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Date: Thu, 24 May 2012 14:00:33 +0100
From: Jonathan Cameron <jic23@kernel.org>
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To: michael.hennerich@analog.com
CC: linux-iio@vger.kernel.org,
	device-drivers-devel@blackfin.uclinux.org
Subject: Re: [PATCH 1/2] iio: frequency: New driver for AD9523 SPI Low Jitter
 Clock Generator
References: <1337612331-14095-1-git-send-email-michael.hennerich@analog.com>
In-Reply-To: <1337612331-14095-1-git-send-email-michael.hennerich@analog.com>
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On 5/21/2012 3:58 PM, michael.hennerich@analog.com wrote:
> From: Michael Hennerich<michael.hennerich@analog.com>
>
> Changes since V1:
>
> Apply Jonathan's review feedback:
> Revise device status attribute names, and split documentation into two sections.
> Add additional comments, and fix indention issues.
> Remove pointless zero initializations.
> Revise return value handling.
> Simplify some code sections.
> Split store_eeprom and sync handling into separate functions.
> Use strtobool where applicable.
> Document platform data structures using kernel-doc style.
>
> Use dev_to_iio_dev
> write_raw IIO_CHAN_INFO_FREQUENCY: Reject values<= 0
> Make patch target drivers/iio

Hi Michael,

Couple of trivial bits inline.  Plenty of time for this so I'll
take one last look when you've addressed those.

I still don't like the immense opaque platform data needed for this.
Feels like there ought to be something clearer and more generic, but
I guess that's a job for another day.

Jonathan
>
> Signed-off-by: Michael Hennerich<michael.hennerich@analog.com>
> ---
>   .../ABI/testing/sysfs-bus-iio-frequency-ad9523     |   37 +
>   drivers/iio/Kconfig                                |    1 +
>   drivers/iio/Makefile                               |    1 +
>   drivers/iio/frequency/Kconfig                      |   23 +
>   drivers/iio/frequency/Makefile                     |    5 +
>   drivers/iio/frequency/ad9523.c                     | 1059 ++++++++++++++++++++
>   include/linux/iio/frequency/ad9523.h               |  195 ++++
>   7 files changed, 1321 insertions(+), 0 deletions(-)
>   create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523
>   create mode 100644 drivers/iio/frequency/Kconfig
>   create mode 100644 drivers/iio/frequency/Makefile
>   create mode 100644 drivers/iio/frequency/ad9523.c
>   create mode 100644 include/linux/iio/frequency/ad9523.h
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523 b/Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523
> new file mode 100644
> index 0000000..2ce9c3f
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-frequency-ad9523
> @@ -0,0 +1,37 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/pll2_feedback_clk_present
> +What:		/sys/bus/iio/devices/iio:deviceX/pll2_reference_clk_present
> +What:		/sys/bus/iio/devices/iio:deviceX/pll1_reference_clk_a_present
> +What:		/sys/bus/iio/devices/iio:deviceX/pll1_reference_clk_b_present
> +What:		/sys/bus/iio/devices/iio:deviceX/pll1_reference_clk_test_present
> +What:		/sys/bus/iio/devices/iio:deviceX/vcxo_clk_present
> +KernelVersion:	3.4.0
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reading returns either '1' or '0'.
> +		'1' means that the clock in question is present.
> +		'0' means that the clock is missing.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/pllY_locked
> +KernelVersion:	3.4.0
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reading returns either '1' or '0'. '1' means that the
> +		pllY is locked.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/store_eeprom
> +KernelVersion:	3.4.0
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Writing '1' stores the current device configuration into
> +		on-chip EEPROM. After power-up or chip reset the device will
> +		automatically load the saved configuration.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/sync_dividers
> +KernelVersion:	3.4.0
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Writing '1' triggers the clock distribution synchronization
> +		functionality. All dividers are reset and the channels start
> +		with their predefined phase offsets (out_altvoltageY_phase).
> +		Writing this file has the effect as driving the external
> +		/SYNC pin low.
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 56eecef..ad09f67 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -50,5 +50,6 @@ config IIO_CONSUMERS_PER_TRIGGER
>
>   source "drivers/iio/adc/Kconfig"
>   source "drivers/iio/amplifiers/Kconfig"
> +source "drivers/iio/frequency/Kconfig"
>
>   endif # IIO
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index e425afd..014e0e4 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
>
>   obj-y += adc/
>   obj-y += amplifiers/
> +obj-y += frequency/
> diff --git a/drivers/iio/frequency/Kconfig b/drivers/iio/frequency/Kconfig
> new file mode 100644
> index 0000000..0458c92
> --- /dev/null
> +++ b/drivers/iio/frequency/Kconfig
> @@ -0,0 +1,23 @@
> +#
> +# Frequency
> +#	Direct Digital Synthesis drivers (DDS)
> +#	Clock Distribution device drivers
> +#	Phase-Locked Loop (PLL) frequency synthesizers
> +#
> +
> +menu "Frequency Synthesizers DDS/PLL"
> +
> +menu "Clock Generator/Distribution"
> +
> +config AD9523
> +	tristate "Analog Devices AD9523 Low Jitter Clock Generator"
> +	depends on SPI
> +	help
> +	  Say yes here to build support for Analog Devices AD9523 Low Jitter
> +	  Clock Generator. The driver provides direct access via sysfs.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ad9523.
> +
> +endmenu
> +endmenu
> diff --git a/drivers/iio/frequency/Makefile b/drivers/iio/frequency/Makefile
> new file mode 100644
> index 0000000..1b5b224
> --- /dev/null
> +++ b/drivers/iio/frequency/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile iio/frequency
> +#
> +
> +obj-$(CONFIG_AD9523) += ad9523.o
> diff --git a/drivers/iio/frequency/ad9523.c b/drivers/iio/frequency/ad9523.c
> new file mode 100644
> index 0000000..77a17de
> --- /dev/null
> +++ b/drivers/iio/frequency/ad9523.c
> @@ -0,0 +1,1059 @@
> +/*
> + * AD9523 SPI Low Jitter Clock Generator
> + *
> + * Copyright 2012 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include<linux/device.h>
> +#include<linux/kernel.h>
> +#include<linux/slab.h>
> +#include<linux/sysfs.h>
> +#include<linux/spi/spi.h>
> +#include<linux/regulator/consumer.h>
> +#include<linux/err.h>
> +#include<linux/module.h>
> +#include<linux/delay.h>
> +
> +#include<linux/iio/iio.h>
> +#include<linux/iio/sysfs.h>
> +#include<linux/iio/frequency/ad9523.h>
> +
> +#define AD9523_READ	(1<<  15)
> +#define AD9523_WRITE	(0<<  15)
> +#define AD9523_CNT(x)	(((x) - 1)<<  13)
> +#define AD9523_ADDR(x)	((x)&  0xFFF)
> +
> +#define AD9523_R1B	(1<<  16)
> +#define AD9523_R2B	(2<<  16)
> +#define AD9523_R3B	(3<<  16)
> +#define AD9523_TRANSF_LEN(x)			((x)>>  16)
> +
> +#define AD9523_SERIAL_PORT_CONFIG		(AD9523_R1B | 0x0)
> +#define AD9523_VERSION_REGISTER			(AD9523_R1B | 0x2)
> +#define AD9523_PART_REGISTER			(AD9523_R1B | 0x3)
> +#define AD9523_READBACK_CTRL			(AD9523_R1B | 0x4)
> +
> +#define AD9523_EEPROM_CUSTOMER_VERSION_ID	(AD9523_R2B | 0x6)
> +
> +#define AD9523_PLL1_REF_A_DIVIDER		(AD9523_R2B | 0x11)
> +#define AD9523_PLL1_REF_B_DIVIDER		(AD9523_R2B | 0x13)
> +#define AD9523_PLL1_REF_TEST_DIVIDER		(AD9523_R1B | 0x14)
> +#define AD9523_PLL1_FEEDBACK_DIVIDER		(AD9523_R2B | 0x17)
> +#define AD9523_PLL1_CHARGE_PUMP_CTRL		(AD9523_R2B | 0x19)
> +#define AD9523_PLL1_INPUT_RECEIVERS_CTRL	(AD9523_R1B | 0x1A)
> +#define AD9523_PLL1_REF_CTRL			(AD9523_R1B | 0x1B)
> +#define AD9523_PLL1_MISC_CTRL			(AD9523_R1B | 0x1C)
> +#define AD9523_PLL1_LOOP_FILTER_CTRL		(AD9523_R1B | 0x1D)
> +
> +#define AD9523_PLL2_CHARGE_PUMP			(AD9523_R1B | 0xF0)
> +#define AD9523_PLL2_FEEDBACK_DIVIDER_AB		(AD9523_R1B | 0xF1)
> +#define AD9523_PLL2_CTRL			(AD9523_R1B | 0xF2)
> +#define AD9523_PLL2_VCO_CTRL			(AD9523_R1B | 0xF3)
> +#define AD9523_PLL2_VCO_DIVIDER			(AD9523_R1B | 0xF4)
> +#define AD9523_PLL2_LOOP_FILTER_CTRL		(AD9523_R2B | 0xF6)
> +#define AD9523_PLL2_R2_DIVIDER			(AD9523_R1B | 0xF7)
> +
> +#define AD9523_CHANNEL_CLOCK_DIST(ch)		(AD9523_R3B | (0x192 + 3 * ch))
> +
> +#define AD9523_PLL1_OUTPUT_CTRL			(AD9523_R1B | 0x1BA)
> +#define AD9523_PLL1_OUTPUT_CHANNEL_CTRL		(AD9523_R1B | 0x1BB)
> +
> +#define AD9523_READBACK_0			(AD9523_R1B | 0x22C)
> +#define AD9523_READBACK_1			(AD9523_R1B | 0x22D)
> +
> +#define AD9523_STATUS_SIGNALS			(AD9523_R3B | 0x232)
> +#define AD9523_POWER_DOWN_CTRL			(AD9523_R1B | 0x233)
> +#define AD9523_IO_UPDATE			(AD9523_R1B | 0x234)
> +
> +#define AD9523_EEPROM_DATA_XFER_STATUS		(AD9523_R1B | 0xB00)
> +#define AD9523_EEPROM_ERROR_READBACK		(AD9523_R1B | 0xB01)
> +#define AD9523_EEPROM_CTRL1			(AD9523_R1B | 0xB02)
> +#define AD9523_EEPROM_CTRL2			(AD9523_R1B | 0xB03)
> +
> +/* AD9523_SERIAL_PORT_CONFIG */
> +
> +#define AD9523_SER_CONF_SDO_ACTIVE		(1<<  7)
> +#define AD9523_SER_CONF_SOFT_RESET		(1<<  5)
> +
> +/* AD9523_READBACK_CTRL */
> +#define AD9523_READBACK_CTRL_READ_BUFFERED	(1<<  0)
> +
> +/* AD9523_PLL1_CHARGE_PUMP_CTRL */
> +#define AD9523_PLL1_CHARGE_PUMP_CURRENT_nA(x)	(((x) / 500)&  0x7F)
> +#define AD9523_PLL1_CHARGE_PUMP_TRISTATE	(1<<  7)
> +#define AD9523_PLL1_CHARGE_PUMP_MODE_NORMAL	(3<<  8)
> +#define AD9523_PLL1_CHARGE_PUMP_MODE_PUMP_DOWN	(2<<  8)
> +#define AD9523_PLL1_CHARGE_PUMP_MODE_PUMP_UP	(1<<  8)
> +#define AD9523_PLL1_CHARGE_PUMP_MODE_TRISTATE	(0<<  8)
> +#define AD9523_PLL1_BACKLASH_PW_MIN		(0<<  10)
> +#define AD9523_PLL1_BACKLASH_PW_LOW		(1<<  10)
> +#define AD9523_PLL1_BACKLASH_PW_HIGH		(2<<  10)
> +#define AD9523_PLL1_BACKLASH_PW_MAX		(3<<  10)
> +
> +/* AD9523_PLL1_INPUT_RECEIVERS_CTRL */
> +#define AD9523_PLL1_REF_TEST_RCV_EN		(1<<  7)
> +#define AD9523_PLL1_REFB_DIFF_RCV_EN		(1<<  6)
> +#define AD9523_PLL1_REFA_DIFF_RCV_EN		(1<<  5)
> +#define AD9523_PLL1_REFB_RCV_EN			(1<<  4)
> +#define AD9523_PLL1_REFA_RCV_EN			(1<<  3)
> +#define AD9523_PLL1_REFA_REFB_PWR_CTRL_EN	(1<<  2)
> +#define AD9523_PLL1_OSC_IN_CMOS_NEG_INP_EN	(1<<  1)
> +#define AD9523_PLL1_OSC_IN_DIFF_EN		(1<<  0)
> +
> +/* AD9523_PLL1_REF_CTRL */
> +#define AD9523_PLL1_BYPASS_REF_TEST_DIV_EN	(1<<  7)
> +#define AD9523_PLL1_BYPASS_FEEDBACK_DIV_EN	(1<<  6)
> +#define AD9523_PLL1_ZERO_DELAY_MODE_INT		(1<<  5)
> +#define AD9523_PLL1_ZERO_DELAY_MODE_EXT		(0<<  5)
> +#define AD9523_PLL1_OSC_IN_PLL_FEEDBACK_EN	(1<<  4)
> +#define AD9523_PLL1_ZD_IN_CMOS_NEG_INP_EN	(1<<  3)
> +#define AD9523_PLL1_ZD_IN_DIFF_EN		(1<<  2)
> +#define AD9523_PLL1_REFB_CMOS_NEG_INP_EN	(1<<  1)
> +#define AD9523_PLL1_REFA_CMOS_NEG_INP_EN	(1<<  0)
> +
> +/* AD9523_PLL1_MISC_CTRL */
> +#define AD9523_PLL1_REFB_INDEP_DIV_CTRL_EN	(1<<  7)
> +#define AD9523_PLL1_OSC_CTRL_FAIL_VCC_BY2_EN	(1<<  6)
> +#define AD9523_PLL1_REF_MODE(x)			((x)<<  2)
> +#define AD9523_PLL1_BYPASS_REFB_DIV		(1<<  1)
> +#define AD9523_PLL1_BYPASS_REFA_DIV		(1<<  0)
> +
> +/* AD9523_PLL1_LOOP_FILTER_CTRL */
> +#define AD9523_PLL1_LOOP_FILTER_RZERO(x)	((x)&  0xF)
> +
> +/* AD9523_PLL2_CHARGE_PUMP */
> +#define AD9523_PLL2_CHARGE_PUMP_CURRENT_nA(x)	((x) / 3500)
> +
> +/* AD9523_PLL2_FEEDBACK_DIVIDER_AB */
> +#define AD9523_PLL2_FB_NDIV_A_CNT(x)		(((x)&  0x3)<<  6)
> +#define AD9523_PLL2_FB_NDIV_B_CNT(x)		(((x)&  0x3F)<<  0)
> +#define AD9523_PLL2_FB_NDIV(a, b)		(4 * (b) + (a))
> +
> +/* AD9523_PLL2_CTRL */
> +#define AD9523_PLL2_CHARGE_PUMP_MODE_NORMAL	(3<<  0)
> +#define AD9523_PLL2_CHARGE_PUMP_MODE_PUMP_DOWN	(2<<  0)
> +#define AD9523_PLL2_CHARGE_PUMP_MODE_PUMP_UP	(1<<  0)
> +#define AD9523_PLL2_CHARGE_PUMP_MODE_TRISTATE	(0<<  0)
> +#define AD9523_PLL2_BACKLASH_PW_MIN		(0<<  2)
> +#define AD9523_PLL2_BACKLASH_PW_LOW		(1<<  2)
> +#define AD9523_PLL2_BACKLASH_PW_HIGH		(2<<  2)
> +#define AD9523_PLL2_BACKLASH_PW_MAX		(3<<  1)
> +#define AD9523_PLL2_BACKLASH_CTRL_EN		(1<<  4)
> +#define AD9523_PLL2_FREQ_DOUBLER_EN		(1<<  5)
> +#define AD9523_PLL2_LOCK_DETECT_PWR_DOWN_EN	(1<<  7)
> +
> +/* AD9523_PLL2_VCO_CTRL */
> +#define AD9523_PLL2_VCO_CALIBRATE		(1<<  1)
> +#define AD9523_PLL2_FORCE_VCO_MIDSCALE		(1<<  2)
> +#define AD9523_PLL2_FORCE_REFERENCE_VALID	(1<<  3)
> +#define AD9523_PLL2_FORCE_RELEASE_SYNC		(1<<  4)
> +
> +/* AD9523_PLL2_VCO_DIVIDER */
> +#define AD9523_PLL2_VCO_DIV_M1(x)		((((x) - 3)&  0x3)<<  0)
> +#define AD9523_PLL2_VCO_DIV_M2(x)		((((x) - 3)&  0x3)<<  4)
> +#define AD9523_PLL2_VCO_DIV_M1_PWR_DOWN_EN	(1<<  2)
> +#define AD9523_PLL2_VCO_DIV_M2_PWR_DOWN_EN	(1<<  6)
> +
> +/* AD9523_PLL2_LOOP_FILTER_CTRL */
> +#define AD9523_PLL2_LOOP_FILTER_CPOLE1(x)	(((x)&  0x7)<<  0)
> +#define AD9523_PLL2_LOOP_FILTER_RZERO(x)	(((x)&  0x7)<<  3)
> +#define AD9523_PLL2_LOOP_FILTER_RPOLE2(x)	(((x)&  0x7)<<  6)
> +#define AD9523_PLL2_LOOP_FILTER_RZERO_BYPASS_EN	(1<<  8)
> +
> +/* AD9523_PLL2_R2_DIVIDER */
> +#define AD9523_PLL2_R2_DIVIDER_VAL(x)		(((x)&  0x1F)<<  0)
> +
> +/* AD9523_CHANNEL_CLOCK_DIST */
> +#define AD9523_CLK_DIST_DIV_PHASE(x)		(((x)&  0x3F)<<  18)
> +#define AD9523_CLK_DIST_DIV_PHASE_REV(x)	((ret>>  18)&  0x3F)
> +#define AD9523_CLK_DIST_DIV(x)			((((x) - 1)&  0x3FF)<<  8)
> +#define AD9523_CLK_DIST_DIV_REV(x)		(((ret>>  8)&  0x3FF) + 1)
> +#define AD9523_CLK_DIST_INV_DIV_OUTPUT_EN	(1<<  7)
> +#define AD9523_CLK_DIST_IGNORE_SYNC_EN		(1<<  6)
> +#define AD9523_CLK_DIST_PWR_DOWN_EN		(1<<  5)
> +#define AD9523_CLK_DIST_LOW_PWR_MODE_EN		(1<<  4)
> +#define AD9523_CLK_DIST_DRIVER_MODE(x)		(((x)&  0xF)<<  0)
> +
> +/* AD9523_PLL1_OUTPUT_CTRL */
> +#define AD9523_PLL1_OUTP_CTRL_VCO_DIV_SEL_CH6_M2	(1<<  7)
> +#define AD9523_PLL1_OUTP_CTRL_VCO_DIV_SEL_CH5_M2	(1<<  6)
> +#define AD9523_PLL1_OUTP_CTRL_VCO_DIV_SEL_CH4_M2	(1<<  5)
> +#define AD9523_PLL1_OUTP_CTRL_CMOS_DRV_WEAK		(1<<  4)
> +#define AD9523_PLL1_OUTP_CTRL_OUTPUT_DIV_1		(0<<  0)
> +#define AD9523_PLL1_OUTP_CTRL_OUTPUT_DIV_2		(1<<  0)
> +#define AD9523_PLL1_OUTP_CTRL_OUTPUT_DIV_4		(2<<  0)
> +#define AD9523_PLL1_OUTP_CTRL_OUTPUT_DIV_8		(4<<  0)
> +#define AD9523_PLL1_OUTP_CTRL_OUTPUT_DIV_16		(8<<  0)
> +
> +/* AD9523_PLL1_OUTPUT_CHANNEL_CTRL */
> +#define AD9523_PLL1_OUTP_CH_CTRL_OUTPUT_PWR_DOWN_EN	(1<<  7)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCO_DIV_SEL_CH9_M2	(1<<  6)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCO_DIV_SEL_CH8_M2	(1<<  5)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCO_DIV_SEL_CH7_M2	(1<<  4)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCXO_SRC_SEL_CH3	(1<<  3)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCXO_SRC_SEL_CH2	(1<<  2)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCXO_SRC_SEL_CH1	(1<<  1)
> +#define AD9523_PLL1_OUTP_CH_CTRL_VCXO_SRC_SEL_CH0	(1<<  0)
> +
> +/* AD9523_READBACK_0 */
> +#define AD9523_READBACK_0_STAT_PLL2_REF_CLK		(1<<  7)
> +#define AD9523_READBACK_0_STAT_PLL2_FB_CLK		(1<<  6)
> +#define AD9523_READBACK_0_STAT_VCXO			(1<<  5)
> +#define AD9523_READBACK_0_STAT_REF_TEST			(1<<  4)
> +#define AD9523_READBACK_0_STAT_REFB			(1<<  3)
> +#define AD9523_READBACK_0_STAT_REFA			(1<<  2)
> +#define AD9523_READBACK_0_STAT_PLL2_LD			(1<<  1)
> +#define AD9523_READBACK_0_STAT_PLL1_LD			(1<<  0)
> +
> +/* AD9523_READBACK_1 */
> +#define AD9523_READBACK_1_HOLDOVER_ACTIVE		(1<<  3)
> +#define AD9523_READBACK_1_AUTOMODE_SEL_REFB		(1<<  2)
> +#define AD9523_READBACK_1_VCO_CALIB_IN_PROGRESS		(1<<  0)
> +
> +/* AD9523_STATUS_SIGNALS */
> +#define AD9523_STATUS_SIGNALS_SYNC_MAN_CTRL		(1<<  16)
> +#define AD9523_STATUS_MONITOR_01_PLL12_LOCKED		(0x302)
> +/* AD9523_POWER_DOWN_CTRL */
> +#define AD9523_POWER_DOWN_CTRL_PLL1_PWR_DOWN		(1<<  2)
> +#define AD9523_POWER_DOWN_CTRL_PLL2_PWR_DOWN		(1<<  1)
> +#define AD9523_POWER_DOWN_CTRL_DIST_PWR_DOWN		(1<<  0)
> +
> +/* AD9523_IO_UPDATE */
> +#define AD9523_IO_UPDATE_EN				(1<<  0)
> +
> +/* AD9523_EEPROM_DATA_XFER_STATUS */
> +#define AD9523_EEPROM_DATA_XFER_IN_PROGRESS		(1<<  0)
> +
> +/* AD9523_EEPROM_ERROR_READBACK */
> +#define AD9523_EEPROM_ERROR_READBACK_FAIL		(1<<  0)
> +
> +/* AD9523_EEPROM_CTRL1 */
> +#define AD9523_EEPROM_CTRL1_SOFT_EEPROM			(1<<  1)
> +#define AD9523_EEPROM_CTRL1_EEPROM_WRITE_PROT_DIS	(1<<  0)
> +
> +/* AD9523_EEPROM_CTRL2 */
> +#define AD9523_EEPROM_CTRL2_REG2EEPROM			(1<<  0)
> +
> +#define AD9523_NUM_CHAN					14
> +#define AD9523_NUM_CHAN_ALT_CLK_SRC			10
> +
> +/* Helpers to avoid excess line breaks */
> +#define AD_IFE(_pde, _a, _b) ((pdata->_pde) ? _a : _b)
> +#define AD_IF(_pde, _a) AD_IFE(_pde, _a, 0)
> +
> +enum {
> +	AD9523_STAT_PLL1_LD,
> +	AD9523_STAT_PLL2_LD,
> +	AD9523_STAT_REFA,
> +	AD9523_STAT_REFB,
> +	AD9523_STAT_REF_TEST,
> +	AD9523_STAT_VCXO,
> +	AD9523_STAT_PLL2_FB_CLK,
> +	AD9523_STAT_PLL2_REF_CLK,
> +	AD9523_SYNC,
> +	AD9523_EEPROM,
> +};
> +
> +enum {
> +	AD9523_VCO1,
> +	AD9523_VCO2,
> +	AD9523_VCXO,
> +	AD9523_NUM_CLK_SRC,
> +};
> +
> +struct ad9523_state {
> +	struct spi_device		*spi;
> +	struct regulator		*reg;
> +	struct ad9523_platform_data	*pdata;
> +	struct iio_chan_spec		ad9523_channels[AD9523_NUM_CHAN];
> +
> +	unsigned long		vcxo_freq;
> +	unsigned long		vco_freq;
> +	unsigned long		vco_out_freq[AD9523_NUM_CLK_SRC];
> +	unsigned char		vco_out_map[AD9523_NUM_CHAN_ALT_CLK_SRC];
> +
> +	/*
> +	 * DMA (thus cache coherency maintenance) requires the
> +	 * transfer buffers to live in their own cache lines.
> +	 */
> +	union {
> +		__be32 d32;
> +		u8 d8[4];
> +	} data[2] ____cacheline_aligned;
> +};
> +
> +static int ad9523_read(struct iio_dev *indio_dev, unsigned addr)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	struct spi_message m;
> +	int ret;
> +
> +	/* We encode the register size 1..3 bytes into the register address.
> +	 * On transfer we get the size from the register datum, and make sure
> +	 * the result is properly aligned.
> +	 */
> +
> +	struct spi_transfer t[] = {
> +		{
> +			.tx_buf =&st->data[0].d8[2],
> +			.len = 2,
> +		}, {
> +			.rx_buf =&st->data[1].d8[4 - AD9523_TRANSF_LEN(addr)],
> +			.len = AD9523_TRANSF_LEN(addr),
> +		},
> +	};
> +
> +	spi_message_init(&m);
> +	spi_message_add_tail(&t[0],&m);
> +	spi_message_add_tail(&t[1],&m);
> +
> +	st->data[0].d32 = cpu_to_be32(AD9523_READ |
> +				      AD9523_CNT(AD9523_TRANSF_LEN(addr)) |
> +				      AD9523_ADDR(addr));
> +
> +	ret = spi_sync(st->spi,&m);
> +	if (ret<  0)
> +		dev_err(&indio_dev->dev, "read failed (%d)", ret);
> +	else
> +		ret = be32_to_cpu(st->data[1].d32)&  (0xFFFFFF>>
> +				  (8 * (3 - AD9523_TRANSF_LEN(addr))));
> +
> +	return ret;
> +};
> +
> +static int ad9523_write(struct iio_dev *indio_dev, unsigned addr, unsigned val)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	struct spi_message m;
> +	int ret;
> +	struct spi_transfer t[] = {
> +		{
> +			.tx_buf =&st->data[0].d8[2],
> +			.len = 2,
> +		}, {
> +			.tx_buf =&st->data[1].d8[4 - AD9523_TRANSF_LEN(addr)],
> +			.len = AD9523_TRANSF_LEN(addr),
> +		},
> +	};
> +
> +	spi_message_init(&m);
> +	spi_message_add_tail(&t[0],&m);
> +	spi_message_add_tail(&t[1],&m);
> +
> +	st->data[0].d32 = cpu_to_be32(AD9523_WRITE |
> +				      AD9523_CNT(AD9523_TRANSF_LEN(addr)) |
> +				      AD9523_ADDR(addr));
> +	st->data[1].d32 = cpu_to_be32(val);
> +
> +	ret = spi_sync(st->spi,&m);
> +
> +	if (ret<  0)
> +		dev_err(&indio_dev->dev, "write failed (%d)", ret);
> +
> +	return ret;
> +}
> +
> +static int ad9523_io_update(struct iio_dev *indio_dev)
> +{
> +	return ad9523_write(indio_dev, AD9523_IO_UPDATE, AD9523_IO_UPDATE_EN);
> +}
> +
> +static int ad9523_vco_out_map(struct iio_dev *indio_dev,
> +			      unsigned ch, bool out)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	int ret;
> +	unsigned mask;
> +
> +	switch (ch) {
> +	case 0 ... 3:
> +		ret = ad9523_read(indio_dev, AD9523_PLL1_OUTPUT_CHANNEL_CTRL);
> +		if (ret<  0)
> +			break;
> +		mask = AD9523_PLL1_OUTP_CH_CTRL_VCXO_SRC_SEL_CH0<<  ch;
> +		if (out) {
> +			ret |= mask;
> +			out = 2;
> +		} else {
> +			ret&= ~mask;
> +		}
> +		ret = ad9523_write(indio_dev,
> +				   AD9523_PLL1_OUTPUT_CHANNEL_CTRL, ret);
> +		break;
> +	case 4 ... 6:
> +		ret = ad9523_read(indio_dev, AD9523_PLL1_OUTPUT_CTRL);
> +		if (ret<  0)
> +			break;
> +		mask = AD9523_PLL1_OUTP_CTRL_VCO_DIV_SEL_CH4_M2<<  (ch - 4);
> +		if (out)
> +			ret |= mask;
> +		else
> +			ret&= ~mask;
> +		ret = ad9523_write(indio_dev, AD9523_PLL1_OUTPUT_CTRL, ret);
> +		break;
> +	case 7 ... 9:
> +		ret = ad9523_read(indio_dev, AD9523_PLL1_OUTPUT_CHANNEL_CTRL);
> +		if (ret<  0)
> +			break;
> +		mask = AD9523_PLL1_OUTP_CH_CTRL_VCO_DIV_SEL_CH7_M2<<  (ch - 7);
> +		if (out)
> +			ret |= mask;
> +		else
> +			ret&= ~mask;
> +		ret = ad9523_write(indio_dev,
> +				   AD9523_PLL1_OUTPUT_CHANNEL_CTRL, ret);
> +		break;
> +	default:
> +		return 0;
> +	}
> +
> +	st->vco_out_map[ch] = out;
> +
> +	return ret;
> +}
> +
> +static int ad9523_set_clock_provider(struct iio_dev *indio_dev,
> +			      unsigned ch, unsigned long freq)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	long tmp1, tmp2;
> +	bool use_alt_clk_src;
> +
> +	switch (ch) {
> +	case 0 ... 3:
> +		use_alt_clk_src = (freq == st->vco_out_freq[AD9523_VCXO]);
> +		break;
> +	case 4 ... 9:
> +		tmp1 = st->vco_out_freq[AD9523_VCO1] / freq;
> +		tmp2 = st->vco_out_freq[AD9523_VCO2] / freq;
> +		tmp1 *= freq;
> +		tmp2 *= freq;
> +		use_alt_clk_src = (abs(tmp1 - freq)>  abs(tmp2 - freq));
> +		break;
> +	default:
> +		/* Ch 10..14: No action required, return success */
> +		return 0;
> +	}
> +
> +	return ad9523_vco_out_map(indio_dev, ch, use_alt_clk_src);
> +}
> +
> +static int ad9523_store_eeprom(struct iio_dev *indio_dev)
> +{
> +	int ret, tmp;
> +
> +	ret = ad9523_write(indio_dev, AD9523_EEPROM_CTRL1,
> +			   AD9523_EEPROM_CTRL1_EEPROM_WRITE_PROT_DIS);
> +	if (ret<  0)
> +		return ret;
> +	ret = ad9523_write(indio_dev, AD9523_EEPROM_CTRL2,
> +			   AD9523_EEPROM_CTRL2_REG2EEPROM);
> +	if (ret<  0)
> +		return ret;
> +
> +	tmp = 4;
> +	do {
> +		msleep(16);
> +		ret = ad9523_read(indio_dev,
> +				  AD9523_EEPROM_DATA_XFER_STATUS);
> +		if (ret<  0)
> +			return ret;
> +	} while ((ret&  AD9523_EEPROM_DATA_XFER_IN_PROGRESS)&&  tmp--);
> +
> +	ret = ad9523_write(indio_dev, AD9523_EEPROM_CTRL1, 0);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_read(indio_dev, AD9523_EEPROM_ERROR_READBACK);
> +	if (ret<  0)
> +		return ret;
> +
> +	if (ret&  AD9523_EEPROM_ERROR_READBACK_FAIL) {
> +		dev_err(&indio_dev->dev, "Verify EEPROM failed");
> +		ret = -EIO;
> +	}
> +
> +	return ret;
> +}
> +
> +static int ad9523_sync(struct iio_dev *indio_dev)
> +{
> +	int ret, tmp;
> +
> +	ret = ad9523_read(indio_dev, AD9523_STATUS_SIGNALS);
> +	if (ret<  0)
> +		return ret;
> +
> +	tmp = ret;
> +	tmp |= AD9523_STATUS_SIGNALS_SYNC_MAN_CTRL;
> +
> +	ret = ad9523_write(indio_dev, AD9523_STATUS_SIGNALS, tmp);
> +	if (ret<  0)
> +		return ret;
> +
> +	ad9523_io_update(indio_dev);
> +	tmp&= ~AD9523_STATUS_SIGNALS_SYNC_MAN_CTRL;
> +
> +	ret = ad9523_write(indio_dev, AD9523_STATUS_SIGNALS, tmp);
> +	if (ret<  0)
> +		return ret;
> +
> +	return ad9523_io_update(indio_dev);
> +}
> +
> +static ssize_t ad9523_store(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf, size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	bool state;
> +	int ret;
> +
> +	ret = strtobool(buf,&state);
> +	if (ret<  0)
> +		return ret;
> +
> +	if (!state)
> +		return 0;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	switch ((u32)this_attr->address) {
> +	case AD9523_SYNC:
> +		ret = ad9523_sync(indio_dev);
> +		break;
> +	case AD9523_EEPROM:
> +		ret = ad9523_store_eeprom(indio_dev);
> +		break;
> +	default:
> +		ret = -ENODEV;
> +	}
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret ? ret : len;
> +}
> +
> +static ssize_t ad9523_show(struct device *dev,
> +			struct device_attribute *attr,
> +			char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	ret = ad9523_read(indio_dev, AD9523_READBACK_0);
> +	if (ret>= 0) {
> +		ret = sprintf(buf, "%d\n", !!(ret&  (1<<
> +			(u32)this_attr->address)));
> +	}
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static IIO_DEVICE_ATTR(pll1_locked, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_PLL1_LD);
> +
> +static IIO_DEVICE_ATTR(pll2_locked, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_PLL2_LD);
> +
> +static IIO_DEVICE_ATTR(pll1_reference_clk_a_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_REFA);
> +
> +static IIO_DEVICE_ATTR(pll1_reference_clk_b_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_REFB);
> +
> +static IIO_DEVICE_ATTR(pll1_reference_clk_test_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_REF_TEST);
> +
> +static IIO_DEVICE_ATTR(vcxo_clk_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_VCXO);
> +
> +static IIO_DEVICE_ATTR(pll2_feedback_clk_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_PLL2_FB_CLK);
> +
> +static IIO_DEVICE_ATTR(pll2_reference_clk_present, S_IRUGO,
> +			ad9523_show,
> +			NULL,
> +			AD9523_STAT_PLL2_REF_CLK);
> +
> +static IIO_DEVICE_ATTR(sync_dividers, S_IWUSR,
> +			NULL,
> +			ad9523_store,
> +			AD9523_SYNC);
> +
> +static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR,
> +			NULL,
> +			ad9523_store,
> +			AD9523_EEPROM);
> +
> +static struct attribute *ad9523_attributes[] = {
> +	&iio_dev_attr_sync_dividers.dev_attr.attr,
> +	&iio_dev_attr_store_eeprom.dev_attr.attr,
> +	&iio_dev_attr_pll2_feedback_clk_present.dev_attr.attr,
> +	&iio_dev_attr_pll2_reference_clk_present.dev_attr.attr,
> +	&iio_dev_attr_pll1_reference_clk_a_present.dev_attr.attr,
> +	&iio_dev_attr_pll1_reference_clk_b_present.dev_attr.attr,
> +	&iio_dev_attr_pll1_reference_clk_test_present.dev_attr.attr,
> +	&iio_dev_attr_vcxo_clk_present.dev_attr.attr,
> +	&iio_dev_attr_pll1_locked.dev_attr.attr,
> +	&iio_dev_attr_pll2_locked.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group ad9523_attribute_group = {
> +	.attrs = ad9523_attributes,
> +};
> +
> +static int ad9523_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan,
> +			   int *val,
> +			   int *val2,
> +			   long m)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	unsigned code;
> +	int ret;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	ret = ad9523_read(indio_dev, AD9523_CHANNEL_CLOCK_DIST(chan->channel));
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	if (ret<  0)
> +		return ret;
> +
> +	switch (m) {
> +	case IIO_CHAN_INFO_RAW:
> +		*val = !(ret&  AD9523_CLK_DIST_PWR_DOWN_EN);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_FREQUENCY:
> +		*val = st->vco_out_freq[st->vco_out_map[chan->channel]] /
> +			AD9523_CLK_DIST_DIV_REV(ret);
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_PHASE:
> +		code = (AD9523_CLK_DIST_DIV_PHASE_REV(ret) * 3141592) /
> +			AD9523_CLK_DIST_DIV_REV(ret);
> +		*val = code / 1000000;
> +		*val2 = (code % 1000000) * 10;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		return -EINVAL;
> +	}
> +};
> +
> +static int ad9523_write_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int val,
> +			    int val2,
> +			    long mask)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	unsigned reg;
> +	int ret, tmp, code;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	ret = ad9523_read(indio_dev, AD9523_CHANNEL_CLOCK_DIST(chan->channel));
> +	if (ret<  0)
> +		goto out;
> +
> +	reg = ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (val)
> +			reg&= ~AD9523_CLK_DIST_PWR_DOWN_EN;
> +		else
> +			reg |= AD9523_CLK_DIST_PWR_DOWN_EN;
> +		break;
> +	case IIO_CHAN_INFO_FREQUENCY:
> +		if (val<= 0) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		ret = ad9523_set_clock_provider(indio_dev, chan->channel, val);
> +		if (ret<  0)
> +			goto out;
> +		tmp = st->vco_out_freq[st->vco_out_map[chan->channel]] / val;
> +		tmp = clamp(tmp, 1, 1024);
> +		reg&= ~(0x3FF<<  8);
> +		reg |= AD9523_CLK_DIST_DIV(tmp);
> +		break;
> +	case IIO_CHAN_INFO_PHASE:
> +		code = val * 1000000 + val2 % 1000000;
> +		tmp = (code * AD9523_CLK_DIST_DIV_REV(ret)) / 3141592;
> +		tmp = clamp(tmp, 0, 63);
> +		reg&= ~AD9523_CLK_DIST_DIV_PHASE(~0);
> +		reg |= AD9523_CLK_DIST_DIV_PHASE(tmp);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	ret = ad9523_write(indio_dev, AD9523_CHANNEL_CLOCK_DIST(chan->channel),
> +			   reg);
> +	if (ret<  0)
> +		goto out;
> +
> +	ad9523_io_update(indio_dev);
> +out:
> +	mutex_unlock(&indio_dev->mlock);
> +	return ret;
> +}
> +
> +static int ad9523_reg_access(struct iio_dev *indio_dev,
> +			      unsigned reg, unsigned writeval,
> +			      unsigned *readval)
> +{
> +	int ret;
> +
> +	mutex_lock(&indio_dev->mlock);
> +	if (readval == NULL) {
> +		ret = ad9523_write(indio_dev, reg | AD9523_R1B, writeval);
> +		ad9523_io_update(indio_dev);
> +	} else {
> +		ret = ad9523_read(indio_dev, reg | AD9523_R1B);
> +		if (ret<  0)
> +			return ret;
> +		*readval = ret;
> +		ret = 0;
> +	}
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static const struct iio_info ad9523_info = {
> +	.read_raw =&ad9523_read_raw,
> +	.write_raw =&ad9523_write_raw,
> +	.debugfs_reg_access =&ad9523_reg_access,
> +	.attrs =&ad9523_attribute_group,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static int ad9523_setup(struct iio_dev *indio_dev)
> +{
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	struct ad9523_platform_data *pdata = st->pdata;
> +	struct ad9523_channel_spec *chan;
> +	unsigned active_mask = 0;
> +	int ret, i;
> +
> +	ret = ad9523_write(indio_dev, AD9523_SERIAL_PORT_CONFIG,
> +			   AD9523_SER_CONF_SOFT_RESET |
> +			  (st->spi->mode&  SPI_3WIRE ? 0 :
> +			  AD9523_SER_CONF_SDO_ACTIVE));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_READBACK_CTRL,
> +			  AD9523_READBACK_CTRL_READ_BUFFERED);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_io_update(indio_dev);
> +	if (ret<  0)
> +		return ret;
> +
> +	/*
> +	 * PLL1 Setup
> +	 */
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_REF_A_DIVIDER,
> +		pdata->refa_r_div);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_REF_B_DIVIDER,
> +		pdata->refb_r_div);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_FEEDBACK_DIVIDER,
> +		pdata->pll1_feedback_div);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_CHARGE_PUMP_CTRL,
> +		AD9523_PLL1_CHARGE_PUMP_CURRENT_nA(pdata->
> +			pll1_charge_pump_current_nA) |
> +		AD9523_PLL1_CHARGE_PUMP_MODE_NORMAL |
> +		AD9523_PLL1_BACKLASH_PW_MIN);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_INPUT_RECEIVERS_CTRL,
> +		AD_IF(refa_diff_rcv_en, AD9523_PLL1_REFA_RCV_EN) |
> +		AD_IF(refb_diff_rcv_en, AD9523_PLL1_REFB_RCV_EN) |
> +		AD_IF(osc_in_diff_en, AD9523_PLL1_OSC_IN_DIFF_EN) |
> +		AD_IF(osc_in_cmos_neg_inp_en,
> +		      AD9523_PLL1_OSC_IN_CMOS_NEG_INP_EN) |
> +		AD_IF(refa_diff_rcv_en, AD9523_PLL1_REFA_DIFF_RCV_EN) |
> +		AD_IF(refb_diff_rcv_en, AD9523_PLL1_REFB_DIFF_RCV_EN));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_REF_CTRL,
> +		AD_IF(zd_in_diff_en, AD9523_PLL1_ZD_IN_DIFF_EN) |
> +		AD_IF(zd_in_cmos_neg_inp_en,
> +		      AD9523_PLL1_ZD_IN_CMOS_NEG_INP_EN) |
> +		AD_IF(zero_delay_mode_internal_en,
> +		      AD9523_PLL1_ZERO_DELAY_MODE_INT) |
> +		AD_IF(osc_in_feedback_en, AD9523_PLL1_OSC_IN_PLL_FEEDBACK_EN) |
> +		AD_IF(refa_cmos_neg_inp_en, AD9523_PLL1_REFA_CMOS_NEG_INP_EN) |
> +		AD_IF(refb_cmos_neg_inp_en, AD9523_PLL1_REFB_CMOS_NEG_INP_EN));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_MISC_CTRL,
> +		AD9523_PLL1_REFB_INDEP_DIV_CTRL_EN |
> +		AD9523_PLL1_REF_MODE(pdata->ref_mode));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL1_LOOP_FILTER_CTRL,
> +		AD9523_PLL1_LOOP_FILTER_RZERO(pdata->pll1_loop_filter_rzero));
> +	if (ret<  0)
> +		return ret;
> +	/*
> +	 * PLL2 Setup
> +	 */
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_CHARGE_PUMP,
> +		AD9523_PLL2_CHARGE_PUMP_CURRENT_nA(pdata->
> +			pll2_charge_pump_current_nA));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_FEEDBACK_DIVIDER_AB,
> +		AD9523_PLL2_FB_NDIV_A_CNT(pdata->pll2_ndiv_a_cnt) |
> +		AD9523_PLL2_FB_NDIV_B_CNT(pdata->pll2_ndiv_b_cnt));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_CTRL,
> +		AD9523_PLL2_CHARGE_PUMP_MODE_NORMAL |
> +		AD9523_PLL2_BACKLASH_CTRL_EN |
> +		AD_IF(pll2_freq_doubler_en, AD9523_PLL2_FREQ_DOUBLER_EN));
> +	if (ret<  0)
> +		return ret;
> +
> +	st->vco_freq = (pdata->vcxo_freq * (pdata->pll2_freq_doubler_en ? 2 : 1)
> +			/ pdata->pll2_r2_div) * AD9523_PLL2_FB_NDIV(pdata->
> +			pll2_ndiv_a_cnt, pdata->pll2_ndiv_b_cnt);
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_VCO_CTRL,
> +		AD9523_PLL2_VCO_CALIBRATE);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_VCO_DIVIDER,
> +		AD9523_PLL2_VCO_DIV_M1(pdata->pll2_vco_diff_m1) |
> +		AD9523_PLL2_VCO_DIV_M2(pdata->pll2_vco_diff_m2) |
> +		AD_IFE(pll2_vco_diff_m1, 0,
> +		       AD9523_PLL2_VCO_DIV_M1_PWR_DOWN_EN) |
> +		AD_IFE(pll2_vco_diff_m2, 0,
> +		       AD9523_PLL2_VCO_DIV_M2_PWR_DOWN_EN));
> +	if (ret<  0)
> +		return ret;
> +
> +	if (pdata->pll2_vco_diff_m1)
> +		st->vco_out_freq[AD9523_VCO1] =
> +			st->vco_freq / pdata->pll2_vco_diff_m1;
> +
> +	if (pdata->pll2_vco_diff_m2)
> +		st->vco_out_freq[AD9523_VCO2] =
> +			st->vco_freq / pdata->pll2_vco_diff_m2;
> +
> +	st->vco_out_freq[AD9523_VCXO] = pdata->vcxo_freq;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_R2_DIVIDER,
> +		AD9523_PLL2_R2_DIVIDER_VAL(pdata->pll2_r2_div));
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_PLL2_LOOP_FILTER_CTRL,
> +		AD9523_PLL2_LOOP_FILTER_CPOLE1(pdata->cpole1) |
> +		AD9523_PLL2_LOOP_FILTER_RZERO(pdata->rzero) |
> +		AD9523_PLL2_LOOP_FILTER_RPOLE2(pdata->rpole2) |
> +		AD_IF(rzero_bypass_en,
> +		      AD9523_PLL2_LOOP_FILTER_RZERO_BYPASS_EN));
> +	if (ret<  0)
> +		return ret;
> +
> +	for (i = 0; i<  pdata->num_channels; i++) {
> +		chan =&pdata->channels[i];
> +		if (chan->channel_num<  AD9523_NUM_CHAN) {
> +			active_mask |= (1<<  chan->channel_num);
> +			ret = ad9523_write(indio_dev,
> +				AD9523_CHANNEL_CLOCK_DIST(chan->channel_num),
> +				AD9523_CLK_DIST_DRIVER_MODE(chan->driver_mode) |
> +				AD9523_CLK_DIST_DIV(chan->channel_divider) |
> +				AD9523_CLK_DIST_DIV_PHASE(chan->divider_phase) |
> +				(chan->sync_ignore_en ?
> +					AD9523_CLK_DIST_IGNORE_SYNC_EN : 0) |
> +				(chan->divider_output_invert_en ?
> +					AD9523_CLK_DIST_INV_DIV_OUTPUT_EN : 0) |
> +				(chan->low_power_mode_en ?
> +					AD9523_CLK_DIST_LOW_PWR_MODE_EN : 0) |
> +				(chan->output_dis ?
> +					AD9523_CLK_DIST_PWR_DOWN_EN : 0));
> +			if (ret<  0)
> +				return ret;
> +
> +			ret = ad9523_vco_out_map(indio_dev, chan->channel_num,
> +					   chan->use_alt_clock_src);
> +			if (ret<  0)
> +				return ret;
> +
> +			st->ad9523_channels[i].type = IIO_ALTVOLTAGE;
> +			st->ad9523_channels[i].output = 1;
> +			st->ad9523_channels[i].indexed = 1;
> +			st->ad9523_channels[i].channel = chan->channel_num;
> +			st->ad9523_channels[i].extend_name =
> +				chan->extended_name;
> +			st->ad9523_channels[i].info_mask =
> +				IIO_CHAN_INFO_RAW_SEPARATE_BIT |
> +				IIO_CHAN_INFO_PHASE_SEPARATE_BIT |
> +				IIO_CHAN_INFO_FREQUENCY_SEPARATE_BIT;
> +		}
> +	}
> +
looks rather like a for_each_clear_bit.
> +	for (i = 0; i<  AD9523_NUM_CHAN; i++)
> +		if (!(active_mask&  (1<<  i)))
> +			ad9523_write(indio_dev,
> +				     AD9523_CHANNEL_CLOCK_DIST(i),
> +				     AD9523_CLK_DIST_DRIVER_MODE(TRISTATE) |
> +				     AD9523_CLK_DIST_PWR_DOWN_EN);
> +
> +	ret = ad9523_write(indio_dev, AD9523_POWER_DOWN_CTRL, 0);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_write(indio_dev, AD9523_STATUS_SIGNALS,
> +			   AD9523_STATUS_MONITOR_01_PLL12_LOCKED);
> +	if (ret<  0)
> +		return ret;
> +
> +	ret = ad9523_io_update(indio_dev);
> +	if (ret<  0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int __devinit ad9523_probe(struct spi_device *spi)
> +{
> +	struct ad9523_platform_data *pdata = spi->dev.platform_data;
> +	struct iio_dev *indio_dev;
> +	struct ad9523_state *st;
> +	int ret;
> +
> +	if (!pdata) {
> +		dev_err(&spi->dev, "no platform data?\n");
> +		return -EINVAL;
> +	}
> +
> +	indio_dev = iio_device_alloc(sizeof(*st));
> +	if (indio_dev == NULL)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +
> +	st->reg = regulator_get(&spi->dev, "vcc");
> +	if (!IS_ERR(st->reg)) {
> +		ret = regulator_enable(st->reg);
> +		if (ret)
> +			goto error_put_reg;
> +	}
> +
> +	spi_set_drvdata(spi, indio_dev);
> +	st->spi = spi;
> +	st->pdata = pdata;
> +
> +	indio_dev->dev.parent =&spi->dev;
> +	indio_dev->name = (pdata->name[0] != 0) ? pdata->name :
> +			  spi_get_device_id(spi)->name;
> +	indio_dev->info =&ad9523_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = st->ad9523_channels;
> +	indio_dev->num_channels = pdata->num_channels;
> +
> +	ret = ad9523_setup(indio_dev);
> +	if (ret<  0)
> +		goto error_disable_reg;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret)
> +		goto error_disable_reg;
> +
> +	dev_info(&spi->dev, "probed %s\n", indio_dev->name);
> +
> +	return 0;
> +
> +error_disable_reg:
> +	if (!IS_ERR(st->reg))
> +		regulator_disable(st->reg);
> +error_put_reg:
> +	if (!IS_ERR(st->reg))
> +		regulator_put(st->reg);
> +
> +	iio_device_free(indio_dev);
> +
> +	return ret;
> +}
> +
> +static int __devexit ad9523_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct ad9523_state *st = iio_priv(indio_dev);
> +	struct regulator *reg = st->reg;
> +
> +	iio_device_unregister(indio_dev);
> +
st is still available so I'd not bother with the temporary for reg.
Personal preference though.
> +	if (!IS_ERR(reg)) {
> +		regulator_disable(reg);
> +		regulator_put(reg);
> +	}
> +
> +	iio_device_free(indio_dev);
> +
> +	return 0;
> +}
> +
> +static const struct spi_device_id ad9523_id[] = {
> +	{"ad9523", 9523},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(spi, ad9523_id);
> +
> +static struct spi_driver ad9523_driver = {
> +	.driver = {
> +		.name	= "ad9523",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= ad9523_probe,
> +	.remove		= __devexit_p(ad9523_remove),
> +	.id_table	= ad9523_id,
> +};
> +module_spi_driver(ad9523_driver);
> +
> +MODULE_AUTHOR("Michael Hennerich<hennerich@blackfin.uclinux.org>");
> +MODULE_DESCRIPTION("Analog Devices AD9523 CLOCKDIST/PLL");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/iio/frequency/ad9523.h b/include/linux/iio/frequency/ad9523.h
> new file mode 100644
> index 0000000..e878f09
> --- /dev/null
> +++ b/include/linux/iio/frequency/ad9523.h
> @@ -0,0 +1,195 @@
> +/*
> + * AD9523 SPI Low Jitter Clock Generator
> + *
> + * Copyright 2012 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#ifndef IIO_FREQUENCY_AD9523_H_
> +#define IIO_FREQUENCY_AD9523_H_
> +
> +enum outp_drv_mode {
> +	TRISTATE,
> +	LVPECL_8mA,
> +	LVDS_4mA,
> +	LVDS_7mA,
> +	HSTL0_16mA,
> +	HSTL1_8mA,
> +	CMOS_CONF1,
> +	CMOS_CONF2,
> +	CMOS_CONF3,
> +	CMOS_CONF4,
> +	CMOS_CONF5,
> +	CMOS_CONF6,
> +	CMOS_CONF7,
> +	CMOS_CONF8,
> +	CMOS_CONF9
> +};
> +
> +enum ref_sel_mode {
> +	NONEREVERTIVE_STAY_ON_REFB,
> +	REVERT_TO_REFA,
> +	SELECT_REFA,
> +	SELECT_REFB,
> +	EXT_REF_SEL
> +};
> +
> +/**
> + * struct ad9523_channel_spec - Output channel configuration
> + *
> + * @channel_num: Output channel number.
> + * @divider_output_invert_en: Invert the polarity of the output clock.
> + * @sync_ignore_en: Ignore chip-level SYNC signal.
> + * @low_power_mode_en: Reduce power used in the differential output modes.
> + * @use_alt_clock_src: Channel divider uses alternative clk source.
> + * @output_dis: Disables, powers down the entire channel.
> + * @driver_mode: Output driver mode (logic level family).
> + * @divider_phase: Divider initial phase after a SYNC. Range 0..63
> +		   LSB = 1/2 of a period of the divider input clock.
> + * @channel_divider: 10-bit channel divider.
> + * @extended_name: Optional descriptive channel name.
> + */
> +
> +struct ad9523_channel_spec {
> +	unsigned		channel_num;
> +	bool			divider_output_invert_en;
> +	bool			sync_ignore_en;
> +	bool			low_power_mode_en;
> +				 /* CH0..CH3 VCXO, CH4..CH9 VCO2 */
> +	bool			use_alt_clock_src;
> +	bool			output_dis;
> +	enum outp_drv_mode	driver_mode;
> +	unsigned char		divider_phase;
> +	unsigned short		channel_divider;
> +	char			extended_name[16];
> +};
> +
> +enum pll1_rzero_resistor {
> +	RZERO_883_OHM,
> +	RZERO_677_OHM,
> +	RZERO_341_OHM,
> +	RZERO_135_OHM,
> +	RZERO_10_OHM,
> +	RZERO_USE_EXT_RES = 8,
> +};
> +
> +enum rpole2_resistor {
> +	RPOLE2_900_OHM,
> +	RPOLE2_450_OHM,
> +	RPOLE2_300_OHM,
> +	RPOLE2_225_OHM,
> +};
> +
> +enum rzero_resistor {
> +	RZERO_3250_OHM,
> +	RZERO_2750_OHM,
> +	RZERO_2250_OHM,
> +	RZERO_2100_OHM,
> +	RZERO_3000_OHM,
> +	RZERO_2500_OHM,
> +	RZERO_2000_OHM,
> +	RZERO_1850_OHM,
> +};
> +
> +enum cpole1_capacitor {
> +	CPOLE1_0_PF,
> +	CPOLE1_8_PF,
> +	CPOLE1_16_PF,
> +	CPOLE1_24_PF,
This underscore version would benefit from and explanatory comment!
> +	_CPOLE1_24_PF,
> +	CPOLE1_32_PF,
> +	CPOLE1_40_PF,
> +	CPOLE1_48_PF,
> +};
> +
> +/**
> + * struct ad9523_platform_data - platform specific information
> + *
> + * @vcxo_freq: External VCXO frequency in Hz
> + * @refa_diff_rcv_en: REFA differential/single-ended input selection.
> + * @refb_diff_rcv_en: REFB differential/single-ended input selection.
> + * @zd_in_diff_en: Zero Delay differential/single-ended input selection.
> + * @osc_in_diff_en: OSC differential/ single-ended input selection.
> + * @refa_cmos_neg_inp_en: REFA single-ended neg./pos. input enable.
> + * @refb_cmos_neg_inp_en: REFB single-ended neg./pos. input enable.
> + * @zd_in_cmos_neg_inp_en: Zero Delay single-ended neg./pos. input enable.
> + * @osc_in_cmos_neg_inp_en: OSC single-ended neg./pos. input enable.
> + * @refa_r_div: PLL1 10-bit REFA R divider.
> + * @refb_r_div: PLL1 10-bit REFB R divider.
> + * @pll1_feedback_div: PLL1 10-bit Feedback N divider.
> + * @pll1_charge_pump_current_nA: Magnitude of PLL1 charge pump current (nA).
> + * @zero_delay_mode_internal_en: Internal, external Zero Delay mode selection.
> + * @osc_in_feedback_en: PLL1 feedback path, local feedback from
> + *			the OSC_IN receiver or zero delay mode
> + * @pll1_loop_filter_rzero: PLL1 Loop Filter Zero Resistor selection.
> + * @ref_mode: Reference selection mode.
> + * @pll2_charge_pump_current_nA: Magnitude of PLL2 charge pump current (nA).
> + * @pll2_ndiv_a_cnt: PLL2 Feedback N-divider, A Counter, range 0..4.
> + * @pll2_ndiv_b_cnt: PLL2 Feedback N-divider, B Counter, range 0..63.
> + * @pll2_freq_doubler_en: PLL2 frequency doubler enable.
> + * @pll2_r2_div: PLL2 R2 divider, range 0..31.
> + * @pll2_vco_diff_m1: VCO1 divider, range 3..5.
> + * @pll2_vco_diff_m2: VCO2 divider, range 3..5.
> + * @rpole2: PLL2 loop filter Rpole resistor value.
> + * @rzero: PLL2 loop filter Rzero resistor value.
> + * @cpole1: PLL2 loop filter Cpole capacitor value.
> + * @rzero_bypass_en: PLL2 loop filter Rzero bypass enable.
> + * @num_channels: Array size of struct ad9523_channel_spec.
> + * @channels: Pointer to channel array.
> + * @name: Optional alternative iio device name.
> + */
> +
> +struct ad9523_platform_data {
> +	unsigned long vcxo_freq;
> +
> +	/* Differential/ Single-Ended Input Configuration */
> +	bool				refa_diff_rcv_en;
> +	bool				refb_diff_rcv_en;
> +	bool				zd_in_diff_en;
> +	bool				osc_in_diff_en;
> +
> +	/*
> +	 * Valid if differential input disabled
> +	 * if false defaults to pos input
> +	 */
> +	bool				refa_cmos_neg_inp_en;
> +	bool				refb_cmos_neg_inp_en;
> +	bool				zd_in_cmos_neg_inp_en;
> +	bool				osc_in_cmos_neg_inp_en;
> +
> +	/* PLL1 Setting */
> +	unsigned short			refa_r_div;
> +	unsigned short			refb_r_div;
> +	unsigned short			pll1_feedback_div;
> +	unsigned short			pll1_charge_pump_current_nA;
> +	bool				zero_delay_mode_internal_en;
> +	bool				osc_in_feedback_en;
> +	enum pll1_rzero_resistor	pll1_loop_filter_rzero;
> +
> +	/* Reference */
> +	enum ref_sel_mode		ref_mode;
> +
> +	/* PLL2 Setting */
> +	unsigned int			pll2_charge_pump_current_nA;
> +	unsigned char			pll2_ndiv_a_cnt;
> +	unsigned char			pll2_ndiv_b_cnt;
> +	bool				pll2_freq_doubler_en;
> +	unsigned char			pll2_r2_div;
> +	unsigned char			pll2_vco_diff_m1; /* 3..5 */
> +	unsigned char			pll2_vco_diff_m2; /* 3..5 */
> +
> +	/* Loop Filter PLL2 */
> +	enum rpole2_resistor		rpole2;
> +	enum rzero_resistor		rzero;
> +	enum cpole1_capacitor		cpole1;
> +	bool				rzero_bypass_en;
> +
> +	/* Output Channel Configuration */
> +	int				num_channels;
> +	struct ad9523_channel_spec	*channels;
> +
> +	char				name[SPI_NAME_SIZE];
> +};
> +
> +#endif /* IIO_FREQUENCY_AD9523_H_ */