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 
52 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
53 MODULE_DESCRIPTION("Socket-CAN driver for CC770 on the platform bus");
54 MODULE_LICENSE("GPL v2");
55 MODULE_ALIAS("platform:" DRV_NAME);
56 
57 #define CC770_PLATFORM_CAN_CLOCK  16000000
58 
cc770_platform_read_reg(const struct cc770_priv * priv,int reg)59 static u8 cc770_platform_read_reg(const struct cc770_priv *priv, int reg)
60 {
61 	return ioread8(priv->reg_base + reg);
62 }
63 
cc770_platform_write_reg(const struct cc770_priv * priv,int reg,u8 val)64 static 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 
cc770_get_of_node_data(struct platform_device * pdev,struct cc770_priv * priv)70 static int cc770_get_of_node_data(struct platform_device *pdev,
71 				  struct cc770_priv *priv)
72 {
73 	struct device_node *np = pdev->dev.of_node;
74 	const u32 *prop;
75 	int prop_size;
76 	u32 clkext;
77 
78 	prop = of_get_property(np, "bosch,external-clock-frequency",
79 			       &prop_size);
80 	if (prop && (prop_size ==  sizeof(u32)))
81 		clkext = *prop;
82 	else
83 		clkext = CC770_PLATFORM_CAN_CLOCK; /* default */
84 	priv->can.clock.freq = clkext;
85 
86 	/* The system clock may not exceed 10 MHz */
87 	if (priv->can.clock.freq > 10000000) {
88 		priv->cpu_interface |= CPUIF_DSC;
89 		priv->can.clock.freq /= 2;
90 	}
91 
92 	/* The memory clock may not exceed 8 MHz */
93 	if (priv->can.clock.freq > 8000000)
94 		priv->cpu_interface |= CPUIF_DMC;
95 
96 	if (of_get_property(np, "bosch,divide-memory-clock", NULL))
97 		priv->cpu_interface |= CPUIF_DMC;
98 	if (of_get_property(np, "bosch,iso-low-speed-mux", NULL))
99 		priv->cpu_interface |= CPUIF_MUX;
100 
101 	if (!of_get_property(np, "bosch,no-comperator-bypass", NULL))
102 		priv->bus_config |= BUSCFG_CBY;
103 	if (of_get_property(np, "bosch,disconnect-rx0-input", NULL))
104 		priv->bus_config |= BUSCFG_DR0;
105 	if (of_get_property(np, "bosch,disconnect-rx1-input", NULL))
106 		priv->bus_config |= BUSCFG_DR1;
107 	if (of_get_property(np, "bosch,disconnect-tx1-output", NULL))
108 		priv->bus_config |= BUSCFG_DT1;
109 	if (of_get_property(np, "bosch,polarity-dominant", NULL))
110 		priv->bus_config |= BUSCFG_POL;
111 
112 	prop = of_get_property(np, "bosch,clock-out-frequency", &prop_size);
113 	if (prop && (prop_size == sizeof(u32)) && *prop > 0) {
114 		u32 cdv = clkext / *prop;
115 		int slew;
116 
117 		if (cdv > 0 && cdv < 16) {
118 			priv->cpu_interface |= CPUIF_CEN;
119 			priv->clkout |= (cdv - 1) & CLKOUT_CD_MASK;
120 
121 			prop = of_get_property(np, "bosch,slew-rate",
122 					       &prop_size);
123 			if (prop && (prop_size == sizeof(u32))) {
124 				slew = *prop;
125 			} else {
126 				/* Determine default slew rate */
127 				slew = (CLKOUT_SL_MASK >>
128 					CLKOUT_SL_SHIFT) -
129 					((cdv * clkext - 1) / 8000000);
130 				if (slew < 0)
131 					slew = 0;
132 			}
133 			priv->clkout |= (slew << CLKOUT_SL_SHIFT) &
134 				CLKOUT_SL_MASK;
135 		} else {
136 			dev_dbg(&pdev->dev, "invalid clock-out-frequency\n");
137 		}
138 	}
139 
140 	return 0;
141 }
142 
cc770_get_platform_data(struct platform_device * pdev,struct cc770_priv * priv)143 static int cc770_get_platform_data(struct platform_device *pdev,
144 				   struct cc770_priv *priv)
145 {
146 
147 	struct cc770_platform_data *pdata = dev_get_platdata(&pdev->dev);
148 
149 	priv->can.clock.freq = pdata->osc_freq;
150 	if (priv->cpu_interface & CPUIF_DSC)
151 		priv->can.clock.freq /= 2;
152 	priv->clkout = pdata->cor;
153 	priv->bus_config = pdata->bcr;
154 	priv->cpu_interface = pdata->cir;
155 
156 	return 0;
157 }
158 
cc770_platform_probe(struct platform_device * pdev)159 static int cc770_platform_probe(struct platform_device *pdev)
160 {
161 	struct net_device *dev;
162 	struct cc770_priv *priv;
163 	struct resource *mem;
164 	resource_size_t mem_size;
165 	void __iomem *base;
166 	int err, irq;
167 
168 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
169 	irq = platform_get_irq(pdev, 0);
170 	if (!mem || irq <= 0)
171 		return -ENODEV;
172 
173 	mem_size = resource_size(mem);
174 	if (!request_mem_region(mem->start, mem_size, pdev->name))
175 		return -EBUSY;
176 
177 	base = ioremap(mem->start, mem_size);
178 	if (!base) {
179 		err = -ENOMEM;
180 		goto exit_release_mem;
181 	}
182 
183 	dev = alloc_cc770dev(0);
184 	if (!dev) {
185 		err = -ENOMEM;
186 		goto exit_unmap_mem;
187 	}
188 
189 	dev->irq = irq;
190 	priv = netdev_priv(dev);
191 	priv->read_reg = cc770_platform_read_reg;
192 	priv->write_reg = cc770_platform_write_reg;
193 	priv->irq_flags = IRQF_SHARED;
194 	priv->reg_base = base;
195 
196 	if (pdev->dev.of_node)
197 		err = cc770_get_of_node_data(pdev, priv);
198 	else if (dev_get_platdata(&pdev->dev))
199 		err = cc770_get_platform_data(pdev, priv);
200 	else
201 		err = -ENODEV;
202 	if (err)
203 		goto exit_free_cc770;
204 
205 	dev_dbg(&pdev->dev,
206 		 "reg_base=0x%p irq=%d clock=%d cpu_interface=0x%02x "
207 		 "bus_config=0x%02x clkout=0x%02x\n",
208 		 priv->reg_base, dev->irq, priv->can.clock.freq,
209 		 priv->cpu_interface, priv->bus_config, priv->clkout);
210 
211 	platform_set_drvdata(pdev, dev);
212 	SET_NETDEV_DEV(dev, &pdev->dev);
213 
214 	err = register_cc770dev(dev);
215 	if (err) {
216 		dev_err(&pdev->dev,
217 			"couldn't register CC700 device (err=%d)\n", err);
218 		goto exit_free_cc770;
219 	}
220 
221 	return 0;
222 
223 exit_free_cc770:
224 	free_cc770dev(dev);
225 exit_unmap_mem:
226 	iounmap(base);
227 exit_release_mem:
228 	release_mem_region(mem->start, mem_size);
229 
230 	return err;
231 }
232 
cc770_platform_remove(struct platform_device * pdev)233 static int cc770_platform_remove(struct platform_device *pdev)
234 {
235 	struct net_device *dev = platform_get_drvdata(pdev);
236 	struct cc770_priv *priv = netdev_priv(dev);
237 	struct resource *mem;
238 
239 	unregister_cc770dev(dev);
240 	iounmap(priv->reg_base);
241 	free_cc770dev(dev);
242 
243 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
244 	release_mem_region(mem->start, resource_size(mem));
245 
246 	return 0;
247 }
248 
249 static const struct of_device_id cc770_platform_table[] = {
250 	{.compatible = "bosch,cc770"}, /* CC770 from Bosch */
251 	{.compatible = "intc,82527"},  /* AN82527 from Intel CP */
252 	{},
253 };
254 MODULE_DEVICE_TABLE(of, cc770_platform_table);
255 
256 static struct platform_driver cc770_platform_driver = {
257 	.driver = {
258 		.name = DRV_NAME,
259 		.of_match_table = cc770_platform_table,
260 	},
261 	.probe = cc770_platform_probe,
262 	.remove = cc770_platform_remove,
263 };
264 
265 module_platform_driver(cc770_platform_driver);
266