1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018, Nuvoton Corporation.
4  * Copyright (c) 2018, Intel Corporation.
5  */
6 
7 #define pr_fmt(fmt) "nuvoton-kcs-bmc: " fmt
8 
9 #include <linux/atomic.h>
10 #include <linux/errno.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18 #include <linux/slab.h>
19 
20 #include "kcs_bmc_device.h"
21 
22 #define DEVICE_NAME	"npcm-kcs-bmc"
23 #define KCS_CHANNEL_MAX	3
24 
25 #define KCS1ST		0x0C
26 #define KCS2ST		0x1E
27 #define KCS3ST		0x30
28 
29 #define KCS1DO		0x0E
30 #define KCS2DO		0x20
31 #define KCS3DO		0x32
32 
33 #define KCS1DI		0x10
34 #define KCS2DI		0x22
35 #define KCS3DI		0x34
36 
37 #define KCS1CTL		0x18
38 #define KCS2CTL		0x2A
39 #define KCS3CTL		0x3C
40 #define    KCS_CTL_IBFIE	BIT(0)
41 #define    KCS_CTL_OBEIE	BIT(1)
42 
43 #define KCS1IE		0x1C
44 #define KCS2IE		0x2E
45 #define KCS3IE		0x40
46 #define    KCS_IE_IRQE          BIT(0)
47 #define    KCS_IE_HIRQE         BIT(3)
48 
49 /*
50  * 7.2.4 Core KCS Registers
51  * Registers in this module are 8 bits. An 8-bit register must be accessed
52  * by an 8-bit read or write.
53  *
54  * sts: KCS Channel n Status Register (KCSnST).
55  * dob: KCS Channel n Data Out Buffer Register (KCSnDO).
56  * dib: KCS Channel n Data In Buffer Register (KCSnDI).
57  * ctl: KCS Channel n Control Register (KCSnCTL).
58  * ie : KCS Channel n  Interrupt Enable Register (KCSnIE).
59  */
60 struct npcm7xx_kcs_reg {
61 	u32 sts;
62 	u32 dob;
63 	u32 dib;
64 	u32 ctl;
65 	u32 ie;
66 };
67 
68 struct npcm7xx_kcs_bmc {
69 	struct kcs_bmc_device kcs_bmc;
70 
71 	struct regmap *map;
72 
73 	const struct npcm7xx_kcs_reg *reg;
74 };
75 
76 static const struct npcm7xx_kcs_reg npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {
77 	{ .sts = KCS1ST, .dob = KCS1DO, .dib = KCS1DI, .ctl = KCS1CTL, .ie = KCS1IE },
78 	{ .sts = KCS2ST, .dob = KCS2DO, .dib = KCS2DI, .ctl = KCS2CTL, .ie = KCS2IE },
79 	{ .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL, .ie = KCS3IE },
80 };
81 
82 static inline struct npcm7xx_kcs_bmc *to_npcm7xx_kcs_bmc(struct kcs_bmc_device *kcs_bmc)
83 {
84 	return container_of(kcs_bmc, struct npcm7xx_kcs_bmc, kcs_bmc);
85 }
86 
87 static u8 npcm7xx_kcs_inb(struct kcs_bmc_device *kcs_bmc, u32 reg)
88 {
89 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
90 	u32 val = 0;
91 	int rc;
92 
93 	rc = regmap_read(priv->map, reg, &val);
94 	WARN(rc != 0, "regmap_read() failed: %d\n", rc);
95 
96 	return rc == 0 ? (u8)val : 0;
97 }
98 
99 static void npcm7xx_kcs_outb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 data)
100 {
101 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
102 	int rc;
103 
104 	rc = regmap_write(priv->map, reg, data);
105 	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
106 }
107 
108 static void npcm7xx_kcs_updateb(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 mask, u8 data)
109 {
110 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
111 	int rc;
112 
113 	rc = regmap_update_bits(priv->map, reg, mask, data);
114 	WARN(rc != 0, "regmap_update_bits() failed: %d\n", rc);
115 }
116 
117 static void npcm7xx_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enable)
118 {
119 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
120 
121 	regmap_update_bits(priv->map, priv->reg->ie, KCS_IE_IRQE | KCS_IE_HIRQE,
122 			   enable ? KCS_IE_IRQE | KCS_IE_HIRQE : 0);
123 }
124 
125 static void npcm7xx_kcs_irq_mask_update(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 state)
126 {
127 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
128 
129 	if (mask & KCS_BMC_EVENT_TYPE_OBE)
130 		regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_OBEIE,
131 				   !!(state & KCS_BMC_EVENT_TYPE_OBE) * KCS_CTL_OBEIE);
132 
133 	if (mask & KCS_BMC_EVENT_TYPE_IBF)
134 		regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
135 				   !!(state & KCS_BMC_EVENT_TYPE_IBF) * KCS_CTL_IBFIE);
136 }
137 
138 static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)
139 {
140 	struct kcs_bmc_device *kcs_bmc = arg;
141 
142 	return kcs_bmc_handle_event(kcs_bmc);
143 }
144 
145 static int npcm7xx_kcs_config_irq(struct kcs_bmc_device *kcs_bmc,
146 				  struct platform_device *pdev)
147 {
148 	struct device *dev = &pdev->dev;
149 	int irq;
150 
151 	irq = platform_get_irq(pdev, 0);
152 	if (irq < 0)
153 		return irq;
154 
155 	return devm_request_irq(dev, irq, npcm7xx_kcs_irq, IRQF_SHARED,
156 				dev_name(dev), kcs_bmc);
157 }
158 
159 static const struct kcs_bmc_device_ops npcm7xx_kcs_ops = {
160 	.irq_mask_update = npcm7xx_kcs_irq_mask_update,
161 	.io_inputb = npcm7xx_kcs_inb,
162 	.io_outputb = npcm7xx_kcs_outb,
163 	.io_updateb = npcm7xx_kcs_updateb,
164 };
165 
166 static int npcm7xx_kcs_probe(struct platform_device *pdev)
167 {
168 	struct device *dev = &pdev->dev;
169 	struct npcm7xx_kcs_bmc *priv;
170 	struct kcs_bmc_device *kcs_bmc;
171 	u32 chan;
172 	int rc;
173 
174 	rc = of_property_read_u32(dev->of_node, "kcs_chan", &chan);
175 	if (rc != 0 || chan == 0 || chan > KCS_CHANNEL_MAX) {
176 		dev_err(dev, "no valid 'kcs_chan' configured\n");
177 		return -ENODEV;
178 	}
179 
180 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
181 	if (!priv)
182 		return -ENOMEM;
183 
184 	priv->map = syscon_node_to_regmap(dev->parent->of_node);
185 	if (IS_ERR(priv->map)) {
186 		dev_err(dev, "Couldn't get regmap\n");
187 		return -ENODEV;
188 	}
189 	priv->reg = &npcm7xx_kcs_reg_tbl[chan - 1];
190 
191 	kcs_bmc = &priv->kcs_bmc;
192 	kcs_bmc->dev = &pdev->dev;
193 	kcs_bmc->channel = chan;
194 	kcs_bmc->ioreg.idr = priv->reg->dib;
195 	kcs_bmc->ioreg.odr = priv->reg->dob;
196 	kcs_bmc->ioreg.str = priv->reg->sts;
197 	kcs_bmc->ops = &npcm7xx_kcs_ops;
198 
199 	platform_set_drvdata(pdev, priv);
200 
201 	rc = npcm7xx_kcs_config_irq(kcs_bmc, pdev);
202 	if (rc)
203 		return rc;
204 
205 	npcm7xx_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE), 0);
206 	npcm7xx_kcs_enable_channel(kcs_bmc, true);
207 
208 	rc = kcs_bmc_add_device(kcs_bmc);
209 	if (rc) {
210 		dev_warn(&pdev->dev, "Failed to register channel %d: %d\n", kcs_bmc->channel, rc);
211 		return rc;
212 	}
213 
214 	pr_info("channel=%u idr=0x%x odr=0x%x str=0x%x\n",
215 		chan,
216 		kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);
217 
218 	return 0;
219 }
220 
221 static int npcm7xx_kcs_remove(struct platform_device *pdev)
222 {
223 	struct npcm7xx_kcs_bmc *priv = platform_get_drvdata(pdev);
224 	struct kcs_bmc_device *kcs_bmc = &priv->kcs_bmc;
225 
226 	kcs_bmc_remove_device(kcs_bmc);
227 
228 	npcm7xx_kcs_enable_channel(kcs_bmc, false);
229 	npcm7xx_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE), 0);
230 
231 	return 0;
232 }
233 
234 static const struct of_device_id npcm_kcs_bmc_match[] = {
235 	{ .compatible = "nuvoton,npcm750-kcs-bmc" },
236 	{ }
237 };
238 MODULE_DEVICE_TABLE(of, npcm_kcs_bmc_match);
239 
240 static struct platform_driver npcm_kcs_bmc_driver = {
241 	.driver = {
242 		.name		= DEVICE_NAME,
243 		.of_match_table	= npcm_kcs_bmc_match,
244 	},
245 	.probe	= npcm7xx_kcs_probe,
246 	.remove	= npcm7xx_kcs_remove,
247 };
248 module_platform_driver(npcm_kcs_bmc_driver);
249 
250 MODULE_LICENSE("GPL v2");
251 MODULE_AUTHOR("Avi Fishman <avifishman70@gmail.com>");
252 MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");
253 MODULE_DESCRIPTION("NPCM7xx device interface to the KCS BMC device");
254