target/linux/bcm27xx/patches-6.1/950-0921-hwmon-pwm-fan-Add-fan-speed-register-support.patch

   1 From 96a8a4776cb142f5d2bb7f6379df9af40e727c0b Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 11 Jul 2023 10:17:29 +0100
   4 Subject: [PATCH] hwmon: (pwm-fan) Add fan speed register support
   5
   6 Some platforms include a fan-speed register that reports RPM directly
   7 as an alternative to counting interrupts from the fan tachometer input.
   8 Add support for reading a register at a given offset (rpm-offset) within
   9 a block declared in another node (rpm-regmap). This indirection allows
  10 the usual address mapping to be performed, and for address sharing with
  11 another driver.
  12
  13 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  14 ---
  15  drivers/hwmon/pwm-fan.c | 59 ++++++++++++++++++++++++++++++++++++-----
  16  1 file changed, 52 insertions(+), 7 deletions(-)
  17
  18 --- a/drivers/hwmon/pwm-fan.c
  19 +++ b/drivers/hwmon/pwm-fan.c
  20 @@ -12,6 +12,7 @@
  21  #include <linux/module.h>
  22  #include <linux/mutex.h>
  23  #include <linux/of.h>
  24 +#include <linux/of_address.h>
  25  #include <linux/platform_device.h>
  26  #include <linux/pwm.h>
  27  #include <linux/regulator/consumer.h>
  28 @@ -51,6 +52,9 @@ struct pwm_fan_ctx {
  29         ktime_t sample_start;
  30         struct timer_list rpm_timer;
  31
  32 +       void __iomem *rpm_regbase;
  33 +       unsigned int rpm_offset;
  34 +
  35         unsigned int pwm_value;
  36         unsigned int pwm_fan_state;
  37         unsigned int pwm_fan_max_state;
  38 @@ -61,6 +65,10 @@ struct pwm_fan_ctx {
  39         struct hwmon_channel_info fan_channel;
  40  };
  41
  42 +static const u32 rpm_reg_channel_config[] = {
  43 +       HWMON_F_INPUT, 0
  44 +};
  45 +
  46  /* This handler assumes self resetting edge triggered interrupt. */
  47  static irqreturn_t pulse_handler(int irq, void *dev_id)
  48  {
  49 @@ -335,7 +343,10 @@ static int pwm_fan_read(struct device *d
  50                 }
  51                 return -EOPNOTSUPP;
  52         case hwmon_fan:
  53 -               *val = ctx->tachs[channel].rpm;
  54 +               if (ctx->rpm_regbase)
  55 +                       *val = (long)readl(ctx->rpm_regbase + ctx->rpm_offset);
  56 +               else
  57 +                       *val = ctx->tachs[channel].rpm;
  58                 return 0;
  59
  60         default:
  61 @@ -470,6 +481,7 @@ static void pwm_fan_cleanup(void *__ctx)
  62         /* Switch off everything */
  63         ctx->enable_mode = pwm_disable_reg_disable;
  64         pwm_fan_power_off(ctx);
  65 +       iounmap(ctx->rpm_regbase);
  66  }
  67
  68  static int pwm_fan_probe(struct platform_device *pdev)
  69 @@ -534,10 +546,23 @@ static int pwm_fan_probe(struct platform
  70                 return ret;
  71
  72         ctx->tach_count = platform_irq_count(pdev);
  73 +       if (ctx->tach_count == 0) {
  74 +               struct device_node *rpm_node;
  75 +
  76 +               rpm_node = of_parse_phandle(dev->of_node, "rpm-regmap", 0);
  77 +               if (rpm_node)
  78 +                       ctx->rpm_regbase = of_iomap(rpm_node, 0);
  79 +       }
  80 +
  81         if (ctx->tach_count < 0)
  82                 return dev_err_probe(dev, ctx->tach_count,
  83                                      "Could not get number of fan tachometer inputs\n");
  84 -       dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
  85 +       if (IS_ERR(ctx->rpm_regbase))
  86 +               return dev_err_probe(dev, PTR_ERR(ctx->rpm_regbase),
  87 +                                    "Could not get rpm reg\n");
  88 +
  89 +       dev_dbg(dev, "%d fan tachometer inputs, %d rpm regmap\n", ctx->tach_count,
  90 +               !!ctx->rpm_regbase);
  91
  92         if (ctx->tach_count) {
  93                 channel_count++;        /* We also have a FAN channel. */
  94 @@ -554,12 +579,24 @@ static int pwm_fan_probe(struct platform
  95                 if (!fan_channel_config)
  96                         return -ENOMEM;
  97                 ctx->fan_channel.config = fan_channel_config;
  98 +       } else if (ctx->rpm_regbase) {
  99 +               channel_count++;        /* We also have a FAN channel. */
 100 +               ctx->fan_channel.type = hwmon_fan;
 101 +               ctx->fan_channel.config = rpm_reg_channel_config;
 102 +
 103 +               if (of_property_read_u32(pdev->dev.of_node, "rpm-offset", &ctx->rpm_offset)) {
 104 +                       dev_err(&pdev->dev, "unable to read 'rpm-offset'");
 105 +                       ret = -EINVAL;
 106 +                       goto error;
 107 +               }
 108         }
 109
 110         channels = devm_kcalloc(dev, channel_count + 1,
 111                                 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
 112 -       if (!channels)
 113 -               return -ENOMEM;
 114 +       if (!channels) {
 115 +               ret = -ENOMEM;
 116 +               goto error;
 117 +       }
 118
 119         channels[0] = HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE);
 120
 121 @@ -602,6 +639,8 @@ static int pwm_fan_probe(struct platform
 122                 mod_timer(&ctx->rpm_timer, jiffies + HZ);
 123
 124                 channels[1] = &ctx->fan_channel;
 125 +       } else if (ctx->rpm_regbase) {
 126 +               channels[1] = &ctx->fan_channel;
 127         }
 128
 129         ctx->info.ops = &pwm_fan_hwmon_ops;
 130 @@ -611,12 +650,13 @@ static int pwm_fan_probe(struct platform
 131                                                      ctx, &ctx->info, NULL);
 132         if (IS_ERR(hwmon)) {
 133                 dev_err(dev, "Failed to register hwmon device\n");
 134 -               return PTR_ERR(hwmon);
 135 +               ret = PTR_ERR(hwmon);
 136 +               goto error;
 137         }
 138
 139         ret = pwm_fan_of_get_cooling_data(dev, ctx);
 140         if (ret)
 141 -               return ret;
 142 +               goto error;
 143
 144         ctx->pwm_fan_state = ctx->pwm_fan_max_state;
 145         if (IS_ENABLED(CONFIG_THERMAL)) {
 146 @@ -627,12 +667,17 @@ static int pwm_fan_probe(struct platform
 147                         dev_err(dev,
 148                                 "Failed to register pwm-fan as cooling device: %d\n",
 149                                 ret);
 150 -                       return ret;
 151 +                       goto error;
 152                 }
 153                 ctx->cdev = cdev;
 154         }
 155
 156         return 0;
 157 +
 158 +error:
 159 +       if (ctx->rpm_regbase)
 160 +               iounmap(ctx->rpm_regbase);
 161 +       return ret;
 162  }
 163
 164  static void pwm_fan_shutdown(struct platform_device *pdev)