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321 lines
8.2 KiB
321 lines
8.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Pinctrl based I2C DeMultiplexer |
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* |
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* Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <[email protected]> |
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* Copyright (C) 2015-16 by Renesas Electronics Corporation |
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* |
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* See the bindings doc for DTS setup and the sysfs doc for usage information. |
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* (look for filenames containing 'i2c-demux-pinctrl' in Documentation/) |
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*/ |
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#include <linux/i2c.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/pinctrl/consumer.h> |
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#include <linux/platform_device.h> |
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#include <linux/pm_runtime.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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struct i2c_demux_pinctrl_chan { |
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struct device_node *parent_np; |
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struct i2c_adapter *parent_adap; |
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struct of_changeset chgset; |
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}; |
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struct i2c_demux_pinctrl_priv { |
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int cur_chan; |
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int num_chan; |
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struct device *dev; |
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const char *bus_name; |
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struct i2c_adapter cur_adap; |
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struct i2c_algorithm algo; |
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struct i2c_demux_pinctrl_chan chan[]; |
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}; |
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static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = adap->algo_data; |
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struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; |
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return __i2c_transfer(parent, msgs, num); |
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} |
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static u32 i2c_demux_functionality(struct i2c_adapter *adap) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = adap->algo_data; |
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struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; |
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return parent->algo->functionality(parent); |
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} |
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static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) |
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{ |
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struct i2c_adapter *adap; |
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struct pinctrl *p; |
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int ret; |
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ret = of_changeset_apply(&priv->chan[new_chan].chgset); |
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if (ret) |
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goto err; |
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adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np); |
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if (!adap) { |
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ret = -ENODEV; |
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goto err_with_revert; |
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} |
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/* |
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* Check if there are pinctrl states at all. Note: we cant' use |
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* devm_pinctrl_get_select() because we need to distinguish between |
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* the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state(). |
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*/ |
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p = devm_pinctrl_get(adap->dev.parent); |
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if (IS_ERR(p)) { |
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ret = PTR_ERR(p); |
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/* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */ |
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if (ret != -ENODEV) |
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goto err_with_put; |
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} else { |
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/* there are states. check and use them */ |
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struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name); |
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if (IS_ERR(s)) { |
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ret = PTR_ERR(s); |
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goto err_with_put; |
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} |
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ret = pinctrl_select_state(p, s); |
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if (ret < 0) |
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goto err_with_put; |
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} |
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priv->chan[new_chan].parent_adap = adap; |
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priv->cur_chan = new_chan; |
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/* Now fill out current adapter structure. cur_chan must be up to date */ |
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priv->algo.master_xfer = i2c_demux_master_xfer; |
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if (adap->algo->master_xfer_atomic) |
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priv->algo.master_xfer_atomic = i2c_demux_master_xfer; |
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priv->algo.functionality = i2c_demux_functionality; |
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snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name), |
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"i2c-demux (master i2c-%d)", i2c_adapter_id(adap)); |
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priv->cur_adap.owner = THIS_MODULE; |
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priv->cur_adap.algo = &priv->algo; |
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priv->cur_adap.algo_data = priv; |
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priv->cur_adap.dev.parent = &adap->dev; |
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priv->cur_adap.class = adap->class; |
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priv->cur_adap.retries = adap->retries; |
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priv->cur_adap.timeout = adap->timeout; |
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priv->cur_adap.quirks = adap->quirks; |
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priv->cur_adap.dev.of_node = priv->dev->of_node; |
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ret = i2c_add_adapter(&priv->cur_adap); |
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if (ret < 0) |
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goto err_with_put; |
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return 0; |
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err_with_put: |
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i2c_put_adapter(adap); |
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err_with_revert: |
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of_changeset_revert(&priv->chan[new_chan].chgset); |
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err: |
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dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret); |
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priv->cur_chan = -EINVAL; |
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return ret; |
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} |
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static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv) |
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{ |
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int ret, cur = priv->cur_chan; |
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if (cur < 0) |
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return 0; |
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i2c_del_adapter(&priv->cur_adap); |
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i2c_put_adapter(priv->chan[cur].parent_adap); |
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ret = of_changeset_revert(&priv->chan[cur].chgset); |
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priv->chan[cur].parent_adap = NULL; |
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priv->cur_chan = -EINVAL; |
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return ret; |
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} |
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static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) |
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{ |
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int ret; |
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if (new_chan == priv->cur_chan) |
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return 0; |
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ret = i2c_demux_deactivate_master(priv); |
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if (ret) |
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return ret; |
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return i2c_demux_activate_master(priv, new_chan); |
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} |
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static ssize_t available_masters_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); |
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int count = 0, i; |
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for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++) |
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count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c", |
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i, priv->chan[i].parent_np, |
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i == priv->num_chan - 1 ? '\n' : ' '); |
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return count; |
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} |
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static DEVICE_ATTR_RO(available_masters); |
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static ssize_t current_master_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); |
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return sprintf(buf, "%d\n", priv->cur_chan); |
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} |
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static ssize_t current_master_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); |
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unsigned int val; |
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int ret; |
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ret = kstrtouint(buf, 0, &val); |
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if (ret < 0) |
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return ret; |
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if (val >= priv->num_chan) |
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return -EINVAL; |
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ret = i2c_demux_change_master(priv, val); |
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return ret < 0 ? ret : count; |
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} |
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static DEVICE_ATTR_RW(current_master); |
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static int i2c_demux_pinctrl_probe(struct platform_device *pdev) |
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{ |
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struct device_node *np = pdev->dev.of_node; |
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struct i2c_demux_pinctrl_priv *priv; |
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struct property *props; |
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int num_chan, i, j, err; |
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num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL); |
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if (num_chan < 2) { |
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dev_err(&pdev->dev, "Need at least two I2C masters to switch\n"); |
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return -EINVAL; |
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} |
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priv = devm_kzalloc(&pdev->dev, struct_size(priv, chan, num_chan), |
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GFP_KERNEL); |
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props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL); |
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if (!priv || !props) |
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return -ENOMEM; |
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err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name); |
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if (err) |
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return err; |
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for (i = 0; i < num_chan; i++) { |
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struct device_node *adap_np; |
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adap_np = of_parse_phandle(np, "i2c-parent", i); |
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if (!adap_np) { |
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dev_err(&pdev->dev, "can't get phandle for parent %d\n", i); |
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err = -ENOENT; |
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goto err_rollback; |
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} |
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priv->chan[i].parent_np = adap_np; |
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props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL); |
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props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL); |
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props[i].length = 3; |
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of_changeset_init(&priv->chan[i].chgset); |
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of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]); |
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} |
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priv->num_chan = num_chan; |
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priv->dev = &pdev->dev; |
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platform_set_drvdata(pdev, priv); |
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pm_runtime_no_callbacks(&pdev->dev); |
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/* switch to first parent as active master */ |
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i2c_demux_activate_master(priv, 0); |
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err = device_create_file(&pdev->dev, &dev_attr_available_masters); |
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if (err) |
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goto err_rollback; |
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err = device_create_file(&pdev->dev, &dev_attr_current_master); |
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if (err) |
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goto err_rollback_available; |
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return 0; |
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err_rollback_available: |
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device_remove_file(&pdev->dev, &dev_attr_available_masters); |
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err_rollback: |
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i2c_demux_deactivate_master(priv); |
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for (j = 0; j < i; j++) { |
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of_node_put(priv->chan[j].parent_np); |
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of_changeset_destroy(&priv->chan[j].chgset); |
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} |
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return err; |
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} |
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static int i2c_demux_pinctrl_remove(struct platform_device *pdev) |
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{ |
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struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev); |
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int i; |
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device_remove_file(&pdev->dev, &dev_attr_current_master); |
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device_remove_file(&pdev->dev, &dev_attr_available_masters); |
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i2c_demux_deactivate_master(priv); |
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for (i = 0; i < priv->num_chan; i++) { |
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of_node_put(priv->chan[i].parent_np); |
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of_changeset_destroy(&priv->chan[i].chgset); |
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} |
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return 0; |
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} |
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static const struct of_device_id i2c_demux_pinctrl_of_match[] = { |
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{ .compatible = "i2c-demux-pinctrl", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match); |
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static struct platform_driver i2c_demux_pinctrl_driver = { |
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.driver = { |
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.name = "i2c-demux-pinctrl", |
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.of_match_table = i2c_demux_pinctrl_of_match, |
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}, |
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.probe = i2c_demux_pinctrl_probe, |
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.remove = i2c_demux_pinctrl_remove, |
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}; |
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module_platform_driver(i2c_demux_pinctrl_driver); |
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MODULE_DESCRIPTION("pinctrl-based I2C demux driver"); |
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MODULE_AUTHOR("Wolfram Sang <[email protected]>"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:i2c-demux-pinctrl");
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