Merge tag 'kbuild-fixes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahi...

[linux-2.6-microblaze.git] / drivers / i2c / busses / i2c-pxa.c

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 1d76482..76f79b6 100644 (file)
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -265,6 +265,9 @@ struct pxa_i2c {
        u32                     hs_mask;
 
        struct i2c_bus_recovery_info recovery;
+       struct pinctrl          *pinctrl;
+       struct pinctrl_state    *pinctrl_default;
+       struct pinctrl_state    *pinctrl_recovery;
 };
 
 #define _IBMR(i2c)     ((i2c)->reg_ibmr)
@@ -1299,12 +1302,13 @@ static void i2c_pxa_prepare_recovery(struct i2c_adapter *adap)
         */
        gpiod_set_value(i2c->recovery.scl_gpiod, ibmr & IBMR_SCLS);
        gpiod_set_value(i2c->recovery.sda_gpiod, ibmr & IBMR_SDAS);
+
+       WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_recovery));
 }
 
 static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap)
 {
        struct pxa_i2c *i2c = adap->algo_data;
-       struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
        u32 isr;
 
        /*
@@ -1318,7 +1322,7 @@ static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap)
                i2c_pxa_do_reset(i2c);
        }
 
-       WARN_ON(pinctrl_select_state(bri->pinctrl, bri->pins_default));
+       WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default));
 
        dev_dbg(&i2c->adap.dev, "recovery: IBMR 0x%08x ISR 0x%08x\n",
                readl(_IBMR(i2c)), readl(_ISR(i2c)));
@@ -1340,20 +1344,76 @@ static int i2c_pxa_init_recovery(struct pxa_i2c *i2c)
        if (IS_ENABLED(CONFIG_I2C_PXA_SLAVE))
                return 0;
 
-       bri->pinctrl = devm_pinctrl_get(dev);
-       if (PTR_ERR(bri->pinctrl) == -ENODEV) {
-               bri->pinctrl = NULL;
+       i2c->pinctrl = devm_pinctrl_get(dev);
+       if (PTR_ERR(i2c->pinctrl) == -ENODEV)
+               i2c->pinctrl = NULL;
+       if (IS_ERR(i2c->pinctrl))
+               return PTR_ERR(i2c->pinctrl);
+
+       if (!i2c->pinctrl)
+               return 0;
+
+       i2c->pinctrl_default = pinctrl_lookup_state(i2c->pinctrl,
+                                                   PINCTRL_STATE_DEFAULT);
+       i2c->pinctrl_recovery = pinctrl_lookup_state(i2c->pinctrl, "recovery");
+
+       if (IS_ERR(i2c->pinctrl_default) || IS_ERR(i2c->pinctrl_recovery)) {
+               dev_info(dev, "missing pinmux recovery information: %ld %ld\n",
+                        PTR_ERR(i2c->pinctrl_default),
+                        PTR_ERR(i2c->pinctrl_recovery));
+               return 0;
+       }
+
+       /*
+        * Claiming GPIOs can influence the pinmux state, and may glitch the
+        * I2C bus. Do this carefully.
+        */
+       bri->scl_gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
+       if (bri->scl_gpiod == ERR_PTR(-EPROBE_DEFER))
+               return -EPROBE_DEFER;
+       if (IS_ERR(bri->scl_gpiod)) {
+               dev_info(dev, "missing scl gpio recovery information: %pe\n",
+                        bri->scl_gpiod);
+               return 0;
+       }
+
+       /*
+        * We have SCL. Pull SCL low and wait a bit so that SDA glitches
+        * have no effect.
+        */
+       gpiod_direction_output(bri->scl_gpiod, 0);
+       udelay(10);
+       bri->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH_OPEN_DRAIN);
+
+       /* Wait a bit in case of a SDA glitch, and then release SCL. */
+       udelay(10);
+       gpiod_direction_output(bri->scl_gpiod, 1);
+
+       if (bri->sda_gpiod == ERR_PTR(-EPROBE_DEFER))
+               return -EPROBE_DEFER;
+
+       if (IS_ERR(bri->sda_gpiod)) {
+               dev_info(dev, "missing sda gpio recovery information: %pe\n",
+                        bri->sda_gpiod);
                return 0;
        }
-       if (IS_ERR(bri->pinctrl))
-               return PTR_ERR(bri->pinctrl);
 
        bri->prepare_recovery = i2c_pxa_prepare_recovery;
        bri->unprepare_recovery = i2c_pxa_unprepare_recovery;
+       bri->recover_bus = i2c_generic_scl_recovery;
 
        i2c->adap.bus_recovery_info = bri;
 
-       return 0;
+       /*
+        * Claiming GPIOs can change the pinmux state, which confuses the
+        * pinctrl since pinctrl's idea of the current setting is unaffected
+        * by the pinmux change caused by claiming the GPIO. Work around that
+        * by switching pinctrl to the GPIO state here. We do it this way to
+        * avoid glitching the I2C bus.
+        */
+       pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_recovery);
+
+       return pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default);
 }
 
 static int i2c_pxa_probe(struct platform_device *dev)