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author | Antony Pavlov <antonynpavlov@gmail.com> | 2015-11-19 01:23:56 +0300 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2015-11-19 08:58:26 +0100 |
commit | 4aa3a0347cc3e8e615bc6ed2d67c38d45ed07e01 (patch) | |
tree | 0bfd166b4b39e07f2ecd623b29d7d337fe189a4c /drivers/i2c | |
parent | c3859ce93c2dc9b182b2335bc881ad2485d00ba0 (diff) | |
download | barebox-4aa3a0347cc3e8e615bc6ed2d67c38d45ed07e01.tar.gz barebox-4aa3a0347cc3e8e615bc6ed2d67c38d45ed07e01.tar.xz |
i2c: add pca954x bus multiplexer driver
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r-- | drivers/i2c/Kconfig | 2 | ||||
-rw-r--r-- | drivers/i2c/Makefile | 2 | ||||
-rw-r--r-- | drivers/i2c/muxes/Kconfig | 14 | ||||
-rw-r--r-- | drivers/i2c/muxes/Makefile | 4 | ||||
-rw-r--r-- | drivers/i2c/muxes/i2c-mux-pca954x.c | 251 |
5 files changed, 272 insertions, 1 deletions
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 21cf0ec55a..56259d82d4 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -13,4 +13,6 @@ config I2C_MUX handle multiplexed I2C bus topologies, by presenting each multiplexed segment as a I2C adapter. +source drivers/i2c/muxes/Kconfig + endif diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index 5ce0d0acad..c93653414e 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -1,2 +1,2 @@ -obj-$(CONFIG_I2C) += i2c.o i2c-smbus.o busses/ algos/ +obj-$(CONFIG_I2C) += i2c.o i2c-smbus.o busses/ algos/ muxes/ obj-$(CONFIG_I2C_MUX) += i2c-mux.o diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig new file mode 100644 index 0000000000..74b73459aa --- /dev/null +++ b/drivers/i2c/muxes/Kconfig @@ -0,0 +1,14 @@ +# +# Multiplexer I2C chip drivers configuration +# + +menu "Multiplexer I2C Chip support" + depends on I2C_MUX + +config I2C_MUX_PCA954x + tristate "Philips PCA954x I2C Mux/switches" + help + If you say yes here you get support for the Philips PCA954x + I2C mux/switch devices. + +endmenu diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile new file mode 100644 index 0000000000..f35d40d0e3 --- /dev/null +++ b/drivers/i2c/muxes/Makefile @@ -0,0 +1,4 @@ +# +# Makefile for multiplexer I2C chip drivers. + +obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c new file mode 100644 index 0000000000..baeae7bb94 --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -0,0 +1,251 @@ +/* + * I2C multiplexer + * + * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it> + * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it> + * + * Ported to barebox from linux-v4.4-rc1 + * Copyright (C) 2015 Antony Pavlov <antonynpavlov@gmail.com> + * + * This module supports the PCA954x series of I2C multiplexer/switch chips + * made by Philips Semiconductors. + * This includes the: + * PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547 + * and PCA9548. + * + * These chips are all controlled via the I2C bus itself, and all have a + * single 8-bit register. The upstream "parent" bus fans out to two, + * four, or eight downstream busses or channels; which of these + * are selected is determined by the chip type and register contents. A + * mux can select only one sub-bus at a time; a switch can select any + * combination simultaneously. + * + * Based on: + * pca954x.c from Kumar Gala <galak@kernel.crashing.org> + * Copyright (C) 2006 + * + * Based on: + * pca954x.c from Ken Harrenstien + * Copyright (C) 2004 Google, Inc. (Ken Harrenstien) + * + * Based on: + * i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com> + * and + * pca9540.c from Jean Delvare <jdelvare@suse.de>. + * + * 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 <common.h> +#include <driver.h> +#include <malloc.h> +#include <i2c/i2c.h> +#include <i2c/i2c-algo-bit.h> +#include <i2c/i2c-mux.h> +#include <init.h> + +#define PCA954X_MAX_NCHANS 8 + +enum pca_type { + pca_9540, + pca_9542, + pca_9543, + pca_9544, + pca_9545, + pca_9546, + pca_9547, + pca_9548, +}; + +struct pca954x { + enum pca_type type; + struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS]; + + u8 last_chan; /* last register value */ +}; + +struct chip_desc { + u8 nchans; + u8 enable; /* used for muxes only */ + enum muxtype { + pca954x_ismux = 0, + pca954x_isswi + } muxtype; +}; + +/* Provide specs for the PCA954x types we know about */ +static const struct chip_desc chips[] = { + [pca_9540] = { + .nchans = 2, + .enable = 0x4, + .muxtype = pca954x_ismux, + }, + [pca_9543] = { + .nchans = 2, + .muxtype = pca954x_isswi, + }, + [pca_9544] = { + .nchans = 4, + .enable = 0x4, + .muxtype = pca954x_ismux, + }, + [pca_9545] = { + .nchans = 4, + .muxtype = pca954x_isswi, + }, + [pca_9547] = { + .nchans = 8, + .enable = 0x8, + .muxtype = pca954x_ismux, + }, + [pca_9548] = { + .nchans = 8, + .muxtype = pca954x_isswi, + }, +}; + +static const struct platform_device_id pca954x_id[] = { + { "pca9540", pca_9540 }, + { "pca9542", pca_9540 }, + { "pca9543", pca_9543 }, + { "pca9544", pca_9544 }, + { "pca9545", pca_9545 }, + { "pca9546", pca_9545 }, + { "pca9547", pca_9547 }, + { "pca9548", pca_9548 }, + { } +}; + +/* 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 pca954x_reg_write(struct i2c_adapter *adap, + struct i2c_client *client, u8 val) +{ + int ret = -ENODEV; + + if (adap->master_xfer) { + struct i2c_msg msg; + char buf[1]; + + msg.addr = client->addr; + msg.flags = 0; + msg.len = 1; + buf[0] = val; + msg.buf = buf; + ret = adap->master_xfer(adap, &msg, 1); + } else { + union i2c_smbus_data data; + ret = i2c_smbus_xfer(adap, client->addr, + 0 /* client->flags */, + I2C_SMBUS_WRITE, + val, I2C_SMBUS_BYTE, &data); + } + + return ret; +} + +static int pca954x_select_chan(struct i2c_adapter *adap, + void *client, u32 chan) +{ + struct pca954x *data = i2c_get_clientdata(client); + const struct chip_desc *chip = &chips[data->type]; + u8 regval; + int ret = 0; + + /* we make switches look like muxes, not sure how to be smarter */ + if (chip->muxtype == pca954x_ismux) + regval = chan | chip->enable; + else + regval = 1 << chan; + + /* Only select the channel if its different from the last channel */ + if (data->last_chan != regval) { + ret = pca954x_reg_write(adap, client, regval); + data->last_chan = regval; + } + + return ret; +} + +/* + * I2C init/probing/exit functions + */ +static int pca954x_probe(struct device_d *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent); + int num, force; + struct pca954x *data; + int ret = -ENODEV; + + data = kzalloc(sizeof(struct pca954x), GFP_KERNEL); + if (!data) { + ret = -ENOMEM; + goto err; + } + + i2c_set_clientdata(client, data); + + /* Read the mux register at addr to verify + * that the mux is in fact present. + */ + if (i2c_smbus_read_byte(client) < 0) { + dev_warn(&client->dev, "probe failed\n"); + goto exit_free; + } + + ret = dev_get_drvdata(dev, (const void **)&data->type); + if (ret) + goto exit_free; + + data->last_chan = 0; /* force the first selection */ + + /* Now create an adapter for each channel */ + for (num = 0; num < chips[data->type].nchans; num++) { + + data->virt_adaps[num] = + i2c_add_mux_adapter(adap, &client->dev, client, + 0, num, pca954x_select_chan, NULL); + + if (data->virt_adaps[num] == NULL) { + ret = -ENODEV; + dev_err(&client->dev, + "failed to register multiplexed adapter" + " %d as bus %d\n", num, force); + goto virt_reg_failed; + } + } + + dev_info(&client->dev, + "registered %d multiplexed busses for I2C %s\n", + num, chips[data->type].muxtype == pca954x_ismux + ? "mux" : "switch"); + + return 0; + +virt_reg_failed: + for (num--; num >= 0; num--) + i2c_del_mux_adapter(data->virt_adaps[num]); +exit_free: + kfree(data); +err: + return ret; +} + +static struct driver_d pca954x_driver = { + .name = "pca954x", + .probe = pca954x_probe, + .id_table = pca954x_id, +}; + +static int __init pca954x_init(void) +{ + return i2c_driver_register(&pca954x_driver); +} +device_initcall(pca954x_init); + +MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); +MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); +MODULE_LICENSE("GPL v2"); |