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Diffstat (limited to 'drivers/i2c/muxes/i2c-demux-pinctrl.c')
-rw-r--r--drivers/i2c/muxes/i2c-demux-pinctrl.c326
1 files changed, 326 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
new file mode 100644
index 000000000..45a3f7e7b
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Pinctrl based I2C DeMultiplexer
+ *
+ * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
+ * Copyright (C) 2015-16 by Renesas Electronics Corporation
+ *
+ * See the bindings doc for DTS setup and the sysfs doc for usage information.
+ * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+struct i2c_demux_pinctrl_chan {
+ struct device_node *parent_np;
+ struct i2c_adapter *parent_adap;
+ struct of_changeset chgset;
+};
+
+struct i2c_demux_pinctrl_priv {
+ int cur_chan;
+ int num_chan;
+ struct device *dev;
+ const char *bus_name;
+ struct i2c_adapter cur_adap;
+ struct i2c_algorithm algo;
+ struct i2c_demux_pinctrl_chan chan[];
+};
+
+static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+ struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+ return __i2c_transfer(parent, msgs, num);
+}
+
+static u32 i2c_demux_functionality(struct i2c_adapter *adap)
+{
+ struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+ struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+ return parent->algo->functionality(parent);
+}
+
+static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+ struct i2c_adapter *adap;
+ struct pinctrl *p;
+ int ret;
+
+ ret = of_changeset_apply(&priv->chan[new_chan].chgset);
+ if (ret)
+ goto err;
+
+ adap = of_get_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
+ if (!adap) {
+ ret = -ENODEV;
+ goto err_with_revert;
+ }
+
+ /*
+ * Check if there are pinctrl states at all. Note: we cant' use
+ * devm_pinctrl_get_select() because we need to distinguish between
+ * the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state().
+ */
+ p = devm_pinctrl_get(adap->dev.parent);
+ if (IS_ERR(p)) {
+ ret = PTR_ERR(p);
+ /* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */
+ if (ret != -ENODEV)
+ goto err_with_put;
+ } else {
+ /* there are states. check and use them */
+ struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name);
+
+ if (IS_ERR(s)) {
+ ret = PTR_ERR(s);
+ goto err_with_put;
+ }
+ ret = pinctrl_select_state(p, s);
+ if (ret < 0)
+ goto err_with_put;
+ }
+
+ priv->chan[new_chan].parent_adap = adap;
+ priv->cur_chan = new_chan;
+
+ /* Now fill out current adapter structure. cur_chan must be up to date */
+ priv->algo.master_xfer = i2c_demux_master_xfer;
+ if (adap->algo->master_xfer_atomic)
+ priv->algo.master_xfer_atomic = i2c_demux_master_xfer;
+ priv->algo.functionality = i2c_demux_functionality;
+
+ snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
+ "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
+ priv->cur_adap.owner = THIS_MODULE;
+ priv->cur_adap.algo = &priv->algo;
+ priv->cur_adap.algo_data = priv;
+ priv->cur_adap.dev.parent = &adap->dev;
+ priv->cur_adap.class = adap->class;
+ priv->cur_adap.retries = adap->retries;
+ priv->cur_adap.timeout = adap->timeout;
+ priv->cur_adap.quirks = adap->quirks;
+ priv->cur_adap.dev.of_node = priv->dev->of_node;
+ ret = i2c_add_adapter(&priv->cur_adap);
+ if (ret < 0)
+ goto err_with_put;
+
+ return 0;
+
+ err_with_put:
+ i2c_put_adapter(adap);
+ err_with_revert:
+ of_changeset_revert(&priv->chan[new_chan].chgset);
+ err:
+ dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
+ priv->cur_chan = -EINVAL;
+ return ret;
+}
+
+static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
+{
+ int ret, cur = priv->cur_chan;
+
+ if (cur < 0)
+ return 0;
+
+ i2c_del_adapter(&priv->cur_adap);
+ i2c_put_adapter(priv->chan[cur].parent_adap);
+
+ ret = of_changeset_revert(&priv->chan[cur].chgset);
+
+ priv->chan[cur].parent_adap = NULL;
+ priv->cur_chan = -EINVAL;
+
+ return ret;
+}
+
+static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+ int ret;
+
+ if (new_chan == priv->cur_chan)
+ return 0;
+
+ ret = i2c_demux_deactivate_master(priv);
+ if (ret)
+ return ret;
+
+ return i2c_demux_activate_master(priv, new_chan);
+}
+
+static ssize_t available_masters_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+ int count = 0, i;
+
+ for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
+ count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c",
+ i, priv->chan[i].parent_np,
+ i == priv->num_chan - 1 ? '\n' : ' ');
+
+ return count;
+}
+static DEVICE_ATTR_RO(available_masters);
+
+static ssize_t current_master_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", priv->cur_chan);
+}
+
+static ssize_t current_master_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret;
+
+ ret = kstrtouint(buf, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val >= priv->num_chan)
+ return -EINVAL;
+
+ ret = i2c_demux_change_master(priv, val);
+
+ return ret < 0 ? ret : count;
+}
+static DEVICE_ATTR_RW(current_master);
+
+static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct i2c_demux_pinctrl_priv *priv;
+ struct property *props;
+ int num_chan, i, j, err;
+
+ num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
+ if (num_chan < 2) {
+ dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
+ return -EINVAL;
+ }
+
+ priv = devm_kzalloc(&pdev->dev, struct_size(priv, chan, num_chan),
+ GFP_KERNEL);
+
+ props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);
+
+ if (!priv || !props)
+ return -ENOMEM;
+
+ err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
+ if (err)
+ return err;
+
+ for (i = 0; i < num_chan; i++) {
+ struct device_node *adap_np;
+
+ adap_np = of_parse_phandle(np, "i2c-parent", i);
+ if (!adap_np) {
+ dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
+ err = -ENOENT;
+ goto err_rollback;
+ }
+ priv->chan[i].parent_np = adap_np;
+
+ props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL);
+ props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL);
+ if (!props[i].name || !props[i].value) {
+ err = -ENOMEM;
+ goto err_rollback;
+ }
+ props[i].length = 3;
+
+ of_changeset_init(&priv->chan[i].chgset);
+ of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]);
+ }
+
+ priv->num_chan = num_chan;
+ priv->dev = &pdev->dev;
+
+ platform_set_drvdata(pdev, priv);
+
+ pm_runtime_no_callbacks(&pdev->dev);
+
+ /* switch to first parent as active master */
+ i2c_demux_activate_master(priv, 0);
+
+ err = device_create_file(&pdev->dev, &dev_attr_available_masters);
+ if (err)
+ goto err_rollback_activation;
+
+ err = device_create_file(&pdev->dev, &dev_attr_current_master);
+ if (err)
+ goto err_rollback_available;
+
+ return 0;
+
+err_rollback_available:
+ device_remove_file(&pdev->dev, &dev_attr_available_masters);
+err_rollback_activation:
+ i2c_demux_deactivate_master(priv);
+err_rollback:
+ for (j = 0; j < i; j++) {
+ of_node_put(priv->chan[j].parent_np);
+ of_changeset_destroy(&priv->chan[j].chgset);
+ }
+
+ return err;
+}
+
+static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
+{
+ struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
+ int i;
+
+ device_remove_file(&pdev->dev, &dev_attr_current_master);
+ device_remove_file(&pdev->dev, &dev_attr_available_masters);
+
+ i2c_demux_deactivate_master(priv);
+
+ for (i = 0; i < priv->num_chan; i++) {
+ of_node_put(priv->chan[i].parent_np);
+ of_changeset_destroy(&priv->chan[i].chgset);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
+ { .compatible = "i2c-demux-pinctrl", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
+
+static struct platform_driver i2c_demux_pinctrl_driver = {
+ .driver = {
+ .name = "i2c-demux-pinctrl",
+ .of_match_table = i2c_demux_pinctrl_of_match,
+ },
+ .probe = i2c_demux_pinctrl_probe,
+ .remove = i2c_demux_pinctrl_remove,
+};
+module_platform_driver(i2c_demux_pinctrl_driver);
+
+MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
+MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-demux-pinctrl");