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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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416912a129
The GPIO pins select which sub bus is connected to the master. Initially tested with an sn74cbtlv3253 switch device wired into the MDIO bus. Signed-off-by: David Daney <david.daney@cavium.com> Signed-off-by: David S. Miller <davem@davemloft.net>
143 lines
2.9 KiB
C
143 lines
2.9 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2011, 2012 Cavium, Inc.
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*/
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#include <linux/platform_device.h>
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#include <linux/device.h>
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#include <linux/of_mdio.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/phy.h>
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#include <linux/mdio-mux.h>
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#include <linux/of_gpio.h>
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#define DRV_VERSION "1.0"
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#define DRV_DESCRIPTION "GPIO controlled MDIO bus multiplexer driver"
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#define MDIO_MUX_GPIO_MAX_BITS 8
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struct mdio_mux_gpio_state {
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int gpio[MDIO_MUX_GPIO_MAX_BITS];
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unsigned int num_gpios;
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void *mux_handle;
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};
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static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
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void *data)
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{
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int change;
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unsigned int n;
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struct mdio_mux_gpio_state *s = data;
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if (current_child == desired_child)
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return 0;
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change = current_child == -1 ? -1 : current_child ^ desired_child;
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for (n = 0; n < s->num_gpios; n++) {
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if (change & 1)
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gpio_set_value_cansleep(s->gpio[n],
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(desired_child & 1) != 0);
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change >>= 1;
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desired_child >>= 1;
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}
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return 0;
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}
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static int __devinit mdio_mux_gpio_probe(struct platform_device *pdev)
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{
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enum of_gpio_flags f;
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struct mdio_mux_gpio_state *s;
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unsigned int num_gpios;
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unsigned int n;
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int r;
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if (!pdev->dev.of_node)
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return -ENODEV;
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num_gpios = of_gpio_count(pdev->dev.of_node);
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if (num_gpios == 0 || num_gpios > MDIO_MUX_GPIO_MAX_BITS)
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return -ENODEV;
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s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
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if (!s)
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return -ENOMEM;
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s->num_gpios = num_gpios;
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for (n = 0; n < num_gpios; ) {
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int gpio = of_get_gpio_flags(pdev->dev.of_node, n, &f);
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if (gpio < 0) {
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r = (gpio == -ENODEV) ? -EPROBE_DEFER : gpio;
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goto err;
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}
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s->gpio[n] = gpio;
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n++;
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r = gpio_request(gpio, "mdio_mux_gpio");
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if (r)
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goto err;
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r = gpio_direction_output(gpio, 0);
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if (r)
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goto err;
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}
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r = mdio_mux_init(&pdev->dev,
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mdio_mux_gpio_switch_fn, &s->mux_handle, s);
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if (r == 0) {
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pdev->dev.platform_data = s;
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return 0;
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}
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err:
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while (n) {
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n--;
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gpio_free(s->gpio[n]);
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}
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devm_kfree(&pdev->dev, s);
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return r;
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}
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static int __devexit mdio_mux_gpio_remove(struct platform_device *pdev)
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{
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struct mdio_mux_gpio_state *s = pdev->dev.platform_data;
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mdio_mux_uninit(s->mux_handle);
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return 0;
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}
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static struct of_device_id mdio_mux_gpio_match[] = {
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{
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.compatible = "mdio-mux-gpio",
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},
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{
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/* Legacy compatible property. */
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.compatible = "cavium,mdio-mux-sn74cbtlv3253",
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, mdio_mux_gpio_match);
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static struct platform_driver mdio_mux_gpio_driver = {
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.driver = {
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.name = "mdio-mux-gpio",
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.owner = THIS_MODULE,
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.of_match_table = mdio_mux_gpio_match,
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},
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.probe = mdio_mux_gpio_probe,
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.remove = __devexit_p(mdio_mux_gpio_remove),
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};
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module_platform_driver(mdio_mux_gpio_driver);
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MODULE_DESCRIPTION(DRV_DESCRIPTION);
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MODULE_VERSION(DRV_VERSION);
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MODULE_AUTHOR("David Daney");
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MODULE_LICENSE("GPL");
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