Contributors: 2
Author Tokens Token Proportion Commits Commit Proportion
Herve Codina 3884 99.95% 1 50.00%
Uwe Kleine-König 2 0.05% 1 50.00%
Total 3886 2 


// SPDX-License-Identifier: GPL-2.0
/*
 * PEF2256 also known as FALC56 driver
 *
 * Copyright 2023 CS GROUP France
 *
 * Author: Herve Codina <herve.codina@bootlin.com>
 */

#include <linux/framer/pef2256.h>
#include <linux/clk.h>
#include <linux/framer/framer-provider.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include "pef2256-regs.h"

enum pef2256_frame_type {
	PEF2256_FRAME_E1_DOUBLEFRAME,
	PEF2256_FRAME_E1_CRC4_MULTIFRAME,
	PEF2256_FRAME_E1_AUTO_MULTIFRAME,
	PEF2256_FRAME_T1J1_4FRAME,
	PEF2256_FRAME_T1J1_12FRAME,
	PEF2256_FRAME_T1J1_24FRAME,
	PEF2256_FRAME_T1J1_72FRAME,
};

struct pef2256 {
	struct device *dev;
	struct regmap *regmap;
	enum pef2256_version version;
	struct clk *mclk;
	struct clk *sclkr;
	struct clk *sclkx;
	struct gpio_desc *reset_gpio;
	unsigned long sysclk_rate;
	u32 data_rate;
	bool is_tx_falling_edge;
	bool is_subordinate;
	enum pef2256_frame_type frame_type;
	u8 channel_phase;
	atomic_t carrier;
	struct framer *framer;
};

static u8 pef2256_read8(struct pef2256 *pef2256, int offset)
{
	int val;

	regmap_read(pef2256->regmap, offset, &val);
	return val;
}

static void pef2256_write8(struct pef2256 *pef2256, int offset, u8 val)
{
	regmap_write(pef2256->regmap, offset, val);
}

static void pef2256_clrbits8(struct pef2256 *pef2256, int offset, u8 clr)
{
	regmap_clear_bits(pef2256->regmap, offset, clr);
}

static void pef2256_setbits8(struct pef2256 *pef2256, int offset, u8 set)
{
	regmap_set_bits(pef2256->regmap, offset, set);
}

static void pef2256_clrsetbits8(struct pef2256 *pef2256, int offset, u8 clr, u8 set)
{
	regmap_update_bits(pef2256->regmap, offset, clr | set, set);
}

enum pef2256_version pef2256_get_version(struct pef2256 *pef2256)
{
	enum pef2256_version version = PEF2256_VERSION_UNKNOWN;
	u8 vstr, wid;

	vstr = pef2256_read8(pef2256, PEF2256_VSTR);
	wid = pef2256_read8(pef2256, PEF2256_WID);

	switch (vstr) {
	case PEF2256_VSTR_VERSION_12:
		if ((wid & PEF2256_12_WID_MASK) == PEF2256_12_WID_VERSION_12)
			version = PEF2256_VERSION_1_2;
		break;
	case PEF2256_VSTR_VERSION_2x:
		switch (wid & PEF2256_2X_WID_MASK) {
		case PEF2256_2X_WID_VERSION_21:
			version = PEF2256_VERSION_2_1;
			break;
		case PEF2256_2X_WID_VERSION_22:
			version = PEF2256_VERSION_2_2;
			break;
		}
		break;
	case PEF2256_VSTR_VERSION_21:
		version = PEF2256_VERSION_2_1;
		break;
	}

	if (version == PEF2256_VERSION_UNKNOWN)
		dev_err(pef2256->dev, "Unknown version (0x%02x, 0x%02x)\n", vstr, wid);

	return version;
}
EXPORT_SYMBOL_GPL(pef2256_get_version);

enum pef2256_gcm_config_item {
	PEF2256_GCM_CONFIG_1544000 = 0,
	PEF2256_GCM_CONFIG_2048000,
	PEF2256_GCM_CONFIG_8192000,
	PEF2256_GCM_CONFIG_10000000,
	PEF2256_GCM_CONFIG_12352000,
	PEF2256_GCM_CONFIG_16384000,
};

struct pef2256_gcm_config {
	u8 gcm_12[6];
	u8 gcm_2x[8];
};

static const struct pef2256_gcm_config pef2256_gcm_configs[] = {
	[PEF2256_GCM_CONFIG_1544000] = {
		.gcm_12 = {0xF0, 0x51, 0x00, 0x80, 0x00, 0x15},
		.gcm_2x = {0x00, 0x15, 0x00, 0x08, 0x00, 0x3F, 0x9C, 0xDF},
	},
	[PEF2256_GCM_CONFIG_2048000] = {
		.gcm_12 = {0x00, 0x58, 0xD2, 0xC2, 0x00, 0x10},
		.gcm_2x = {0x00, 0x18, 0xFB, 0x0B, 0x00, 0x2F, 0xDB, 0xDF},
	},
	[PEF2256_GCM_CONFIG_8192000] = {
		.gcm_12 = {0x00, 0x58, 0xD2, 0xC2, 0x03, 0x10},
		.gcm_2x = {0x00, 0x18, 0xFB, 0x0B, 0x00, 0x0B, 0xDB, 0xDF},
	},
	[PEF2256_GCM_CONFIG_10000000] = {
		.gcm_12 = {0x90, 0x51, 0x81, 0x8F, 0x04, 0x10},
		.gcm_2x = {0x40, 0x1B, 0x3D, 0x0A, 0x00, 0x07, 0xC9, 0xDC},
	},
	[PEF2256_GCM_CONFIG_12352000] = {
		.gcm_12 = {0xF0, 0x51, 0x00, 0x80, 0x07, 0x15},
		.gcm_2x = {0x00, 0x19, 0x00, 0x08, 0x01, 0x0A, 0x98, 0xDA},
	},
	[PEF2256_GCM_CONFIG_16384000] = {
		.gcm_12 = {0x00, 0x58, 0xD2, 0xC2, 0x07, 0x10},
		.gcm_2x = {0x00, 0x18, 0xFB, 0x0B, 0x01, 0x0B, 0xDB, 0xDF},
	},
};

static int pef2256_setup_gcm(struct pef2256 *pef2256)
{
	enum pef2256_gcm_config_item item;
	unsigned long mclk_rate;
	const u8 *gcm;
	int i, count;

	mclk_rate = clk_get_rate(pef2256->mclk);
	switch (mclk_rate) {
	case 1544000:
		item = PEF2256_GCM_CONFIG_1544000;
		break;
	case 2048000:
		item = PEF2256_GCM_CONFIG_2048000;
		break;
	case 8192000:
		item = PEF2256_GCM_CONFIG_8192000;
		break;
	case 10000000:
		item = PEF2256_GCM_CONFIG_10000000;
		break;
	case 12352000:
		item = PEF2256_GCM_CONFIG_12352000;
		break;
	case 16384000:
		item = PEF2256_GCM_CONFIG_16384000;
		break;
	default:
		dev_err(pef2256->dev, "Unsupported v2.x MCLK rate %lu\n", mclk_rate);
		return -EINVAL;
	}

	BUILD_BUG_ON(item >= ARRAY_SIZE(pef2256_gcm_configs));

	if (pef2256->version == PEF2256_VERSION_1_2) {
		gcm = pef2256_gcm_configs[item].gcm_12;
		count = ARRAY_SIZE(pef2256_gcm_configs[item].gcm_12);
	} else {
		gcm = pef2256_gcm_configs[item].gcm_2x;
		count = ARRAY_SIZE(pef2256_gcm_configs[item].gcm_2x);
	}

	for (i = 0; i < count; i++)
		pef2256_write8(pef2256, PEF2256_GCM(i + 1), *(gcm + i));

	return 0;
}

static int pef2256_setup_e1_line(struct pef2256 *pef2256)
{
	u8 fmr1, fmr2;

	/* RCLK output : DPLL clock, DCO-X enabled, DCO-X internal ref clock */
	pef2256_write8(pef2256, PEF2256_CMR1, 0x00);

	/* SCLKR selected, SCLKX selected,
	 * receive synchro pulse sourced by SYPR,
	 * transmit synchro pulse sourced by SYPX,
	 * DCO-X center frequency enabled
	 */
	pef2256_write8(pef2256, PEF2256_CMR2, PEF2256_CMR2_DCOXC);

	if (pef2256->is_subordinate) {
		/* select RCLK source = 2M,  disable switching from RCLK to SYNC */
		pef2256_clrsetbits8(pef2256, PEF2256_CMR1, PEF2256_CMR1_RS_MASK,
				    PEF2256_CMR1_RS_DCOR_2048 | PEF2256_CMR1_DCS);
	}

	/* slave mode, local loop off, mode short-haul
	 * In v2.x, bit3 is a forced 1 bit in the datasheet -> Need to be set.
	 */
	if (pef2256->version == PEF2256_VERSION_1_2)
		pef2256_write8(pef2256, PEF2256_LIM0, 0x00);
	else
		pef2256_write8(pef2256, PEF2256_LIM0, PEF2256_2X_LIM0_BIT3);

	/* "master" mode */
	if (!pef2256->is_subordinate)
		pef2256_setbits8(pef2256, PEF2256_LIM0, PEF2256_LIM0_MAS);

	/* analog interface selected, remote loop off */
	pef2256_write8(pef2256, PEF2256_LIM1, 0x00);

	/* receive input threshold = 0,21V */
	if (pef2256->version == PEF2256_VERSION_1_2)
		pef2256_clrsetbits8(pef2256, PEF2256_LIM1, PEF2256_12_LIM1_RIL_MASK,
				    PEF2256_12_LIM1_RIL_210);
	else
		pef2256_clrsetbits8(pef2256, PEF2256_LIM1, PEF2256_2X_LIM1_RIL_MASK,
				    PEF2256_2X_LIM1_RIL_210);

	/* transmit pulse mask, default value from datasheet
	 * transmit line in normal operation
	 */
	if (pef2256->version == PEF2256_VERSION_1_2)
		pef2256_write8(pef2256, PEF2256_XPM0, 0x7B);
	else
		pef2256_write8(pef2256, PEF2256_XPM0, 0x9C);
	pef2256_write8(pef2256, PEF2256_XPM1, 0x03);
	pef2256_write8(pef2256, PEF2256_XPM2, 0x00);

	/* HDB3 coding, no alarm simulation */
	pef2256_write8(pef2256, PEF2256_FMR0, PEF2256_FMR0_XC_HDB3 | PEF2256_FMR0_RC_HDB3);

	/* E1, frame format, 2 Mbit/s system data rate, no AIS
	 * transmission to remote end or system interface, payload loop
	 * off, transmit remote alarm on
	 */
	fmr1 = 0x00;
	fmr2 = PEF2256_FMR2_AXRA;
	switch (pef2256->frame_type) {
	case PEF2256_FRAME_E1_DOUBLEFRAME:
		fmr2 |= PEF2256_FMR2_RFS_DOUBLEFRAME;
		break;
	case PEF2256_FRAME_E1_CRC4_MULTIFRAME:
		fmr1 |= PEF2256_FMR1_XFS;
		fmr2 |= PEF2256_FMR2_RFS_CRC4_MULTIFRAME;
		break;
	case PEF2256_FRAME_E1_AUTO_MULTIFRAME:
		fmr1 |= PEF2256_FMR1_XFS;
		fmr2 |= PEF2256_FMR2_RFS_AUTO_MULTIFRAME;
		break;
	default:
		dev_err(pef2256->dev, "Unsupported frame type %d\n", pef2256->frame_type);
		return -EINVAL;
	}
	pef2256_clrsetbits8(pef2256, PEF2256_FMR1, PEF2256_FMR1_XFS, fmr1);
	pef2256_write8(pef2256, PEF2256_FMR2, fmr2);

	if (!pef2256->is_subordinate) {
		/* SEC input, active high */
		pef2256_write8(pef2256, PEF2256_GPC1, PEF2256_GPC1_CSFP_SEC_IN_HIGH);
	} else {
		/* FSC output, active high */
		pef2256_write8(pef2256, PEF2256_GPC1, PEF2256_GPC1_CSFP_FSC_OUT_HIGH);
	}

	/* SCLKR, SCLKX, RCLK configured to inputs,
	 * XFMS active low, CLK1 and CLK2 pin configuration
	 */
	pef2256_write8(pef2256, PEF2256_PC5, 0x00);
	pef2256_write8(pef2256, PEF2256_PC6, 0x00);

	/* port RCLK is output */
	pef2256_setbits8(pef2256, PEF2256_PC5, PEF2256_PC5_CRP);

	return 0;
}

static void pef2256_setup_e1_los(struct pef2256 *pef2256)
{
	/* detection of LOS alarm = 176 pulses (ie (10 + 1) * 16) */
	pef2256_write8(pef2256, PEF2256_PCD, 10);
	/* recovery of LOS alarm = 22 pulses (ie 21 + 1) */
	pef2256_write8(pef2256, PEF2256_PCR, 21);
	/* E1 default for the receive slicer threshold */
	pef2256_write8(pef2256, PEF2256_LIM2, PEF2256_LIM2_SLT_THR50);
	if (pef2256->is_subordinate) {
		/* Loop-timed */
		pef2256_setbits8(pef2256, PEF2256_LIM2, PEF2256_LIM2_ELT);
	}
}

static int pef2256_setup_e1_system(struct pef2256 *pef2256)
{
	u8 sic1, fmr1;

	/* 2.048 MHz system clocking rate, receive buffer 2 frames, transmit
	 * buffer bypass, data sampled and transmitted on the falling edge of
	 * SCLKR/X, automatic freeze signaling, data is active in the first
	 * channel phase
	 */
	pef2256_write8(pef2256, PEF2256_SIC1, 0x00);
	pef2256_write8(pef2256, PEF2256_SIC2, 0x00);
	pef2256_write8(pef2256, PEF2256_SIC3, 0x00);

	if (pef2256->is_subordinate) {
		/* transmit buffer size = 2 frames, transparent mode */
		pef2256_clrsetbits8(pef2256, PEF2256_SIC1, PEF2256_SIC1_XBS_MASK,
				    PEF2256_SIC1_XBS_2FRAMES);
	}

	if (pef2256->version != PEF2256_VERSION_1_2) {
		/* during inactive channel phase switch RDO/RSIG into tri-state */
		pef2256_setbits8(pef2256, PEF2256_SIC3, PEF2256_SIC3_RTRI);
	}

	if (pef2256->is_tx_falling_edge) {
		/* falling edge sync pulse transmit, rising edge sync pulse receive */
		pef2256_clrsetbits8(pef2256, PEF2256_SIC3, PEF2256_SIC3_RESX, PEF2256_SIC3_RESR);
	} else {
		/* rising edge sync pulse transmit, falling edge sync pulse receive */
		pef2256_clrsetbits8(pef2256, PEF2256_SIC3, PEF2256_SIC3_RESR, PEF2256_SIC3_RESX);
	}

	/* transmit offset counter (XCO10..0) = 4 */
	pef2256_write8(pef2256, PEF2256_XC0, 0);
	pef2256_write8(pef2256, PEF2256_XC1, 4);
	/* receive offset counter (RCO10..0) = 4 */
	pef2256_write8(pef2256, PEF2256_RC0, 0);
	pef2256_write8(pef2256, PEF2256_RC1, 4);

	/* system clock rate */
	switch (pef2256->sysclk_rate) {
	case 2048000:
		sic1 = PEF2256_SIC1_SSC_2048;
		break;
	case 4096000:
		sic1 = PEF2256_SIC1_SSC_4096;
		break;
	case 8192000:
		sic1 = PEF2256_SIC1_SSC_8192;
		break;
	case 16384000:
		sic1 = PEF2256_SIC1_SSC_16384;
		break;
	default:
		dev_err(pef2256->dev, "Unsupported sysclk rate %lu\n", pef2256->sysclk_rate);
		return -EINVAL;
	}
	pef2256_clrsetbits8(pef2256, PEF2256_SIC1, PEF2256_SIC1_SSC_MASK, sic1);

	/* data clock rate */
	switch (pef2256->data_rate) {
	case 2048000:
		fmr1 = PEF2256_FMR1_SSD_2048;
		sic1 = PEF2256_SIC1_SSD_2048;
		break;
	case 4096000:
		fmr1 = PEF2256_FMR1_SSD_4096;
		sic1 = PEF2256_SIC1_SSD_4096;
		break;
	case 8192000:
		fmr1 = PEF2256_FMR1_SSD_8192;
		sic1 = PEF2256_SIC1_SSD_8192;
		break;
	case 16384000:
		fmr1 = PEF2256_FMR1_SSD_16384;
		sic1 = PEF2256_SIC1_SSD_16384;
		break;
	default:
		dev_err(pef2256->dev, "Unsupported data rate %u\n", pef2256->data_rate);
		return -EINVAL;
	}
	pef2256_clrsetbits8(pef2256, PEF2256_FMR1, PEF2256_FMR1_SSD_MASK, fmr1);
	pef2256_clrsetbits8(pef2256, PEF2256_SIC1, PEF2256_SIC1_SSD_MASK, sic1);

	/* channel phase */
	pef2256_clrsetbits8(pef2256, PEF2256_SIC2, PEF2256_SIC2_SICS_MASK,
			    PEF2256_SIC2_SICS(pef2256->channel_phase));

	return 0;
}

static void pef2256_setup_e1_signaling(struct pef2256 *pef2256)
{
	/* All bits of the transmitted service word are cleared */
	pef2256_write8(pef2256, PEF2256_XSW, PEF2256_XSW_XY(0x1F));

	/* CAS disabled and clear spare bit values */
	pef2256_write8(pef2256, PEF2256_XSP, 0x00);

	if (pef2256->is_subordinate) {
		/* transparent mode */
		pef2256_setbits8(pef2256, PEF2256_XSW, PEF2256_XSW_XTM);
	}

	/* Si-Bit, Spare bit For International, FAS word */
	pef2256_setbits8(pef2256, PEF2256_XSW, PEF2256_XSW_XSIS);
	pef2256_setbits8(pef2256, PEF2256_XSP, PEF2256_XSP_XSIF);

	/* no transparent mode active */
	pef2256_write8(pef2256, PEF2256_TSWM, 0x00);
}

static void pef2256_setup_e1_errors(struct pef2256 *pef2256)
{
	/* error counter latched every 1s */
	pef2256_setbits8(pef2256, PEF2256_FMR1, PEF2256_FMR1_ECM);

	/* error counter mode COFA */
	pef2256_setbits8(pef2256, PEF2256_GCR, PEF2256_GCR_ECMC);

	/* errors in service words have no influence */
	pef2256_setbits8(pef2256, PEF2256_RC0, PEF2256_RC0_SWD);

	/* 4 consecutive incorrect FAS causes loss of sync */
	pef2256_setbits8(pef2256, PEF2256_RC0, PEF2256_RC0_ASY4);
}

static int pef2256_setup_e1(struct pef2256 *pef2256)
{
	int ret;

	/* Setup, Master clocking mode (GCM8..1) */
	ret = pef2256_setup_gcm(pef2256);
	if (ret)
		return ret;

	/* Select E1 mode */
	pef2256_write8(pef2256, PEF2256_FMR1, 0x00);

	/* internal second timer, power on */
	pef2256_write8(pef2256, PEF2256_GCR, 0x00);

	/* Setup line interface */
	ret = pef2256_setup_e1_line(pef2256);
	if (ret)
		return ret;

	/* Setup Loss-of-signal detection and recovery */
	pef2256_setup_e1_los(pef2256);

	/* Setup system interface */
	ret = pef2256_setup_e1_system(pef2256);
	if (ret)
		return ret;

	/* Setup signaling */
	pef2256_setup_e1_signaling(pef2256);

	/* Setup errors counters and condition */
	pef2256_setup_e1_errors(pef2256);

	/* status changed interrupt at both up and down */
	pef2256_setbits8(pef2256, PEF2256_GCR, PEF2256_GCR_SCI);

	/* Clear any ISR2 pending interrupts and unmask needed interrupts */
	pef2256_read8(pef2256, PEF2256_ISR2);
	pef2256_clrbits8(pef2256, PEF2256_IMR2, PEF2256_INT2_LOS | PEF2256_INT2_AIS);

	/* reset lines */
	pef2256_write8(pef2256, PEF2256_CMDR, PEF2256_CMDR_RRES | PEF2256_CMDR_XRES);
	return 0;
}

static void pef2256_isr_default_handler(struct pef2256 *pef2256, u8 nbr, u8 isr)
{
	dev_warn_ratelimited(pef2256->dev, "ISR%u: 0x%02x not handled\n", nbr, isr);
}

static bool pef2256_is_carrier_on(struct pef2256 *pef2256)
{
	u8 frs0;

	frs0 = pef2256_read8(pef2256, PEF2256_FRS0);
	return !(frs0 & (PEF2256_FRS0_LOS | PEF2256_FRS0_AIS));
}

static void pef2256_isr2_handler(struct pef2256 *pef2256, u8 nbr, u8 isr)
{
	bool carrier;

	if (isr & (PEF2256_INT2_LOS | PEF2256_INT2_AIS)) {
		carrier = pef2256_is_carrier_on(pef2256);
		if (atomic_xchg(&pef2256->carrier, carrier) != carrier)
			framer_notify_status_change(pef2256->framer);
	}
}

static irqreturn_t pef2256_irq_handler(int irq, void *priv)
{
	static void (*pef2256_isr_handler[])(struct pef2256 *, u8, u8) = {
		[0] = pef2256_isr_default_handler,
		[1] = pef2256_isr_default_handler,
		[2] = pef2256_isr2_handler,
		[3] = pef2256_isr_default_handler,
		[4] = pef2256_isr_default_handler,
		[5] = pef2256_isr_default_handler
	};
	struct pef2256 *pef2256 = (struct pef2256 *)priv;
	u8 gis;
	u8 isr;
	u8 n;

	gis = pef2256_read8(pef2256, PEF2256_GIS);

	for (n = 0; n < ARRAY_SIZE(pef2256_isr_handler); n++) {
		if (gis & PEF2256_GIS_ISR(n)) {
			isr = pef2256_read8(pef2256, PEF2256_ISR(n));
			pef2256_isr_handler[n](pef2256, n, isr);
		}
	}

	return IRQ_HANDLED;
}

static int pef2256_check_rates(struct pef2256 *pef2256, unsigned long sysclk_rate,
			       unsigned long data_rate)
{
	unsigned long rate;

	switch (sysclk_rate) {
	case 2048000:
	case 4096000:
	case 8192000:
	case 16384000:
		break;
	default:
		dev_err(pef2256->dev, "Unsupported system clock rate %lu\n", sysclk_rate);
		return -EINVAL;
	}

	for (rate = data_rate; rate <= data_rate * 4; rate *= 2) {
		if (rate == sysclk_rate)
			return 0;
	}
	dev_err(pef2256->dev, "Unsupported data rate %lu with system clock rate %lu\n",
		data_rate, sysclk_rate);
	return -EINVAL;
}

static int pef2556_of_parse(struct pef2256 *pef2256, struct device_node *np)
{
	int ret;

	pef2256->data_rate = 2048000;
	ret = of_property_read_u32(np, "lantiq,data-rate-bps", &pef2256->data_rate);
	if (ret && ret != -EINVAL) {
		dev_err(pef2256->dev, "%pOF: failed to read lantiq,data-rate-bps\n", np);
		return ret;
	}

	ret =  pef2256_check_rates(pef2256, pef2256->sysclk_rate, pef2256->data_rate);
	if (ret)
		return ret;

	pef2256->is_tx_falling_edge = of_property_read_bool(np, "lantiq,clock-falling-edge");

	pef2256->channel_phase = 0;
	ret = of_property_read_u8(np, "lantiq,channel-phase", &pef2256->channel_phase);
	if (ret && ret != -EINVAL) {
		dev_err(pef2256->dev, "%pOF: failed to read lantiq,channel-phase\n",
			np);
		return ret;
	}
	if (pef2256->channel_phase >= pef2256->sysclk_rate / pef2256->data_rate) {
		dev_err(pef2256->dev, "%pOF: Invalid lantiq,channel-phase %u\n",
			np, pef2256->channel_phase);
		return -EINVAL;
	}

	return 0;
}

static const struct regmap_config pef2256_regmap_config = {
	.reg_bits = 32,
	.val_bits = 8,
	.max_register = 0xff,
};

static const struct mfd_cell pef2256_devs[] = {
	{ .name = "lantiq-pef2256-pinctrl", },
};

static int pef2256_add_audio_devices(struct pef2256 *pef2256)
{
	const char *compatible = "lantiq,pef2256-codec";
	struct mfd_cell *audio_devs;
	struct device_node *np;
	unsigned int count = 0;
	unsigned int i;
	int ret;

	for_each_available_child_of_node(pef2256->dev->of_node, np) {
		if (of_device_is_compatible(np, compatible))
			count++;
	}

	if (!count)
		return 0;

	audio_devs = kcalloc(count, sizeof(*audio_devs), GFP_KERNEL);
	if (!audio_devs)
		return -ENOMEM;

	for (i = 0; i < count; i++) {
		audio_devs[i].name = "framer-codec";
		audio_devs[i].of_compatible = compatible;
		audio_devs[i].id = i;
	}

	ret = mfd_add_devices(pef2256->dev, 0, audio_devs, count, NULL, 0, NULL);
	kfree(audio_devs);
	return ret;
}

static int pef2256_framer_get_status(struct framer *framer, struct framer_status *status)
{
	struct pef2256 *pef2256 = framer_get_drvdata(framer);

	status->link_is_on = !!atomic_read(&pef2256->carrier);
	return 0;
}

static int pef2256_framer_set_config(struct framer *framer, const struct framer_config *config)
{
	struct pef2256 *pef2256 = framer_get_drvdata(framer);

	if (config->iface != FRAMER_IFACE_E1) {
		dev_err(pef2256->dev, "Only E1 line is currently supported\n");
		return -EOPNOTSUPP;
	}

	switch (config->clock_type) {
	case FRAMER_CLOCK_EXT:
		pef2256->is_subordinate = true;
		break;
	case FRAMER_CLOCK_INT:
		pef2256->is_subordinate = false;
		break;
	default:
		return -EINVAL;
	}

	/* Apply the new settings */
	return pef2256_setup_e1(pef2256);
}

static int pef2256_framer_get_config(struct framer *framer, struct framer_config *config)
{
	struct pef2256 *pef2256 = framer_get_drvdata(framer);

	config->iface = FRAMER_IFACE_E1;
	config->clock_type = pef2256->is_subordinate ? FRAMER_CLOCK_EXT : FRAMER_CLOCK_INT;
	config->line_clock_rate = 2048000;
	return 0;
}

static const struct framer_ops pef2256_framer_ops = {
	.owner = THIS_MODULE,
	.get_status = pef2256_framer_get_status,
	.get_config = pef2256_framer_get_config,
	.set_config = pef2256_framer_set_config,
};

static int pef2256_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	unsigned long sclkr_rate, sclkx_rate;
	struct framer_provider *framer_provider;
	struct pef2256 *pef2256;
	const char *version_txt;
	void __iomem *iomem;
	int ret;
	int irq;

	pef2256 = devm_kzalloc(&pdev->dev, sizeof(*pef2256), GFP_KERNEL);
	if (!pef2256)
		return -ENOMEM;

	pef2256->dev = &pdev->dev;
	atomic_set(&pef2256->carrier, 0);

	pef2256->is_subordinate = true;
	pef2256->frame_type = PEF2256_FRAME_E1_DOUBLEFRAME;

	iomem = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(iomem))
		return PTR_ERR(iomem);

	pef2256->regmap = devm_regmap_init_mmio(&pdev->dev, iomem,
						&pef2256_regmap_config);
	if (IS_ERR(pef2256->regmap)) {
		dev_err(&pdev->dev, "Failed to initialise Regmap (%ld)\n",
			PTR_ERR(pef2256->regmap));
		return PTR_ERR(pef2256->regmap);
	}

	pef2256->mclk = devm_clk_get_enabled(&pdev->dev, "mclk");
	if (IS_ERR(pef2256->mclk))
		return PTR_ERR(pef2256->mclk);

	pef2256->sclkr = devm_clk_get_enabled(&pdev->dev, "sclkr");
	if (IS_ERR(pef2256->sclkr))
		return PTR_ERR(pef2256->sclkr);

	pef2256->sclkx = devm_clk_get_enabled(&pdev->dev, "sclkx");
	if (IS_ERR(pef2256->sclkx))
		return PTR_ERR(pef2256->sclkx);

	/* Both SCLKR (receive) and SCLKX (transmit) must have the same rate,
	 * stored as sysclk_rate.
	 * The exact value will be checked at pef2256_check_rates()
	 */
	sclkr_rate = clk_get_rate(pef2256->sclkr);
	sclkx_rate = clk_get_rate(pef2256->sclkx);
	if (sclkr_rate != sclkx_rate) {
		dev_err(pef2256->dev, "clk rate mismatch. sclkr %lu Hz, sclkx %lu Hz\n",
			sclkr_rate, sclkx_rate);
		return -EINVAL;
	}
	pef2256->sysclk_rate = sclkr_rate;

	/* Reset the component. The MCLK clock must be active during reset */
	pef2256->reset_gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
	if (IS_ERR(pef2256->reset_gpio))
		return PTR_ERR(pef2256->reset_gpio);
	if (pef2256->reset_gpio) {
		gpiod_set_value_cansleep(pef2256->reset_gpio, 1);
		usleep_range(10, 20);
		gpiod_set_value_cansleep(pef2256->reset_gpio, 0);
		usleep_range(10, 20);
	}

	pef2256->version = pef2256_get_version(pef2256);
	switch (pef2256->version) {
	case PEF2256_VERSION_1_2:
		version_txt = "1.2";
		break;
	case PEF2256_VERSION_2_1:
		version_txt = "2.1";
		break;
	case PEF2256_VERSION_2_2:
		version_txt = "2.2";
		break;
	default:
		return -ENODEV;
	}
	dev_info(pef2256->dev, "Version %s detected\n", version_txt);

	ret = pef2556_of_parse(pef2256, np);
	if (ret)
		return ret;

	/* Create the framer. It can be used on interrupts */
	pef2256->framer = devm_framer_create(pef2256->dev, NULL, &pef2256_framer_ops);
	if (IS_ERR(pef2256->framer))
		return PTR_ERR(pef2256->framer);

	framer_set_drvdata(pef2256->framer, pef2256);

	/* Disable interrupts */
	pef2256_write8(pef2256, PEF2256_IMR0, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR1, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR2, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR3, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR4, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR5, 0xff);

	/* Clear any pending interrupts */
	pef2256_read8(pef2256, PEF2256_ISR0);
	pef2256_read8(pef2256, PEF2256_ISR1);
	pef2256_read8(pef2256, PEF2256_ISR2);
	pef2256_read8(pef2256, PEF2256_ISR3);
	pef2256_read8(pef2256, PEF2256_ISR4);
	pef2256_read8(pef2256, PEF2256_ISR5);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;
	ret = devm_request_irq(pef2256->dev, irq, pef2256_irq_handler, 0, "pef2256", pef2256);
	if (ret < 0)
		return ret;

	platform_set_drvdata(pdev, pef2256);

	ret = mfd_add_devices(pef2256->dev, 0, pef2256_devs,
			      ARRAY_SIZE(pef2256_devs), NULL, 0, NULL);
	if (ret) {
		dev_err(pef2256->dev, "add devices failed (%d)\n", ret);
		return ret;
	}

	ret = pef2256_setup_e1(pef2256);
	if (ret)
		return ret;

	framer_provider = devm_framer_provider_of_register(pef2256->dev,
							   framer_provider_simple_of_xlate);
	if (IS_ERR(framer_provider))
		return PTR_ERR(framer_provider);

	/* Add audio devices */
	ret = pef2256_add_audio_devices(pef2256);
	if (ret < 0) {
		dev_err(pef2256->dev, "add audio devices failed (%d)\n", ret);
		return ret;
	}

	return 0;
}

static void pef2256_remove(struct platform_device *pdev)
{
	struct pef2256 *pef2256 = platform_get_drvdata(pdev);

	/* Disable interrupts */
	pef2256_write8(pef2256, PEF2256_IMR0, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR1, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR2, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR3, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR4, 0xff);
	pef2256_write8(pef2256, PEF2256_IMR5, 0xff);
}

static const struct of_device_id pef2256_id_table[] = {
	{ .compatible = "lantiq,pef2256" },
	{} /* sentinel */
};
MODULE_DEVICE_TABLE(of, pef2256_id_table);

static struct platform_driver pef2256_driver = {
	.driver = {
		.name = "lantiq-pef2256",
		.of_match_table = pef2256_id_table,
	},
	.probe = pef2256_probe,
	.remove_new = pef2256_remove,
};
module_platform_driver(pef2256_driver);

struct regmap *pef2256_get_regmap(struct pef2256 *pef2256)
{
	return pef2256->regmap;
}
EXPORT_SYMBOL_GPL(pef2256_get_regmap);

MODULE_AUTHOR("Herve Codina <herve.codina@bootlin.com>");
MODULE_DESCRIPTION("PEF2256 driver");
MODULE_LICENSE("GPL");