drivers/hwmon/gxp-fan-ctrl.c

   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
  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
  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
  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
  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
  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
  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
  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
 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
 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
 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");