* [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
@ 2018-02-23 5:22 Ken Chen
2018-03-08 3:02 ` Joel Stanley
0 siblings, 1 reply; 6+ messages in thread
From: Ken Chen @ 2018-02-23 5:22 UTC (permalink / raw)
To: openbmc; +Cc: Ken Chen, joel
Initial PCA9641 2 chennel I2C bus master arbiter
Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
---
drivers/i2c/muxes/Kconfig | 9 +
drivers/i2c/muxes/Makefile | 1 +
drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
3 files changed, 382 insertions(+)
create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 1712132..1cd1ad3 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
This driver can also be built as a module. If so, the module
will be called i2c-mux-pca954x.
+config I2C_MUX_PCA9641
+ tristate "NXP PCA9641 I2C Master demultiplexer"
+ help
+ If you say yes here you get support for the NXP PCA9641
+ I2C Master demultiplexer with an arbiter function.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-mux-pca9641.
+
config I2C_MUX_PINCTRL
tristate "pinctrl-based I2C multiplexer"
depends on PINCTRL
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index 4a67d31..f95d5f5 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
+obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
new file mode 100644
index 0000000..ca7b816
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
@@ -0,0 +1,372 @@
+/*
+ * I2C demultiplexer driver for PCA9641 bus master demultiplexer
+ *
+ * Copyright (c) 2010 Ericsson AB.
+ *
+ * Author: Ken Chen <chen.kenyy@inventec.com>
+ *
+ * Derived from:
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+
+#include <linux/i2c/pca954x.h>
+
+/*
+ * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
+ * connected to a single slave bus.
+ *
+ * It is designed for high reliability dual master I2C bus applications where
+ * correct system operation is required, even when two I2C master issue their
+ * commands at the same time. The arbiter will select a winner and let it work
+ * uninterrupted, and the losing master will take control of the I2C bus after
+ * the winnter has finished. The arbiter also allows for queued requests where
+ * a master requests the downstream bus while the other master has control.
+ *
+ */
+
+#define PCA9641_ID 0x01
+#define PCA9641_ID_MAGIC 0x38
+
+#define PCA9641_CONTROL 0x01
+#define PCA9641_STATUS 0x02
+#define PCA9641_TIME 0x03
+
+#define PCA9641_CTL_LOCK_REQ (1 << 0)
+#define PCA9641_CTL_LOCK_GRANT (1 << 1)
+#define PCA9641_CTL_BUS_CONNECT (1 << 2)
+#define PCA9641_CTL_BUS_INIT (1 << 3)
+#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
+#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
+#define PCA9641_CTL_SMBUS_DIS (1 << 6)
+#define PCA9641_CTL_PRIORITY (1 << 7)
+
+#define PCA9641_STS_OTHER_LOCK (1 << 0)
+#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
+#define PCA9641_STS_BUS_HUNG (1 << 2)
+#define PCA9641_STS_MBOX_EMPTY (1 << 3)
+#define PCA9641_STS_MBOX_FULL (1 << 4)
+#define PCA9641_STS_TEST_INT (1 << 5)
+#define PCA9641_STS_SCL_IO (1 << 6)
+#define PCA9641_STS_SDA_IO (1 << 7)
+
+#define PCA9641_RES_TIME 0x03
+
+#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
+#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
+
+/* arbitration timeouts, in jiffies */
+#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
+#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
+
+/* arbitration retry delays, in us */
+#define SELECT_DELAY_SHORT 50
+#define SELECT_DELAY_LONG 1000
+
+struct pca9641 {
+ struct i2c_client *client;
+ unsigned long select_timeout;
+ unsigned long arb_timeout;
+};
+
+static const struct i2c_device_id pca9641_id[] = {
+ {"pca9641", 0},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, pca9641_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id pca9641_of_match[] = {
+ { .compatible = "nxp,pca9641" },
+ {}
+};
+#endif
+
+/*
+ * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
+ * as they will try to lock the adapter a second time.
+ */
+static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
+{
+ struct i2c_adapter *adap = client->adapter;
+ int ret;
+
+ if (adap->algo->master_xfer) {
+ struct i2c_msg msg;
+ char buf[2];
+
+ msg.addr = client->addr;
+ msg.flags = 0;
+ msg.len = 2;
+ buf[0] = command;
+ buf[1] = val;
+ msg.buf = buf;
+ ret = __i2c_transfer(adap, &msg, 1);
+ } else {
+ union i2c_smbus_data data;
+
+ data.byte = val;
+ ret = adap->algo->smbus_xfer(adap, client->addr,
+ client->flags,
+ I2C_SMBUS_WRITE,
+ command,
+ I2C_SMBUS_BYTE_DATA, &data);
+ }
+
+ return ret;
+}
+
+/*
+ * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
+ * as they will try to lock adapter a second time.
+ */
+static int pca9641_reg_read(struct i2c_client *client, u8 command)
+{
+ struct i2c_adapter *adap = client->adapter;
+ int ret;
+ u8 val;
+
+ if (adap->algo->master_xfer) {
+ struct i2c_msg msg[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = &command
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 1,
+ .buf = &val
+ }
+ };
+ ret = __i2c_transfer(adap, msg, 2);
+ if (ret == 2)
+ ret = val;
+ else if (ret >= 0)
+ ret = -EIO;
+ } else {
+ union i2c_smbus_data data;
+
+ ret = adap->algo->smbus_xfer(adap, client->addr,
+ client->flags,
+ I2C_SMBUS_READ,
+ command,
+ I2C_SMBUS_BYTE_DATA, &data);
+ if (!ret)
+ ret = data.byte;
+ }
+ return ret;
+}
+
+/*
+ * Arbitration management functions
+ */
+static void pca9641_release_bus(struct i2c_client *client)
+{
+ int reg;
+
+ pca9641_reg_write(client, PCA9641_CONTROL, 0);
+}
+
+/*
+ * Channel arbitration
+ *
+ * Return values:
+ * <0: error
+ * 0 : bus not acquired
+ * 1 : bus acquired
+ */
+static int pca9641_arbitrate(struct i2c_client *client)
+{
+ struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+ struct pca9641 *data = i2c_mux_priv(muxc);
+ int reg_ctl, reg_sts;
+
+ reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
+ if (reg_ctl < 0)
+ return reg_ctl;
+ reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
+
+ if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
+ /*
+ * Bus is off. Request ownership or turn it on unless
+ * other master requested ownership.
+ */
+ reg_ctl |= PCA9641_CTL_LOCK_REQ;
+ pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
+
+ udelay(100);
+
+ reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
+
+ if (lock_grant(reg_ctl)) {
+ /*
+ * Other master did not request ownership,
+ * or arbitration timeout expired. Take the bus.
+ */
+ reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
+ pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
+ data->select_timeout = SELECT_DELAY_SHORT;
+
+ return 1;
+ } else {
+ /*
+ * Other master requested ownership.
+ * Set extra long timeout to give it time to acquire it.
+ */
+ data->select_timeout = SELECT_DELAY_LONG * 2;
+ }
+ } else if (lock_grant(reg_ctl)) {
+ /*
+ * Bus is on, and we own it. We are done with acquisition.
+ */
+ reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
+ pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
+
+ return 1;
+ } else if (other_lock(reg_sts)) {
+ /*
+ * Other master owns the bus.
+ * If arbitration timeout has expired, force ownership.
+ * Otherwise request it.
+ */
+ data->select_timeout = SELECT_DELAY_LONG;
+ reg_ctl |= PCA9641_CTL_LOCK_REQ;
+ pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
+
+ /*
+ * if (time_is_before_eq_jiffies(data->arb_timeout)) {
+ * TODO:Time is up, take the bus and reset it.
+ *
+ *} else {
+ * TODO: Request bus ownership if needed
+ *
+ *}
+ */
+ }
+ return 0;
+}
+
+static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
+{
+ struct pca9641 *data = i2c_mux_priv(muxc);
+ struct i2c_client *client = data->client;
+ int ret;
+ unsigned long timeout = jiffies + ARB2_TIMEOUT;
+ /* give up after this time */
+
+ data->arb_timeout = jiffies + ARB_TIMEOUT;
+ /* force bus ownership after this time */
+
+ do {
+ ret = pca9641_arbitrate(client);
+ if (ret)
+ return ret < 0 ? ret : 0;
+
+ if (data->select_timeout == SELECT_DELAY_SHORT)
+ udelay(data->select_timeout);
+ else
+ msleep(data->select_timeout / 1000);
+ } while (time_is_after_eq_jiffies(timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
+{
+ struct pca9641 *data = i2c_mux_priv(muxc);
+ struct i2c_client *client = data->client;
+
+ pca9641_release_bus(client);
+ return 0;
+}
+
+/*
+ * I2C init/probing/exit functions
+ */
+static int pca9641_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adap = client->adapter;
+ struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
+ struct i2c_mux_core *muxc;
+ struct pca9641 *data;
+ int force;
+ int ret;
+
+ if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -ENODEV;
+
+ /*
+ * I2C accesses are unprotected here.
+ * We have to lock the adapter before releasing the bus.
+ */
+ i2c_lock_adapter(adap);
+ pca9641_release_bus(client);
+ i2c_unlock_adapter(adap);
+
+ /* Create mux adapter */
+
+ force = 0;
+ if (pdata)
+ force = pdata->modes[0].adap_id;
+ muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
+ I2C_MUX_ARBITRATOR,
+ pca9641_select_chan, pca9641_release_chan);
+ if (!muxc)
+ return -ENOMEM;
+
+ data = i2c_mux_priv(muxc);
+ data->client = client;
+
+ i2c_set_clientdata(client, muxc);
+
+
+ ret = i2c_mux_add_adapter(muxc, force, 0, 0);
+ if (ret) {
+ dev_err(&client->dev, "failed to register master demultiplexer\n");
+ return ret;
+ }
+
+ dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
+ client->name);
+
+ return 0;
+}
+
+static int pca9641_remove(struct i2c_client *client)
+{
+ struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+
+ i2c_mux_del_adapters(muxc);
+ return 0;
+}
+
+static struct i2c_driver pca9641_driver = {
+ .driver = {
+ .name = "pca9641",
+ .of_match_table = of_match_ptr(pca9641_of_match),
+ },
+ .probe = pca9641_probe,
+ .remove = pca9641_remove,
+ .id_table = pca9641_id,
+};
+
+module_i2c_driver(pca9641_driver);
+
+MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
+MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
+MODULE_LICENSE("GPL v2");
--
2.9.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
2018-02-23 5:22 [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver Ken Chen
@ 2018-03-08 3:02 ` Joel Stanley
2018-03-08 5:06 ` ChenKenYY 陳永營 TAO
0 siblings, 1 reply; 6+ messages in thread
From: Joel Stanley @ 2018-03-08 3:02 UTC (permalink / raw)
To: Ken Chen; +Cc: OpenBMC Maillist
Hello Ken,
On Fri, Feb 23, 2018 at 3:52 PM, Ken Chen <chen.kenyy@inventec.com> wrote:
> Initial PCA9641 2 chennel I2C bus master arbiter
>
> Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
The code here looks good. I did some searching, and found that someone
submitted a driver for this part about a year ago:
https://patchwork.ozlabs.org/patch/726491/
Unfortunately the submitter did not send another version after it was
reviewed. I suggest we take up the patch that was submitted, make the
changes suggested, and submit it upstream. Are you able to take on
that work?
Cheers,
Joel
> ---
> drivers/i2c/muxes/Kconfig | 9 +
> drivers/i2c/muxes/Makefile | 1 +
> drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 382 insertions(+)
> create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
>
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index 1712132..1cd1ad3 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
> This driver can also be built as a module. If so, the module
> will be called i2c-mux-pca954x.
>
> +config I2C_MUX_PCA9641
> + tristate "NXP PCA9641 I2C Master demultiplexer"
> + help
> + If you say yes here you get support for the NXP PCA9641
> + I2C Master demultiplexer with an arbiter function.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-mux-pca9641.
> +
> config I2C_MUX_PINCTRL
> tristate "pinctrl-based I2C multiplexer"
> depends on PINCTRL
> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
> index 4a67d31..f95d5f5 100644
> --- a/drivers/i2c/muxes/Makefile
> +++ b/drivers/i2c/muxes/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
> +obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
> obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
> new file mode 100644
> index 0000000..ca7b816
> --- /dev/null
> +++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
> @@ -0,0 +1,372 @@
> +/*
> + * I2C demultiplexer driver for PCA9641 bus master demultiplexer
> + *
> + * Copyright (c) 2010 Ericsson AB.
> + *
> + * Author: Ken Chen <chen.kenyy@inventec.com>
> + *
> + * Derived from:
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/jiffies.h>
> +#include <linux/delay.h>
> +#include <linux/slab.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c-mux.h>
> +
> +#include <linux/i2c/pca954x.h>
> +
> +/*
> + * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
> + * connected to a single slave bus.
> + *
> + * It is designed for high reliability dual master I2C bus applications where
> + * correct system operation is required, even when two I2C master issue their
> + * commands at the same time. The arbiter will select a winner and let it work
> + * uninterrupted, and the losing master will take control of the I2C bus after
> + * the winnter has finished. The arbiter also allows for queued requests where
> + * a master requests the downstream bus while the other master has control.
> + *
> + */
> +
> +#define PCA9641_ID 0x01
> +#define PCA9641_ID_MAGIC 0x38
> +
> +#define PCA9641_CONTROL 0x01
> +#define PCA9641_STATUS 0x02
> +#define PCA9641_TIME 0x03
> +
> +#define PCA9641_CTL_LOCK_REQ (1 << 0)
> +#define PCA9641_CTL_LOCK_GRANT (1 << 1)
> +#define PCA9641_CTL_BUS_CONNECT (1 << 2)
> +#define PCA9641_CTL_BUS_INIT (1 << 3)
> +#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
> +#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
> +#define PCA9641_CTL_SMBUS_DIS (1 << 6)
> +#define PCA9641_CTL_PRIORITY (1 << 7)
> +
> +#define PCA9641_STS_OTHER_LOCK (1 << 0)
> +#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
> +#define PCA9641_STS_BUS_HUNG (1 << 2)
> +#define PCA9641_STS_MBOX_EMPTY (1 << 3)
> +#define PCA9641_STS_MBOX_FULL (1 << 4)
> +#define PCA9641_STS_TEST_INT (1 << 5)
> +#define PCA9641_STS_SCL_IO (1 << 6)
> +#define PCA9641_STS_SDA_IO (1 << 7)
> +
> +#define PCA9641_RES_TIME 0x03
> +
> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
> +
> +/* arbitration timeouts, in jiffies */
> +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
> +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
> +
> +/* arbitration retry delays, in us */
> +#define SELECT_DELAY_SHORT 50
> +#define SELECT_DELAY_LONG 1000
> +
> +struct pca9641 {
> + struct i2c_client *client;
> + unsigned long select_timeout;
> + unsigned long arb_timeout;
> +};
> +
> +static const struct i2c_device_id pca9641_id[] = {
> + {"pca9641", 0},
> + {}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, pca9641_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id pca9641_of_match[] = {
> + { .compatible = "nxp,pca9641" },
> + {}
> +};
> +#endif
> +
> +/*
> + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
> + * as they will try to lock the adapter a second time.
> + */
> +static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
> +{
> + struct i2c_adapter *adap = client->adapter;
> + int ret;
> +
> + if (adap->algo->master_xfer) {
> + struct i2c_msg msg;
> + char buf[2];
> +
> + msg.addr = client->addr;
> + msg.flags = 0;
> + msg.len = 2;
> + buf[0] = command;
> + buf[1] = val;
> + msg.buf = buf;
> + ret = __i2c_transfer(adap, &msg, 1);
> + } else {
> + union i2c_smbus_data data;
> +
> + data.byte = val;
> + ret = adap->algo->smbus_xfer(adap, client->addr,
> + client->flags,
> + I2C_SMBUS_WRITE,
> + command,
> + I2C_SMBUS_BYTE_DATA, &data);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
> + * as they will try to lock adapter a second time.
> + */
> +static int pca9641_reg_read(struct i2c_client *client, u8 command)
> +{
> + struct i2c_adapter *adap = client->adapter;
> + int ret;
> + u8 val;
> +
> + if (adap->algo->master_xfer) {
> + struct i2c_msg msg[2] = {
> + {
> + .addr = client->addr,
> + .flags = 0,
> + .len = 1,
> + .buf = &command
> + },
> + {
> + .addr = client->addr,
> + .flags = I2C_M_RD,
> + .len = 1,
> + .buf = &val
> + }
> + };
> + ret = __i2c_transfer(adap, msg, 2);
> + if (ret == 2)
> + ret = val;
> + else if (ret >= 0)
> + ret = -EIO;
> + } else {
> + union i2c_smbus_data data;
> +
> + ret = adap->algo->smbus_xfer(adap, client->addr,
> + client->flags,
> + I2C_SMBUS_READ,
> + command,
> + I2C_SMBUS_BYTE_DATA, &data);
> + if (!ret)
> + ret = data.byte;
> + }
> + return ret;
> +}
> +
> +/*
> + * Arbitration management functions
> + */
> +static void pca9641_release_bus(struct i2c_client *client)
> +{
> + int reg;
> +
> + pca9641_reg_write(client, PCA9641_CONTROL, 0);
> +}
> +
> +/*
> + * Channel arbitration
> + *
> + * Return values:
> + * <0: error
> + * 0 : bus not acquired
> + * 1 : bus acquired
> + */
> +static int pca9641_arbitrate(struct i2c_client *client)
> +{
> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
> + struct pca9641 *data = i2c_mux_priv(muxc);
> + int reg_ctl, reg_sts;
> +
> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
> + if (reg_ctl < 0)
> + return reg_ctl;
> + reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
> +
> + if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
> + /*
> + * Bus is off. Request ownership or turn it on unless
> + * other master requested ownership.
> + */
> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
> +
> + udelay(100);
> +
> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
> +
> + if (lock_grant(reg_ctl)) {
> + /*
> + * Other master did not request ownership,
> + * or arbitration timeout expired. Take the bus.
> + */
> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
> + data->select_timeout = SELECT_DELAY_SHORT;
> +
> + return 1;
> + } else {
> + /*
> + * Other master requested ownership.
> + * Set extra long timeout to give it time to acquire it.
> + */
> + data->select_timeout = SELECT_DELAY_LONG * 2;
> + }
> + } else if (lock_grant(reg_ctl)) {
> + /*
> + * Bus is on, and we own it. We are done with acquisition.
> + */
> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
> +
> + return 1;
> + } else if (other_lock(reg_sts)) {
> + /*
> + * Other master owns the bus.
> + * If arbitration timeout has expired, force ownership.
> + * Otherwise request it.
> + */
> + data->select_timeout = SELECT_DELAY_LONG;
> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
> +
> + /*
> + * if (time_is_before_eq_jiffies(data->arb_timeout)) {
> + * TODO:Time is up, take the bus and reset it.
> + *
> + *} else {
> + * TODO: Request bus ownership if needed
> + *
> + *}
> + */
> + }
> + return 0;
> +}
> +
> +static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
> +{
> + struct pca9641 *data = i2c_mux_priv(muxc);
> + struct i2c_client *client = data->client;
> + int ret;
> + unsigned long timeout = jiffies + ARB2_TIMEOUT;
> + /* give up after this time */
> +
> + data->arb_timeout = jiffies + ARB_TIMEOUT;
> + /* force bus ownership after this time */
> +
> + do {
> + ret = pca9641_arbitrate(client);
> + if (ret)
> + return ret < 0 ? ret : 0;
> +
> + if (data->select_timeout == SELECT_DELAY_SHORT)
> + udelay(data->select_timeout);
> + else
> + msleep(data->select_timeout / 1000);
> + } while (time_is_after_eq_jiffies(timeout));
> +
> + return -ETIMEDOUT;
> +}
> +
> +static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
> +{
> + struct pca9641 *data = i2c_mux_priv(muxc);
> + struct i2c_client *client = data->client;
> +
> + pca9641_release_bus(client);
> + return 0;
> +}
> +
> +/*
> + * I2C init/probing/exit functions
> + */
> +static int pca9641_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct i2c_adapter *adap = client->adapter;
> + struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
> + struct i2c_mux_core *muxc;
> + struct pca9641 *data;
> + int force;
> + int ret;
> +
> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
> + return -ENODEV;
> +
> + /*
> + * I2C accesses are unprotected here.
> + * We have to lock the adapter before releasing the bus.
> + */
> + i2c_lock_adapter(adap);
> + pca9641_release_bus(client);
> + i2c_unlock_adapter(adap);
> +
> + /* Create mux adapter */
> +
> + force = 0;
> + if (pdata)
> + force = pdata->modes[0].adap_id;
> + muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
> + I2C_MUX_ARBITRATOR,
> + pca9641_select_chan, pca9641_release_chan);
> + if (!muxc)
> + return -ENOMEM;
> +
> + data = i2c_mux_priv(muxc);
> + data->client = client;
> +
> + i2c_set_clientdata(client, muxc);
> +
> +
> + ret = i2c_mux_add_adapter(muxc, force, 0, 0);
> + if (ret) {
> + dev_err(&client->dev, "failed to register master demultiplexer\n");
> + return ret;
> + }
> +
> + dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
> + client->name);
> +
> + return 0;
> +}
> +
> +static int pca9641_remove(struct i2c_client *client)
> +{
> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
> +
> + i2c_mux_del_adapters(muxc);
> + return 0;
> +}
> +
> +static struct i2c_driver pca9641_driver = {
> + .driver = {
> + .name = "pca9641",
> + .of_match_table = of_match_ptr(pca9641_of_match),
> + },
> + .probe = pca9641_probe,
> + .remove = pca9641_remove,
> + .id_table = pca9641_id,
> +};
> +
> +module_i2c_driver(pca9641_driver);
> +
> +MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
> +MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.9.3
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
2018-03-08 3:02 ` Joel Stanley
@ 2018-03-08 5:06 ` ChenKenYY 陳永營 TAO
2018-03-08 5:34 ` Joel Stanley
0 siblings, 1 reply; 6+ messages in thread
From: ChenKenYY 陳永營 TAO @ 2018-03-08 5:06 UTC (permalink / raw)
To: Joel Stanley; +Cc: OpenBMC Maillist
Hi Joel,
Sure, I can take it, but I need some instructions on the next action.
Thanks,
Ken
2018-03-08 11:02 GMT+08:00 Joel Stanley <joel@jms.id.au>:
> Hello Ken,
>
> On Fri, Feb 23, 2018 at 3:52 PM, Ken Chen <chen.kenyy@inventec.com> wrote:
>> Initial PCA9641 2 chennel I2C bus master arbiter
>>
>> Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
>
> The code here looks good. I did some searching, and found that someone
> submitted a driver for this part about a year ago:
>
> https://patchwork.ozlabs.org/patch/726491/
>
> Unfortunately the submitter did not send another version after it was
> reviewed. I suggest we take up the patch that was submitted, make the
> changes suggested, and submit it upstream. Are you able to take on
> that work?
>
> Cheers,
>
> Joel
>
>> ---
>> drivers/i2c/muxes/Kconfig | 9 +
>> drivers/i2c/muxes/Makefile | 1 +
>> drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 382 insertions(+)
>> create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
>>
>> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
>> index 1712132..1cd1ad3 100644
>> --- a/drivers/i2c/muxes/Kconfig
>> +++ b/drivers/i2c/muxes/Kconfig
>> @@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
>> This driver can also be built as a module. If so, the module
>> will be called i2c-mux-pca954x.
>>
>> +config I2C_MUX_PCA9641
>> + tristate "NXP PCA9641 I2C Master demultiplexer"
>> + help
>> + If you say yes here you get support for the NXP PCA9641
>> + I2C Master demultiplexer with an arbiter function.
>> +
>> + This driver can also be built as a module. If so, the module
>> + will be called i2c-mux-pca9641.
>> +
>> config I2C_MUX_PINCTRL
>> tristate "pinctrl-based I2C multiplexer"
>> depends on PINCTRL
>> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
>> index 4a67d31..f95d5f5 100644
>> --- a/drivers/i2c/muxes/Makefile
>> +++ b/drivers/i2c/muxes/Makefile
>> @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
>> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
>> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
>> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
>> +obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
>> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
>> obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
>>
>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
>> new file mode 100644
>> index 0000000..ca7b816
>> --- /dev/null
>> +++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
>> @@ -0,0 +1,372 @@
>> +/*
>> + * I2C demultiplexer driver for PCA9641 bus master demultiplexer
>> + *
>> + * Copyright (c) 2010 Ericsson AB.
>> + *
>> + * Author: Ken Chen <chen.kenyy@inventec.com>
>> + *
>> + * Derived from:
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2. This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/delay.h>
>> +#include <linux/slab.h>
>> +#include <linux/device.h>
>> +#include <linux/i2c.h>
>> +#include <linux/i2c-mux.h>
>> +
>> +#include <linux/i2c/pca954x.h>
>> +
>> +/*
>> + * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
>> + * connected to a single slave bus.
>> + *
>> + * It is designed for high reliability dual master I2C bus applications where
>> + * correct system operation is required, even when two I2C master issue their
>> + * commands at the same time. The arbiter will select a winner and let it work
>> + * uninterrupted, and the losing master will take control of the I2C bus after
>> + * the winnter has finished. The arbiter also allows for queued requests where
>> + * a master requests the downstream bus while the other master has control.
>> + *
>> + */
>> +
>> +#define PCA9641_ID 0x01
>> +#define PCA9641_ID_MAGIC 0x38
>> +
>> +#define PCA9641_CONTROL 0x01
>> +#define PCA9641_STATUS 0x02
>> +#define PCA9641_TIME 0x03
>> +
>> +#define PCA9641_CTL_LOCK_REQ (1 << 0)
>> +#define PCA9641_CTL_LOCK_GRANT (1 << 1)
>> +#define PCA9641_CTL_BUS_CONNECT (1 << 2)
>> +#define PCA9641_CTL_BUS_INIT (1 << 3)
>> +#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
>> +#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
>> +#define PCA9641_CTL_SMBUS_DIS (1 << 6)
>> +#define PCA9641_CTL_PRIORITY (1 << 7)
>> +
>> +#define PCA9641_STS_OTHER_LOCK (1 << 0)
>> +#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
>> +#define PCA9641_STS_BUS_HUNG (1 << 2)
>> +#define PCA9641_STS_MBOX_EMPTY (1 << 3)
>> +#define PCA9641_STS_MBOX_FULL (1 << 4)
>> +#define PCA9641_STS_TEST_INT (1 << 5)
>> +#define PCA9641_STS_SCL_IO (1 << 6)
>> +#define PCA9641_STS_SDA_IO (1 << 7)
>> +
>> +#define PCA9641_RES_TIME 0x03
>> +
>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
>> +
>> +/* arbitration timeouts, in jiffies */
>> +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
>> +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
>> +
>> +/* arbitration retry delays, in us */
>> +#define SELECT_DELAY_SHORT 50
>> +#define SELECT_DELAY_LONG 1000
>> +
>> +struct pca9641 {
>> + struct i2c_client *client;
>> + unsigned long select_timeout;
>> + unsigned long arb_timeout;
>> +};
>> +
>> +static const struct i2c_device_id pca9641_id[] = {
>> + {"pca9641", 0},
>> + {}
>> +};
>> +
>> +MODULE_DEVICE_TABLE(i2c, pca9641_id);
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id pca9641_of_match[] = {
>> + { .compatible = "nxp,pca9641" },
>> + {}
>> +};
>> +#endif
>> +
>> +/*
>> + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>> + * as they will try to lock the adapter a second time.
>> + */
>> +static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
>> +{
>> + struct i2c_adapter *adap = client->adapter;
>> + int ret;
>> +
>> + if (adap->algo->master_xfer) {
>> + struct i2c_msg msg;
>> + char buf[2];
>> +
>> + msg.addr = client->addr;
>> + msg.flags = 0;
>> + msg.len = 2;
>> + buf[0] = command;
>> + buf[1] = val;
>> + msg.buf = buf;
>> + ret = __i2c_transfer(adap, &msg, 1);
>> + } else {
>> + union i2c_smbus_data data;
>> +
>> + data.byte = val;
>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>> + client->flags,
>> + I2C_SMBUS_WRITE,
>> + command,
>> + I2C_SMBUS_BYTE_DATA, &data);
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +/*
>> + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>> + * as they will try to lock adapter a second time.
>> + */
>> +static int pca9641_reg_read(struct i2c_client *client, u8 command)
>> +{
>> + struct i2c_adapter *adap = client->adapter;
>> + int ret;
>> + u8 val;
>> +
>> + if (adap->algo->master_xfer) {
>> + struct i2c_msg msg[2] = {
>> + {
>> + .addr = client->addr,
>> + .flags = 0,
>> + .len = 1,
>> + .buf = &command
>> + },
>> + {
>> + .addr = client->addr,
>> + .flags = I2C_M_RD,
>> + .len = 1,
>> + .buf = &val
>> + }
>> + };
>> + ret = __i2c_transfer(adap, msg, 2);
>> + if (ret == 2)
>> + ret = val;
>> + else if (ret >= 0)
>> + ret = -EIO;
>> + } else {
>> + union i2c_smbus_data data;
>> +
>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>> + client->flags,
>> + I2C_SMBUS_READ,
>> + command,
>> + I2C_SMBUS_BYTE_DATA, &data);
>> + if (!ret)
>> + ret = data.byte;
>> + }
>> + return ret;
>> +}
>> +
>> +/*
>> + * Arbitration management functions
>> + */
>> +static void pca9641_release_bus(struct i2c_client *client)
>> +{
>> + int reg;
>> +
>> + pca9641_reg_write(client, PCA9641_CONTROL, 0);
>> +}
>> +
>> +/*
>> + * Channel arbitration
>> + *
>> + * Return values:
>> + * <0: error
>> + * 0 : bus not acquired
>> + * 1 : bus acquired
>> + */
>> +static int pca9641_arbitrate(struct i2c_client *client)
>> +{
>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>> + struct pca9641 *data = i2c_mux_priv(muxc);
>> + int reg_ctl, reg_sts;
>> +
>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>> + if (reg_ctl < 0)
>> + return reg_ctl;
>> + reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
>> +
>> + if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
>> + /*
>> + * Bus is off. Request ownership or turn it on unless
>> + * other master requested ownership.
>> + */
>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>> +
>> + udelay(100);
>> +
>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>> +
>> + if (lock_grant(reg_ctl)) {
>> + /*
>> + * Other master did not request ownership,
>> + * or arbitration timeout expired. Take the bus.
>> + */
>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>> + data->select_timeout = SELECT_DELAY_SHORT;
>> +
>> + return 1;
>> + } else {
>> + /*
>> + * Other master requested ownership.
>> + * Set extra long timeout to give it time to acquire it.
>> + */
>> + data->select_timeout = SELECT_DELAY_LONG * 2;
>> + }
>> + } else if (lock_grant(reg_ctl)) {
>> + /*
>> + * Bus is on, and we own it. We are done with acquisition.
>> + */
>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>> +
>> + return 1;
>> + } else if (other_lock(reg_sts)) {
>> + /*
>> + * Other master owns the bus.
>> + * If arbitration timeout has expired, force ownership.
>> + * Otherwise request it.
>> + */
>> + data->select_timeout = SELECT_DELAY_LONG;
>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>> +
>> + /*
>> + * if (time_is_before_eq_jiffies(data->arb_timeout)) {
>> + * TODO:Time is up, take the bus and reset it.
>> + *
>> + *} else {
>> + * TODO: Request bus ownership if needed
>> + *
>> + *}
>> + */
>> + }
>> + return 0;
>> +}
>> +
>> +static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
>> +{
>> + struct pca9641 *data = i2c_mux_priv(muxc);
>> + struct i2c_client *client = data->client;
>> + int ret;
>> + unsigned long timeout = jiffies + ARB2_TIMEOUT;
>> + /* give up after this time */
>> +
>> + data->arb_timeout = jiffies + ARB_TIMEOUT;
>> + /* force bus ownership after this time */
>> +
>> + do {
>> + ret = pca9641_arbitrate(client);
>> + if (ret)
>> + return ret < 0 ? ret : 0;
>> +
>> + if (data->select_timeout == SELECT_DELAY_SHORT)
>> + udelay(data->select_timeout);
>> + else
>> + msleep(data->select_timeout / 1000);
>> + } while (time_is_after_eq_jiffies(timeout));
>> +
>> + return -ETIMEDOUT;
>> +}
>> +
>> +static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
>> +{
>> + struct pca9641 *data = i2c_mux_priv(muxc);
>> + struct i2c_client *client = data->client;
>> +
>> + pca9641_release_bus(client);
>> + return 0;
>> +}
>> +
>> +/*
>> + * I2C init/probing/exit functions
>> + */
>> +static int pca9641_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct i2c_adapter *adap = client->adapter;
>> + struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
>> + struct i2c_mux_core *muxc;
>> + struct pca9641 *data;
>> + int force;
>> + int ret;
>> +
>> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
>> + return -ENODEV;
>> +
>> + /*
>> + * I2C accesses are unprotected here.
>> + * We have to lock the adapter before releasing the bus.
>> + */
>> + i2c_lock_adapter(adap);
>> + pca9641_release_bus(client);
>> + i2c_unlock_adapter(adap);
>> +
>> + /* Create mux adapter */
>> +
>> + force = 0;
>> + if (pdata)
>> + force = pdata->modes[0].adap_id;
>> + muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
>> + I2C_MUX_ARBITRATOR,
>> + pca9641_select_chan, pca9641_release_chan);
>> + if (!muxc)
>> + return -ENOMEM;
>> +
>> + data = i2c_mux_priv(muxc);
>> + data->client = client;
>> +
>> + i2c_set_clientdata(client, muxc);
>> +
>> +
>> + ret = i2c_mux_add_adapter(muxc, force, 0, 0);
>> + if (ret) {
>> + dev_err(&client->dev, "failed to register master demultiplexer\n");
>> + return ret;
>> + }
>> +
>> + dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
>> + client->name);
>> +
>> + return 0;
>> +}
>> +
>> +static int pca9641_remove(struct i2c_client *client)
>> +{
>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>> +
>> + i2c_mux_del_adapters(muxc);
>> + return 0;
>> +}
>> +
>> +static struct i2c_driver pca9641_driver = {
>> + .driver = {
>> + .name = "pca9641",
>> + .of_match_table = of_match_ptr(pca9641_of_match),
>> + },
>> + .probe = pca9641_probe,
>> + .remove = pca9641_remove,
>> + .id_table = pca9641_id,
>> +};
>> +
>> +module_i2c_driver(pca9641_driver);
>> +
>> +MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
>> +MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.9.3
>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
2018-03-08 5:06 ` ChenKenYY 陳永營 TAO
@ 2018-03-08 5:34 ` Joel Stanley
2018-03-12 6:40 ` ChenKenYY 陳永營 TAO
0 siblings, 1 reply; 6+ messages in thread
From: Joel Stanley @ 2018-03-08 5:34 UTC (permalink / raw)
To: ChenKenYY 陳永營 TAO; +Cc: OpenBMC Maillist
On Thu, Mar 8, 2018 at 3:36 PM, ChenKenYY 陳永營 TAO
<chen.kenyy@inventec.com> wrote:
> Hi Joel,
>
> Sure, I can take it, but I need some instructions on the next action.
Okay. I suggest you download the patch from patchwork and apply it to
the latest kernel release, 4.16-rc4:
https://patchwork.ozlabs.org/patch/726491/
You can download it by clicking the 'mbox' link at the top right of the page.
Now you will have a file called
RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch.
$ git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
$ cd linux
$ git checkout -b pca9641-mux v4.16-rc4
$ git am ~/Downloads/RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch
From there, take a look at the comments on the two reviews that Vidya had:
https://patchwork.ozlabs.org/patch/726491/#1580479
https://patchwork.ozlabs.org/patch/726491/#1582916
Fix those issues, and add your signed off by:
$ git add drivers/i2c/muxes/i2c-mux-pca9541.c
$ git commit --amend -s
Then test this driver on your board. To do this, modify the device
tree. You should be able to do this by modifying the ast2500-evb
device tree, and boot that on your system.
Once this is working, use the checkpatch.pl tool to check for common mistakes:
$ ./scripts/checkpatch.pl drivers/i2c/muxes/i2c-mux-pca9541.c
Then use get_maintainer.pl to get a list of people you should send the patch to:
$ ./scripts/get_maintainer.pl -f drivers/i2c/muxes/i2c-mux-pca9541.c
Guenter Roeck <linux@roeck-us.net> (maintainer:PCA9541 I2C BUS MASTER
SELECTOR DRIVER)
Peter Rosin <peda@axentia.se> (maintainer:I2C MUXES)
Wolfram Sang <wsa@the-dreams.de> (maintainer:I2C SUBSYSTEM)
linux-i2c@vger.kernel.org (open list:PCA9541 I2C BUS MASTER SELECTOR DRIVER)
linux-kernel@vger.kernel.org (open list)
In addition, please add me to this list so I can help. Then send the
patch out, with a comment in the commit message (below the ---) that
you have continued this work from the previous author, and have tested
it on your system.
Cheers,
Joel
>
> Thanks,
> Ken
>
> 2018-03-08 11:02 GMT+08:00 Joel Stanley <joel@jms.id.au>:
>> Hello Ken,
>>
>> On Fri, Feb 23, 2018 at 3:52 PM, Ken Chen <chen.kenyy@inventec.com> wrote:
>>> Initial PCA9641 2 chennel I2C bus master arbiter
>>>
>>> Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
>>
>> The code here looks good. I did some searching, and found that someone
>> submitted a driver for this part about a year ago:
>>
>> https://patchwork.ozlabs.org/patch/726491/
>>
>> Unfortunately the submitter did not send another version after it was
>> reviewed. I suggest we take up the patch that was submitted, make the
>> changes suggested, and submit it upstream. Are you able to take on
>> that work?
>>
>> Cheers,
>>
>> Joel
>>
>>> ---
>>> drivers/i2c/muxes/Kconfig | 9 +
>>> drivers/i2c/muxes/Makefile | 1 +
>>> drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 382 insertions(+)
>>> create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
>>>
>>> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
>>> index 1712132..1cd1ad3 100644
>>> --- a/drivers/i2c/muxes/Kconfig
>>> +++ b/drivers/i2c/muxes/Kconfig
>>> @@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
>>> This driver can also be built as a module. If so, the module
>>> will be called i2c-mux-pca954x.
>>>
>>> +config I2C_MUX_PCA9641
>>> + tristate "NXP PCA9641 I2C Master demultiplexer"
>>> + help
>>> + If you say yes here you get support for the NXP PCA9641
>>> + I2C Master demultiplexer with an arbiter function.
>>> +
>>> + This driver can also be built as a module. If so, the module
>>> + will be called i2c-mux-pca9641.
>>> +
>>> config I2C_MUX_PINCTRL
>>> tristate "pinctrl-based I2C multiplexer"
>>> depends on PINCTRL
>>> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
>>> index 4a67d31..f95d5f5 100644
>>> --- a/drivers/i2c/muxes/Makefile
>>> +++ b/drivers/i2c/muxes/Makefile
>>> @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
>>> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
>>> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
>>> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
>>> +obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
>>> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
>>> obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
>>>
>>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>> new file mode 100644
>>> index 0000000..ca7b816
>>> --- /dev/null
>>> +++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>> @@ -0,0 +1,372 @@
>>> +/*
>>> + * I2C demultiplexer driver for PCA9641 bus master demultiplexer
>>> + *
>>> + * Copyright (c) 2010 Ericsson AB.
>>> + *
>>> + * Author: Ken Chen <chen.kenyy@inventec.com>
>>> + *
>>> + * Derived from:
>>> + *
>>> + * This file is licensed under the terms of the GNU General Public
>>> + * License version 2. This program is licensed "as is" without any
>>> + * warranty of any kind, whether express or implied.
>>> + */
>>> +
>>> +#include <linux/module.h>
>>> +#include <linux/jiffies.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/device.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/i2c-mux.h>
>>> +
>>> +#include <linux/i2c/pca954x.h>
>>> +
>>> +/*
>>> + * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
>>> + * connected to a single slave bus.
>>> + *
>>> + * It is designed for high reliability dual master I2C bus applications where
>>> + * correct system operation is required, even when two I2C master issue their
>>> + * commands at the same time. The arbiter will select a winner and let it work
>>> + * uninterrupted, and the losing master will take control of the I2C bus after
>>> + * the winnter has finished. The arbiter also allows for queued requests where
>>> + * a master requests the downstream bus while the other master has control.
>>> + *
>>> + */
>>> +
>>> +#define PCA9641_ID 0x01
>>> +#define PCA9641_ID_MAGIC 0x38
>>> +
>>> +#define PCA9641_CONTROL 0x01
>>> +#define PCA9641_STATUS 0x02
>>> +#define PCA9641_TIME 0x03
>>> +
>>> +#define PCA9641_CTL_LOCK_REQ (1 << 0)
>>> +#define PCA9641_CTL_LOCK_GRANT (1 << 1)
>>> +#define PCA9641_CTL_BUS_CONNECT (1 << 2)
>>> +#define PCA9641_CTL_BUS_INIT (1 << 3)
>>> +#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
>>> +#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
>>> +#define PCA9641_CTL_SMBUS_DIS (1 << 6)
>>> +#define PCA9641_CTL_PRIORITY (1 << 7)
>>> +
>>> +#define PCA9641_STS_OTHER_LOCK (1 << 0)
>>> +#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
>>> +#define PCA9641_STS_BUS_HUNG (1 << 2)
>>> +#define PCA9641_STS_MBOX_EMPTY (1 << 3)
>>> +#define PCA9641_STS_MBOX_FULL (1 << 4)
>>> +#define PCA9641_STS_TEST_INT (1 << 5)
>>> +#define PCA9641_STS_SCL_IO (1 << 6)
>>> +#define PCA9641_STS_SDA_IO (1 << 7)
>>> +
>>> +#define PCA9641_RES_TIME 0x03
>>> +
>>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
>>> +
>>> +/* arbitration timeouts, in jiffies */
>>> +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
>>> +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
>>> +
>>> +/* arbitration retry delays, in us */
>>> +#define SELECT_DELAY_SHORT 50
>>> +#define SELECT_DELAY_LONG 1000
>>> +
>>> +struct pca9641 {
>>> + struct i2c_client *client;
>>> + unsigned long select_timeout;
>>> + unsigned long arb_timeout;
>>> +};
>>> +
>>> +static const struct i2c_device_id pca9641_id[] = {
>>> + {"pca9641", 0},
>>> + {}
>>> +};
>>> +
>>> +MODULE_DEVICE_TABLE(i2c, pca9641_id);
>>> +
>>> +#ifdef CONFIG_OF
>>> +static const struct of_device_id pca9641_of_match[] = {
>>> + { .compatible = "nxp,pca9641" },
>>> + {}
>>> +};
>>> +#endif
>>> +
>>> +/*
>>> + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>> + * as they will try to lock the adapter a second time.
>>> + */
>>> +static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
>>> +{
>>> + struct i2c_adapter *adap = client->adapter;
>>> + int ret;
>>> +
>>> + if (adap->algo->master_xfer) {
>>> + struct i2c_msg msg;
>>> + char buf[2];
>>> +
>>> + msg.addr = client->addr;
>>> + msg.flags = 0;
>>> + msg.len = 2;
>>> + buf[0] = command;
>>> + buf[1] = val;
>>> + msg.buf = buf;
>>> + ret = __i2c_transfer(adap, &msg, 1);
>>> + } else {
>>> + union i2c_smbus_data data;
>>> +
>>> + data.byte = val;
>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>> + client->flags,
>>> + I2C_SMBUS_WRITE,
>>> + command,
>>> + I2C_SMBUS_BYTE_DATA, &data);
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +/*
>>> + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>> + * as they will try to lock adapter a second time.
>>> + */
>>> +static int pca9641_reg_read(struct i2c_client *client, u8 command)
>>> +{
>>> + struct i2c_adapter *adap = client->adapter;
>>> + int ret;
>>> + u8 val;
>>> +
>>> + if (adap->algo->master_xfer) {
>>> + struct i2c_msg msg[2] = {
>>> + {
>>> + .addr = client->addr,
>>> + .flags = 0,
>>> + .len = 1,
>>> + .buf = &command
>>> + },
>>> + {
>>> + .addr = client->addr,
>>> + .flags = I2C_M_RD,
>>> + .len = 1,
>>> + .buf = &val
>>> + }
>>> + };
>>> + ret = __i2c_transfer(adap, msg, 2);
>>> + if (ret == 2)
>>> + ret = val;
>>> + else if (ret >= 0)
>>> + ret = -EIO;
>>> + } else {
>>> + union i2c_smbus_data data;
>>> +
>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>> + client->flags,
>>> + I2C_SMBUS_READ,
>>> + command,
>>> + I2C_SMBUS_BYTE_DATA, &data);
>>> + if (!ret)
>>> + ret = data.byte;
>>> + }
>>> + return ret;
>>> +}
>>> +
>>> +/*
>>> + * Arbitration management functions
>>> + */
>>> +static void pca9641_release_bus(struct i2c_client *client)
>>> +{
>>> + int reg;
>>> +
>>> + pca9641_reg_write(client, PCA9641_CONTROL, 0);
>>> +}
>>> +
>>> +/*
>>> + * Channel arbitration
>>> + *
>>> + * Return values:
>>> + * <0: error
>>> + * 0 : bus not acquired
>>> + * 1 : bus acquired
>>> + */
>>> +static int pca9641_arbitrate(struct i2c_client *client)
>>> +{
>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>> + int reg_ctl, reg_sts;
>>> +
>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>> + if (reg_ctl < 0)
>>> + return reg_ctl;
>>> + reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
>>> +
>>> + if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
>>> + /*
>>> + * Bus is off. Request ownership or turn it on unless
>>> + * other master requested ownership.
>>> + */
>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>> +
>>> + udelay(100);
>>> +
>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>> +
>>> + if (lock_grant(reg_ctl)) {
>>> + /*
>>> + * Other master did not request ownership,
>>> + * or arbitration timeout expired. Take the bus.
>>> + */
>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>> + data->select_timeout = SELECT_DELAY_SHORT;
>>> +
>>> + return 1;
>>> + } else {
>>> + /*
>>> + * Other master requested ownership.
>>> + * Set extra long timeout to give it time to acquire it.
>>> + */
>>> + data->select_timeout = SELECT_DELAY_LONG * 2;
>>> + }
>>> + } else if (lock_grant(reg_ctl)) {
>>> + /*
>>> + * Bus is on, and we own it. We are done with acquisition.
>>> + */
>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>> +
>>> + return 1;
>>> + } else if (other_lock(reg_sts)) {
>>> + /*
>>> + * Other master owns the bus.
>>> + * If arbitration timeout has expired, force ownership.
>>> + * Otherwise request it.
>>> + */
>>> + data->select_timeout = SELECT_DELAY_LONG;
>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>> +
>>> + /*
>>> + * if (time_is_before_eq_jiffies(data->arb_timeout)) {
>>> + * TODO:Time is up, take the bus and reset it.
>>> + *
>>> + *} else {
>>> + * TODO: Request bus ownership if needed
>>> + *
>>> + *}
>>> + */
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
>>> +{
>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>> + struct i2c_client *client = data->client;
>>> + int ret;
>>> + unsigned long timeout = jiffies + ARB2_TIMEOUT;
>>> + /* give up after this time */
>>> +
>>> + data->arb_timeout = jiffies + ARB_TIMEOUT;
>>> + /* force bus ownership after this time */
>>> +
>>> + do {
>>> + ret = pca9641_arbitrate(client);
>>> + if (ret)
>>> + return ret < 0 ? ret : 0;
>>> +
>>> + if (data->select_timeout == SELECT_DELAY_SHORT)
>>> + udelay(data->select_timeout);
>>> + else
>>> + msleep(data->select_timeout / 1000);
>>> + } while (time_is_after_eq_jiffies(timeout));
>>> +
>>> + return -ETIMEDOUT;
>>> +}
>>> +
>>> +static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
>>> +{
>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>> + struct i2c_client *client = data->client;
>>> +
>>> + pca9641_release_bus(client);
>>> + return 0;
>>> +}
>>> +
>>> +/*
>>> + * I2C init/probing/exit functions
>>> + */
>>> +static int pca9641_probe(struct i2c_client *client,
>>> + const struct i2c_device_id *id)
>>> +{
>>> + struct i2c_adapter *adap = client->adapter;
>>> + struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
>>> + struct i2c_mux_core *muxc;
>>> + struct pca9641 *data;
>>> + int force;
>>> + int ret;
>>> +
>>> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
>>> + return -ENODEV;
>>> +
>>> + /*
>>> + * I2C accesses are unprotected here.
>>> + * We have to lock the adapter before releasing the bus.
>>> + */
>>> + i2c_lock_adapter(adap);
>>> + pca9641_release_bus(client);
>>> + i2c_unlock_adapter(adap);
>>> +
>>> + /* Create mux adapter */
>>> +
>>> + force = 0;
>>> + if (pdata)
>>> + force = pdata->modes[0].adap_id;
>>> + muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
>>> + I2C_MUX_ARBITRATOR,
>>> + pca9641_select_chan, pca9641_release_chan);
>>> + if (!muxc)
>>> + return -ENOMEM;
>>> +
>>> + data = i2c_mux_priv(muxc);
>>> + data->client = client;
>>> +
>>> + i2c_set_clientdata(client, muxc);
>>> +
>>> +
>>> + ret = i2c_mux_add_adapter(muxc, force, 0, 0);
>>> + if (ret) {
>>> + dev_err(&client->dev, "failed to register master demultiplexer\n");
>>> + return ret;
>>> + }
>>> +
>>> + dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
>>> + client->name);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int pca9641_remove(struct i2c_client *client)
>>> +{
>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>> +
>>> + i2c_mux_del_adapters(muxc);
>>> + return 0;
>>> +}
>>> +
>>> +static struct i2c_driver pca9641_driver = {
>>> + .driver = {
>>> + .name = "pca9641",
>>> + .of_match_table = of_match_ptr(pca9641_of_match),
>>> + },
>>> + .probe = pca9641_probe,
>>> + .remove = pca9641_remove,
>>> + .id_table = pca9641_id,
>>> +};
>>> +
>>> +module_i2c_driver(pca9641_driver);
>>> +
>>> +MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
>>> +MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
>>> +MODULE_LICENSE("GPL v2");
>>> --
>>> 2.9.3
>>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
2018-03-08 5:34 ` Joel Stanley
@ 2018-03-12 6:40 ` ChenKenYY 陳永營 TAO
2018-03-13 3:52 ` Joel Stanley
0 siblings, 1 reply; 6+ messages in thread
From: ChenKenYY 陳永營 TAO @ 2018-03-12 6:40 UTC (permalink / raw)
To: Joel Stanley; +Cc: OpenBMC Maillist
Hi Joel,
Could I use an independent .c file(PCA9641) to upstream this driver?
Because the reference code has probe issue and sperate the difference
device behavior between PCA9541 and PCA9641 by function.
So I think It would be better using an independent .c file.
Best Regards,
Ken
2018-03-08 13:34 GMT+08:00 Joel Stanley <joel@jms.id.au>:
> On Thu, Mar 8, 2018 at 3:36 PM, ChenKenYY 陳永營 TAO
> <chen.kenyy@inventec.com> wrote:
>> Hi Joel,
>>
>> Sure, I can take it, but I need some instructions on the next action.
>
> Okay. I suggest you download the patch from patchwork and apply it to
> the latest kernel release, 4.16-rc4:
>
> https://patchwork.ozlabs.org/patch/726491/
>
> You can download it by clicking the 'mbox' link at the top right of the page.
>
> Now you will have a file called
> RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch.
>
> $ git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> $ cd linux
> $ git checkout -b pca9641-mux v4.16-rc4
> $ git am ~/Downloads/RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch
>
>
> From there, take a look at the comments on the two reviews that Vidya had:
>
> https://patchwork.ozlabs.org/patch/726491/#1580479
> https://patchwork.ozlabs.org/patch/726491/#1582916
>
> Fix those issues, and add your signed off by:
>
> $ git add drivers/i2c/muxes/i2c-mux-pca9541.c
> $ git commit --amend -s
>
> Then test this driver on your board. To do this, modify the device
> tree. You should be able to do this by modifying the ast2500-evb
> device tree, and boot that on your system.
>
> Once this is working, use the checkpatch.pl tool to check for common mistakes:
>
> $ ./scripts/checkpatch.pl drivers/i2c/muxes/i2c-mux-pca9541.c
>
> Then use get_maintainer.pl to get a list of people you should send the patch to:
>
> $ ./scripts/get_maintainer.pl -f drivers/i2c/muxes/i2c-mux-pca9541.c
> Guenter Roeck <linux@roeck-us.net> (maintainer:PCA9541 I2C BUS MASTER
> SELECTOR DRIVER)
> Peter Rosin <peda@axentia.se> (maintainer:I2C MUXES)
> Wolfram Sang <wsa@the-dreams.de> (maintainer:I2C SUBSYSTEM)
> linux-i2c@vger.kernel.org (open list:PCA9541 I2C BUS MASTER SELECTOR DRIVER)
> linux-kernel@vger.kernel.org (open list)
>
> In addition, please add me to this list so I can help. Then send the
> patch out, with a comment in the commit message (below the ---) that
> you have continued this work from the previous author, and have tested
> it on your system.
>
> Cheers,
>
> Joel
>
>>
>> Thanks,
>> Ken
>>
>> 2018-03-08 11:02 GMT+08:00 Joel Stanley <joel@jms.id.au>:
>>> Hello Ken,
>>>
>>> On Fri, Feb 23, 2018 at 3:52 PM, Ken Chen <chen.kenyy@inventec.com> wrote:
>>>> Initial PCA9641 2 chennel I2C bus master arbiter
>>>>
>>>> Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
>>>
>>> The code here looks good. I did some searching, and found that someone
>>> submitted a driver for this part about a year ago:
>>>
>>> https://patchwork.ozlabs.org/patch/726491/
>>>
>>> Unfortunately the submitter did not send another version after it was
>>> reviewed. I suggest we take up the patch that was submitted, make the
>>> changes suggested, and submit it upstream. Are you able to take on
>>> that work?
>>>
>>> Cheers,
>>>
>>> Joel
>>>
>>>> ---
>>>> drivers/i2c/muxes/Kconfig | 9 +
>>>> drivers/i2c/muxes/Makefile | 1 +
>>>> drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
>>>> 3 files changed, 382 insertions(+)
>>>> create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
>>>>
>>>> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
>>>> index 1712132..1cd1ad3 100644
>>>> --- a/drivers/i2c/muxes/Kconfig
>>>> +++ b/drivers/i2c/muxes/Kconfig
>>>> @@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
>>>> This driver can also be built as a module. If so, the module
>>>> will be called i2c-mux-pca954x.
>>>>
>>>> +config I2C_MUX_PCA9641
>>>> + tristate "NXP PCA9641 I2C Master demultiplexer"
>>>> + help
>>>> + If you say yes here you get support for the NXP PCA9641
>>>> + I2C Master demultiplexer with an arbiter function.
>>>> +
>>>> + This driver can also be built as a module. If so, the module
>>>> + will be called i2c-mux-pca9641.
>>>> +
>>>> config I2C_MUX_PINCTRL
>>>> tristate "pinctrl-based I2C multiplexer"
>>>> depends on PINCTRL
>>>> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
>>>> index 4a67d31..f95d5f5 100644
>>>> --- a/drivers/i2c/muxes/Makefile
>>>> +++ b/drivers/i2c/muxes/Makefile
>>>> @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
>>>> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
>>>> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
>>>> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
>>>> +obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
>>>> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
>>>> obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
>>>>
>>>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>>> new file mode 100644
>>>> index 0000000..ca7b816
>>>> --- /dev/null
>>>> +++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>>> @@ -0,0 +1,372 @@
>>>> +/*
>>>> + * I2C demultiplexer driver for PCA9641 bus master demultiplexer
>>>> + *
>>>> + * Copyright (c) 2010 Ericsson AB.
>>>> + *
>>>> + * Author: Ken Chen <chen.kenyy@inventec.com>
>>>> + *
>>>> + * Derived from:
>>>> + *
>>>> + * This file is licensed under the terms of the GNU General Public
>>>> + * License version 2. This program is licensed "as is" without any
>>>> + * warranty of any kind, whether express or implied.
>>>> + */
>>>> +
>>>> +#include <linux/module.h>
>>>> +#include <linux/jiffies.h>
>>>> +#include <linux/delay.h>
>>>> +#include <linux/slab.h>
>>>> +#include <linux/device.h>
>>>> +#include <linux/i2c.h>
>>>> +#include <linux/i2c-mux.h>
>>>> +
>>>> +#include <linux/i2c/pca954x.h>
>>>> +
>>>> +/*
>>>> + * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
>>>> + * connected to a single slave bus.
>>>> + *
>>>> + * It is designed for high reliability dual master I2C bus applications where
>>>> + * correct system operation is required, even when two I2C master issue their
>>>> + * commands at the same time. The arbiter will select a winner and let it work
>>>> + * uninterrupted, and the losing master will take control of the I2C bus after
>>>> + * the winnter has finished. The arbiter also allows for queued requests where
>>>> + * a master requests the downstream bus while the other master has control.
>>>> + *
>>>> + */
>>>> +
>>>> +#define PCA9641_ID 0x01
>>>> +#define PCA9641_ID_MAGIC 0x38
>>>> +
>>>> +#define PCA9641_CONTROL 0x01
>>>> +#define PCA9641_STATUS 0x02
>>>> +#define PCA9641_TIME 0x03
>>>> +
>>>> +#define PCA9641_CTL_LOCK_REQ (1 << 0)
>>>> +#define PCA9641_CTL_LOCK_GRANT (1 << 1)
>>>> +#define PCA9641_CTL_BUS_CONNECT (1 << 2)
>>>> +#define PCA9641_CTL_BUS_INIT (1 << 3)
>>>> +#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
>>>> +#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
>>>> +#define PCA9641_CTL_SMBUS_DIS (1 << 6)
>>>> +#define PCA9641_CTL_PRIORITY (1 << 7)
>>>> +
>>>> +#define PCA9641_STS_OTHER_LOCK (1 << 0)
>>>> +#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
>>>> +#define PCA9641_STS_BUS_HUNG (1 << 2)
>>>> +#define PCA9641_STS_MBOX_EMPTY (1 << 3)
>>>> +#define PCA9641_STS_MBOX_FULL (1 << 4)
>>>> +#define PCA9641_STS_TEST_INT (1 << 5)
>>>> +#define PCA9641_STS_SCL_IO (1 << 6)
>>>> +#define PCA9641_STS_SDA_IO (1 << 7)
>>>> +
>>>> +#define PCA9641_RES_TIME 0x03
>>>> +
>>>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>>>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
>>>> +
>>>> +/* arbitration timeouts, in jiffies */
>>>> +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
>>>> +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
>>>> +
>>>> +/* arbitration retry delays, in us */
>>>> +#define SELECT_DELAY_SHORT 50
>>>> +#define SELECT_DELAY_LONG 1000
>>>> +
>>>> +struct pca9641 {
>>>> + struct i2c_client *client;
>>>> + unsigned long select_timeout;
>>>> + unsigned long arb_timeout;
>>>> +};
>>>> +
>>>> +static const struct i2c_device_id pca9641_id[] = {
>>>> + {"pca9641", 0},
>>>> + {}
>>>> +};
>>>> +
>>>> +MODULE_DEVICE_TABLE(i2c, pca9641_id);
>>>> +
>>>> +#ifdef CONFIG_OF
>>>> +static const struct of_device_id pca9641_of_match[] = {
>>>> + { .compatible = "nxp,pca9641" },
>>>> + {}
>>>> +};
>>>> +#endif
>>>> +
>>>> +/*
>>>> + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>>> + * as they will try to lock the adapter a second time.
>>>> + */
>>>> +static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
>>>> +{
>>>> + struct i2c_adapter *adap = client->adapter;
>>>> + int ret;
>>>> +
>>>> + if (adap->algo->master_xfer) {
>>>> + struct i2c_msg msg;
>>>> + char buf[2];
>>>> +
>>>> + msg.addr = client->addr;
>>>> + msg.flags = 0;
>>>> + msg.len = 2;
>>>> + buf[0] = command;
>>>> + buf[1] = val;
>>>> + msg.buf = buf;
>>>> + ret = __i2c_transfer(adap, &msg, 1);
>>>> + } else {
>>>> + union i2c_smbus_data data;
>>>> +
>>>> + data.byte = val;
>>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>>> + client->flags,
>>>> + I2C_SMBUS_WRITE,
>>>> + command,
>>>> + I2C_SMBUS_BYTE_DATA, &data);
>>>> + }
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +/*
>>>> + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>>> + * as they will try to lock adapter a second time.
>>>> + */
>>>> +static int pca9641_reg_read(struct i2c_client *client, u8 command)
>>>> +{
>>>> + struct i2c_adapter *adap = client->adapter;
>>>> + int ret;
>>>> + u8 val;
>>>> +
>>>> + if (adap->algo->master_xfer) {
>>>> + struct i2c_msg msg[2] = {
>>>> + {
>>>> + .addr = client->addr,
>>>> + .flags = 0,
>>>> + .len = 1,
>>>> + .buf = &command
>>>> + },
>>>> + {
>>>> + .addr = client->addr,
>>>> + .flags = I2C_M_RD,
>>>> + .len = 1,
>>>> + .buf = &val
>>>> + }
>>>> + };
>>>> + ret = __i2c_transfer(adap, msg, 2);
>>>> + if (ret == 2)
>>>> + ret = val;
>>>> + else if (ret >= 0)
>>>> + ret = -EIO;
>>>> + } else {
>>>> + union i2c_smbus_data data;
>>>> +
>>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>>> + client->flags,
>>>> + I2C_SMBUS_READ,
>>>> + command,
>>>> + I2C_SMBUS_BYTE_DATA, &data);
>>>> + if (!ret)
>>>> + ret = data.byte;
>>>> + }
>>>> + return ret;
>>>> +}
>>>> +
>>>> +/*
>>>> + * Arbitration management functions
>>>> + */
>>>> +static void pca9641_release_bus(struct i2c_client *client)
>>>> +{
>>>> + int reg;
>>>> +
>>>> + pca9641_reg_write(client, PCA9641_CONTROL, 0);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Channel arbitration
>>>> + *
>>>> + * Return values:
>>>> + * <0: error
>>>> + * 0 : bus not acquired
>>>> + * 1 : bus acquired
>>>> + */
>>>> +static int pca9641_arbitrate(struct i2c_client *client)
>>>> +{
>>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>> + int reg_ctl, reg_sts;
>>>> +
>>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>>> + if (reg_ctl < 0)
>>>> + return reg_ctl;
>>>> + reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
>>>> +
>>>> + if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
>>>> + /*
>>>> + * Bus is off. Request ownership or turn it on unless
>>>> + * other master requested ownership.
>>>> + */
>>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>> +
>>>> + udelay(100);
>>>> +
>>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>>> +
>>>> + if (lock_grant(reg_ctl)) {
>>>> + /*
>>>> + * Other master did not request ownership,
>>>> + * or arbitration timeout expired. Take the bus.
>>>> + */
>>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>> + data->select_timeout = SELECT_DELAY_SHORT;
>>>> +
>>>> + return 1;
>>>> + } else {
>>>> + /*
>>>> + * Other master requested ownership.
>>>> + * Set extra long timeout to give it time to acquire it.
>>>> + */
>>>> + data->select_timeout = SELECT_DELAY_LONG * 2;
>>>> + }
>>>> + } else if (lock_grant(reg_ctl)) {
>>>> + /*
>>>> + * Bus is on, and we own it. We are done with acquisition.
>>>> + */
>>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>> +
>>>> + return 1;
>>>> + } else if (other_lock(reg_sts)) {
>>>> + /*
>>>> + * Other master owns the bus.
>>>> + * If arbitration timeout has expired, force ownership.
>>>> + * Otherwise request it.
>>>> + */
>>>> + data->select_timeout = SELECT_DELAY_LONG;
>>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>> +
>>>> + /*
>>>> + * if (time_is_before_eq_jiffies(data->arb_timeout)) {
>>>> + * TODO:Time is up, take the bus and reset it.
>>>> + *
>>>> + *} else {
>>>> + * TODO: Request bus ownership if needed
>>>> + *
>>>> + *}
>>>> + */
>>>> + }
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
>>>> +{
>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>> + struct i2c_client *client = data->client;
>>>> + int ret;
>>>> + unsigned long timeout = jiffies + ARB2_TIMEOUT;
>>>> + /* give up after this time */
>>>> +
>>>> + data->arb_timeout = jiffies + ARB_TIMEOUT;
>>>> + /* force bus ownership after this time */
>>>> +
>>>> + do {
>>>> + ret = pca9641_arbitrate(client);
>>>> + if (ret)
>>>> + return ret < 0 ? ret : 0;
>>>> +
>>>> + if (data->select_timeout == SELECT_DELAY_SHORT)
>>>> + udelay(data->select_timeout);
>>>> + else
>>>> + msleep(data->select_timeout / 1000);
>>>> + } while (time_is_after_eq_jiffies(timeout));
>>>> +
>>>> + return -ETIMEDOUT;
>>>> +}
>>>> +
>>>> +static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
>>>> +{
>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>> + struct i2c_client *client = data->client;
>>>> +
>>>> + pca9641_release_bus(client);
>>>> + return 0;
>>>> +}
>>>> +
>>>> +/*
>>>> + * I2C init/probing/exit functions
>>>> + */
>>>> +static int pca9641_probe(struct i2c_client *client,
>>>> + const struct i2c_device_id *id)
>>>> +{
>>>> + struct i2c_adapter *adap = client->adapter;
>>>> + struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
>>>> + struct i2c_mux_core *muxc;
>>>> + struct pca9641 *data;
>>>> + int force;
>>>> + int ret;
>>>> +
>>>> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
>>>> + return -ENODEV;
>>>> +
>>>> + /*
>>>> + * I2C accesses are unprotected here.
>>>> + * We have to lock the adapter before releasing the bus.
>>>> + */
>>>> + i2c_lock_adapter(adap);
>>>> + pca9641_release_bus(client);
>>>> + i2c_unlock_adapter(adap);
>>>> +
>>>> + /* Create mux adapter */
>>>> +
>>>> + force = 0;
>>>> + if (pdata)
>>>> + force = pdata->modes[0].adap_id;
>>>> + muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
>>>> + I2C_MUX_ARBITRATOR,
>>>> + pca9641_select_chan, pca9641_release_chan);
>>>> + if (!muxc)
>>>> + return -ENOMEM;
>>>> +
>>>> + data = i2c_mux_priv(muxc);
>>>> + data->client = client;
>>>> +
>>>> + i2c_set_clientdata(client, muxc);
>>>> +
>>>> +
>>>> + ret = i2c_mux_add_adapter(muxc, force, 0, 0);
>>>> + if (ret) {
>>>> + dev_err(&client->dev, "failed to register master demultiplexer\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> + dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
>>>> + client->name);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int pca9641_remove(struct i2c_client *client)
>>>> +{
>>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>>> +
>>>> + i2c_mux_del_adapters(muxc);
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static struct i2c_driver pca9641_driver = {
>>>> + .driver = {
>>>> + .name = "pca9641",
>>>> + .of_match_table = of_match_ptr(pca9641_of_match),
>>>> + },
>>>> + .probe = pca9641_probe,
>>>> + .remove = pca9641_remove,
>>>> + .id_table = pca9641_id,
>>>> +};
>>>> +
>>>> +module_i2c_driver(pca9641_driver);
>>>> +
>>>> +MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
>>>> +MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
>>>> +MODULE_LICENSE("GPL v2");
>>>> --
>>>> 2.9.3
>>>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver
2018-03-12 6:40 ` ChenKenYY 陳永營 TAO
@ 2018-03-13 3:52 ` Joel Stanley
0 siblings, 0 replies; 6+ messages in thread
From: Joel Stanley @ 2018-03-13 3:52 UTC (permalink / raw)
To: ChenKenYY 陳永營 TAO; +Cc: OpenBMC Maillist
On Mon, Mar 12, 2018 at 5:10 PM, ChenKenYY 陳永營 TAO
<chen.kenyy@inventec.com> wrote:
> Hi Joel,
>
> Could I use an independent .c file(PCA9641) to upstream this driver?
> Because the reference code has probe issue and sperate the difference
> device behavior between PCA9541 and PCA9641 by function.
> So I think It would be better using an independent .c file.
If you think that there is a good reason to do a separate
implementation, then we should submit your version upstream and add
that information to your commit message.
Cheers,
Joel
>
>
> Best Regards,
> Ken
>
> 2018-03-08 13:34 GMT+08:00 Joel Stanley <joel@jms.id.au>:
>> On Thu, Mar 8, 2018 at 3:36 PM, ChenKenYY 陳永營 TAO
>> <chen.kenyy@inventec.com> wrote:
>>> Hi Joel,
>>>
>>> Sure, I can take it, but I need some instructions on the next action.
>>
>> Okay. I suggest you download the patch from patchwork and apply it to
>> the latest kernel release, 4.16-rc4:
>>
>> https://patchwork.ozlabs.org/patch/726491/
>>
>> You can download it by clicking the 'mbox' link at the top right of the page.
>>
>> Now you will have a file called
>> RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch.
>>
>> $ git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>> $ cd linux
>> $ git checkout -b pca9641-mux v4.16-rc4
>> $ git am ~/Downloads/RFC-i2c-mux-Driver-for-PCA9641-I2C-Master-Arbiter.patch
>>
>>
>> From there, take a look at the comments on the two reviews that Vidya had:
>>
>> https://patchwork.ozlabs.org/patch/726491/#1580479
>> https://patchwork.ozlabs.org/patch/726491/#1582916
>>
>> Fix those issues, and add your signed off by:
>>
>> $ git add drivers/i2c/muxes/i2c-mux-pca9541.c
>> $ git commit --amend -s
>>
>> Then test this driver on your board. To do this, modify the device
>> tree. You should be able to do this by modifying the ast2500-evb
>> device tree, and boot that on your system.
>>
>> Once this is working, use the checkpatch.pl tool to check for common mistakes:
>>
>> $ ./scripts/checkpatch.pl drivers/i2c/muxes/i2c-mux-pca9541.c
>>
>> Then use get_maintainer.pl to get a list of people you should send the patch to:
>>
>> $ ./scripts/get_maintainer.pl -f drivers/i2c/muxes/i2c-mux-pca9541.c
>> Guenter Roeck <linux@roeck-us.net> (maintainer:PCA9541 I2C BUS MASTER
>> SELECTOR DRIVER)
>> Peter Rosin <peda@axentia.se> (maintainer:I2C MUXES)
>> Wolfram Sang <wsa@the-dreams.de> (maintainer:I2C SUBSYSTEM)
>> linux-i2c@vger.kernel.org (open list:PCA9541 I2C BUS MASTER SELECTOR DRIVER)
>> linux-kernel@vger.kernel.org (open list)
>>
>> In addition, please add me to this list so I can help. Then send the
>> patch out, with a comment in the commit message (below the ---) that
>> you have continued this work from the previous author, and have tested
>> it on your system.
>>
>> Cheers,
>>
>> Joel
>>
>>>
>>> Thanks,
>>> Ken
>>>
>>> 2018-03-08 11:02 GMT+08:00 Joel Stanley <joel@jms.id.au>:
>>>> Hello Ken,
>>>>
>>>> On Fri, Feb 23, 2018 at 3:52 PM, Ken Chen <chen.kenyy@inventec.com> wrote:
>>>>> Initial PCA9641 2 chennel I2C bus master arbiter
>>>>>
>>>>> Signed-off-by: Ken Chen <chen.kenyy@inventec.com>
>>>>
>>>> The code here looks good. I did some searching, and found that someone
>>>> submitted a driver for this part about a year ago:
>>>>
>>>> https://patchwork.ozlabs.org/patch/726491/
>>>>
>>>> Unfortunately the submitter did not send another version after it was
>>>> reviewed. I suggest we take up the patch that was submitted, make the
>>>> changes suggested, and submit it upstream. Are you able to take on
>>>> that work?
>>>>
>>>> Cheers,
>>>>
>>>> Joel
>>>>
>>>>> ---
>>>>> drivers/i2c/muxes/Kconfig | 9 +
>>>>> drivers/i2c/muxes/Makefile | 1 +
>>>>> drivers/i2c/muxes/i2c-mux-pca9641.c | 372 ++++++++++++++++++++++++++++++++++++
>>>>> 3 files changed, 382 insertions(+)
>>>>> create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c
>>>>>
>>>>> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
>>>>> index 1712132..1cd1ad3 100644
>>>>> --- a/drivers/i2c/muxes/Kconfig
>>>>> +++ b/drivers/i2c/muxes/Kconfig
>>>>> @@ -73,6 +73,15 @@ config I2C_MUX_PCA954x
>>>>> This driver can also be built as a module. If so, the module
>>>>> will be called i2c-mux-pca954x.
>>>>>
>>>>> +config I2C_MUX_PCA9641
>>>>> + tristate "NXP PCA9641 I2C Master demultiplexer"
>>>>> + help
>>>>> + If you say yes here you get support for the NXP PCA9641
>>>>> + I2C Master demultiplexer with an arbiter function.
>>>>> +
>>>>> + This driver can also be built as a module. If so, the module
>>>>> + will be called i2c-mux-pca9641.
>>>>> +
>>>>> config I2C_MUX_PINCTRL
>>>>> tristate "pinctrl-based I2C multiplexer"
>>>>> depends on PINCTRL
>>>>> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
>>>>> index 4a67d31..f95d5f5 100644
>>>>> --- a/drivers/i2c/muxes/Makefile
>>>>> +++ b/drivers/i2c/muxes/Makefile
>>>>> @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C_MUX_LTC4306) += i2c-mux-ltc4306.o
>>>>> obj-$(CONFIG_I2C_MUX_MLXCPLD) += i2c-mux-mlxcpld.o
>>>>> obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
>>>>> obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
>>>>> +obj-$(CONFIG_I2C_MUX_PCA9641) += i2c-mux-pca9641.o
>>>>> obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
>>>>> obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o
>>>>>
>>>>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9641.c b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>>>> new file mode 100644
>>>>> index 0000000..ca7b816
>>>>> --- /dev/null
>>>>> +++ b/drivers/i2c/muxes/i2c-mux-pca9641.c
>>>>> @@ -0,0 +1,372 @@
>>>>> +/*
>>>>> + * I2C demultiplexer driver for PCA9641 bus master demultiplexer
>>>>> + *
>>>>> + * Copyright (c) 2010 Ericsson AB.
>>>>> + *
>>>>> + * Author: Ken Chen <chen.kenyy@inventec.com>
>>>>> + *
>>>>> + * Derived from:
>>>>> + *
>>>>> + * This file is licensed under the terms of the GNU General Public
>>>>> + * License version 2. This program is licensed "as is" without any
>>>>> + * warranty of any kind, whether express or implied.
>>>>> + */
>>>>> +
>>>>> +#include <linux/module.h>
>>>>> +#include <linux/jiffies.h>
>>>>> +#include <linux/delay.h>
>>>>> +#include <linux/slab.h>
>>>>> +#include <linux/device.h>
>>>>> +#include <linux/i2c.h>
>>>>> +#include <linux/i2c-mux.h>
>>>>> +
>>>>> +#include <linux/i2c/pca954x.h>
>>>>> +
>>>>> +/*
>>>>> + * The PCA9641 is two I2C bus masters demultiplexer. It supports two I2C masters
>>>>> + * connected to a single slave bus.
>>>>> + *
>>>>> + * It is designed for high reliability dual master I2C bus applications where
>>>>> + * correct system operation is required, even when two I2C master issue their
>>>>> + * commands at the same time. The arbiter will select a winner and let it work
>>>>> + * uninterrupted, and the losing master will take control of the I2C bus after
>>>>> + * the winnter has finished. The arbiter also allows for queued requests where
>>>>> + * a master requests the downstream bus while the other master has control.
>>>>> + *
>>>>> + */
>>>>> +
>>>>> +#define PCA9641_ID 0x01
>>>>> +#define PCA9641_ID_MAGIC 0x38
>>>>> +
>>>>> +#define PCA9641_CONTROL 0x01
>>>>> +#define PCA9641_STATUS 0x02
>>>>> +#define PCA9641_TIME 0x03
>>>>> +
>>>>> +#define PCA9641_CTL_LOCK_REQ (1 << 0)
>>>>> +#define PCA9641_CTL_LOCK_GRANT (1 << 1)
>>>>> +#define PCA9641_CTL_BUS_CONNECT (1 << 2)
>>>>> +#define PCA9641_CTL_BUS_INIT (1 << 3)
>>>>> +#define PCA9641_CTL_SMBUS_SWRST (1 << 4)
>>>>> +#define PCA9641_CTL_IDLE_TIMER_DIS (1 << 5)
>>>>> +#define PCA9641_CTL_SMBUS_DIS (1 << 6)
>>>>> +#define PCA9641_CTL_PRIORITY (1 << 7)
>>>>> +
>>>>> +#define PCA9641_STS_OTHER_LOCK (1 << 0)
>>>>> +#define PCA9641_STS_BUS_INIT_FAIL (1 << 1)
>>>>> +#define PCA9641_STS_BUS_HUNG (1 << 2)
>>>>> +#define PCA9641_STS_MBOX_EMPTY (1 << 3)
>>>>> +#define PCA9641_STS_MBOX_FULL (1 << 4)
>>>>> +#define PCA9641_STS_TEST_INT (1 << 5)
>>>>> +#define PCA9641_STS_SCL_IO (1 << 6)
>>>>> +#define PCA9641_STS_SDA_IO (1 << 7)
>>>>> +
>>>>> +#define PCA9641_RES_TIME 0x03
>>>>> +
>>>>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>>>>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
>>>>> +
>>>>> +/* arbitration timeouts, in jiffies */
>>>>> +#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
>>>>> +#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
>>>>> +
>>>>> +/* arbitration retry delays, in us */
>>>>> +#define SELECT_DELAY_SHORT 50
>>>>> +#define SELECT_DELAY_LONG 1000
>>>>> +
>>>>> +struct pca9641 {
>>>>> + struct i2c_client *client;
>>>>> + unsigned long select_timeout;
>>>>> + unsigned long arb_timeout;
>>>>> +};
>>>>> +
>>>>> +static const struct i2c_device_id pca9641_id[] = {
>>>>> + {"pca9641", 0},
>>>>> + {}
>>>>> +};
>>>>> +
>>>>> +MODULE_DEVICE_TABLE(i2c, pca9641_id);
>>>>> +
>>>>> +#ifdef CONFIG_OF
>>>>> +static const struct of_device_id pca9641_of_match[] = {
>>>>> + { .compatible = "nxp,pca9641" },
>>>>> + {}
>>>>> +};
>>>>> +#endif
>>>>> +
>>>>> +/*
>>>>> + * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>>>> + * as they will try to lock the adapter a second time.
>>>>> + */
>>>>> +static int pca9641_reg_write(struct i2c_client *client, u8 command, u8 val)
>>>>> +{
>>>>> + struct i2c_adapter *adap = client->adapter;
>>>>> + int ret;
>>>>> +
>>>>> + if (adap->algo->master_xfer) {
>>>>> + struct i2c_msg msg;
>>>>> + char buf[2];
>>>>> +
>>>>> + msg.addr = client->addr;
>>>>> + msg.flags = 0;
>>>>> + msg.len = 2;
>>>>> + buf[0] = command;
>>>>> + buf[1] = val;
>>>>> + msg.buf = buf;
>>>>> + ret = __i2c_transfer(adap, &msg, 1);
>>>>> + } else {
>>>>> + union i2c_smbus_data data;
>>>>> +
>>>>> + data.byte = val;
>>>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>>>> + client->flags,
>>>>> + I2C_SMBUS_WRITE,
>>>>> + command,
>>>>> + I2C_SMBUS_BYTE_DATA, &data);
>>>>> + }
>>>>> +
>>>>> + return ret;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
>>>>> + * as they will try to lock adapter a second time.
>>>>> + */
>>>>> +static int pca9641_reg_read(struct i2c_client *client, u8 command)
>>>>> +{
>>>>> + struct i2c_adapter *adap = client->adapter;
>>>>> + int ret;
>>>>> + u8 val;
>>>>> +
>>>>> + if (adap->algo->master_xfer) {
>>>>> + struct i2c_msg msg[2] = {
>>>>> + {
>>>>> + .addr = client->addr,
>>>>> + .flags = 0,
>>>>> + .len = 1,
>>>>> + .buf = &command
>>>>> + },
>>>>> + {
>>>>> + .addr = client->addr,
>>>>> + .flags = I2C_M_RD,
>>>>> + .len = 1,
>>>>> + .buf = &val
>>>>> + }
>>>>> + };
>>>>> + ret = __i2c_transfer(adap, msg, 2);
>>>>> + if (ret == 2)
>>>>> + ret = val;
>>>>> + else if (ret >= 0)
>>>>> + ret = -EIO;
>>>>> + } else {
>>>>> + union i2c_smbus_data data;
>>>>> +
>>>>> + ret = adap->algo->smbus_xfer(adap, client->addr,
>>>>> + client->flags,
>>>>> + I2C_SMBUS_READ,
>>>>> + command,
>>>>> + I2C_SMBUS_BYTE_DATA, &data);
>>>>> + if (!ret)
>>>>> + ret = data.byte;
>>>>> + }
>>>>> + return ret;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * Arbitration management functions
>>>>> + */
>>>>> +static void pca9641_release_bus(struct i2c_client *client)
>>>>> +{
>>>>> + int reg;
>>>>> +
>>>>> + pca9641_reg_write(client, PCA9641_CONTROL, 0);
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * Channel arbitration
>>>>> + *
>>>>> + * Return values:
>>>>> + * <0: error
>>>>> + * 0 : bus not acquired
>>>>> + * 1 : bus acquired
>>>>> + */
>>>>> +static int pca9641_arbitrate(struct i2c_client *client)
>>>>> +{
>>>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>>> + int reg_ctl, reg_sts;
>>>>> +
>>>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>>>> + if (reg_ctl < 0)
>>>>> + return reg_ctl;
>>>>> + reg_sts = pca9641_reg_read(client, PCA9641_STATUS);
>>>>> +
>>>>> + if (!other_lock(reg_sts) && !lock_grant(reg_ctl)) {
>>>>> + /*
>>>>> + * Bus is off. Request ownership or turn it on unless
>>>>> + * other master requested ownership.
>>>>> + */
>>>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>>> +
>>>>> + udelay(100);
>>>>> +
>>>>> + reg_ctl = pca9641_reg_read(client, PCA9641_CONTROL);
>>>>> +
>>>>> + if (lock_grant(reg_ctl)) {
>>>>> + /*
>>>>> + * Other master did not request ownership,
>>>>> + * or arbitration timeout expired. Take the bus.
>>>>> + */
>>>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>>> + data->select_timeout = SELECT_DELAY_SHORT;
>>>>> +
>>>>> + return 1;
>>>>> + } else {
>>>>> + /*
>>>>> + * Other master requested ownership.
>>>>> + * Set extra long timeout to give it time to acquire it.
>>>>> + */
>>>>> + data->select_timeout = SELECT_DELAY_LONG * 2;
>>>>> + }
>>>>> + } else if (lock_grant(reg_ctl)) {
>>>>> + /*
>>>>> + * Bus is on, and we own it. We are done with acquisition.
>>>>> + */
>>>>> + reg_ctl |= PCA9641_CTL_BUS_CONNECT | PCA9641_CTL_LOCK_REQ;
>>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>>> +
>>>>> + return 1;
>>>>> + } else if (other_lock(reg_sts)) {
>>>>> + /*
>>>>> + * Other master owns the bus.
>>>>> + * If arbitration timeout has expired, force ownership.
>>>>> + * Otherwise request it.
>>>>> + */
>>>>> + data->select_timeout = SELECT_DELAY_LONG;
>>>>> + reg_ctl |= PCA9641_CTL_LOCK_REQ;
>>>>> + pca9641_reg_write(client, PCA9641_CONTROL, reg_ctl);
>>>>> +
>>>>> + /*
>>>>> + * if (time_is_before_eq_jiffies(data->arb_timeout)) {
>>>>> + * TODO:Time is up, take the bus and reset it.
>>>>> + *
>>>>> + *} else {
>>>>> + * TODO: Request bus ownership if needed
>>>>> + *
>>>>> + *}
>>>>> + */
>>>>> + }
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static int pca9641_select_chan(struct i2c_mux_core *muxc, u32 chan)
>>>>> +{
>>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>>> + struct i2c_client *client = data->client;
>>>>> + int ret;
>>>>> + unsigned long timeout = jiffies + ARB2_TIMEOUT;
>>>>> + /* give up after this time */
>>>>> +
>>>>> + data->arb_timeout = jiffies + ARB_TIMEOUT;
>>>>> + /* force bus ownership after this time */
>>>>> +
>>>>> + do {
>>>>> + ret = pca9641_arbitrate(client);
>>>>> + if (ret)
>>>>> + return ret < 0 ? ret : 0;
>>>>> +
>>>>> + if (data->select_timeout == SELECT_DELAY_SHORT)
>>>>> + udelay(data->select_timeout);
>>>>> + else
>>>>> + msleep(data->select_timeout / 1000);
>>>>> + } while (time_is_after_eq_jiffies(timeout));
>>>>> +
>>>>> + return -ETIMEDOUT;
>>>>> +}
>>>>> +
>>>>> +static int pca9641_release_chan(struct i2c_mux_core *muxc, u32 chan)
>>>>> +{
>>>>> + struct pca9641 *data = i2c_mux_priv(muxc);
>>>>> + struct i2c_client *client = data->client;
>>>>> +
>>>>> + pca9641_release_bus(client);
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * I2C init/probing/exit functions
>>>>> + */
>>>>> +static int pca9641_probe(struct i2c_client *client,
>>>>> + const struct i2c_device_id *id)
>>>>> +{
>>>>> + struct i2c_adapter *adap = client->adapter;
>>>>> + struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
>>>>> + struct i2c_mux_core *muxc;
>>>>> + struct pca9641 *data;
>>>>> + int force;
>>>>> + int ret;
>>>>> +
>>>>> + if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
>>>>> + return -ENODEV;
>>>>> +
>>>>> + /*
>>>>> + * I2C accesses are unprotected here.
>>>>> + * We have to lock the adapter before releasing the bus.
>>>>> + */
>>>>> + i2c_lock_adapter(adap);
>>>>> + pca9641_release_bus(client);
>>>>> + i2c_unlock_adapter(adap);
>>>>> +
>>>>> + /* Create mux adapter */
>>>>> +
>>>>> + force = 0;
>>>>> + if (pdata)
>>>>> + force = pdata->modes[0].adap_id;
>>>>> + muxc = i2c_mux_alloc(adap, &client->dev, 8, sizeof(*data),
>>>>> + I2C_MUX_ARBITRATOR,
>>>>> + pca9641_select_chan, pca9641_release_chan);
>>>>> + if (!muxc)
>>>>> + return -ENOMEM;
>>>>> +
>>>>> + data = i2c_mux_priv(muxc);
>>>>> + data->client = client;
>>>>> +
>>>>> + i2c_set_clientdata(client, muxc);
>>>>> +
>>>>> +
>>>>> + ret = i2c_mux_add_adapter(muxc, force, 0, 0);
>>>>> + if (ret) {
>>>>> + dev_err(&client->dev, "failed to register master demultiplexer\n");
>>>>> + return ret;
>>>>> + }
>>>>> +
>>>>> + dev_info(&client->dev, "registered master demultiplexer for I2C %s\n",
>>>>> + client->name);
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static int pca9641_remove(struct i2c_client *client)
>>>>> +{
>>>>> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
>>>>> +
>>>>> + i2c_mux_del_adapters(muxc);
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static struct i2c_driver pca9641_driver = {
>>>>> + .driver = {
>>>>> + .name = "pca9641",
>>>>> + .of_match_table = of_match_ptr(pca9641_of_match),
>>>>> + },
>>>>> + .probe = pca9641_probe,
>>>>> + .remove = pca9641_remove,
>>>>> + .id_table = pca9641_id,
>>>>> +};
>>>>> +
>>>>> +module_i2c_driver(pca9641_driver);
>>>>> +
>>>>> +MODULE_AUTHOR("Ken Chen <chen.kenyy@inventec.com>");
>>>>> +MODULE_DESCRIPTION("PCA9641 I2C master demultiplexer driver");
>>>>> +MODULE_LICENSE("GPL v2");
>>>>> --
>>>>> 2.9.3
>>>>>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-03-13 3:53 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-02-23 5:22 [PATCH linux dev-4.13] drivers: i2c: master arbiter: create driver Ken Chen
2018-03-08 3:02 ` Joel Stanley
2018-03-08 5:06 ` ChenKenYY 陳永營 TAO
2018-03-08 5:34 ` Joel Stanley
2018-03-12 6:40 ` ChenKenYY 陳永營 TAO
2018-03-13 3:52 ` Joel Stanley
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