[media] media: i2c: max2175: Add MAX2175 support

This patch adds driver support for the MAX2175 chip. This is Maxim
Integrated's RF to Bits tuner front end chip designed for software-defined
radio solutions. This driver exposes the tuner as a sub-device instance
with standard and custom controls to configure the device.

Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/v4l-drivers/index.rst

@@ -42,6 +42,7 @@ For more details see the file COPYING in the source distribution of Linux.
 	davinci-vpbe
 	fimc
 	ivtv
+	max2175
 	meye
 	omap3isp
 	omap4_camera

Documentation/media/v4l-drivers/max2175.rst

@@ -0,0 +1,62 @@
+Maxim Integrated MAX2175 RF to bits tuner driver
+================================================
+
+The MAX2175 driver implements the following driver-specific controls:
+
+``V4L2_CID_MAX2175_I2S_ENABLE``
+-------------------------------
+    Enable/Disable I2S output of the tuner. This is a private control
+    that can be accessed only using the subdev interface.
+    Refer to Documentation/media/kapi/v4l2-controls for more details.
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 4
+
+    * - ``(0)``
+      - I2S output is disabled.
+    * - ``(1)``
+      - I2S output is enabled.
+
+``V4L2_CID_MAX2175_HSLS``
+-------------------------
+    The high-side/low-side (HSLS) control of the tuner for a given band.
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 4
+
+    * - ``(0)``
+      - The LO frequency position is below the desired frequency.
+    * - ``(1)``
+      - The LO frequency position is above the desired frequency.
+
+``V4L2_CID_MAX2175_RX_MODE (menu)``
+-----------------------------------
+    The Rx mode controls a number of preset parameters of the tuner like
+    sample clock (sck), sampling rate etc. These multiple settings are
+    provided under one single label called Rx mode in the datasheet. The
+    list below shows the supported modes with a brief description.
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 4
+
+    * - ``"Europe modes"``
+    * - ``"FM 1.2" (0)``
+      - This configures FM band with a sample rate of 0.512 million
+        samples/sec with a 10.24 MHz sck.
+    * - ``"DAB 1.2" (1)``
+      - This configures VHF band with a sample rate of 2.048 million
+        samples/sec with a 32.768 MHz sck.
+
+    * - ``"North America modes"``
+    * - ``"FM 1.0" (0)``
+      - This configures FM band with a sample rate of 0.7441875 million
+        samples/sec with a 14.88375 MHz sck.
+    * - ``"DAB 1.2" (1)``
+      - This configures FM band with a sample rate of 0.372 million
+        samples/sec with a 7.441875 MHz sck.

drivers/media/i2c/Kconfig

@@ -796,6 +796,18 @@ config VIDEO_SAA6752HS
 	  To compile this driver as a module, choose M here: the
 	  module will be called saa6752hs.
 
+comment "SDR tuner chips"
+
+config SDR_MAX2175
+	tristate "Maxim 2175 RF to Bits tuner"
+	depends on VIDEO_V4L2 && MEDIA_SDR_SUPPORT && I2C
+	---help---
+	  Support for Maxim 2175 tuner. It is an advanced analog/digital
+	  radio receiver with RF-to-Bits front-end designed for SDR solutions.
+
+	  To compile this driver as a module, choose M here; the
+	  module will be called max2175.
+
 comment "Miscellaneous helper chips"
 
 config VIDEO_THS7303

drivers/media/i2c/Makefile

@@ -86,3 +86,5 @@ obj-$(CONFIG_VIDEO_IR_I2C)  += ir-kbd-i2c.o
 obj-$(CONFIG_VIDEO_ML86V7667)	+= ml86v7667.o
 obj-$(CONFIG_VIDEO_OV2659)	+= ov2659.o
 obj-$(CONFIG_VIDEO_TC358743)	+= tc358743.o
+
+obj-$(CONFIG_SDR_MAX2175) += max2175.o

drivers/media/i2c/max2175.h

@@ -0,0 +1,109 @@
+/*
+ * Maxim Integrated MAX2175 RF to Bits tuner driver
+ *
+ * This driver & most of the hard coded values are based on the reference
+ * application delivered by Maxim for this device.
+ *
+ * Copyright (C) 2016 Maxim Integrated Products
+ * Copyright (C) 2017 Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __MAX2175_H__
+#define __MAX2175_H__
+
+#define MAX2175_EU_XTAL_FREQ	36864000	/* In Hz */
+#define MAX2175_NA_XTAL_FREQ	40186125	/* In Hz */
+
+enum max2175_region {
+	MAX2175_REGION_EU = 0,	/* Europe */
+	MAX2175_REGION_NA,	/* North America */
+};
+
+enum max2175_band {
+	MAX2175_BAND_AM = 0,
+	MAX2175_BAND_FM,
+	MAX2175_BAND_VHF,
+	MAX2175_BAND_L,
+};
+
+enum max2175_eu_mode {
+	/* EU modes */
+	MAX2175_EU_FM_1_2 = 0,
+	MAX2175_DAB_1_2,
+
+	/*
+	 * Other possible modes to add in future
+	 * MAX2175_DAB_1_0,
+	 * MAX2175_DAB_1_3,
+	 * MAX2175_EU_FM_2_2,
+	 * MAX2175_EU_FMHD_4_0,
+	 * MAX2175_EU_AM_1_0,
+	 * MAX2175_EU_AM_2_2,
+	 */
+};
+
+enum max2175_na_mode {
+	/* NA modes */
+	MAX2175_NA_FM_1_0 = 0,
+	MAX2175_NA_FM_2_0,
+
+	/*
+	 * Other possible modes to add in future
+	 * MAX2175_NA_FMHD_1_0,
+	 * MAX2175_NA_FMHD_1_2,
+	 * MAX2175_NA_AM_1_0,
+	 * MAX2175_NA_AM_1_2,
+	 */
+};
+
+/* Supported I2S modes */
+enum {
+	MAX2175_I2S_MODE0 = 0,
+	MAX2175_I2S_MODE1,
+	MAX2175_I2S_MODE2,
+	MAX2175_I2S_MODE3,
+	MAX2175_I2S_MODE4,
+};
+
+/* Coefficient table groups */
+enum {
+	MAX2175_CH_MSEL = 0,
+	MAX2175_EQ_MSEL,
+	MAX2175_AA_MSEL,
+};
+
+/* HSLS LO injection polarity */
+enum {
+	MAX2175_LO_BELOW_DESIRED = 0,
+	MAX2175_LO_ABOVE_DESIRED,
+};
+
+/* Channel FSM modes */
+enum max2175_csm_mode {
+	MAX2175_LOAD_TO_BUFFER = 0,
+	MAX2175_PRESET_TUNE,
+	MAX2175_SEARCH,
+	MAX2175_AF_UPDATE,
+	MAX2175_JUMP_FAST_TUNE,
+	MAX2175_CHECK,
+	MAX2175_LOAD_AND_SWAP,
+	MAX2175_END,
+	MAX2175_BUFFER_PLUS_PRESET_TUNE,
+	MAX2175_BUFFER_PLUS_SEARCH,
+	MAX2175_BUFFER_PLUS_AF_UPDATE,
+	MAX2175_BUFFER_PLUS_JUMP_FAST_TUNE,
+	MAX2175_BUFFER_PLUS_CHECK,
+	MAX2175_BUFFER_PLUS_LOAD_AND_SWAP,
+	MAX2175_NO_ACTION
+};
+
+#endif /* __MAX2175_H__ */

include/uapi/linux/max2175.h

@@ -0,0 +1,28 @@
+/*
+ * max2175.h
+ *
+ * Maxim Integrated MAX2175 RF to Bits tuner driver - user space header file.
+ *
+ * Copyright (C) 2016 Maxim Integrated Products
+ * Copyright (C) 2017 Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __UAPI_MAX2175_H_
+#define __UAPI_MAX2175_H_
+
+#include <linux/v4l2-controls.h>
+
+#define V4L2_CID_MAX2175_I2S_ENABLE	(V4L2_CID_USER_MAX217X_BASE + 0x01)
+#define V4L2_CID_MAX2175_HSLS		(V4L2_CID_USER_MAX217X_BASE + 0x02)
+#define V4L2_CID_MAX2175_RX_MODE	(V4L2_CID_USER_MAX217X_BASE + 0x03)
+
+#endif /* __UAPI_MAX2175_H_ */