Author: ian
Date: Thu Jun 29 01:59:39 2017
New Revision: 320462
URL: https://svnweb.freebsd.org/changeset/base/320462
Log:
Add bus recovery handling to the imx5/imx6 i2c driver.
Modified:
head/sys/arm/freescale/imx/imx_i2c.c
Modified: head/sys/arm/freescale/imx/imx_i2c.c
==============================================================================
--- head/sys/arm/freescale/imx/imx_i2c.c Thu Jun 29 01:50:58 2017
(r320461)
+++ head/sys/arm/freescale/imx/imx_i2c.c Thu Jun 29 01:59:39 2017
(r320462)
@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
+#include <sys/gpio.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/module.h>
@@ -61,12 +62,16 @@ __FBSDID("$FreeBSD$");
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
+#include <dev/iicbus/iic_recover_bus.h>
#include "iicbus_if.h"
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
+#include <dev/fdt/fdt_pinctrl.h>
+#include <dev/gpio/gpiobusvar.h>
+
#define I2C_ADDR_REG 0x00 /* I2C slave address register */
#define I2C_FDR_REG 0x04 /* I2C frequency divider register */
#define I2C_CONTROL_REG 0x08 /* I2C control register */
@@ -130,6 +135,9 @@ struct i2c_softc {
struct resource *res;
int rid;
sbintime_t byte_time_sbt;
+ int rb_pinctl_idx;
+ gpio_pin_t rb_sclpin;
+ gpio_pin_t rb_sdapin;
};
static phandle_t i2c_get_node(device_t, device_t);
@@ -274,6 +282,68 @@ i2c_error_handler(struct i2c_softc *sc, int error)
}
static int
+i2c_recover_getsda(void *ctx)
+{
+ bool active;
+
+ gpio_pin_is_active(((struct i2c_softc *)ctx)->rb_sdapin, &active);
+ return (active);
+}
+
+static void
+i2c_recover_setsda(void *ctx, int value)
+{
+
+ gpio_pin_set_active(((struct i2c_softc *)ctx)->rb_sdapin, value);
+}
+
+static int
+i2c_recover_getscl(void *ctx)
+{
+ bool active;
+
+ gpio_pin_is_active(((struct i2c_softc *)ctx)->rb_sclpin, &active);
+ return (active);
+
+}
+
+static void
+i2c_recover_setscl(void *ctx, int value)
+{
+
+ gpio_pin_set_active(((struct i2c_softc *)ctx)->rb_sclpin, value);
+}
+
+static int
+i2c_recover_bus(struct i2c_softc *sc)
+{
+ struct iicrb_pin_access pins;
+ int err;
+
+ /*
+ * If we have gpio pinmux config, reconfigure the pins to gpio mode,
+ * invoke iic_recover_bus which checks for a hung bus and bitbangs a
+ * recovery sequence if necessary, then configure the pins back to i2c
+ * mode (idx 0).
+ */
+ if (sc->rb_pinctl_idx == 0)
+ return (0);
+
+ fdt_pinctrl_configure(sc->dev, sc->rb_pinctl_idx);
+
+ pins.ctx = sc;
+ pins.getsda = i2c_recover_getsda;
+ pins.setsda = i2c_recover_setsda;
+ pins.getscl = i2c_recover_getscl;
+ pins.setscl = i2c_recover_setscl;
+ err = iic_recover_bus(&pins);
+
+ fdt_pinctrl_configure(sc->dev, 0);
+
+ return (err);
+}
+
+static int
i2c_probe(device_t dev)
{
@@ -291,7 +361,10 @@ i2c_probe(device_t dev)
static int
i2c_attach(device_t dev)
{
+ char wrkstr[16];
struct i2c_softc *sc;
+ phandle_t node;
+ int err, cfgidx;
sc = device_get_softc(dev);
sc->dev = dev;
@@ -310,6 +383,49 @@ i2c_attach(device_t dev)
return (ENXIO);
}
+ /*
+ * Set up for bus recovery using gpio pins, if the pinctrl and gpio
+ * properties are present. This is optional. If all the config data is
+ * not in place, we just don't do gpio bitbang bus recovery.
+ */
+ node = ofw_bus_get_node(sc->dev);
+
+ err = gpio_pin_get_by_ofw_property(dev, node, "scl-gpios",
+ &sc->rb_sclpin);
+ if (err != 0)
+ goto no_recovery;
+ err = gpio_pin_get_by_ofw_property(dev, node, "sda-gpios",
+ &sc->rb_sdapin);
+ if (err != 0)
+ goto no_recovery;
+
+ /*
+ * Preset the gpio pins to output high (idle bus state). The signal
+ * won't actually appear on the pins until the bus recovery code changes
+ * the pinmux config from i2c to gpio.
+ */
+ gpio_pin_setflags(sc->rb_sclpin, GPIO_PIN_OUTPUT);
+ gpio_pin_setflags(sc->rb_sdapin, GPIO_PIN_OUTPUT);
+ gpio_pin_set_active(sc->rb_sclpin, true);
+ gpio_pin_set_active(sc->rb_sdapin, true);
+
+ /*
+ * Obtain the index of pinctrl node for bus recovery using gpio pins,
+ * then confirm that pinctrl properties exist for that index and for the
+ * default pinctrl-0. If sc->rb_pinctl_idx is non-zero, the reset code
+ * will also do a bus recovery, so setting this value must be last.
+ */
+ err = ofw_bus_find_string_index(node, "pinctrl-names", "gpio", &cfgidx);
+ if (err == 0) {
+ snprintf(wrkstr, sizeof(wrkstr), "pinctrl-%d", cfgidx);
+ if (OF_hasprop(node, "pinctrl-0") && OF_hasprop(node, wrkstr))
+ sc->rb_pinctl_idx = cfgidx;
+ }
+
+no_recovery:
+
+ /* We don't do a hardware reset here because iicbus_attach() does it. */
+
bus_generic_attach(dev);
return (0);
}
@@ -339,7 +455,7 @@ i2c_repeated_start(device_t dev, u_char slave, int tim
}
static int
-i2c_start(device_t dev, u_char slave, int timeout)
+i2c_start_ll(device_t dev, u_char slave, int timeout)
{
struct i2c_softc *sc;
int error;
@@ -361,6 +477,31 @@ i2c_start(device_t dev, u_char slave, int timeout)
}
static int
+i2c_start(device_t dev, u_char slave, int timeout)
+{
+ struct i2c_softc *sc;
+ int error;
+
+ sc = device_get_softc(dev);
+
+ /*
+ * Invoke the low-level code to put the bus into master mode and address
+ * the given slave. If that fails, idle the controller and attempt a
+ * bus recovery, and then try again one time. Signaling a start and
+ * addressing the slave is the only operation that a low-level driver
+ * can safely retry without any help from the upper layers that know
+ * more about the slave device.
+ */
+ if ((error = i2c_start_ll(dev, slave, timeout)) != 0) {
+ i2c_write_reg(sc, I2C_CONTROL_REG, 0x0);
+ if ((error = i2c_recover_bus(sc)) != 0)
+ return (error);
+ error = i2c_start_ll(dev, slave, timeout);
+ }
+ return (error);
+}
+
+static int
i2c_stop(device_t dev)
{
struct i2c_softc *sc;
@@ -409,7 +550,12 @@ i2c_reset(device_t dev, u_char speed, u_char addr, u_c
i2c_write_reg(sc, I2C_STATUS_REG, 0x0);
i2c_write_reg(sc, I2C_CONTROL_REG, 0x0);
i2c_write_reg(sc, I2C_FDR_REG, (uint8_t)clkdiv_table[i].regcode);
- return (IIC_NOERR);
+
+ /*
+ * Now that the controller is idle, perform bus recovery. If the bus
+ * isn't hung, this a fairly fast no-op.
+ */
+ return (i2c_recover_bus(sc));
}
static int
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