target/linux/ipq806x/patches-4.4/019-4-nvmem-Add-backwards-compatibility-support-for-older-EEPROM-drivers.patch

   1 From b6c217ab9be6895384cf0b284ace84ad79e5c53b Mon Sep 17 00:00:00 2001
   2 From: Andrew Lunn <andrew@lunn.ch>
   3 Date: Fri, 26 Feb 2016 20:59:19 +0100
   4 Subject: nvmem: Add backwards compatibility support for older EEPROM drivers.
   5
   6 Older drivers made an 'eeprom' file available in the /sys device
   7 directory. Have the NVMEM core provide this to retain backwards
   8 compatibility.
   9
  10 Signed-off-by: Andrew Lunn <andrew@lunn.ch>
  11 Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  12 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  13 ---
  14  drivers/nvmem/core.c           | 84 ++++++++++++++++++++++++++++++++++++++----
  15  include/linux/nvmem-provider.h |  4 +-
  16  2 files changed, 79 insertions(+), 9 deletions(-)
  17
  18 --- a/drivers/nvmem/core.c
  19 +++ b/drivers/nvmem/core.c
  20 @@ -38,8 +38,13 @@ struct nvmem_device {
  21         int                     users;
  22         size_t                  size;
  23         bool                    read_only;
  24 +       int                     flags;
  25 +       struct bin_attribute    eeprom;
  26 +       struct device           *base_dev;
  27  };
  28
  29 +#define FLAG_COMPAT            BIT(0)
  30 +
  31  struct nvmem_cell {
  32         const char              *name;
  33         int                     offset;
  34 @@ -56,16 +61,26 @@ static DEFINE_IDA(nvmem_ida);
  35  static LIST_HEAD(nvmem_cells);
  36  static DEFINE_MUTEX(nvmem_cells_mutex);
  37
  38 +#ifdef CONFIG_DEBUG_LOCK_ALLOC
  39 +static struct lock_class_key eeprom_lock_key;
  40 +#endif
  41 +
  42  #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
  43
  44  static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
  45                                     struct bin_attribute *attr,
  46                                     char *buf, loff_t pos, size_t count)
  47  {
  48 -       struct device *dev = container_of(kobj, struct device, kobj);
  49 -       struct nvmem_device *nvmem = to_nvmem_device(dev);
  50 +       struct device *dev;
  51 +       struct nvmem_device *nvmem;
  52         int rc;
  53
  54 +       if (attr->private)
  55 +               dev = attr->private;
  56 +       else
  57 +               dev = container_of(kobj, struct device, kobj);
  58 +       nvmem = to_nvmem_device(dev);
  59 +
  60         /* Stop the user from reading */
  61         if (pos >= nvmem->size)
  62                 return 0;
  63 @@ -90,10 +105,16 @@ static ssize_t bin_attr_nvmem_write(stru
  64                                      struct bin_attribute *attr,
  65                                      char *buf, loff_t pos, size_t count)
  66  {
  67 -       struct device *dev = container_of(kobj, struct device, kobj);
  68 -       struct nvmem_device *nvmem = to_nvmem_device(dev);
  69 +       struct device *dev;
  70 +       struct nvmem_device *nvmem;
  71         int rc;
  72
  73 +       if (attr->private)
  74 +               dev = attr->private;
  75 +       else
  76 +               dev = container_of(kobj, struct device, kobj);
  77 +       nvmem = to_nvmem_device(dev);
  78 +
  79         /* Stop the user from writing */
  80         if (pos >= nvmem->size)
  81                 return 0;
  82 @@ -349,6 +370,43 @@ err:
  83         return rval;
  84  }
  85
  86 +/*
  87 + * nvmem_setup_compat() - Create an additional binary entry in
  88 + * drivers sys directory, to be backwards compatible with the older
  89 + * drivers/misc/eeprom drivers.
  90 + */
  91 +static int nvmem_setup_compat(struct nvmem_device *nvmem,
  92 +                             const struct nvmem_config *config)
  93 +{
  94 +       int rval;
  95 +
  96 +       if (!config->base_dev)
  97 +               return -EINVAL;
  98 +
  99 +       if (nvmem->read_only)
 100 +               nvmem->eeprom = bin_attr_ro_root_nvmem;
 101 +       else
 102 +               nvmem->eeprom = bin_attr_rw_root_nvmem;
 103 +       nvmem->eeprom.attr.name = "eeprom";
 104 +       nvmem->eeprom.size = nvmem->size;
 105 +#ifdef CONFIG_DEBUG_LOCK_ALLOC
 106 +       nvmem->eeprom.attr.key = &eeprom_lock_key;
 107 +#endif
 108 +       nvmem->eeprom.private = &nvmem->dev;
 109 +       nvmem->base_dev = config->base_dev;
 110 +
 111 +       rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
 112 +       if (rval) {
 113 +               dev_err(&nvmem->dev,
 114 +                       "Failed to create eeprom binary file %d\n", rval);
 115 +               return rval;
 116 +       }
 117 +
 118 +       nvmem->flags |= FLAG_COMPAT;
 119 +
 120 +       return 0;
 121 +}
 122 +
 123  /**
 124   * nvmem_register() - Register a nvmem device for given nvmem_config.
 125   * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 126 @@ -416,16 +474,23 @@ struct nvmem_device *nvmem_register(cons
 127         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
 128
 129         rval = device_add(&nvmem->dev);
 130 -       if (rval) {
 131 -               ida_simple_remove(&nvmem_ida, nvmem->id);
 132 -               kfree(nvmem);
 133 -               return ERR_PTR(rval);
 134 +       if (rval)
 135 +               goto out;
 136 +
 137 +       if (config->compat) {
 138 +               rval = nvmem_setup_compat(nvmem, config);
 139 +               if (rval)
 140 +                       goto out;
 141         }
 142
 143         if (config->cells)
 144                 nvmem_add_cells(nvmem, config);
 145
 146         return nvmem;
 147 +out:
 148 +       ida_simple_remove(&nvmem_ida, nvmem->id);
 149 +       kfree(nvmem);
 150 +       return ERR_PTR(rval);
 151  }
 152  EXPORT_SYMBOL_GPL(nvmem_register);
 153
 154 @@ -445,6 +510,9 @@ int nvmem_unregister(struct nvmem_device
 155         }
 156         mutex_unlock(&nvmem_mutex);
 157
 158 +       if (nvmem->flags & FLAG_COMPAT)
 159 +               device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 160 +
 161         nvmem_device_remove_all_cells(nvmem);
 162         device_del(&nvmem->dev);
 163
 164 --- a/include/linux/nvmem-provider.h
 165 +++ b/include/linux/nvmem-provider.h
 166 @@ -24,6 +24,9 @@ struct nvmem_config {
 167         int                     ncells;
 168         bool                    read_only;
 169         bool                    root_only;
 170 +       /* To be only used by old driver/misc/eeprom drivers */
 171 +       bool                    compat;
 172 +       struct device           *base_dev;
 173  };
 174
 175  #if IS_ENABLED(CONFIG_NVMEM)
 176 @@ -44,5 +47,4 @@ static inline int nvmem_unregister(struc
 177  }
 178
 179  #endif /* CONFIG_NVMEM */
 180 -
 181  #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */