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Diffstat (limited to 'drivers/i2c/muxes/i2c-mux-mlxcpld.c')
-rw-r--r--drivers/i2c/muxes/i2c-mux-mlxcpld.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-mlxcpld.c b/drivers/i2c/muxes/i2c-mux-mlxcpld.c
new file mode 100644
index 000000000..1a879f6a3
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-mux-mlxcpld.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/*
+ * Mellanox i2c mux driver
+ *
+ * Copyright (C) 2016-2020 Mellanox Technologies
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_data/mlxcpld.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* mlxcpld_mux - mux control structure:
+ * @last_val - last selected register value or -1 if mux deselected
+ * @client - I2C device client
+ * @pdata: platform data
+ */
+struct mlxcpld_mux {
+ int last_val;
+ struct i2c_client *client;
+ struct mlxcpld_mux_plat_data pdata;
+};
+
+/* MUX logic description.
+ * Driver can support different mux control logic, according to CPLD
+ * implementation.
+ *
+ * Connectivity schema.
+ *
+ * i2c-mlxcpld Digital Analog
+ * driver
+ * *--------* * -> mux1 (virt bus2) -> mux -> |
+ * | I2CLPC | i2c physical * -> mux2 (virt bus3) -> mux -> |
+ * | bridge | bus 1 *---------* |
+ * | logic |---------------------> * mux reg * |
+ * | in CPLD| *---------* |
+ * *--------* i2c-mux-mlxpcld ^ * -> muxn (virt busn) -> mux -> |
+ * | driver | |
+ * | *---------------* | Devices
+ * | * CPLD (i2c bus)* select |
+ * | * registers for *--------*
+ * | * mux selection * deselect
+ * | *---------------*
+ * | |
+ * <--------> <----------->
+ * i2c cntrl Board cntrl reg
+ * reg space space (mux select,
+ * IO, LED, WD, info)
+ *
+ */
+
+/* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()
+ * for this as they will try to lock adapter a second time.
+ */
+static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,
+ struct mlxcpld_mux *mux, u32 val)
+{
+ struct i2c_client *client = mux->client;
+ union i2c_smbus_data data;
+ struct i2c_msg msg;
+ u8 buf[3];
+
+ switch (mux->pdata.reg_size) {
+ case 1:
+ data.byte = val;
+ return __i2c_smbus_xfer(adap, client->addr, client->flags,
+ I2C_SMBUS_WRITE, mux->pdata.sel_reg_addr,
+ I2C_SMBUS_BYTE_DATA, &data);
+ case 2:
+ buf[0] = mux->pdata.sel_reg_addr >> 8;
+ buf[1] = mux->pdata.sel_reg_addr;
+ buf[2] = val;
+ msg.addr = client->addr;
+ msg.buf = buf;
+ msg.len = mux->pdata.reg_size + 1;
+ msg.flags = 0;
+ return __i2c_transfer(adap, &msg, 1);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
+{
+ struct mlxcpld_mux *mux = i2c_mux_priv(muxc);
+ u32 regval = chan;
+ int err = 0;
+
+ if (mux->pdata.reg_size == 1)
+ regval += 1;
+
+ /* Only select the channel if its different from the last channel */
+ if (mux->last_val != regval) {
+ err = mlxcpld_mux_reg_write(muxc->parent, mux, regval);
+ mux->last_val = err < 0 ? -1 : regval;
+ }
+
+ return err;
+}
+
+static int mlxcpld_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
+{
+ struct mlxcpld_mux *mux = i2c_mux_priv(muxc);
+
+ /* Deselect active channel */
+ mux->last_val = -1;
+
+ return mlxcpld_mux_reg_write(muxc->parent, mux, 0);
+}
+
+/* Probe/reomove functions */
+static int mlxcpld_mux_probe(struct platform_device *pdev)
+{
+ struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&pdev->dev);
+ struct i2c_client *client = to_i2c_client(pdev->dev.parent);
+ struct i2c_mux_core *muxc;
+ struct mlxcpld_mux *data;
+ int num, err;
+ u32 func;
+
+ if (!pdata)
+ return -EINVAL;
+
+ switch (pdata->reg_size) {
+ case 1:
+ func = I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
+ break;
+ case 2:
+ func = I2C_FUNC_I2C;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (!i2c_check_functionality(client->adapter, func))
+ return -ENODEV;
+
+ muxc = i2c_mux_alloc(client->adapter, &pdev->dev, pdata->num_adaps,
+ sizeof(*data), 0, mlxcpld_mux_select_chan,
+ mlxcpld_mux_deselect);
+ if (!muxc)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, muxc);
+ data = i2c_mux_priv(muxc);
+ data->client = client;
+ memcpy(&data->pdata, pdata, sizeof(*pdata));
+ data->last_val = -1; /* force the first selection */
+
+ /* Create an adapter for each channel. */
+ for (num = 0; num < pdata->num_adaps; num++) {
+ err = i2c_mux_add_adapter(muxc, 0, pdata->chan_ids[num], 0);
+ if (err)
+ goto virt_reg_failed;
+ }
+
+ /* Notify caller when all channels' adapters are created. */
+ if (pdata->completion_notify)
+ pdata->completion_notify(pdata->handle, muxc->parent, muxc->adapter);
+
+ return 0;
+
+virt_reg_failed:
+ i2c_mux_del_adapters(muxc);
+ return err;
+}
+
+static int mlxcpld_mux_remove(struct platform_device *pdev)
+{
+ struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
+
+ i2c_mux_del_adapters(muxc);
+ return 0;
+}
+
+static struct platform_driver mlxcpld_mux_driver = {
+ .driver = {
+ .name = "i2c-mux-mlxcpld",
+ },
+ .probe = mlxcpld_mux_probe,
+ .remove = mlxcpld_mux_remove,
+};
+
+module_platform_driver(mlxcpld_mux_driver);
+
+MODULE_AUTHOR("Michael Shych (michaels@mellanox.com)");
+MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:i2c-mux-mlxcpld");