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Date: Thu, 12 Mar 2020 14:31:25 +0100
From: Neil Armstrong <narmstrong@...libre.com>
To: broonie@...nel.org
Cc: Sunny Luo <sunny.luo@...ogic.com>, linux-spi@...r.kernel.org,
linux-amlogic@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Yixun Lan <yixun.lan@...ogic.com>,
Neil Armstrong <narmstrong@...libre.com>
Subject: [PATCH 3/9] spi: meson-spicc: add a linear clock divider support
From: Sunny Luo <sunny.luo@...ogic.com>
The SPICC controller in Meson-AXG SoC is capable of using
a linear clock divider to reach a much fine tuned range of clocks,
while the old controller only use a power of two clock divider,
result at a more coarse clock range.
Also convert the clock registration into Common Clock Framework.
Signed-off-by: Sunny Luo <sunny.luo@...ogic.com>
Signed-off-by: Yixun Lan <yixun.lan@...ogic.com>
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
drivers/spi/Kconfig | 1 +
drivers/spi/spi-meson-spicc.c | 204 +++++++++++++++++++++++++++-------
2 files changed, 165 insertions(+), 40 deletions(-)
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index d6ed0c355954..7f86e591fba3 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -415,6 +415,7 @@ config SPI_FSL_ESPI
config SPI_MESON_SPICC
tristate "Amlogic Meson SPICC controller"
+ depends on COMMON_CLK
depends on ARCH_MESON || COMPILE_TEST
help
This enables master mode support for the SPICC (SPI communication
diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
index ba70ef94a82a..bd434d9055d9 100644
--- a/drivers/spi/spi-meson-spicc.c
+++ b/drivers/spi/spi-meson-spicc.c
@@ -116,6 +116,9 @@
#define SPICC_DWADDR 0x24 /* Write Address of DMA */
#define SPICC_ENH_CTL0 0x38 /* Enhanced Feature */
+#define SPICC_ENH_CLK_CS_DELAY_MASK GENMASK(15, 0)
+#define SPICC_ENH_DATARATE_MASK GENMASK(23, 16)
+#define SPICC_ENH_DATARATE_EN BIT(24)
#define SPICC_ENH_MOSI_OEN BIT(25)
#define SPICC_ENH_CLK_OEN BIT(26)
#define SPICC_ENH_CS_OEN BIT(27)
@@ -130,6 +133,7 @@
struct meson_spicc_data {
bool has_oen;
+ bool has_enhance_clk_div;
};
struct meson_spicc_device {
@@ -137,6 +141,7 @@ struct meson_spicc_device {
struct platform_device *pdev;
void __iomem *base;
struct clk *core;
+ struct clk *clk;
struct spi_message *message;
struct spi_transfer *xfer;
const struct meson_spicc_data *data;
@@ -322,40 +327,6 @@ static irqreturn_t meson_spicc_irq(int irq, void *data)
return IRQ_HANDLED;
}
-static u32 meson_spicc_setup_speed(struct meson_spicc_device *spicc, u32 conf,
- u32 speed)
-{
- unsigned long parent, value;
- unsigned int i, div;
-
- parent = clk_get_rate(spicc->core);
-
- /* Find closest inferior/equal possible speed */
- for (i = 0 ; i < 7 ; ++i) {
- /* 2^(data_rate+2) */
- value = parent >> (i + 2);
-
- if (value <= speed)
- break;
- }
-
- /* If provided speed it lower than max divider, use max divider */
- if (i > 7) {
- div = 7;
- dev_warn_once(&spicc->pdev->dev, "unable to get close to speed %u\n",
- speed);
- } else
- div = i;
-
- dev_dbg(&spicc->pdev->dev, "parent %lu, speed %u -> %lu (%u)\n",
- parent, speed, value, div);
-
- conf &= ~SPICC_DATARATE_MASK;
- conf |= FIELD_PREP(SPICC_DATARATE_MASK, div);
-
- return conf;
-}
-
static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
struct spi_transfer *xfer)
{
@@ -364,9 +335,6 @@ static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
/* Read original configuration */
conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG);
- /* Select closest divider */
- conf = meson_spicc_setup_speed(spicc, conf, xfer->speed_hz);
-
/* Setup word width */
conf &= ~SPICC_BITLENGTH_MASK;
conf |= FIELD_PREP(SPICC_BITLENGTH_MASK,
@@ -375,6 +343,8 @@ static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
/* Ignore if unchanged */
if (conf != conf_orig)
writel_relaxed(conf, spicc->base + SPICC_CONREG);
+
+ clk_set_rate(spicc->clk, xfer->speed_hz);
}
static int meson_spicc_transfer_one(struct spi_master *master,
@@ -481,9 +451,6 @@ static int meson_spicc_unprepare_transfer(struct spi_master *master)
/* Disable all IRQs */
writel(0, spicc->base + SPICC_INTREG);
- /* Disable controller */
- writel_bits_relaxed(SPICC_ENABLE, 0, spicc->base + SPICC_CONREG);
-
device_reset_optional(&spicc->pdev->dev);
return 0;
@@ -502,6 +469,152 @@ static void meson_spicc_cleanup(struct spi_device *spi)
spi->controller_state = NULL;
}
+/*
+ * The Clock Mux
+ * x-----------------x x------------x x------\
+ * |---| pow2 fixed div |---| pow2 div |----| |
+ * | x-----------------x x------------x | |
+ * src ---| | mux |-- out
+ * | x-----------------x x------------x | |
+ * |---| enh fixed div |---| enh div |0---| |
+ * x-----------------x x------------x x------/
+ *
+ * Clk path for GX series:
+ * src -> pow2 fixed div -> pow2 div -> out
+ *
+ * Clk path for AXG series:
+ * src -> pow2 fixed div -> pow2 div -> mux -> out
+ * src -> enh fixed div -> enh div -> mux -> out
+ */
+
+static int meson_spicc_clk_init(struct meson_spicc_device *spicc)
+{
+ struct device *dev = &spicc->pdev->dev;
+ struct clk_fixed_factor *pow2_fixed_div, *enh_fixed_div;
+ struct clk_divider *pow2_div, *enh_div;
+ struct clk_mux *mux;
+ struct clk_init_data init;
+ struct clk *clk;
+ struct clk_parent_data parent_data[2];
+ char name[64];
+
+ memset(&init, 0, sizeof(init));
+ memset(&parent_data, 0, sizeof(parent_data));
+
+ init.parent_data = parent_data;
+
+ /* algorithm for pow2 div: rate = freq / 4 / (2 ^ N) */
+
+ pow2_fixed_div = devm_kzalloc(dev, sizeof(*pow2_fixed_div), GFP_KERNEL);
+ if (!pow2_fixed_div)
+ return -ENOMEM;
+
+ snprintf(name, sizeof(name), "%s#pow2_fixed_div", dev_name(dev));
+ init.name = name;
+ init.ops = &clk_fixed_factor_ops;
+ init.flags = 0;
+ parent_data[0].hw = __clk_get_hw(spicc->core);
+ init.num_parents = 1;
+
+ pow2_fixed_div->mult = 1,
+ pow2_fixed_div->div = 4,
+ pow2_fixed_div->hw.init = &init;
+
+ clk = devm_clk_register(dev, &pow2_fixed_div->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ return PTR_ERR(clk);
+
+ pow2_div = devm_kzalloc(dev, sizeof(*pow2_div), GFP_KERNEL);
+ if (!pow2_div)
+ return -ENOMEM;
+
+ snprintf(name, sizeof(name), "%s#pow2_div", dev_name(dev));
+ init.name = name;
+ init.ops = &clk_divider_ops;
+ init.flags = CLK_SET_RATE_PARENT;
+ parent_data[0].hw = &pow2_fixed_div->hw;
+ init.num_parents = 1;
+
+ pow2_div->shift = 16,
+ pow2_div->width = 3,
+ pow2_div->flags = CLK_DIVIDER_POWER_OF_TWO,
+ pow2_div->reg = spicc->base + SPICC_CONREG;
+ pow2_div->hw.init = &init;
+
+ clk = devm_clk_register(dev, &pow2_div->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ return PTR_ERR(clk);
+
+ if (!spicc->data->has_enhance_clk_div) {
+ spicc->clk = clk;
+ return 0;
+ }
+
+ /* algorithm for enh div: rate = freq / 2 / (N + 1) */
+
+ enh_fixed_div = devm_kzalloc(dev, sizeof(*enh_fixed_div), GFP_KERNEL);
+ if (!enh_fixed_div)
+ return -ENOMEM;
+
+ snprintf(name, sizeof(name), "%s#enh_fixed_div", dev_name(dev));
+ init.name = name;
+ init.ops = &clk_fixed_factor_ops;
+ init.flags = 0;
+ parent_data[0].hw = __clk_get_hw(spicc->core);
+ init.num_parents = 1;
+
+ enh_fixed_div->mult = 1,
+ enh_fixed_div->div = 2,
+ enh_fixed_div->hw.init = &init;
+
+ clk = devm_clk_register(dev, &enh_fixed_div->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ return PTR_ERR(clk);
+
+ enh_div = devm_kzalloc(dev, sizeof(*enh_div), GFP_KERNEL);
+ if (!enh_div)
+ return -ENOMEM;
+
+ snprintf(name, sizeof(name), "%s#enh_div", dev_name(dev));
+ init.name = name;
+ init.ops = &clk_divider_ops;
+ init.flags = CLK_SET_RATE_PARENT;
+ parent_data[0].hw = &enh_fixed_div->hw;
+ init.num_parents = 1;
+
+ enh_div->shift = 16,
+ enh_div->width = 8,
+ enh_div->reg = spicc->base + SPICC_ENH_CTL0;
+ enh_div->hw.init = &init;
+
+ clk = devm_clk_register(dev, &enh_div->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ return PTR_ERR(clk);
+
+ mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+ if (!mux)
+ return -ENOMEM;
+
+ snprintf(name, sizeof(name), "%s#sel", dev_name(dev));
+ init.name = name;
+ init.ops = &clk_mux_ops;
+ parent_data[0].hw = &pow2_div->hw;
+ parent_data[1].hw = &enh_div->hw;
+ init.num_parents = 2;
+ init.flags = CLK_SET_RATE_PARENT;
+
+ mux->mask = 0x1,
+ mux->shift = 24,
+ mux->reg = spicc->base + SPICC_ENH_CTL0;
+ mux->hw.init = &init;
+
+ spicc->clk = devm_clk_register(dev, &mux->hw);
+ if (WARN_ON(IS_ERR(spicc->clk)))
+ return PTR_ERR(spicc->clk);
+
+ return 0;
+}
+
static int meson_spicc_probe(struct platform_device *pdev)
{
struct spi_master *master;
@@ -533,6 +646,10 @@ static int meson_spicc_probe(struct platform_device *pdev)
goto out_master;
}
+ /* Set master mode and enable controller */
+ writel_relaxed(SPICC_ENABLE | SPICC_MODE_MASTER,
+ spicc->base + SPICC_CONREG);
+
/* Disable all IRQs */
writel_relaxed(0, spicc->base + SPICC_INTREG);
@@ -584,6 +701,12 @@ static int meson_spicc_probe(struct platform_device *pdev)
meson_spicc_oen_enable(spicc);
+ ret = meson_spicc_clk_init(spicc);
+ if (ret) {
+ dev_err(&pdev->dev, "clock registration failed\n");
+ goto out_master;
+ }
+
ret = devm_spi_register_master(&pdev->dev, master);
if (ret) {
dev_err(&pdev->dev, "spi master registration failed\n");
@@ -618,6 +741,7 @@ static const struct meson_spicc_data meson_spicc_gx_data = {
static const struct meson_spicc_data meson_spicc_axg_data = {
.has_oen = true,
+ .has_enhance_clk_div = true,
};
static const struct of_device_id meson_spicc_of_match[] = {
--
2.22.0
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