[RFC PATCH 8/8] clk: Add clock driver for the RISC-V RPMI clock service group
Stephen Boyd
sboyd at kernel.org
Tue Dec 17 12:14:19 PST 2024
Quoting Anup Patel (2024-12-16 00:48:17)
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index bf4bd45adc3a..95ef59e439bf 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -107,6 +107,7 @@ obj-$(CONFIG_COMMON_CLK_VC5) += clk-versaclock5.o
> obj-$(CONFIG_COMMON_CLK_VC7) += clk-versaclock7.o
> obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
> obj-$(CONFIG_COMMON_CLK_XGENE) += clk-xgene.o
> +obj-$(CONFIG_COMMON_CLK_RPMI) += clk-rpmi.o
Keep this sorted by filename.
>
> # please keep this section sorted lexicographically by directory path name
> obj-y += actions/
> diff --git a/drivers/clk/clk-rpmi.c b/drivers/clk/clk-rpmi.c
> new file mode 100644
> index 000000000000..ed8e32527d3d
> --- /dev/null
> +++ b/drivers/clk/clk-rpmi.c
> @@ -0,0 +1,588 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RISC-V MPXY Based Clock Driver
> + *
> + * Copyright (C) 2024 Ventana Micro Systems Ltd.
> + */
> +
> +#include <linux/io.h>
Is this include used?
> +#include <linux/mm.h>
Is this include used?
> +#include <linux/of.h>
Is this include used?
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/mailbox/riscv-rpmi-message.h>
> +#include <linux/mailbox_client.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
Did you mean mod_devicetable.h?
> +#include <linux/clk-provider.h>
Please sort includes alphabetically.
> +
> +#define RPMI_CLK_MAX_NUM_RATES 16
> +#define RPMI_CLK_NAME_LEN 16
> +
> +#define GET_RATE_LO_U32(rate_u64) ((u32)rate_u64)
> +#define GET_RATE_HI_U32(rate_u64) ((u32)((u64)(rate_u64) >> 32))
Use upper_32_bits() and lower_32_bits() instead.
> +#define GET_RATE_U64(hi_u32, lo_u32) ((u64)(hi_u32) << 32 | (lo_u32))
I couldn't find a macro for this one which is kinda surprising.
> +
> +enum rpmi_clk_config {
> + RPMI_CLK_DISABLE = 0,
> + RPMI_CLK_ENABLE = 1,
> +};
> +
> +enum rpmi_clk_type {
> + RPMI_CLK_DISCRETE = 0,
> + RPMI_CLK_LINEAR = 1,
> + RPMI_CLK_TYPE_MAX_IDX,
> +};
> +
> +struct rpmi_clk_context {
> + struct device *dev;
> + struct mbox_chan *chan;
> + struct mbox_client client;
> +};
> +
> +union rpmi_clk_rate {
> + struct {
> + u32 lo;
> + u32 hi;
> + } discrete[RPMI_CLK_MAX_NUM_RATES];
> + struct {
> + u32 min_lo;
> + u32 min_hi;
> + u32 max_lo;
> + u32 max_hi;
> + u32 step_lo;
> + u32 step_hi;
> + } linear;
> +};
> +
> +union rpmi_clk_rates {
> + u64 discrete[RPMI_CLK_MAX_NUM_RATES];
> + struct {
> + u64 min;
> + u64 max;
> + u64 step;
> + } linear;
> +};
> +
> +struct rpmi_clk {
> + struct rpmi_clk_context *context;
> + u32 id;
> + u32 num_rates;
> + u32 transition_latency;
> + enum rpmi_clk_type type;
> + union rpmi_clk_rates *rates;
> + char name[RPMI_CLK_NAME_LEN];
> + struct clk_hw hw;
> +};
> +
> +#define to_rpmi_clk(clk) container_of(clk, struct rpmi_clk, hw)
> +
> +struct rpmi_get_num_clocks_rx {
> + s32 status;
> + u32 num_clocks;
> +};
> +
> +struct rpmi_get_attrs_tx {
> + u32 clkid;
Maybe just 'id', unless the spec calls this 'clkid'?
> +};
> +
> +struct rpmi_get_attrs_rx {
> + s32 status;
> + u32 flags;
> + u32 num_rates;
> + u32 transition_latency;
> + char name[RPMI_CLK_NAME_LEN];
> +};
> +
> +struct rpmi_get_supp_rates_tx {
> + u32 clkid;
> + u32 clk_rate_idx;
> +};
> +
> +struct rpmi_get_supp_rates_rx {
> + u32 status;
> + u32 flags;
> + u32 remaining;
> + u32 returned;
> + union rpmi_clk_rate rates;
> +};
> +
> +struct rpmi_get_rate_tx {
> + u32 clkid;
> +};
> +
> +struct rpmi_get_rate_rx {
> + u32 status;
> + u32 lo;
> + u32 hi;
> +};
> +
> +struct rpmi_set_rate_tx {
> + u32 clkid;
> + u32 flags;
> + u32 lo;
> + u32 hi;
> +};
> +
> +struct rpmi_set_rate_rx {
> + u32 status;
> +};
> +
> +struct rpmi_set_config_tx {
> + u32 clkid;
> + u32 config;
> +};
> +
> +struct rpmi_set_config_rx {
> + u32 status;
> +};
> +
> +static int rpmi_clk_get_num_clocks(struct rpmi_clk_context *context)
> +{
> + struct rpmi_get_num_clocks_rx rx;
> + struct rpmi_mbox_message msg;
> + int ret;
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_NUM_CLOCKS,
> + NULL, 0, &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rpmi_to_linux_error(rx.status);
> +
> + return rx.num_clocks;
> +}
> +
> +/**
This isn't kernel-doc so either remove the extra '*' or write
kernel-doc.
> + * Get the RPMI Clock Attributes.
> + * These attributes belong to a particular clock(clkid)
> + * which are different from the MPXY channel attributes.
> + */
> +static int rpmi_clk_get_attrs(u32 clkid, struct rpmi_clk *rpmi_clk)
> +{
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_mbox_message msg;
> + struct rpmi_get_attrs_tx tx;
> + struct rpmi_get_attrs_rx rx;
> + u8 format;
> + int ret;
> +
> + tx.clkid = cpu_to_le32(clkid);
Run sparse and fix errors please. I assume that the mailbox interactions
need to have __le32 marked structs.
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_ATTRIBUTES,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rpmi_to_linux_error(rx.status);
> +
> + rpmi_clk->id = clkid;
> + rpmi_clk->num_rates = rx.num_rates;
> + rpmi_clk->transition_latency = rx.transition_latency;
> + strscpy(rpmi_clk->name, rx.name, RPMI_CLK_NAME_LEN);
> +
> + format = rx.flags & 1U;
> + if (format >= RPMI_CLK_TYPE_MAX_IDX)
How is this possible?
> + return -EINVAL;
> +
> + rpmi_clk->type = format;
> +
> + return 0;
> +}
> +
> +static int rpmi_clk_get_supported_rates(u32 clkid, struct rpmi_clk *rpmi_clk)
> +{
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_get_supp_rates_tx tx;
> + struct rpmi_get_supp_rates_rx rx;
> + struct rpmi_mbox_message msg;
> + size_t clk_rate_idx = 0;
> + int ret, rateidx, j;
> +
> + tx.clkid = cpu_to_le32(clkid);
> + tx.clk_rate_idx = 0;
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_SUPPORTED_RATES,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rpmi_to_linux_error(rx.status);
> + if (!rx.returned)
> + return -EINVAL;
> +
> + if (rpmi_clk->type == RPMI_CLK_DISCRETE) {
> + for (rateidx = 0; rateidx < rx.returned; rateidx++) {
> + rpmi_clk->rates->discrete[rateidx] =
> + GET_RATE_U64(rx.rates.discrete[rateidx].hi,
> + rx.rates.discrete[rateidx].lo);
> + }
> +
> + while (rx.remaining) {
> + clk_rate_idx += rx.returned;
> + tx.clk_rate_idx = clk_rate_idx;
> +
> + rpmi_mbox_init_send_with_response(&msg,
> + RPMI_CLK_SRV_GET_SUPPORTED_RATES,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> +
> + for (j = 0; j < rx.returned; j++) {
> + if (rateidx >= (clk_rate_idx + rx.returned))
> + break;
> + rpmi_clk->rates->discrete[rateidx++] =
> + GET_RATE_U64(rx.rates.discrete[j].hi,
> + rx.rates.discrete[j].lo);
> + }
> + }
> + } else if (rpmi_clk->type == RPMI_CLK_LINEAR) {
> + rpmi_clk->rates->linear.min =
> + GET_RATE_U64(rx.rates.linear.min_hi,
> + rx.rates.linear.min_lo);
> + rpmi_clk->rates->linear.max =
> + GET_RATE_U64(rx.rates.linear.max_hi,
> + rx.rates.linear.max_lo);
> + rpmi_clk->rates->linear.step =
> + GET_RATE_U64(rx.rates.linear.step_hi,
> + rx.rates.linear.step_lo);
> + }
> +
> + return 0;
> +}
> +
> +static unsigned long rpmi_clk_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_mbox_message msg;
> + struct rpmi_get_rate_tx tx;
> + struct rpmi_get_rate_rx rx;
> + int ret;
> +
> + tx.clkid = cpu_to_le32(rpmi_clk->id);
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_RATE,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rx.status;
> +
> + return GET_RATE_U64(rx.hi, rx.lo);
> +}
> +
> +static long rpmi_clk_round_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
> + u64 fmin, fmax, ftmp;
> +
> + if (rpmi_clk->type == RPMI_CLK_DISCRETE)
> + return rate;
> +
> + fmin = rpmi_clk->rates->linear.min;
> + fmax = rpmi_clk->rates->linear.max;
> +
> + if (rate <= fmin)
> + return fmin;
> + else if (rate >= fmax)
> + return fmax;
> +
> + ftmp = rate - fmin;
> + ftmp += rpmi_clk->rates->linear.step - 1;
> + do_div(ftmp, rpmi_clk->rates->linear.step);
> +
> + return ftmp * rpmi_clk->rates->linear.step + fmin;
> +}
> +
> +static int rpmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_mbox_message msg;
> + struct rpmi_set_rate_tx tx;
> + struct rpmi_set_rate_rx rx;
> + int ret;
> +
> + tx.clkid = cpu_to_le32(rpmi_clk->id);
> + tx.lo = cpu_to_le32(GET_RATE_LO_U32(rate));
> + tx.hi = cpu_to_le32(GET_RATE_HI_U32(rate));
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_RATE,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rpmi_to_linux_error(rx.status);
> +
> + return 0;
> +}
> +
> +static int rpmi_clk_enable(struct clk_hw *hw)
> +{
> + struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_mbox_message msg;
> + struct rpmi_set_config_tx tx;
> + struct rpmi_set_config_rx rx;
> + int ret;
> +
> + tx.config = cpu_to_le32(RPMI_CLK_ENABLE);
> + tx.clkid = cpu_to_le32(rpmi_clk->id);
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_CONFIG,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret)
> + return ret;
> + if (rx.status)
> + return rpmi_to_linux_error(rx.status);
> +
> + return 0;
> +}
> +
> +static void rpmi_clk_disable(struct clk_hw *hw)
> +{
> + struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
> + struct rpmi_clk_context *context = rpmi_clk->context;
> + struct rpmi_mbox_message msg;
> + struct rpmi_set_config_tx tx;
> + struct rpmi_set_config_rx rx;
> + int ret;
> +
> + tx.config = cpu_to_le32(RPMI_CLK_DISABLE);
> + tx.clkid = cpu_to_le32(rpmi_clk->id);
> +
> + rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_CONFIG,
> + &tx, sizeof(tx), &rx, sizeof(rx));
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret || rx.status)
> + pr_err("Failed to disable clk-%u\n", rpmi_clk->id);
> +}
> +
> +static const struct clk_ops rpmi_clk_ops = {
> + .recalc_rate = rpmi_clk_recalc_rate,
> + .round_rate = rpmi_clk_round_rate,
Please implement determine_rate instead.
> + .set_rate = rpmi_clk_set_rate,
> + .prepare = rpmi_clk_enable,
> + .unprepare = rpmi_clk_disable,
> +};
> +
> +static struct clk_hw *rpmi_clk_enumerate(struct rpmi_clk_context *context, u32 clkid)
> +{
> + struct device *dev = context->dev;
> + unsigned long min_rate, max_rate;
> + union rpmi_clk_rates *rates;
> + struct rpmi_clk *rpmi_clk;
> + struct clk_init_data init;
Use init = { } to initialize everything to zero.
> + struct clk_hw *clk_hw;
> + int ret;
> +
> + rates = devm_kzalloc(dev, sizeof(union rpmi_clk_rates), GFP_KERNEL);
> + if (!rates)
> + return ERR_PTR(-ENOMEM);
> +
> + rpmi_clk = devm_kzalloc(dev, sizeof(struct rpmi_clk), GFP_KERNEL);
> + if (!rpmi_clk)
> + return ERR_PTR(-ENOMEM);
> + rpmi_clk->context = context;
> + rpmi_clk->rates = rates;
> +
> + ret = rpmi_clk_get_attrs(clkid, rpmi_clk);
> + if (ret) {
> + dev_err(dev, "Failed to get clk-%u attributes\n", clkid);
Please use dev_err_probe() and helpers.
> + return ERR_PTR(ret);
> + }
> +
> + ret = rpmi_clk_get_supported_rates(clkid, rpmi_clk);
> + if (ret) {
> + dev_err(dev, "Get supported rates failed for clk-%u, %d\n",
> + clkid, ret);
> + return ERR_PTR(ret);
> + }
> +
> + init.flags = CLK_GET_RATE_NOCACHE;
> + init.num_parents = 0;
> + init.ops = &rpmi_clk_ops;
> + init.name = rpmi_clk->name;
> + clk_hw = &rpmi_clk->hw;
> + clk_hw->init = &init;
> +
> + ret = devm_clk_hw_register(dev, clk_hw);
> + if (ret) {
> + dev_err(dev, "Unable to register clk-%u\n", clkid);
> + return ERR_PTR(ret);
> + }
> +
> + if (rpmi_clk->type == RPMI_CLK_DISCRETE) {
> + min_rate = rpmi_clk->rates->discrete[0];
> + max_rate = rpmi_clk->rates->discrete[rpmi_clk->num_rates - 1];
> + } else {
> + min_rate = rpmi_clk->rates->linear.min;
> + max_rate = rpmi_clk->rates->linear.max;
> + }
> +
> + clk_hw_set_rate_range(clk_hw, min_rate, max_rate);
> +
> + return NULL;
Why does it return NULL?
> +}
> +
> +static void rpmi_clk_receive_message(struct mbox_client *cl, void *msg)
> +{
> + /* Nothing to do here. */
> +}
> +
> +static int rpmi_clk_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct clk_hw_onecell_data *clk_data;
> + struct rpmi_clk_context *context;
> + struct rpmi_mbox_message msg;
> + int ret, num_clocks, i;
> + struct clk_hw *hw_ptr;
> +
> + /* Allocate RPMI clock context */
> + context = devm_kzalloc(dev, sizeof(*context), GFP_KERNEL);
> + if (!context)
> + return -ENOMEM;
> + context->dev = dev;
> + platform_set_drvdata(pdev, context);
> +
> + /* Setup mailbox client */
> + context->client.dev = context->dev;
> + context->client.rx_callback = rpmi_clk_receive_message;
> + context->client.tx_block = false;
> + context->client.knows_txdone = true;
> + context->client.tx_tout = 0;
> +
> + /* Request mailbox channel */
> + context->chan = mbox_request_channel(&context->client, 0);
> + if (IS_ERR(context->chan))
> + return PTR_ERR(context->chan);
> +
> + /* Validate RPMI specification version */
> + rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SPEC_VERSION);
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret) {
> + dev_err(dev, "Failed to get spec version\n");
Use dev_err_probe()
> + goto fail_free_channel;
> + }
> + if (msg.attr.value < RPMI_MKVER(1, 0)) {
> + dev_err(dev,
> + "msg protocol version mismatch, expected 0x%x, found 0x%x\n",
> + RPMI_MKVER(1, 0), msg.attr.value);
> + ret = -EINVAL;
> + goto fail_free_channel;
> + }
> +
> + /* Validate clock service group ID */
> + rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SERVICEGROUP_ID);
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret) {
> + dev_err(dev, "Failed to get service group ID\n");
> + goto fail_free_channel;
> + }
> + if (msg.attr.value != RPMI_SRVGRP_CLOCK) {
> + dev_err(dev,
> + "service group match failed, expected 0x%x, found 0x%x\n",
> + RPMI_SRVGRP_CLOCK, msg.attr.value);
> + ret = -EINVAL;
> + goto fail_free_channel;
> + }
> +
> + /* Validate clock service group version */
> + rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SERVICEGROUP_VERSION);
> + ret = rpmi_mbox_send_message(context->chan, &msg);
> + if (ret) {
> + dev_err(dev, "Failed to get service group version\n");
> + goto fail_free_channel;
> + }
> + if (msg.attr.value < RPMI_MKVER(1, 0)) {
> + dev_err(dev,
> + "service group version failed, expected 0x%x, found 0x%x\n",
> + RPMI_MKVER(1, 0), msg.attr.value);
> + ret = -EINVAL;
> + goto fail_free_channel;
> + }
> +
> + /* Find-out number of clocks */
> + num_clocks = rpmi_clk_get_num_clocks(context);
> + if (!num_clocks) {
> + dev_err(dev, "No clocks found\n");
> + ret = -ENODEV;
> + goto fail_free_channel;
> + }
> +
> + /* Allocate clock data */
> + clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, num_clocks),
> + GFP_KERNEL);
> + if (!clk_data) {
> + ret = -ENOMEM;
> + goto fail_free_channel;
> + }
> + clk_data->num = num_clocks;
> +
> + /* Setup clock data */
> + for (i = 0; i < clk_data->num; i++) {
> + hw_ptr = rpmi_clk_enumerate(context, i);
> + if (IS_ERR(hw_ptr)) {
> + dev_err(dev, "failed to register clk-%d\n", i);
> + ret = PTR_ERR(hw_ptr);
> + goto fail_free_channel;
> + }
> + clk_data->hws[i] = hw_ptr;
> + }
> +
> + /* Register clock HW provider */
> + ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
> + if (ret) {
> + dev_err(dev, "failed to register clock HW provider\n");
> + goto fail_free_channel;
> + }
> +
> + dev_info(dev, "clk HW provider registered with %d clocks\n",
> + num_clocks);
Remove this info print please.
> + return 0;
> +
> +fail_free_channel:
> + mbox_free_channel(context->chan);
> + return ret;
> +}
> +
> +static void rpmi_clk_remove(struct platform_device *pdev)
> +{
> + struct rpmi_clk_context *context = platform_get_drvdata(pdev);
> +
> + mbox_free_channel(context->chan);
> +}
> +
> +static const struct of_device_id rpmi_clk_of_match[] = {
> + { .compatible = "riscv,rpmi-clock" },
> + { },
Nitpick: Drop comma so nothing can come after.
> +};
> +
Nitpick: Drop extra newline.
> +MODULE_DEVICE_TABLE(of, rpmi_clk_of_match);
> +
> +static struct platform_driver rpmi_clk_driver = {
> + .driver = {
> + .name = "riscv-rpmi-clock",
> + .of_match_table = rpmi_clk_of_match,
> + },
> + .probe = rpmi_clk_probe,
> + .remove = rpmi_clk_remove,
> +};
> +module_platform_driver(rpmi_clk_driver);
> +
> +MODULE_AUTHOR("Rahul Pathak <rpathak at ventanamicro.com>");
> +MODULE_DESCRIPTION("Clock Driver based on RPMI message protocol");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mailbox/riscv-rpmi-message.h b/include/linux/mailbox/riscv-rpmi-message.h
> index 8f4b3a0edbce..4e9478c4c0a3 100644
> --- a/include/linux/mailbox/riscv-rpmi-message.h
> +++ b/include/linux/mailbox/riscv-rpmi-message.h
> @@ -89,6 +89,22 @@ static inline int rpmi_to_linux_error(int rpmi_error)
> }
> }
>
> +/** RPMI service group IDs */
> +#define RPMI_SRVGRP_CLOCK 0x00007
> +
> +/** RPMI clock service IDs */
> +enum rpmi_clock_service_id {
> + RPMI_CLK_SRV_ENABLE_NOTIFICATION = 0x01,
> + RPMI_CLK_SRV_GET_NUM_CLOCKS = 0x02,
> + RPMI_CLK_SRV_GET_ATTRIBUTES = 0x03,
> + RPMI_CLK_SRV_GET_SUPPORTED_RATES = 0x04,
> + RPMI_CLK_SRV_SET_CONFIG = 0x05,
> + RPMI_CLK_SRV_GET_CONFIG = 0x06,
> + RPMI_CLK_SRV_SET_RATE = 0x07,
> + RPMI_CLK_SRV_GET_RATE = 0x08,
> + RPMI_CLK_SRV_ID_MAX_COUNT,
> +};
> +
What is the benefit of the enum vs. just having a #define?
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