Re: [PATCH v3 1/2] mtd: rawnand: meson: discard the common MMC sub clock framework

From: Neil Armstrong
Date: Fri Mar 18 2022 - 10:02:42 EST


Hi,

On 18/03/2022 13:41, Liang Yang wrote:
EMMC and NAND have the same clock control register named 'SD_EMMC_CLOCK' which is
defined in EMMC port internally. bit0~5 of 'SD_EMMC_CLOCK' is the divider and
bit6~7 is the mux for fix pll and xtal.A common MMC and NAND sub-clock has been
implemented and can be used by the eMMC and NAND controller (which are mutually
exclusive anyway). Let's use this new clock.

Signed-off-by: Liang Yang <liang.yang@xxxxxxxxxxx>
---
drivers/mtd/nand/raw/meson_nand.c | 101 ++++++++++++++++--------------
1 file changed, 53 insertions(+), 48 deletions(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index ac3be92872d0..257ffc8a41ab 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -10,6 +10,7 @@
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
+#include <linux/clk-provider.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/mtd.h>
#include <linux/mfd/syscon.h>
@@ -19,6 +20,7 @@
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_address.h>
#include <linux/sched/task_stack.h>
#define NFC_REG_CMD 0x00
@@ -104,6 +106,9 @@
#define PER_INFO_BYTE 8
+#define CLK_DIV_SHIFT 0
+#define CLK_DIV_WIDTH 6
+
struct meson_nfc_nand_chip {
struct list_head node;
struct nand_chip nand;
@@ -151,15 +156,15 @@ struct meson_nfc {
struct nand_controller controller;
struct clk *core_clk;
struct clk *device_clk;
- struct clk *phase_tx;
- struct clk *phase_rx;
+ struct clk *nand_clk;
+ struct clk_divider nand_divider;
unsigned long clk_rate;
u32 bus_timing;
struct device *dev;
void __iomem *reg_base;
- struct regmap *reg_clk;
+ void __iomem *sd_emmc_clock;
struct completion completion;
struct list_head chips;
const struct meson_nfc_data *data;
@@ -235,7 +240,7 @@ static void meson_nfc_select_chip(struct nand_chip *nand, int chip)
nfc->timing.tbers_max = meson_chip->tbers_max;
if (nfc->clk_rate != meson_chip->clk_rate) {
- ret = clk_set_rate(nfc->device_clk, meson_chip->clk_rate);
+ ret = clk_set_rate(nfc->nand_clk, meson_chip->clk_rate);
if (ret) {
dev_err(nfc->dev, "failed to set clock rate\n");
return;
@@ -406,7 +411,6 @@ static int meson_nfc_queue_rb(struct meson_nfc *nfc, int timeout_ms)
cmd = NFC_CMD_RB | NFC_CMD_RB_INT
| nfc->param.chip_select | nfc->timing.tbers_max;
writel(cmd, nfc->reg_base + NFC_REG_CMD);
-
ret = wait_for_completion_timeout(&nfc->completion,
msecs_to_jiffies(timeout_ms));
if (ret == 0)
@@ -985,9 +989,11 @@ static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
.free = meson_ooblayout_free,
};
+struct clk_parent_data nfc_divider_parent_data[1];
static int meson_nfc_clk_init(struct meson_nfc *nfc)
{
int ret;
+ struct clk_init_data init = {0};
/* request core clock */
nfc->core_clk = devm_clk_get(nfc->dev, "core");
@@ -1002,21 +1008,26 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
return PTR_ERR(nfc->device_clk);
}
- nfc->phase_tx = devm_clk_get(nfc->dev, "tx");
- if (IS_ERR(nfc->phase_tx)) {
- dev_err(nfc->dev, "failed to get TX clk\n");
- return PTR_ERR(nfc->phase_tx);
- }
-
- nfc->phase_rx = devm_clk_get(nfc->dev, "rx");
- if (IS_ERR(nfc->phase_rx)) {
- dev_err(nfc->dev, "failed to get RX clk\n");
- return PTR_ERR(nfc->phase_rx);
- }
+ init.name = devm_kstrdup(nfc->dev, "nfc#div", GFP_KERNEL);
+ init.ops = &clk_divider_ops;
+ nfc_divider_parent_data[0].fw_name = "device";
+ init.parent_data = nfc_divider_parent_data;
+ init.num_parents = 1;
+ nfc->nand_divider.reg = nfc->sd_emmc_clock;
+ nfc->nand_divider.shift = CLK_DIV_SHIFT;
+ nfc->nand_divider.width = CLK_DIV_WIDTH;
+ nfc->nand_divider.hw.init = &init;
+ nfc->nand_divider.flags = CLK_DIVIDER_ONE_BASED |
+ CLK_DIVIDER_ROUND_CLOSEST |
+ CLK_DIVIDER_ALLOW_ZERO;
+
+ nfc->nand_clk = devm_clk_register(nfc->dev, &nfc->nand_divider.hw);
+ if (IS_ERR(nfc->nand_clk))
+ return PTR_ERR(nfc->nand_clk);
/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
- regmap_update_bits(nfc->reg_clk,
- 0, CLK_SELECT_NAND, CLK_SELECT_NAND);
+ writel(CLK_SELECT_NAND | readl(nfc->sd_emmc_clock),
+ nfc->sd_emmc_clock);
ret = clk_prepare_enable(nfc->core_clk);
if (ret) {
@@ -1030,29 +1041,21 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
goto err_device_clk;
}
- ret = clk_prepare_enable(nfc->phase_tx);
- if (ret) {
- dev_err(nfc->dev, "failed to enable TX clock\n");
- goto err_phase_tx;
- }
-
- ret = clk_prepare_enable(nfc->phase_rx);
+ ret = clk_prepare_enable(nfc->nand_clk);
if (ret) {
- dev_err(nfc->dev, "failed to enable RX clock\n");
- goto err_phase_rx;
+ dev_err(nfc->dev, "pre enable NFC divider fail\n");
+ goto err_nand_clk;
}
- ret = clk_set_rate(nfc->device_clk, 24000000);
+ ret = clk_set_rate(nfc->nand_clk, 24000000);
if (ret)
- goto err_disable_rx;
+ goto err_disable_clk;
return 0;
-err_disable_rx:
- clk_disable_unprepare(nfc->phase_rx);
-err_phase_rx:
- clk_disable_unprepare(nfc->phase_tx);
-err_phase_tx:
+err_disable_clk:
+ clk_disable_unprepare(nfc->nand_clk);
+err_nand_clk:
clk_disable_unprepare(nfc->device_clk);
err_device_clk:
clk_disable_unprepare(nfc->core_clk);
@@ -1061,8 +1064,7 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
static void meson_nfc_disable_clk(struct meson_nfc *nfc)
{
- clk_disable_unprepare(nfc->phase_rx);
- clk_disable_unprepare(nfc->phase_tx);
+ clk_disable_unprepare(nfc->nand_clk);
clk_disable_unprepare(nfc->device_clk);
clk_disable_unprepare(nfc->core_clk);
}
@@ -1373,9 +1375,10 @@ MODULE_DEVICE_TABLE(of, meson_nfc_id_table);
static int meson_nfc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
struct meson_nfc *nfc;
- struct resource *res;
- int ret, irq;
+ struct resource res;
+ int ret, irq, i;
nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
if (!nfc)
@@ -1388,21 +1391,23 @@ static int meson_nfc_probe(struct platform_device *pdev)
nand_controller_init(&nfc->controller);
INIT_LIST_HEAD(&nfc->chips);
init_completion(&nfc->completion);
-
nfc->dev = dev;
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- nfc->reg_base = devm_ioremap_resource(dev, res);
+ i = of_property_match_string(node, "reg-names", "nfc");
+ if (of_address_to_resource(node, i, &res))
+ return -ENOENT;
+
+ nfc->reg_base = devm_ioremap_resource(dev, &res);
if (IS_ERR(nfc->reg_base))
return PTR_ERR(nfc->reg_base);

You can use devm_platform_ioremap_resource_byname() here which is musch simpler,
and permits dropping platform_get_resource() at the same time.

- nfc->reg_clk =
- syscon_regmap_lookup_by_phandle(dev->of_node,
- "amlogic,mmc-syscon");
- if (IS_ERR(nfc->reg_clk)) {
- dev_err(dev, "Failed to lookup clock base\n");
- return PTR_ERR(nfc->reg_clk);
- }
+ i = of_property_match_string(node, "reg-names", "emmc");
+ if (of_address_to_resource(node, i, &res))
+ return -ENOENT;
+
+ nfc->sd_emmc_clock = devm_ioremap_resource(dev, &res);
+ if (IS_ERR(nfc->sd_emmc_clock))
+ return PTR_ERR(nfc->sd_emmc_clock);

Same here.

irq = platform_get_irq(pdev, 0);
if (irq < 0)

Thanks !
Neil