@@ -16,6 +16,7 @@
#include <linux/device.h>
#include <linux/nvmem-provider.h>
+#include <linux/nvmem-consumer.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
@@ -379,6 +380,351 @@ int nvmem_unregister(struct nvmem_device *nvmem)
}
EXPORT_SYMBOL_GPL(nvmem_unregister);
+static struct nvmem_device *__nvmem_device_get(struct device_node *np,
+ struct nvmem_cell **cellp,
+ const char *cell_id)
+{
+ struct nvmem_device *nvmem = NULL;
+
+ mutex_lock(&nvmem_mutex);
+
+ if (np) {
+ nvmem = of_nvmem_find(np);
+ if (!nvmem) {
+ mutex_unlock(&nvmem_mutex);
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+ } else {
+ struct nvmem_cell *cell = nvmem_find_cell(cell_id);
+
+ if (cell) {
+ nvmem = cell->nvmem;
+ *cellp = cell;
+ }
+
+ if (!nvmem) {
+ mutex_unlock(&nvmem_mutex);
+ return ERR_PTR(-ENOENT);
+ }
+ }
+
+ nvmem->users++;
+ mutex_unlock(&nvmem_mutex);
+
+ if (!try_module_get(nvmem->owner)) {
+ dev_err(&nvmem->dev,
+ "could not increase module refcount for cell %s\n",
+ nvmem->name);
+
+ mutex_lock(&nvmem_mutex);
+ nvmem->users--;
+ mutex_unlock(&nvmem_mutex);
+
+ return ERR_PTR(-EINVAL);
+ }
+
+ return nvmem;
+}
+
+static int __nvmem_device_put(struct nvmem_device *nvmem)
+{
+ module_put(nvmem->owner);
+ mutex_lock(&nvmem_mutex);
+ nvmem->users--;
+ mutex_unlock(&nvmem_mutex);
+
+ return 0;
+}
+
+static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
+{
+ struct nvmem_cell *cell = NULL;
+ struct nvmem_device *nvmem;
+
+ nvmem = __nvmem_device_get(NULL, &cell, cell_id);
+ if (IS_ERR(nvmem))
+ return (struct nvmem_cell *)nvmem;
+
+
+ return cell;
+
+}
+
+static struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+ const char *name)
+{
+ struct device_node *cell_np, *nvmem_np;
+ struct nvmem_cell *cell;
+ struct nvmem_device *nvmem;
+ const __be32 *addr;
+ int rval, len, index;
+
+ index = of_property_match_string(np, "nvmem-cell-names", name);
+
+ cell_np = of_parse_phandle(np, "nvmem-cell", index);
+ if (!cell_np)
+ return ERR_PTR(-EINVAL);
+
+ nvmem_np = of_get_next_parent(cell_np);
+ if (!nvmem_np)
+ return ERR_PTR(-EINVAL);
+
+ nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
+ if (IS_ERR(nvmem))
+ return (struct nvmem_cell *)nvmem;
+
+ addr = of_get_property(cell_np, "reg", &len);
+ if (!addr || (len < 2 * sizeof(int))) {
+ dev_err(&nvmem->dev, "of_i2c: invalid reg on %s\n",
+ cell_np->full_name);
+ rval = -EINVAL;
+ goto err_mem;
+ }
+
+ cell = kzalloc(sizeof(*cell), GFP_KERNEL);
+ if (!cell) {
+ rval = -ENOMEM;
+ goto err_mem;
+ }
+
+ cell->nvmem = nvmem;
+ cell->offset = be32_to_cpup(addr++);
+ cell->bytes = be32_to_cpup(addr);
+ cell->name = cell_np->name;
+
+ of_property_read_u32(cell_np, "bit-offset", &cell->bit_offset);
+ of_property_read_u32(cell_np, "nbits", &cell->nbits);
+
+ if (cell->nbits)
+ cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
+ BITS_PER_BYTE);
+
+ if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
+ dev_err(&nvmem->dev,
+ "cell %s unaligned to nvmem stride %d\n",
+ cell->name, nvmem->stride);
+ rval = -EINVAL;
+ goto err_sanity;
+ }
+
+ nvmem_cell_add(cell);
+
+ return cell;
+
+err_sanity:
+ kfree(cell);
+
+err_mem:
+ __nvmem_device_put(nvmem);
+
+ return ERR_PTR(rval);
+
+}
+
+/**
+ * nvmem_cell_get(): Get nvmem cell of device form a given index
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @index: nvmem index in nvmems property.
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell. The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
+{
+ struct nvmem_cell *cell;
+
+ if (dev->of_node) { /* try dt first */
+ cell = of_nvmem_cell_get(dev->of_node, cell_id);
+ if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
+ return cell;
+ }
+
+ return nvmem_cell_get_from_list(cell_id);
+
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_get);
+
+/**
+ * nvmem_cell_put(): Release previously allocated nvmem cell.
+ *
+ * @cell: Previously allocated nvmem cell by nvmem_cell_get()
+ * or nvmem_cell_get().
+ */
+void nvmem_cell_put(struct nvmem_cell *cell)
+{
+ struct nvmem_device *nvmem = cell->nvmem;
+
+ __nvmem_device_put(nvmem);
+ nvmem_cell_drop(cell);
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_put);
+
+static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
+ void *buf)
+{
+ u8 *p, *b;
+ int i, bit_offset = cell->bit_offset;
+
+ p = b = buf;
+ if (bit_offset) {
+ /* First shift */
+ *b++ >>= bit_offset;
+
+ /* setup rest of the bytes if any */
+ for (i = 1; i < cell->bytes; i++) {
+ /* Get bits from next byte and shift them towards msb */
+ *p |= *b << (BITS_PER_BYTE - bit_offset);
+
+ p = b;
+ *b++ >>= bit_offset;
+ }
+
+ /* result fits in less bytes */
+ if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
+ *p-- = 0;
+ }
+ /* clear msb bits if any leftover in the last byte */
+ *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
+}
+
+static int __nvmem_cell_read(struct nvmem_device *nvmem,
+ struct nvmem_cell *cell,
+ void *buf, ssize_t *len)
+{
+ int rc;
+
+ rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
+
+ if (IS_ERR_VALUE(rc))
+ return rc;
+
+ /* shift bits in-place */
+ if (cell->bit_offset || cell->bit_offset)
+ nvmem_shift_read_buffer_in_place(cell, buf);
+
+ *len = cell->bytes;
+
+ return *len;
+}
+/**
+ * nvmem_cell_read(): Read a given nvmem cell
+ *
+ * @cell: nvmem cell to be read.
+ * @len: pointer to length of cell which will be populated on successful read.
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a char * bufffer. The buffer should be freed by the consumer with a
+ * kfree().
+ */
+void *nvmem_cell_read(struct nvmem_cell *cell, ssize_t *len)
+{
+ struct nvmem_device *nvmem = cell->nvmem;
+ u8 *buf;
+ int rc;
+
+ if (!nvmem || !nvmem->regmap)
+ return ERR_PTR(-EINVAL);
+
+ buf = kzalloc(cell->bytes, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ rc = __nvmem_cell_read(nvmem, cell, buf, len);
+ if (IS_ERR_VALUE(rc)) {
+ kfree(buf);
+ return ERR_PTR(rc);
+ }
+
+ return buf;
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_read);
+
+static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
+ u8 *_buf, int len)
+{
+ struct nvmem_device *nvmem = cell->nvmem;
+ int i, rc, nbits, bit_offset = cell->bit_offset;
+ u8 v, *p, *buf, *b, pbyte, pbits;
+
+ nbits = cell->nbits;
+ buf = kzalloc(cell->bytes, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(buf, _buf, len);
+ p = b = buf;
+
+ if (bit_offset) {
+ pbyte = *b;
+ *b <<= bit_offset;
+
+ /* setup the first byte with lsb bits from nvmem */
+ rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
+ *b++ |= GENMASK(bit_offset - 1, 0) & v;
+
+ /* setup rest of the byte if any */
+ for (i = 1; i < cell->bytes; i++) {
+ /* Get last byte bits and shift them towards lsb */
+ pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
+ pbyte = *b;
+ p = b;
+ *b <<= bit_offset;
+ *b++ |= pbits;
+ }
+ }
+
+ /* 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,
+ cell->offset + cell->bytes - 1, &v, 1);
+ *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
+
+ }
+
+ return buf;
+}
+
+/**
+ * nvmem_cell_write(): Write to a given nvmem cell
+ *
+ * @cell: nvmem cell to be written.
+ * @buf: Buffer to be written.
+ * @len: length of buffer to be written to nvmem cell.
+ *
+ * The return value will be an length of bytes written or non zero on failure.
+ */
+int nvmem_cell_write(struct nvmem_cell *cell, void *buf, ssize_t len)
+{
+ struct nvmem_device *nvmem = cell->nvmem;
+ int rc;
+ void *wbuf = buf;
+
+ if (!nvmem || !nvmem->regmap || nvmem->read_only ||
+ (cell->bit_offset == 0 && len != cell->bytes))
+ return -EINVAL;
+
+ if (cell->bit_offset || cell->nbits) {
+ wbuf = nvmem_cell_prepare_write_buffer(cell, buf, len);
+ if (IS_ERR(wbuf))
+ return PTR_ERR(wbuf);
+ }
+
+ rc = regmap_raw_write(nvmem->regmap, cell->offset, wbuf, cell->bytes);
+
+ /* free the tmp buffer */
+ if (cell->bit_offset)
+ kfree(wbuf);
+
+ if (IS_ERR_VALUE(rc))
+ return rc;
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_write);
+
static int nvmem_init(void)
{
return class_register(&nvmem_class);
new file mode 100644
@@ -0,0 +1,49 @@
+/*
+ * nvmem framework consumer.
+ *
+ * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+ * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _LINUX_NVMEM_CONSUMER_H
+#define _LINUX_NVMEM_CONSUMER_H
+
+/* consumer cookie */
+struct nvmem_cell;
+
+#if IS_ENABLED(CONFIG_NVMEM)
+
+/* Cell based interface */
+struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *name);
+void nvmem_cell_put(struct nvmem_cell *cell);
+void *nvmem_cell_read(struct nvmem_cell *cell, ssize_t *len);
+int nvmem_cell_write(struct nvmem_cell *cell, void *buf, ssize_t len);
+
+#else
+
+struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *name)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
+static inline void nvmem_cell_put(struct nvmem_cell *cell)
+{
+}
+
+static inline char *nvmem_cell_read(struct nvmem_cell *cell, ssize_t *len)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
+static inline int nvmem_cell_write(struct nvmem_cell *cell,
+ const char *buf, ssize_t len)
+{
+ return -ENOSYS;
+}
+#endif /* CONFIG_NVMEM */
+
+#endif /* ifndef _LINUX_NVMEM_CONSUMER_H */