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 	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 
cc770_get_platform_data(struct platform_device * pdev,struct cc770_priv * priv)133 static 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 
cc770_platform_probe(struct platform_device * pdev)149 static 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 
213 exit_free_cc770:
214 	free_cc770dev(dev);
215 exit_unmap_mem:
216 	iounmap(base);
217 exit_release_mem:
218 	release_mem_region(mem->start, mem_size);
219 
220 	return err;
221 }
222 
cc770_platform_remove(struct platform_device * pdev)223 static 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 
237 static 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 };
242 MODULE_DEVICE_TABLE(of, cc770_platform_table);
243 
244 static 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 
253 module_platform_driver(cc770_platform_driver);
254