| Message ID | 1475853669-22480-4-git-send-email-pantelis.antoniou@konsulko.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On 2016-10-07 17:21, Pantelis Antoniou wrote: > From: Georgi Vlaev <gvlaev@juniper.net> > > Add support for Juniper I2C Slave RE multiplexer driver. > > This I2C multiplexer driver allows the RE to access some of > the FPC I2C buses. It's compatible only with the FPC variant of the > I2CS. > > Signed-off-by: Georgi Vlaev <gvlaev@juniper.net> > Signed-off-by: Guenter Roeck <groeck@juniper.net> > [Ported from Juniper kernel] > Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> > --- > drivers/i2c/muxes/Kconfig | 10 +++ > drivers/i2c/muxes/Makefile | 1 + > drivers/i2c/muxes/i2c-mux-i2cs.c | 155 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 166 insertions(+) > create mode 100644 drivers/i2c/muxes/i2c-mux-i2cs.c > > diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig > index f45a9cb..c95380d 100644 > --- a/drivers/i2c/muxes/Kconfig > +++ b/drivers/i2c/muxes/Kconfig > @@ -30,6 +30,16 @@ config I2C_MUX_GPIO > This driver can also be built as a module. If so, the module > will be called i2c-mux-gpio. > > +config I2C_MUX_I2CS > + tristate "Juniper I2C Slave MFD client RE multiplexer" > + depends on MFD_JUNIPER_I2CS > + help > + Select this to enable the Juniper I2C Slave RE multiplexer driver > + on the relevant Juniper platforms. > + > + This driver can also be built as a module. If so, the module > + will be called i2c-mux-i2cs. > + > config I2C_MUX_PCA9541 > tristate "NXP PCA9541 I2C Master Selector" > help > diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile > index 78d8cba..45b4287 100644 > --- a/drivers/i2c/muxes/Makefile > +++ b/drivers/i2c/muxes/Makefile > @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o > obj-$(CONFIG_I2C_DEMUX_PINCTRL) += i2c-demux-pinctrl.o > > obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o > +obj-$(CONFIG_I2C_MUX_I2CS) += i2c-mux-i2cs.o > obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o > obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o > obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o > diff --git a/drivers/i2c/muxes/i2c-mux-i2cs.c b/drivers/i2c/muxes/i2c-mux-i2cs.c Please name the file i2c-mux-jnx-i2cs.c. Or something else a bit more specific. > new file mode 100644 > index 0000000..c498a44 > --- /dev/null > +++ b/drivers/i2c/muxes/i2c-mux-i2cs.c > @@ -0,0 +1,155 @@ > +/* > + * Juniper Networks I2CS RE mux driver > + * > + * Copyright (C) 2012, 2013, 2014 Juniper Networks. All rights reserved. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/init.h> init? > +#include <linux/device.h> > +#include <linux/module.h> > +#include <linux/kernel.h> > +#include <linux/i2c.h> > +#include <linux/i2c-mux.h> > +#include <linux/regmap.h> regmap? > +#include <linux/platform_device.h> > +#include <linux/mfd/jnx-i2cs-core.h> > + > +#define MISC_IO_RE_EN 0x01 > + > +/* > + * Read/write to mux register. > + * Don't use i2c_transfer()/i2c_smbus_xfer() > + * for this as they will try to lock adapter a second time > + */ If this is the only concern, you should consider making this gate mux-locked instead of parent-locked. Then you can avoid all these unlocked games. But there are caveats, so you better read Documentation/i2c/i2c-topology for the details before you change. > +static int i2cs_mux_read_byte(struct i2c_client *client, > + u8 offset, u8 *val) > +{ > + struct i2c_msg msg[2]; > + > + msg[0].addr = client->addr; > + msg[0].flags = 0; > + msg[0].len = 1; > + msg[0].buf = &offset; > + > + msg[1].addr = client->addr; > + msg[1].flags = I2C_M_RD; > + msg[1].len = 1; > + msg[1].buf = val; > + > + return client->adapter->algo->master_xfer(client->adapter, msg, 2); If you still want to be parent-locked, use __i2c_transfer. In either case, consider adding code that handles the case of no algo->master_xfer (some i2c adapters only support algo->smbus_xfer). > +} > + > +static int i2cs_mux_write_byte(struct i2c_client *client, u8 offset, u8 val) > +{ > + struct i2c_msg msg; > + char buf[2]; > + > + msg.addr = client->addr; > + msg.flags = 0; > + msg.len = 2; > + buf[0] = offset; > + buf[1] = val; > + msg.buf = buf; > + > + return client->adapter->algo->master_xfer(client->adapter, &msg, 1); > +} > + > +static int i2cs_mux_select(struct i2c_mux_core *muxc, u32 chan) > +{ > + int ret; > + u8 val = 0; > + struct i2c_client *client = i2c_mux_priv(muxc); > + > + ret = i2cs_mux_read_byte(client, I2CS_MISC_IO, &val); > + if (ret < 0) > + return ret; > + > + val |= MISC_IO_RE_EN; > + ret = i2cs_mux_write_byte(client, I2CS_MISC_IO, val); > + To me, it sounds as if I2CS_MISC_IO is a register with more than one bit and that you are open to nasty races here. You probably need to interact with the mfd parent and arrange some locking. > + return ret; > +} > + > +static int i2cs_mux_deselect(struct i2c_mux_core *muxc, u32 chan) > +{ > + int ret; > + u8 val = 0; > + struct i2c_client *client = i2c_mux_priv(muxc); > + > + ret = i2cs_mux_read_byte(client, I2CS_MISC_IO, &val); > + if (ret < 0) > + return ret; > + > + val &= ~MISC_IO_RE_EN; > + ret = i2cs_mux_write_byte(client, I2CS_MISC_IO, val); > + > + return 0; > +} > + > +static int i2cs_mux_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct i2c_client *client; > + struct i2c_mux_core *muxc; > + int ret; > + > + if (!dev->parent) > + return -ENODEV; > + > + client = i2c_verify_client(dev->parent); > + if (!client) > + return -ENODEV; > + > + muxc = i2c_mux_alloc(client->adapter, &client->dev, 1, 0, 0, > + i2cs_mux_select, i2cs_mux_deselect); You only have one child adapter, making this a gate. Please use the I2C_MUX_GATE flag which should be available in 4.9. This also affects the preferred devicetree, see comment on that patch. > + if (!muxc) > + return -ENOMEM; > + muxc->priv = client; > + > + ret = i2c_mux_add_adapter(muxc, 0, 0, 0); > + if (ret) > + return ret; > + > + platform_set_drvdata(pdev, muxc); > + > + return 0; > +} > + > +static int i2cs_mux_remove(struct platform_device *pdev) > +{ > + i2c_mux_del_adapters(platform_get_drvdata(pdev)); > + > + return 0; > +} > + > +static const struct of_device_id i2cs_mux_of_match[] = { > + { .compatible = "jnx,i2c-mux-i2cs", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, i2cs_mux_of_match); > + > +static struct platform_driver i2cs_mux_driver = { > + .driver = { > + .name = "i2c-mux-i2cs", > + .owner = THIS_MODULE, Drop this line. Cheers, Peter > + .of_match_table = of_match_ptr(i2cs_mux_of_match), > + }, > + .probe = i2cs_mux_probe, > + .remove = i2cs_mux_remove, > +}; > +module_platform_driver(i2cs_mux_driver); > + > +MODULE_DESCRIPTION("Juniper Networks I2CS RE Mux driver"); > +MODULE_AUTHOR("Georgi Vlaev <gvlaev@juniper.net>"); > +MODULE_LICENSE("GPL"); > +MODULE_ALIAS("platform:i2c-mux-i2cs"); > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig index f45a9cb..c95380d 100644 --- a/drivers/i2c/muxes/Kconfig +++ b/drivers/i2c/muxes/Kconfig @@ -30,6 +30,16 @@ config I2C_MUX_GPIO This driver can also be built as a module. If so, the module will be called i2c-mux-gpio. +config I2C_MUX_I2CS + tristate "Juniper I2C Slave MFD client RE multiplexer" + depends on MFD_JUNIPER_I2CS + help + Select this to enable the Juniper I2C Slave RE multiplexer driver + on the relevant Juniper platforms. + + This driver can also be built as a module. If so, the module + will be called i2c-mux-i2cs. + config I2C_MUX_PCA9541 tristate "NXP PCA9541 I2C Master Selector" help diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile index 78d8cba..45b4287 100644 --- a/drivers/i2c/muxes/Makefile +++ b/drivers/i2c/muxes/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o obj-$(CONFIG_I2C_DEMUX_PINCTRL) += i2c-demux-pinctrl.o obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o +obj-$(CONFIG_I2C_MUX_I2CS) += i2c-mux-i2cs.o obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o diff --git a/drivers/i2c/muxes/i2c-mux-i2cs.c b/drivers/i2c/muxes/i2c-mux-i2cs.c new file mode 100644 index 0000000..c498a44 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-i2cs.c @@ -0,0 +1,155 @@ +/* + * Juniper Networks I2CS RE mux driver + * + * Copyright (C) 2012, 2013, 2014 Juniper Networks. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/init.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/i2c.h> +#include <linux/i2c-mux.h> +#include <linux/regmap.h> +#include <linux/platform_device.h> +#include <linux/mfd/jnx-i2cs-core.h> + +#define MISC_IO_RE_EN 0x01 + +/* + * Read/write to mux register. + * Don't use i2c_transfer()/i2c_smbus_xfer() + * for this as they will try to lock adapter a second time + */ +static int i2cs_mux_read_byte(struct i2c_client *client, + u8 offset, u8 *val) +{ + struct i2c_msg msg[2]; + + msg[0].addr = client->addr; + msg[0].flags = 0; + msg[0].len = 1; + msg[0].buf = &offset; + + msg[1].addr = client->addr; + msg[1].flags = I2C_M_RD; + msg[1].len = 1; + msg[1].buf = val; + + return client->adapter->algo->master_xfer(client->adapter, msg, 2); +} + +static int i2cs_mux_write_byte(struct i2c_client *client, u8 offset, u8 val) +{ + struct i2c_msg msg; + char buf[2]; + + msg.addr = client->addr; + msg.flags = 0; + msg.len = 2; + buf[0] = offset; + buf[1] = val; + msg.buf = buf; + + return client->adapter->algo->master_xfer(client->adapter, &msg, 1); +} + +static int i2cs_mux_select(struct i2c_mux_core *muxc, u32 chan) +{ + int ret; + u8 val = 0; + struct i2c_client *client = i2c_mux_priv(muxc); + + ret = i2cs_mux_read_byte(client, I2CS_MISC_IO, &val); + if (ret < 0) + return ret; + + val |= MISC_IO_RE_EN; + ret = i2cs_mux_write_byte(client, I2CS_MISC_IO, val); + + return ret; +} + +static int i2cs_mux_deselect(struct i2c_mux_core *muxc, u32 chan) +{ + int ret; + u8 val = 0; + struct i2c_client *client = i2c_mux_priv(muxc); + + ret = i2cs_mux_read_byte(client, I2CS_MISC_IO, &val); + if (ret < 0) + return ret; + + val &= ~MISC_IO_RE_EN; + ret = i2cs_mux_write_byte(client, I2CS_MISC_IO, val); + + return 0; +} + +static int i2cs_mux_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct i2c_client *client; + struct i2c_mux_core *muxc; + int ret; + + if (!dev->parent) + return -ENODEV; + + client = i2c_verify_client(dev->parent); + if (!client) + return -ENODEV; + + muxc = i2c_mux_alloc(client->adapter, &client->dev, 1, 0, 0, + i2cs_mux_select, i2cs_mux_deselect); + if (!muxc) + return -ENOMEM; + muxc->priv = client; + + ret = i2c_mux_add_adapter(muxc, 0, 0, 0); + if (ret) + return ret; + + platform_set_drvdata(pdev, muxc); + + return 0; +} + +static int i2cs_mux_remove(struct platform_device *pdev) +{ + i2c_mux_del_adapters(platform_get_drvdata(pdev)); + + return 0; +} + +static const struct of_device_id i2cs_mux_of_match[] = { + { .compatible = "jnx,i2c-mux-i2cs", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2cs_mux_of_match); + +static struct platform_driver i2cs_mux_driver = { + .driver = { + .name = "i2c-mux-i2cs", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(i2cs_mux_of_match), + }, + .probe = i2cs_mux_probe, + .remove = i2cs_mux_remove, +}; +module_platform_driver(i2cs_mux_driver); + +MODULE_DESCRIPTION("Juniper Networks I2CS RE Mux driver"); +MODULE_AUTHOR("Georgi Vlaev <gvlaev@juniper.net>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:i2c-mux-i2cs");