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nvmem: core: remove regmap dependency
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nvmem uses regmap_raw_read/write apis to read/write data from providers,
regmap raw apis stopped working with recent kernels which removed raw
accessors on mmio bus. This resulted in broken nvmem for providers
which are based on regmap mmio bus. This issue can be fixed temporarly
by moving to other regmap apis, but we might hit same issue in future.
Moving to interfaces based on read/write callbacks from providers would
be more robust.

This patch removes regmap dependency from nvmem and introduces
read/write callbacks from the providers.

Without this patch nvmem providers like qfprom based on regmap mmio
bus would not work.

Reported-by: Rajendra Nayak <rjendra@qti.qualcomm.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Srinivas Kandagatla authored and Greg Kroah-Hartman committed May 1, 2016
1 parent 326071b commit 795ddd1
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Showing 3 changed files with 50 additions and 28 deletions.
1 change: 0 additions & 1 deletion drivers/nvmem/Kconfig
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
menuconfig NVMEM
tristate "NVMEM Support"
select REGMAP
help
Support for NVMEM(Non Volatile Memory) devices like EEPROM, EFUSES...

Expand Down
67 changes: 40 additions & 27 deletions drivers/nvmem/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,12 +23,10 @@
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>

struct nvmem_device {
const char *name;
struct regmap *regmap;
struct module *owner;
struct device dev;
int stride;
Expand All @@ -41,6 +39,9 @@ struct nvmem_device {
int flags;
struct bin_attribute eeprom;
struct device *base_dev;
nvmem_reg_read_t reg_read;
nvmem_reg_write_t reg_write;
void *priv;
};

#define FLAG_COMPAT BIT(0)
Expand All @@ -66,6 +67,23 @@ static struct lock_class_key eeprom_lock_key;
#endif

#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
void *val, size_t bytes)
{
if (nvmem->reg_read)
return nvmem->reg_read(nvmem->priv, offset, val, bytes);

return -EINVAL;
}

static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
void *val, size_t bytes)
{
if (nvmem->reg_write)
return nvmem->reg_write(nvmem->priv, offset, val, bytes);

return -EINVAL;
}

static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
Expand Down Expand Up @@ -93,7 +111,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,

count = round_down(count, nvmem->word_size);

rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
rc = nvmem_reg_read(nvmem, pos, buf, count);

if (IS_ERR_VALUE(rc))
return rc;
Expand Down Expand Up @@ -127,7 +145,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,

count = round_down(count, nvmem->word_size);

rc = regmap_raw_write(nvmem->regmap, pos, buf, count);
rc = nvmem_reg_write(nvmem, pos, buf, count);

if (IS_ERR_VALUE(rc))
return rc;
Expand Down Expand Up @@ -421,18 +439,11 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
{
struct nvmem_device *nvmem;
struct device_node *np;
struct regmap *rm;
int rval;

if (!config->dev)
return ERR_PTR(-EINVAL);

rm = dev_get_regmap(config->dev, NULL);
if (!rm) {
dev_err(config->dev, "Regmap not found\n");
return ERR_PTR(-EINVAL);
}

nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
if (!nvmem)
return ERR_PTR(-ENOMEM);
Expand All @@ -444,14 +455,16 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
}

nvmem->id = rval;
nvmem->regmap = rm;
nvmem->owner = config->owner;
nvmem->stride = regmap_get_reg_stride(rm);
nvmem->word_size = regmap_get_val_bytes(rm);
nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
nvmem->stride = config->stride;
nvmem->word_size = config->word_size;
nvmem->size = config->size;
nvmem->dev.type = &nvmem_provider_type;
nvmem->dev.bus = &nvmem_bus_type;
nvmem->dev.parent = config->dev;
nvmem->priv = config->priv;
nvmem->reg_read = config->reg_read;
nvmem->reg_write = config->reg_write;
np = config->dev->of_node;
nvmem->dev.of_node = np;
dev_set_name(&nvmem->dev, "%s%d",
Expand Down Expand Up @@ -948,7 +961,7 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
{
int rc;

rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);

if (IS_ERR_VALUE(rc))
return rc;
Expand Down Expand Up @@ -977,7 +990,7 @@ void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
u8 *buf;
int rc;

if (!nvmem || !nvmem->regmap)
if (!nvmem)
return ERR_PTR(-EINVAL);

buf = kzalloc(cell->bytes, GFP_KERNEL);
Expand Down Expand Up @@ -1014,7 +1027,7 @@ static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
*b <<= bit_offset;

/* setup the first byte with lsb bits from nvmem */
rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
*b++ |= GENMASK(bit_offset - 1, 0) & v;

/* setup rest of the byte if any */
Expand All @@ -1031,7 +1044,7 @@ static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
/* if it's not end on byte boundary */
if ((nbits + bit_offset) % BITS_PER_BYTE) {
/* setup the last byte with msb bits from nvmem */
rc = regmap_raw_read(nvmem->regmap,
rc = nvmem_reg_read(nvmem,
cell->offset + cell->bytes - 1, &v, 1);
*p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;

Expand All @@ -1054,7 +1067,7 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
struct nvmem_device *nvmem = cell->nvmem;
int rc;

if (!nvmem || !nvmem->regmap || nvmem->read_only ||
if (!nvmem || nvmem->read_only ||
(cell->bit_offset == 0 && len != cell->bytes))
return -EINVAL;

Expand All @@ -1064,7 +1077,7 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
return PTR_ERR(buf);
}

rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);
rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);

/* free the tmp buffer */
if (cell->bit_offset || cell->nbits)
Expand Down Expand Up @@ -1094,7 +1107,7 @@ ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
int rc;
ssize_t len;

if (!nvmem || !nvmem->regmap)
if (!nvmem)
return -EINVAL;

rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
Expand Down Expand Up @@ -1124,7 +1137,7 @@ int nvmem_device_cell_write(struct nvmem_device *nvmem,
struct nvmem_cell cell;
int rc;

if (!nvmem || !nvmem->regmap)
if (!nvmem)
return -EINVAL;

rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
Expand Down Expand Up @@ -1152,10 +1165,10 @@ int nvmem_device_read(struct nvmem_device *nvmem,
{
int rc;

if (!nvmem || !nvmem->regmap)
if (!nvmem)
return -EINVAL;

rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);
rc = nvmem_reg_read(nvmem, offset, buf, bytes);

if (IS_ERR_VALUE(rc))
return rc;
Expand All @@ -1180,10 +1193,10 @@ int nvmem_device_write(struct nvmem_device *nvmem,
{
int rc;

if (!nvmem || !nvmem->regmap)
if (!nvmem)
return -EINVAL;

rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);
rc = nvmem_reg_write(nvmem, offset, buf, bytes);

if (IS_ERR_VALUE(rc))
return rc;
Expand Down
10 changes: 10 additions & 0 deletions include/linux/nvmem-provider.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,10 @@

struct nvmem_device;
struct nvmem_cell_info;
typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
void *val, size_t bytes);
typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
void *val, size_t bytes);

struct nvmem_config {
struct device *dev;
Expand All @@ -24,6 +28,12 @@ struct nvmem_config {
int ncells;
bool read_only;
bool root_only;
nvmem_reg_read_t reg_read;
nvmem_reg_write_t reg_write;
int size;
int word_size;
int stride;
void *priv;
/* To be only used by old driver/misc/eeprom drivers */
bool compat;
struct device *base_dev;
Expand Down

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