linux-kernel - [PATCH v3] i2c: pxa: move to generic GPIO recovery

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Date:   Sun, 4 Oct 2020 13:07:11 +0300
From:   Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
To:     <linux-i2c@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <wsa@...nel.org>, <rmk+kernel@...linux.org.uk>,
        <alpawi@...zon.com>,
        Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Subject: [PATCH v3] i2c: pxa: move to generic GPIO recovery

Starting with
commit 75820314de26 ("i2c: core: add generic I2C GPIO recovery")
GPIO bus recovery is supported by the I2C core, so we can remove the
driver implementation and use that one instead.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
---

patch not tested.

Changes in v3:
 - fix compile errors from unprepare_recovery callback

Changes in v2:
 - readded the pinctrl state change to default from the
   unprepare_recovery callback;

 drivers/i2c/busses/i2c-pxa.c | 76 ++++--------------------------------
 1 file changed, 8 insertions(+), 68 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 35ca2c02c9b9..a636ea0eb50a 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -264,9 +264,6 @@ 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)
@@ -1305,13 +1302,12 @@ 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;
 
 	/*
@@ -1325,7 +1321,7 @@ static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap)
 		i2c_pxa_do_reset(i2c);
 	}
 
-	WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default));
+	WARN_ON(pinctrl_select_state(bri->pinctrl, bri->pins_default));
 
 	dev_dbg(&i2c->adap.dev, "recovery: IBMR 0x%08x ISR 0x%08x\n",
 	        readl(_IBMR(i2c)), readl(_ISR(i2c)));
@@ -1347,76 +1343,20 @@ static int i2c_pxa_init_recovery(struct pxa_i2c *i2c)
 	if (IS_ENABLED(CONFIG_I2C_PXA_SLAVE))
 		return 0;
 
-	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);
+	bri->pinctrl = devm_pinctrl_get(dev);
+	if (PTR_ERR(bri->pinctrl) == -ENODEV) {
+		bri->pinctrl = NULL;
 		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;
 
-	/*
-	 * 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);
+	return 0;
 }
 
 static int i2c_pxa_probe(struct platform_device *dev)
-- 
2.25.1