xref: /openbmc/linux/drivers/hwmon/gxp-fan-ctrl.c (revision 39f03438)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
3 
4 #include <linux/bits.h>
5 #include <linux/err.h>
6 #include <linux/hwmon.h>
7 #include <linux/io.h>
8 #include <linux/module.h>
9 #include <linux/mod_devicetable.h>
10 #include <linux/platform_device.h>
11 
12 #define OFS_FAN_INST	0 /* Is 0 because plreg base will be set at INST */
13 #define OFS_FAN_FAIL	2 /* Is 2 bytes after base */
14 #define OFS_SEVSTAT	0 /* Is 0 because fn2 base will be set at SEVSTAT */
15 #define POWER_BIT	24
16 
17 struct gxp_fan_ctrl_drvdata {
18 	void __iomem	*base;
19 	void __iomem	*plreg;
20 	void __iomem	*fn2;
21 };
22 
fan_installed(struct device * dev,int fan)23 static bool fan_installed(struct device *dev, int fan)
24 {
25 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
26 	u8 val;
27 
28 	val = readb(drvdata->plreg + OFS_FAN_INST);
29 
30 	return !!(val & BIT(fan));
31 }
32 
fan_failed(struct device * dev,int fan)33 static long fan_failed(struct device *dev, int fan)
34 {
35 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
36 	u8 val;
37 
38 	val = readb(drvdata->plreg + OFS_FAN_FAIL);
39 
40 	return !!(val & BIT(fan));
41 }
42 
fan_enabled(struct device * dev,int fan)43 static long fan_enabled(struct device *dev, int fan)
44 {
45 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
46 	u32 val;
47 
48 	/*
49 	 * Check the power status as if the platform is off the value
50 	 * reported for the PWM will be incorrect. Report fan as
51 	 * disabled.
52 	 */
53 	val = readl(drvdata->fn2 + OFS_SEVSTAT);
54 
55 	return !!((val & BIT(POWER_BIT)) && fan_installed(dev, fan));
56 }
57 
gxp_pwm_write(struct device * dev,u32 attr,int channel,long val)58 static int gxp_pwm_write(struct device *dev, u32 attr, int channel, long val)
59 {
60 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
61 
62 	switch (attr) {
63 	case hwmon_pwm_input:
64 		if (val > 255 || val < 0)
65 			return -EINVAL;
66 		writeb(val, drvdata->base + channel);
67 		return 0;
68 	default:
69 		return -EOPNOTSUPP;
70 	}
71 }
72 
gxp_fan_ctrl_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)73 static int gxp_fan_ctrl_write(struct device *dev, enum hwmon_sensor_types type,
74 			      u32 attr, int channel, long val)
75 {
76 	switch (type) {
77 	case hwmon_pwm:
78 		return gxp_pwm_write(dev, attr, channel, val);
79 	default:
80 		return -EOPNOTSUPP;
81 	}
82 }
83 
gxp_fan_read(struct device * dev,u32 attr,int channel,long * val)84 static int gxp_fan_read(struct device *dev, u32 attr, int channel, long *val)
85 {
86 	switch (attr) {
87 	case hwmon_fan_enable:
88 		*val = fan_enabled(dev, channel);
89 		return 0;
90 	case hwmon_fan_fault:
91 		*val = fan_failed(dev, channel);
92 		return 0;
93 	default:
94 		return -EOPNOTSUPP;
95 	}
96 }
97 
gxp_pwm_read(struct device * dev,u32 attr,int channel,long * val)98 static int gxp_pwm_read(struct device *dev, u32 attr, int channel, long *val)
99 {
100 	struct gxp_fan_ctrl_drvdata *drvdata = dev_get_drvdata(dev);
101 	u32 reg;
102 
103 	/*
104 	 * Check the power status of the platform. If the platform is off
105 	 * the value reported for the PWM will be incorrect. In this case
106 	 * report a PWM of zero.
107 	 */
108 
109 	reg = readl(drvdata->fn2 + OFS_SEVSTAT);
110 
111 	if (reg & BIT(POWER_BIT))
112 		*val = fan_installed(dev, channel) ? readb(drvdata->base + channel) : 0;
113 	else
114 		*val = 0;
115 
116 	return 0;
117 }
118 
gxp_fan_ctrl_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)119 static int gxp_fan_ctrl_read(struct device *dev, enum hwmon_sensor_types type,
120 			     u32 attr, int channel, long *val)
121 {
122 	switch (type) {
123 	case hwmon_fan:
124 		return gxp_fan_read(dev, attr, channel, val);
125 	case hwmon_pwm:
126 		return gxp_pwm_read(dev, attr, channel, val);
127 	default:
128 		return -EOPNOTSUPP;
129 	}
130 }
131 
gxp_fan_ctrl_is_visible(const void * _data,enum hwmon_sensor_types type,u32 attr,int channel)132 static umode_t gxp_fan_ctrl_is_visible(const void *_data,
133 				       enum hwmon_sensor_types type,
134 				       u32 attr, int channel)
135 {
136 	umode_t mode = 0;
137 
138 	switch (type) {
139 	case hwmon_fan:
140 		switch (attr) {
141 		case hwmon_fan_enable:
142 		case hwmon_fan_fault:
143 			mode = 0444;
144 			break;
145 		default:
146 			break;
147 		}
148 		break;
149 	case hwmon_pwm:
150 		switch (attr) {
151 		case hwmon_pwm_input:
152 			mode = 0644;
153 			break;
154 		default:
155 			break;
156 		}
157 		break;
158 	default:
159 		break;
160 	}
161 
162 	return mode;
163 }
164 
165 static const struct hwmon_ops gxp_fan_ctrl_ops = {
166 	.is_visible = gxp_fan_ctrl_is_visible,
167 	.read = gxp_fan_ctrl_read,
168 	.write = gxp_fan_ctrl_write,
169 };
170 
171 static const struct hwmon_channel_info * const gxp_fan_ctrl_info[] = {
172 	HWMON_CHANNEL_INFO(fan,
173 			   HWMON_F_FAULT | HWMON_F_ENABLE,
174 			   HWMON_F_FAULT | HWMON_F_ENABLE,
175 			   HWMON_F_FAULT | HWMON_F_ENABLE,
176 			   HWMON_F_FAULT | HWMON_F_ENABLE,
177 			   HWMON_F_FAULT | HWMON_F_ENABLE,
178 			   HWMON_F_FAULT | HWMON_F_ENABLE,
179 			   HWMON_F_FAULT | HWMON_F_ENABLE,
180 			   HWMON_F_FAULT | HWMON_F_ENABLE),
181 	HWMON_CHANNEL_INFO(pwm,
182 			   HWMON_PWM_INPUT,
183 			   HWMON_PWM_INPUT,
184 			   HWMON_PWM_INPUT,
185 			   HWMON_PWM_INPUT,
186 			   HWMON_PWM_INPUT,
187 			   HWMON_PWM_INPUT,
188 			   HWMON_PWM_INPUT,
189 			   HWMON_PWM_INPUT),
190 	NULL
191 };
192 
193 static const struct hwmon_chip_info gxp_fan_ctrl_chip_info = {
194 	.ops = &gxp_fan_ctrl_ops,
195 	.info = gxp_fan_ctrl_info,
196 
197 };
198 
gxp_fan_ctrl_probe(struct platform_device * pdev)199 static int gxp_fan_ctrl_probe(struct platform_device *pdev)
200 {
201 	struct gxp_fan_ctrl_drvdata *drvdata;
202 	struct device *dev = &pdev->dev;
203 	struct device *hwmon_dev;
204 
205 	drvdata = devm_kzalloc(dev, sizeof(struct gxp_fan_ctrl_drvdata),
206 			       GFP_KERNEL);
207 	if (!drvdata)
208 		return -ENOMEM;
209 
210 	drvdata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
211 	if (IS_ERR(drvdata->base))
212 		return dev_err_probe(dev, PTR_ERR(drvdata->base),
213 				     "failed to map base\n");
214 
215 	drvdata->plreg = devm_platform_ioremap_resource_byname(pdev,
216 							       "pl");
217 	if (IS_ERR(drvdata->plreg))
218 		return dev_err_probe(dev, PTR_ERR(drvdata->plreg),
219 				     "failed to map plreg\n");
220 
221 	drvdata->fn2 = devm_platform_ioremap_resource_byname(pdev,
222 							     "fn2");
223 	if (IS_ERR(drvdata->fn2))
224 		return dev_err_probe(dev, PTR_ERR(drvdata->fn2),
225 				     "failed to map fn2\n");
226 
227 	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
228 							 "hpe_gxp_fan_ctrl",
229 							 drvdata,
230 							 &gxp_fan_ctrl_chip_info,
231 							 NULL);
232 
233 	return PTR_ERR_OR_ZERO(hwmon_dev);
234 }
235 
236 static const struct of_device_id gxp_fan_ctrl_of_match[] = {
237 	{ .compatible = "hpe,gxp-fan-ctrl", },
238 	{},
239 };
240 MODULE_DEVICE_TABLE(of, gxp_fan_ctrl_of_match);
241 
242 static struct platform_driver gxp_fan_ctrl_driver = {
243 	.probe		= gxp_fan_ctrl_probe,
244 	.driver = {
245 		.name	= "gxp-fan-ctrl",
246 		.of_match_table = gxp_fan_ctrl_of_match,
247 	},
248 };
249 module_platform_driver(gxp_fan_ctrl_driver);
250 
251 MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
252 MODULE_DESCRIPTION("HPE GXP fan controller");
253 MODULE_LICENSE("GPL");
254