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: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 33f5588a50c0738a049c52239ff406cfec1fc806..fe0cd205502de94658d455b494070df8d76f139c 100644 (file)
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -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);