Commit 58b92424 authored by Shubhrajyoti Datta's avatar Shubhrajyoti Datta Committed by Wolfram Sang
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i2c: cadence: Add standard bus recovery support 



Hook up the standard GPIO/pinctrl-based recovery support.
We are doing the recovery at the beginning on a timeout.

Multiple people have contributed to the series.
Original patch from Cirag and another one from Robert.

Signed-off-by: default avatarShubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Acked-by: default avatarMichal Simek <michal.simek@amd.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent bdc4af28

drivers/i2c/busses/i2c-cadence.c

+19 −1
Original line number Diff line number Diff line
@@ -10,10 +10,12 @@ 
#include <linux/i2c.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/iopoll.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/of.h>

#include <linux/pm_runtime.h>

#include <linux/pinctrl/consumer.h>



/* Register offsets for the I2C device. */

#define CDNS_I2C_CR_OFFSET		0x00 /* Control Register, RW */
@@ -127,6 +129,8 @@ 
#define CDNS_I2C_TIMEOUT_MAX	0xFF



#define CDNS_I2C_BROKEN_HOLD_BIT	BIT(0)

#define CDNS_I2C_POLL_US	100000

#define CDNS_I2C_TIMEOUT_US	500000



#define cdns_i2c_readreg(offset)       readl_relaxed(id->membase + offset)

#define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)
@@ -204,6 +208,7 @@ struct cdns_i2c { 
	struct notifier_block clk_rate_change_nb;

	u32 quirks;

	u32 ctrl_reg;

	struct i2c_bus_recovery_info rinfo;

#if IS_ENABLED(CONFIG_I2C_SLAVE)

	u16 ctrl_reg_diva_divb;

	struct i2c_client *slave;
@@ -840,8 +845,14 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 
#endif



	/* Check if the bus is free */

	if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA) {



	ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET,

					 reg,

					 !(reg & CDNS_I2C_SR_BA),

					 CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US);

	if (ret) {

		ret = -EAGAIN;

		i2c_recover_bus(adap);

		goto out;

	}
@@ -1250,6 +1261,12 @@ static int cdns_i2c_probe(struct platform_device *pdev) 
		id->quirks = data->quirks;

	}



	id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev);

	if (IS_ERR(id->rinfo.pinctrl)) {

		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");

		return PTR_ERR(id->rinfo.pinctrl);

	}



	id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem);

	if (IS_ERR(id->membase))

		return PTR_ERR(id->membase);
@@ -1266,6 +1283,7 @@ static int cdns_i2c_probe(struct platform_device *pdev) 
	id->adap.retries = 3;		/* Default retry value. */

	id->adap.algo_data = id;

	id->adap.dev.parent = &pdev->dev;

	id->adap.bus_recovery_info = &id->rinfo;

	init_completion(&id->xfer_done);

	snprintf(id->adap.name, sizeof(id->adap.name),

		 "Cadence I2C at %08lx", (unsigned long)r_mem->start);