[PATCH v9 2/5] mtd: rawnand: meson: fix the clock

Liang Yang
2022-09-07T08:04:53Z

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. At the beginning,
a common MMC and NAND sub-clock was discussed and planed to be implemented
as NFC clock provider, but now this series of patches of a common MMC and
NAND sub-clock are never being accepted. the reasons for giving up are:
1. EMMC and NAND, which are mutually exclusive anyway
2. coupling the EMMC and NAND.
3. it seems that a common MMC and NAND sub-clock is over engineered.
and let us see the link fot more information:
https://lore.kernel.org/all/20220121074508.42168-5-liang.yang@amlogic.com
so The meson nfc can't work now, let us rework the clock.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Liang Yang <liang.yang@amlogic.com>
---
drivers/mtd/nand/raw/meson_nand.c | 82 +++++++++++++++----------------
1 file changed, 41 insertions(+), 41 deletions(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 817bddccb775..6b1c813c0795 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>
@@ -56,6 +57,9 @@

#define NFC_RB_IRQ_EN BIT(21)

+#define CLK_DIV_SHIFT 0
+#define CLK_DIV_WIDTH 6
+
#define CMDRWGEN(cmd_dir, ran, bch, short_mode, page_size, pages) \
( \
(cmd_dir) | \
@@ -151,15 +155,15 @@ 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 *reg_clk;
struct completion completion;
struct list_head chips;
const struct meson_nfc_data *data;
@@ -235,7 +239,7 @@ 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;
@@ -987,6 +991,8 @@ static const struct mtd_ooblayout_ops meson_ooblayout_ops = {

static int meson_nfc_clk_init(struct meson_nfc *nfc)
{
+ struct clk_parent_data nfc_divider_parent_data[1];
+ struct clk_init_data init = {0};
int ret;

/* request core clock */
@@ -1002,21 +1008,28 @@ 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_kasprintf(nfc->dev,
+ GFP_KERNEL, "%s#div",
+ dev_name(nfc->dev));
+ 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->reg_clk;
+ 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->reg_clk),
+ nfc->reg_clk);

ret = clk_prepare_enable(nfc->core_clk);
if (ret) {
@@ -1030,29 +1043,21 @@ static int meson_nfc_clk_init(struct meson_nfc *nfc)
goto err_device_clk;
}

- ret = clk_prepare_enable(nfc->phase_tx);
+ ret = clk_prepare_enable(nfc->nand_clk);
if (ret) {
- dev_err(nfc->dev, "failed to enable TX clock\n");
- goto err_phase_tx;
+ dev_err(nfc->dev, "pre enable NFC divider fail\n");
+ goto err_nand_clk;
}

- ret = clk_prepare_enable(nfc->phase_rx);
- if (ret) {
- dev_err(nfc->dev, "failed to enable RX clock\n");
- goto err_phase_rx;
- }
-
- 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 +1066,7 @@ 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);
}
@@ -1396,13 +1400,9 @@ static int meson_nfc_probe(struct platform_device *pdev)
if (IS_ERR(nfc->reg_base))
return PTR_ERR(nfc->reg_base);

- 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");
+ nfc->reg_clk = devm_platform_ioremap_resource_byname(pdev, "emmc");
+ if (IS_ERR(nfc->reg_clk))
return PTR_ERR(nfc->reg_clk);
- }

irq = platform_get_irq(pdev, 0);
if (irq < 0)
--
2.37.1