msm: demod_wrapper: Add driver for Demod wrapper block on mpq8092

Introduction

============

Demod wrapper is used for TV signals receptions and include several

hardware components as can be seen in the following scheme:

                                      +-------+               ++------------->

 Satellite                            |       |         TSIF  |   +-------+

 Tuner    +--------+       +----+     |UCCP330|+--------------+-->|TS-BRG |+->

 Signal-->| ADC0   ++----->|RXFE|+--->|Demod  |   +-------+       +-------+

          +--------+   ++->|IMG |     |       |+->|Resamp.|+--+

                       |   +----+     |       |   +-------+   +

                       |              +-------+               |

 ATV&DTV  +--------+   +                                      |

 Tuner -->| ADC1   |+--+                                      +  SIF+CVBS

 Signal   +--------+   +                                      +-------------->

                       |              +-------+               +  To Albacore

                       |              |       |               |

                       |   +----+     |FORZA  |               |

 External +--------+   ++->|RXFE|+--->|Demod  |   +-------+   +

 ATV   -->| ADC2   |+----->|ATV |+-+  |       |+->|Resamp.|+--+

 Receiver +--------+       +----+  +  |       |   +-------+   |

 Signal                            |  +-------+               +

                                   +--------------------------+

The driver controls and navigates Analog TV (atv) or Digital TV (dtv) signal

throughout the demod wrapper hardware components (Forza and UCCP330 are

not under the demod wrapper driver scope).

Demod wrapper driver configures the units under its responsibility.

The functionality of configuring the units should belong to a single driver

because this driver encapsulates all the knowledge and management needed for

such a complicated configuration.

Other drivers interacts with this driver in the following way:

* UCCP330 demod and Forza demod drivers use the demod wrapper driver as

  part of the demodulate operation.

* External receivers use the demod wrapper driver to filter their output

  signals.

* Topology driver uses the demod wrapper driver to configure the ts-bridge.

Hardware description

====================

The demod wrapper consists from the following hardware components:

- ADC - analog to digital convertor.

- RXFE components - filters signal.

- Resamplers for analog signals.

- TS bridge - navigates TSIF output.

- UCCP330 Demod - has a separate driver.

- Forza Demod - has a separate driver.

The demod wrapper driver sets all the clocks needed to activate the

components under its responsibility.

The dependency drivers will use deferred probing to ensure the correct

initialization order.

Software description

====================

The driver encapsulates the activation and configuration of the components

in the demod wrapper.

The paths of the signal that enters the demod wrapper are divided to

functional paths:

- Forza path - signal is navigated from ADC1 -> RXFE_ATV -> FORZA Demod ->

  Resample -> SIF+CVBS output

- UCCP330 Satellite path - signal is navigated from ADC0 -> RXFE_IMG ->

  TSIF output (may or may not pass the TS-BRIDGE)

- UCCP330 Terrestrial/Cable path - signal is navigated from ADC1 ->

  RXFE_IMG -> TSIF output (may or may not pass the TS-BRIDGE)

- external atv path - signal is navigated from ADC2 -> RXFE_ATV ->

  SIF+CVBS output

The user of the demod wrapper driver can activate the desired path.

The driver knows for each chosen functional path to configure its units

to allow the expected signal flow.

The only paths that can operate in parallel are:

* external atv path with UCCP330 Satellite path.

* external atv path with UCCP330 Terrestrial/Cable path.

All the other options are mutually exclusive: if one of those paths is

active, a set path request for the other will

override the previous path.

The driver is protected from concurrent requests by using a mutex.

Design

======

The demod wrapper driver is a regular Linux platform driver designed to support

the needed functionality of the HW components in demod wrapper block available

on specific SoCs.

Subsystem Restart (SSR)

=======================

The hardware IP does not have any firmware and therefore SSR support is not requried.

Interface

=========

The driver exposes an api to user space.

The driver creates device at /dev/demod_wrapper.

The api is:

- open

- close

- ioctl

	DEMOD_WRAPPER_SET_PATH - configures a signal path (used for all paths

	types except UCCP330 Satellite path)

	DEMOD_WRAPPER_SET_PATH_UCCP330_SAT - configures a signal path os type

	UCCP330 Satellite path

	DEMOD_WRAPPER_RELEASE_PATH - releases a specific path

	DEMOD_WRAPPER_TS_BRIDGE_INIT - initializes ts bridge

	DEMOD_WRAPPER_TS_BRIDGE_ENABLE - enables ts bridge

	DEMOD_WRAPPER_TS_BRIDGE_DISABLE - disables ts bridge

The ioctl functions use different structures, as described below:

demod_wrapper_path_type:

 - demod_wrapper_forza_atv

 - demod_wrapper_uccp330_dtv_s

 - demod_wrapper_uccp330_dtv_t_c

 - demod_wrapper_ext_atv

demod_wrapper_baud_rate:

 - demod_wrapper_narrow

 - demod_wrapper_medium

 - demod_wrapper_wide

demod_wrapper_ts_bridge:

 - demod_wrapper_ts_serial

 - demod_wrapper_ts_parallel

The driver exposes all the registers of the components in demod wrapper

via debugfs. You can find the registers in debugfs under demod_wrapper

directory.

Configuration Sequences

------------------------

Paths related call sequence :

1. set_path

2. release_path (optional)

Ts-bridge related call sequence:

1. bridge_init

2. bridge_enable

3. bridge_disable

Demod Wrapper - HW block in broadcast subsystem

The Demod wrapper block contains HW units that

are responsible for navigating and filtering an analog TV or

digital TV signal to integrated demodulators.

The driver supports the operation of those units and provides

a way to set and configure a desired signal path.

documentation: Documentation/arm/msm/demod_wrapper.txt.

The devicetree representation of the MSM_DEMOD_WRAPPER block should be:

Required properties:

- compatible: "qcom,msm-demod-wrapper"

- reg: physical memory base addresses and sizes for demod_wrapper.

- vdd-supply: power regulator (GDSC) supplying power to the broadcast subsystem.

- adc-supply: power regulator supplying power to adcs in the demod wrapper block.

Example :

	dw: msm-demod-wrapper@fc600000 {

		compatible = "qcom,msm-demod-wrapper";

		reg = <0xfc600000 0xdd000>;

		vdd-supply = <&gdsc_bcss>;

		adc-supply = <&pma8084_l27>;

	};

	CI: communication with the internal Conditional Access Module (CAM)

	over Common Interface (CI).

	This can also be compiled as a loadable module.

config DEMOD_WRAPPER

	depends on ARCH_MPQ8092

	tristate "Demod Wrapper (Part of broadcast HW block) Support"

	---help---

	The Demod wrapper block contains HW units that

	are responsible for navigating and filtering an analog TV or

	digital TV signal to integrated demodulators.

	The driver supports the operation of those units and provides

	a way to set and configure a desired signal path.

obj-$(CONFIG_CI_BRIDGE_SPI) += ci-bridge-spi.o

obj-$(CONFIG_TSC) += tsc.o

obj-$(CONFIG_ENSIGMA_UCCP_330) += ensigma_uccp330.o

obj-$(CONFIG_DEMOD_WRAPPER) += demod_wrapper.o