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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20201003162141.925518-1-codrin.ciubotariu@microchip.com>
Date:   Sat, 3 Oct 2020 19:21:41 +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] 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>
---

This patch is not tested.
The only different thing should be the fact that the pinctl state is
now switched back to the default state after the bus is enabled.

 drivers/i2c/busses/i2c-pxa.c | 75 +++---------------------------------
 1 file changed, 6 insertions(+), 69 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 35ca2c02c9b9..dd357b6e6c61 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)
@@ -1305,8 +1302,6 @@ 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)
@@ -1325,8 +1320,6 @@ 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));
-
 	dev_dbg(&i2c->adap.dev, "recovery: IBMR 0x%08x ISR 0x%08x\n",
 	        readl(_IBMR(i2c)), readl(_ISR(i2c)));
 
@@ -1347,76 +1340,20 @@ 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