, dout;
+	unsigned int reg;
+
+	axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_OUT1, &reg);
+	dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+	axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_DIV, &reg);
+	d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+	axi_clkgen_read(axi_clkgen, AXI_CLKGEN_REG_CLK_FB1, &reg);
+	m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+
+	if (d == 0 || dout == 0)
+		return 0;
+
+	return parent_rate / d * m / dout;
+}
+
+static const struct clk_ops axi_clkgen_ops = {
+	.recalc_rate = axi_clkgen_recalc_rate,
+	.round_rate = axi_clkgen_round_rate,
+	.set_rate = axi_clkgen_set_rate,
+};
+
+static int axi_clkgen_probe(struct platform_device *pdev)
+{
+	struct axi_clkgen *axi_clkgen;
+	struct clk_init_data init;
+	const char *parent_name;
+	const char *clk_name;
+	struct resource *mem;
+	struct clk *clk;
+
+	axi_clkgen = devm_kzalloc(&pdev->dev, sizeof(*axi_clkgen),
+			GFP_KERNEL);
+	if (!axi_clkgen)
+		return -ENOMEM;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	axi_clkgen->base = devm_request_and_ioremap(&pdev->dev, mem);
+	if (!axi_clkgen->base)
+		return -ENXIO;
+
+	parent_name = of_clk_get_parent_name(pdev->dev.of_node, 0);
+	clk_name = pdev->dev.of_node->name;
+
+	of_property_read_string(pdev->dev.of_node, "clock-output-names",
+		&clk_name);
+
+	init.name = clk_name;
+	init.ops = &axi_clkgen_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	axi_clkgen->clk_hw.init = &init;
+	clk = devm_clk_register(&pdev->dev, &axi_clkgen->clk_hw);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
+
+	platform_set_drvdata(pdev, axi_clkgen);
+
+	return 0;
+}
+
+static int axi_clkgen_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+
+	return 0;
+}
+
+static const struct of_device_id axi_clkgen_ids[] = {
+	{ .compatible = "adi,axi-clkgen-1.00.a" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, axi_clkgen_ids);
+
+static struct platform_driver axi_clkgen_driver = {
+	.driver = {
+		.name = "adi-axi-clkgen",
+		.owner = THIS_MODULE,
+		.of_match_table = axi_clkgen_ids,
+	},
+	.probe = axi_clkgen_probe,
+	.remove = axi_clkgen_remove,
+};
+module_platform_driver(axi_clkgen_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Driver for the Analog Devices AXI clkgen pcore clock generator");