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
 17struct gxp_fan_ctrl_drvdata {
 18	void __iomem	*base;
 19	void __iomem	*plreg;
 20	void __iomem	*fn2;
 21};
 22
 23static 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
 33static 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
 43static 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
 58static 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
 73static 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
 84static 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
 98static 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
119static 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
132static 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
165static 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
171static 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
193static 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
199static 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
236static const struct of_device_id gxp_fan_ctrl_of_match[] = {
237	{ .compatible = "hpe,gxp-fan-ctrl", },
238	{},
239};
240MODULE_DEVICE_TABLE(of, gxp_fan_ctrl_of_match);
241
242static 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};
249module_platform_driver(gxp_fan_ctrl_driver);
250
251MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
252MODULE_DESCRIPTION("HPE GXP fan controller");
253MODULE_LICENSE("GPL");