cc770_platform.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for CC770 and AN82527 CAN controllers on the platform bus
  4 *
  5 * Copyright (C) 2009, 2011 Wolfgang Grandegger <wg@grandegger.com>
  6 */
  7
  8/*
  9 * If platform data are used you should have similar definitions
 10 * in your board-specific code:
 11 *
 12 *   static struct cc770_platform_data myboard_cc770_pdata = {
 13 *           .osc_freq = 16000000,
 14 *           .cir = 0x41,
 15 *           .cor = 0x20,
 16 *           .bcr = 0x40,
 17 *   };
 18 *
 19 * Please see include/linux/can/platform/cc770.h for description of
 20 * above fields.
 21 *
 22 * If the device tree is used, you need a CAN node definition in your
 23 * DTS file similar to:
 24 *
 25 *   can@3,100 {
 26 *           compatible = "bosch,cc770";
 27 *           reg = <3 0x100 0x80>;
 28 *           interrupts = <2 0>;
 29 *           interrupt-parent = <&mpic>;
 30 *           bosch,external-clock-frequency = <16000000>;
 31 *   };
 32 *
 33 * See "Documentation/devicetree/bindings/net/can/cc770.txt" for further
 34 * information.
 35 */
 36
 37#include <linux/kernel.h>
 38#include <linux/module.h>
 39#include <linux/interrupt.h>
 40#include <linux/netdevice.h>
 41#include <linux/delay.h>
 42#include <linux/platform_device.h>
 43#include <linux/of.h>
 44#include <linux/can.h>
 45#include <linux/can/dev.h>
 46#include <linux/can/platform/cc770.h>
 47
 48#include "cc770.h"
 49
 50#define DRV_NAME "cc770_platform"
 51
 52MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 53MODULE_DESCRIPTION("Socket-CAN driver for CC770 on the platform bus");
 54MODULE_LICENSE("GPL v2");
 55MODULE_ALIAS("platform:" DRV_NAME);
 56
 57#define CC770_PLATFORM_CAN_CLOCK  16000000
 58
 59static u8 cc770_platform_read_reg(const struct cc770_priv *priv, int reg)
 60{
 61	return ioread8(priv->reg_base + reg);
 62}
 63
 64static void cc770_platform_write_reg(const struct cc770_priv *priv, int reg,
 65				     u8 val)
 66{
 67	iowrite8(val, priv->reg_base + reg);
 68}
 69
 70static int cc770_get_of_node_data(struct platform_device *pdev,
 71				  struct cc770_priv *priv)
 72{
 73	u32 clkext = CC770_PLATFORM_CAN_CLOCK, clkout = 0;
 74	struct device_node *np = pdev->dev.of_node;
 75
 76	of_property_read_u32(np, "bosch,external-clock-frequency", &clkext);
 77	priv->can.clock.freq = clkext;
 78
 79	/* The system clock may not exceed 10 MHz */
 80	if (priv->can.clock.freq > 10000000) {
 81		priv->cpu_interface |= CPUIF_DSC;
 82		priv->can.clock.freq /= 2;
 83	}
 84
 85	/* The memory clock may not exceed 8 MHz */
 86	if (priv->can.clock.freq > 8000000)
 87		priv->cpu_interface |= CPUIF_DMC;
 88
 89	if (of_property_read_bool(np, "bosch,divide-memory-clock"))
 90		priv->cpu_interface |= CPUIF_DMC;
 91	if (of_property_read_bool(np, "bosch,iso-low-speed-mux"))
 92		priv->cpu_interface |= CPUIF_MUX;
 93
 94	if (!of_property_read_bool(np, "bosch,no-comperator-bypass"))
 95		priv->bus_config |= BUSCFG_CBY;
 96	if (of_property_read_bool(np, "bosch,disconnect-rx0-input"))
 97		priv->bus_config |= BUSCFG_DR0;
 98	if (of_property_read_bool(np, "bosch,disconnect-rx1-input"))
 99		priv->bus_config |= BUSCFG_DR1;
100	if (of_property_read_bool(np, "bosch,disconnect-tx1-output"))
101		priv->bus_config |= BUSCFG_DT1;
102	if (of_property_read_bool(np, "bosch,polarity-dominant"))
103		priv->bus_config |= BUSCFG_POL;
104
105	of_property_read_u32(np, "bosch,clock-out-frequency", &clkout);
106	if (clkout > 0) {
107		u32 cdv = clkext / clkout;
108
109		if (cdv > 0 && cdv < 16) {
110			u32 slew;
111
112			priv->cpu_interface |= CPUIF_CEN;
113			priv->clkout |= (cdv - 1) & CLKOUT_CD_MASK;
114
115			if (of_property_read_u32(np, "bosch,slew-rate", &slew)) {
116				/* Determine default slew rate */
117				slew = (CLKOUT_SL_MASK >>
118					CLKOUT_SL_SHIFT) -
119					((cdv * clkext - 1) / 8000000);
120				if (slew > (CLKOUT_SL_MASK >> CLKOUT_SL_SHIFT))
121					slew = 0;
122			}
123			priv->clkout |= (slew << CLKOUT_SL_SHIFT) &
124				CLKOUT_SL_MASK;
125		} else {
126			dev_dbg(&pdev->dev, "invalid clock-out-frequency\n");
127		}
128	}
129
130	return 0;
131}
132
133static int cc770_get_platform_data(struct platform_device *pdev,
134				   struct cc770_priv *priv)
135{
136
137	struct cc770_platform_data *pdata = dev_get_platdata(&pdev->dev);
138
139	priv->can.clock.freq = pdata->osc_freq;
140	if (priv->cpu_interface & CPUIF_DSC)
141		priv->can.clock.freq /= 2;
142	priv->clkout = pdata->cor;
143	priv->bus_config = pdata->bcr;
144	priv->cpu_interface = pdata->cir;
145
146	return 0;
147}
148
149static int cc770_platform_probe(struct platform_device *pdev)
150{
151	struct net_device *dev;
152	struct cc770_priv *priv;
153	struct resource *mem;
154	resource_size_t mem_size;
155	void __iomem *base;
156	int err, irq;
157
158	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
159	irq = platform_get_irq(pdev, 0);
160	if (!mem || irq <= 0)
161		return -ENODEV;
162
163	mem_size = resource_size(mem);
164	if (!request_mem_region(mem->start, mem_size, pdev->name))
165		return -EBUSY;
166
167	base = ioremap(mem->start, mem_size);
168	if (!base) {
169		err = -ENOMEM;
170		goto exit_release_mem;
171	}
172
173	dev = alloc_cc770dev(0);
174	if (!dev) {
175		err = -ENOMEM;
176		goto exit_unmap_mem;
177	}
178
179	dev->irq = irq;
180	priv = netdev_priv(dev);
181	priv->read_reg = cc770_platform_read_reg;
182	priv->write_reg = cc770_platform_write_reg;
183	priv->irq_flags = IRQF_SHARED;
184	priv->reg_base = base;
185
186	if (pdev->dev.of_node)
187		err = cc770_get_of_node_data(pdev, priv);
188	else if (dev_get_platdata(&pdev->dev))
189		err = cc770_get_platform_data(pdev, priv);
190	else
191		err = -ENODEV;
192	if (err)
193		goto exit_free_cc770;
194
195	dev_dbg(&pdev->dev,
196		 "reg_base=0x%p irq=%d clock=%d cpu_interface=0x%02x "
197		 "bus_config=0x%02x clkout=0x%02x\n",
198		 priv->reg_base, dev->irq, priv->can.clock.freq,
199		 priv->cpu_interface, priv->bus_config, priv->clkout);
200
201	platform_set_drvdata(pdev, dev);
202	SET_NETDEV_DEV(dev, &pdev->dev);
203
204	err = register_cc770dev(dev);
205	if (err) {
206		dev_err(&pdev->dev,
207			"couldn't register CC700 device (err=%d)\n", err);
208		goto exit_free_cc770;
209	}
210
211	return 0;
212
213exit_free_cc770:
214	free_cc770dev(dev);
215exit_unmap_mem:
216	iounmap(base);
217exit_release_mem:
218	release_mem_region(mem->start, mem_size);
219
220	return err;
221}
222
223static void cc770_platform_remove(struct platform_device *pdev)
224{
225	struct net_device *dev = platform_get_drvdata(pdev);
226	struct cc770_priv *priv = netdev_priv(dev);
227	struct resource *mem;
228
229	unregister_cc770dev(dev);
230	iounmap(priv->reg_base);
231	free_cc770dev(dev);
232
233	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
234	release_mem_region(mem->start, resource_size(mem));
235}
236
237static const struct of_device_id cc770_platform_table[] = {
238	{.compatible = "bosch,cc770"}, /* CC770 from Bosch */
239	{.compatible = "intc,82527"},  /* AN82527 from Intel CP */
240	{},
241};
242MODULE_DEVICE_TABLE(of, cc770_platform_table);
243
244static struct platform_driver cc770_platform_driver = {
245	.driver = {
246		.name = DRV_NAME,
247		.of_match_table = cc770_platform_table,
248	},
249	.probe = cc770_platform_probe,
250	.remove = cc770_platform_remove,
251};
252
253module_platform_driver(cc770_platform_driver);