diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/muxes/i2c-mux-pinctrl.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c new file mode 100644 index 000000000..cc6818aab --- /dev/null +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c @@ -0,0 +1,210 @@ +/* + * I2C multiplexer using pinctrl API + * + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/i2c.h> +#include <linux/i2c-mux.h> +#include <linux/module.h> +#include <linux/pinctrl/consumer.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/of.h> +#include "../../pinctrl/core.h" + +struct i2c_mux_pinctrl { + struct pinctrl *pinctrl; + struct pinctrl_state **states; +}; + +static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan) +{ + struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc); + + return pinctrl_select_state(mux->pinctrl, mux->states[chan]); +} + +static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan) +{ + return i2c_mux_pinctrl_select(muxc, muxc->num_adapters); +} + +static struct i2c_adapter *i2c_mux_pinctrl_root_adapter( + struct pinctrl_state *state) +{ + struct i2c_adapter *root = NULL; + struct pinctrl_setting *setting; + struct i2c_adapter *pin_root; + + list_for_each_entry(setting, &state->settings, node) { + pin_root = i2c_root_adapter(setting->pctldev->dev); + if (!pin_root) + return NULL; + if (!root) + root = pin_root; + else if (root != pin_root) + return NULL; + } + + return root; +} + +static struct i2c_adapter *i2c_mux_pinctrl_parent_adapter(struct device *dev) +{ + struct device_node *np = dev->of_node; + struct device_node *parent_np; + struct i2c_adapter *parent; + + parent_np = of_parse_phandle(np, "i2c-parent", 0); + if (!parent_np) { + dev_err(dev, "Cannot parse i2c-parent\n"); + return ERR_PTR(-ENODEV); + } + parent = of_find_i2c_adapter_by_node(parent_np); + of_node_put(parent_np); + if (!parent) + return ERR_PTR(-EPROBE_DEFER); + + return parent; +} + +static int i2c_mux_pinctrl_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct i2c_mux_core *muxc; + struct i2c_mux_pinctrl *mux; + struct i2c_adapter *parent; + struct i2c_adapter *root; + int num_names, i, ret; + const char *name; + + num_names = of_property_count_strings(np, "pinctrl-names"); + if (num_names < 0) { + dev_err(dev, "Cannot parse pinctrl-names: %d\n", + num_names); + return num_names; + } + + parent = i2c_mux_pinctrl_parent_adapter(dev); + if (IS_ERR(parent)) + return PTR_ERR(parent); + + muxc = i2c_mux_alloc(parent, dev, num_names, + sizeof(*mux) + num_names * sizeof(*mux->states), + 0, i2c_mux_pinctrl_select, NULL); + if (!muxc) { + ret = -ENOMEM; + goto err_put_parent; + } + mux = i2c_mux_priv(muxc); + mux->states = (struct pinctrl_state **)(mux + 1); + + platform_set_drvdata(pdev, muxc); + + mux->pinctrl = devm_pinctrl_get(dev); + if (IS_ERR(mux->pinctrl)) { + ret = PTR_ERR(mux->pinctrl); + dev_err(dev, "Cannot get pinctrl: %d\n", ret); + goto err_put_parent; + } + + for (i = 0; i < num_names; i++) { + ret = of_property_read_string_index(np, "pinctrl-names", i, + &name); + if (ret < 0) { + dev_err(dev, "Cannot parse pinctrl-names: %d\n", ret); + goto err_put_parent; + } + + mux->states[i] = pinctrl_lookup_state(mux->pinctrl, name); + if (IS_ERR(mux->states[i])) { + ret = PTR_ERR(mux->states[i]); + dev_err(dev, "Cannot look up pinctrl state %s: %d\n", + name, ret); + goto err_put_parent; + } + + if (strcmp(name, "idle")) + continue; + + if (i != num_names - 1) { + dev_err(dev, "idle state must be last\n"); + ret = -EINVAL; + goto err_put_parent; + } + muxc->deselect = i2c_mux_pinctrl_deselect; + } + + root = i2c_root_adapter(&muxc->parent->dev); + + muxc->mux_locked = true; + for (i = 0; i < num_names; i++) { + if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) { + muxc->mux_locked = false; + break; + } + } + if (muxc->mux_locked) + dev_info(dev, "mux-locked i2c mux\n"); + + /* Do not add any adapter for the idle state (if it's there at all). */ + for (i = 0; i < num_names - !!muxc->deselect; i++) { + ret = i2c_mux_add_adapter(muxc, 0, i, 0); + if (ret) + goto err_del_adapter; + } + + return 0; + +err_del_adapter: + i2c_mux_del_adapters(muxc); +err_put_parent: + i2c_put_adapter(parent); + + return ret; +} + +static int i2c_mux_pinctrl_remove(struct platform_device *pdev) +{ + struct i2c_mux_core *muxc = platform_get_drvdata(pdev); + + i2c_mux_del_adapters(muxc); + i2c_put_adapter(muxc->parent); + + return 0; +} + +static const struct of_device_id i2c_mux_pinctrl_of_match[] = { + { .compatible = "i2c-mux-pinctrl", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match); + +static struct platform_driver i2c_mux_pinctrl_driver = { + .driver = { + .name = "i2c-mux-pinctrl", + .of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match), + }, + .probe = i2c_mux_pinctrl_probe, + .remove = i2c_mux_pinctrl_remove, +}; +module_platform_driver(i2c_mux_pinctrl_driver); + +MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver"); +MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:i2c-mux-pinctrl"); |