From e8c73772d43d53d1548ff2c667122fa199873d88 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Wed, 12 Oct 2022 14:20:07 +0100 Subject: [PATCH] clk: rp1: Add sdio-clk driver Signed-off-by: Phil Elwell --- drivers/clk/Kconfig | 6 + drivers/clk/Makefile | 1 + drivers/clk/clk-rp1-sdio.c | 600 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 607 insertions(+) create mode 100644 drivers/clk/clk-rp1-sdio.c diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 3ca6061..9d3e035 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -95,6 +95,12 @@ config COMMON_CLK_RP1 help Enable common clock framework support for Raspberry Pi RP1 +config COMMON_CLK_RP1_SDIO + tristate "Clock driver for the RP1 SDIO interfaces" + depends on MFD_RP1 + help + SDIO clock driver for the RP1 support chip + config COMMON_CLK_HI655X tristate "Clock driver for Hi655x" if EXPERT depends on (MFD_HI655X_PMIC || COMPILE_TEST) diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 3730887..0cec771 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -60,6 +60,7 @@ obj-$(CONFIG_COMMON_CLK_PWM) += clk-pwm.o obj-$(CONFIG_CLK_QORIQ) += clk-qoriq.o obj-$(CONFIG_COMMON_CLK_RK808) += clk-rk808.o obj-$(CONFIG_COMMON_CLK_RP1) += clk-rp1.o +obj-$(CONFIG_COMMON_CLK_RP1_SDIO) += clk-rp1-sdio.o obj-$(CONFIG_COMMON_CLK_HI655X) += clk-hi655x.o obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o obj-$(CONFIG_COMMON_CLK_SCMI) += clk-scmi.o diff --git a/drivers/clk/clk-rp1-sdio.c b/drivers/clk/clk-rp1-sdio.c new file mode 100644 index 0000000..7412e24 --- /dev/null +++ b/drivers/clk/clk-rp1-sdio.c @@ -0,0 +1,600 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * SDIO clock driver for RP1 + * + * Copyright (C) 2023 Raspberry Pi Ltd. + */ + +#include +#include +#include +#include +#include + +// Register : MODE +#define MODE 0x00000000 +#define MODE_BITS 0x70030000 +#define MODE_RESET 0x00000000 +// Field : MODE_STEPS_PER_CYCLE +#define MODE_STEPS_PER_CYCLE_RESET 0x0 +#define MODE_STEPS_PER_CYCLE_BITS 0x70000000 +#define MODE_STEPS_PER_CYCLE_MSB 30 +#define MODE_STEPS_PER_CYCLE_LSB 28 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_20 0x0 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_10 0x1 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_16 0x2 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_8 0x3 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_12 0x4 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_6 0x5 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_5 0x6 +#define MODE_STEPS_PER_CYCLE_VALUE_STEPS_4 0x7 +// Field : MODE_SRC_SEL +#define MODE_SRC_SEL_RESET 0x0 +#define MODE_SRC_SEL_BITS 0x00030000 +#define MODE_SRC_SEL_MSB 17 +#define MODE_SRC_SEL_LSB 16 +#define MODE_SRC_SEL_VALUE_STOP 0x0 +#define MODE_SRC_SEL_VALUE_CLK_ALT_SRC 0x1 +#define MODE_SRC_SEL_VALUE_PLL_SYS_VCO 0x2 +#define MODE_SRC_SEL_VALUE_PLL_SYS_VCO_AGAIN 0x3 +// Register : FROMIP +#define FROMIP 0x00000004 +#define FROMIP_BITS 0x0f9713ff +#define FROMIP_RESET 0x00000000 +// Field : FROMIP_TUNING_CCLK_SEL +#define FROMIP_TUNING_CCLK_SEL_RESET 0x0 +#define FROMIP_TUNING_CCLK_SEL_BITS 0x0f000000 +#define FROMIP_TUNING_CCLK_SEL_MSB 27 +#define FROMIP_TUNING_CCLK_SEL_LSB 24 +// Field : FROMIP_TUNING_CCLK_UPDATE +#define FROMIP_TUNING_CCLK_UPDATE_RESET 0x0 +#define FROMIP_TUNING_CCLK_UPDATE_BITS 0x00800000 +#define FROMIP_TUNING_CCLK_UPDATE_MSB 23 +#define FROMIP_TUNING_CCLK_UPDATE_LSB 23 +// Field : FROMIP_SAMPLE_CCLK_SEL +#define FROMIP_SAMPLE_CCLK_SEL_RESET 0x0 +#define FROMIP_SAMPLE_CCLK_SEL_BITS 0x00100000 +#define FROMIP_SAMPLE_CCLK_SEL_MSB 20 +#define FROMIP_SAMPLE_CCLK_SEL_LSB 20 +// Field : FROMIP_CLK2CARD_ON +#define FROMIP_CLK2CARD_ON_RESET 0x0 +#define FROMIP_CLK2CARD_ON_BITS 0x00040000 +#define FROMIP_CLK2CARD_ON_MSB 18 +#define FROMIP_CLK2CARD_ON_LSB 18 +// Field : FROMIP_CARD_CLK_STABLE +#define FROMIP_CARD_CLK_STABLE_RESET 0x0 +#define FROMIP_CARD_CLK_STABLE_BITS 0x00020000 +#define FROMIP_CARD_CLK_STABLE_MSB 17 +#define FROMIP_CARD_CLK_STABLE_LSB 17 +// Field : FROMIP_CARD_CLK_EN +#define FROMIP_CARD_CLK_EN_RESET 0x0 +#define FROMIP_CARD_CLK_EN_BITS 0x00010000 +#define FROMIP_CARD_CLK_EN_MSB 16 +#define FROMIP_CARD_CLK_EN_LSB 16 +// Field : FROMIP_CLK_GEN_SEL +#define FROMIP_CLK_GEN_SEL_RESET 0x0 +#define FROMIP_CLK_GEN_SEL_BITS 0x00001000 +#define FROMIP_CLK_GEN_SEL_MSB 12 +#define FROMIP_CLK_GEN_SEL_LSB 12 +// Field : FROMIP_FREQ_SEL +#define FROMIP_FREQ_SEL_RESET 0x000 +#define FROMIP_FREQ_SEL_BITS 0x000003ff +#define FROMIP_FREQ_SEL_MSB 9 +#define FROMIP_FREQ_SEL_LSB 0 +// Register : LOCAL +#define LOCAL 0x00000008 +#define LOCAL_BITS 0x1f9713ff +#define LOCAL_RESET 0x00000000 +// Field : LOCAL_TUNING_CCLK_SEL +#define LOCAL_TUNING_CCLK_SEL_RESET 0x00 +#define LOCAL_TUNING_CCLK_SEL_BITS 0x1f000000 +#define LOCAL_TUNING_CCLK_SEL_MSB 28 +#define LOCAL_TUNING_CCLK_SEL_LSB 24 +// Field : LOCAL_TUNING_CCLK_UPDATE +#define LOCAL_TUNING_CCLK_UPDATE_RESET 0x0 +#define LOCAL_TUNING_CCLK_UPDATE_BITS 0x00800000 +#define LOCAL_TUNING_CCLK_UPDATE_MSB 23 +#define LOCAL_TUNING_CCLK_UPDATE_LSB 23 +// Field : LOCAL_SAMPLE_CCLK_SEL +#define LOCAL_SAMPLE_CCLK_SEL_RESET 0x0 +#define LOCAL_SAMPLE_CCLK_SEL_BITS 0x00100000 +#define LOCAL_SAMPLE_CCLK_SEL_MSB 20 +#define LOCAL_SAMPLE_CCLK_SEL_LSB 20 +// Field : LOCAL_CLK2CARD_ON +#define LOCAL_CLK2CARD_ON_RESET 0x0 +#define LOCAL_CLK2CARD_ON_BITS 0x00040000 +#define LOCAL_CLK2CARD_ON_MSB 18 +#define LOCAL_CLK2CARD_ON_LSB 18 +// Field : LOCAL_CARD_CLK_STABLE +#define LOCAL_CARD_CLK_STABLE_RESET 0x0 +#define LOCAL_CARD_CLK_STABLE_BITS 0x00020000 +#define LOCAL_CARD_CLK_STABLE_MSB 17 +#define LOCAL_CARD_CLK_STABLE_LSB 17 +// Field : LOCAL_CARD_CLK_EN +#define LOCAL_CARD_CLK_EN_RESET 0x0 +#define LOCAL_CARD_CLK_EN_BITS 0x00010000 +#define LOCAL_CARD_CLK_EN_MSB 16 +#define LOCAL_CARD_CLK_EN_LSB 16 +// Field : LOCAL_CLK_GEN_SEL +#define LOCAL_CLK_GEN_SEL_RESET 0x0 +#define LOCAL_CLK_GEN_SEL_BITS 0x00001000 +#define LOCAL_CLK_GEN_SEL_MSB 12 +#define LOCAL_CLK_GEN_SEL_LSB 12 +#define LOCAL_CLK_GEN_SEL_VALUE_PROGCLOCKMODE 0x0 +#define LOCAL_CLK_GEN_SEL_VALUE_DIVCLOCKMODE 0x1 +// Field : LOCAL_FREQ_SEL +#define LOCAL_FREQ_SEL_RESET 0x000 +#define LOCAL_FREQ_SEL_BITS 0x000003ff +#define LOCAL_FREQ_SEL_MSB 9 +#define LOCAL_FREQ_SEL_LSB 0 +// Register : USE_LOCAL +#define USE_LOCAL 0x0000000c +#define USE_LOCAL_BITS 0x01951001 +#define USE_LOCAL_RESET 0x00000000 +// Field : USE_LOCAL_TUNING_CCLK_SEL +#define USE_LOCAL_TUNING_CCLK_SEL_RESET 0x0 +#define USE_LOCAL_TUNING_CCLK_SEL_BITS 0x01000000 +#define USE_LOCAL_TUNING_CCLK_SEL_MSB 24 +#define USE_LOCAL_TUNING_CCLK_SEL_LSB 24 +// Field : USE_LOCAL_TUNING_CCLK_UPDATE +#define USE_LOCAL_TUNING_CCLK_UPDATE_RESET 0x0 +#define USE_LOCAL_TUNING_CCLK_UPDATE_BITS 0x00800000 +#define USE_LOCAL_TUNING_CCLK_UPDATE_MSB 23 +#define USE_LOCAL_TUNING_CCLK_UPDATE_LSB 23 +// Field : USE_LOCAL_SAMPLE_CCLK_SEL +#define USE_LOCAL_SAMPLE_CCLK_SEL_RESET 0x0 +#define USE_LOCAL_SAMPLE_CCLK_SEL_BITS 0x00100000 +#define USE_LOCAL_SAMPLE_CCLK_SEL_MSB 20 +#define USE_LOCAL_SAMPLE_CCLK_SEL_LSB 20 +// Field : USE_LOCAL_CLK2CARD_ON +#define USE_LOCAL_CLK2CARD_ON_RESET 0x0 +#define USE_LOCAL_CLK2CARD_ON_BITS 0x00040000 +#define USE_LOCAL_CLK2CARD_ON_MSB 18 +#define USE_LOCAL_CLK2CARD_ON_LSB 18 +// Field : USE_LOCAL_CARD_CLK_EN +#define USE_LOCAL_CARD_CLK_EN_RESET 0x0 +#define USE_LOCAL_CARD_CLK_EN_BITS 0x00010000 +#define USE_LOCAL_CARD_CLK_EN_MSB 16 +#define USE_LOCAL_CARD_CLK_EN_LSB 16 +// Field : USE_LOCAL_CLK_GEN_SEL +#define USE_LOCAL_CLK_GEN_SEL_RESET 0x0 +#define USE_LOCAL_CLK_GEN_SEL_BITS 0x00001000 +#define USE_LOCAL_CLK_GEN_SEL_MSB 12 +#define USE_LOCAL_CLK_GEN_SEL_LSB 12 +// Field : USE_LOCAL_FREQ_SEL +#define USE_LOCAL_FREQ_SEL_RESET 0x0 +#define USE_LOCAL_FREQ_SEL_BITS 0x00000001 +#define USE_LOCAL_FREQ_SEL_MSB 0 +#define USE_LOCAL_FREQ_SEL_LSB 0 +// Register : SD_DELAY +#define SD_DELAY 0x00000010 +#define SD_DELAY_BITS 0x0000001f +#define SD_DELAY_RESET 0x00000000 +// Field : SD_DELAY_STEPS +#define SD_DELAY_STEPS_RESET 0x00 +#define SD_DELAY_STEPS_BITS 0x0000001f +#define SD_DELAY_STEPS_MSB 4 +#define SD_DELAY_STEPS_LSB 0 +// Register : RX_DELAY +#define RX_DELAY 0x00000014 +#define RX_DELAY_BITS 0x19f3331f +#define RX_DELAY_RESET 0x00000000 +// Field : RX_DELAY_BYPASS +#define RX_DELAY_BYPASS_RESET 0x0 +#define RX_DELAY_BYPASS_BITS 0x10000000 +#define RX_DELAY_BYPASS_MSB 28 +#define RX_DELAY_BYPASS_LSB 28 +// Field : RX_DELAY_FAIL_ACTUAL +#define RX_DELAY_FAIL_ACTUAL_RESET 0x0 +#define RX_DELAY_FAIL_ACTUAL_BITS 0x08000000 +#define RX_DELAY_FAIL_ACTUAL_MSB 27 +#define RX_DELAY_FAIL_ACTUAL_LSB 27 +// Field : RX_DELAY_ACTUAL +#define RX_DELAY_ACTUAL_RESET 0x00 +#define RX_DELAY_ACTUAL_BITS 0x01f00000 +#define RX_DELAY_ACTUAL_MSB 24 +#define RX_DELAY_ACTUAL_LSB 20 +// Field : RX_DELAY_OFFSET +#define RX_DELAY_OFFSET_RESET 0x0 +#define RX_DELAY_OFFSET_BITS 0x00030000 +#define RX_DELAY_OFFSET_MSB 17 +#define RX_DELAY_OFFSET_LSB 16 +// Field : RX_DELAY_OVERFLOW +#define RX_DELAY_OVERFLOW_RESET 0x0 +#define RX_DELAY_OVERFLOW_BITS 0x00003000 +#define RX_DELAY_OVERFLOW_MSB 13 +#define RX_DELAY_OVERFLOW_LSB 12 +#define RX_DELAY_OVERFLOW_VALUE_ALLOW 0x0 +#define RX_DELAY_OVERFLOW_VALUE_CLAMP 0x1 +#define RX_DELAY_OVERFLOW_VALUE_FAIL 0x2 +// Field : RX_DELAY_MAP +#define RX_DELAY_MAP_RESET 0x0 +#define RX_DELAY_MAP_BITS 0x00000300 +#define RX_DELAY_MAP_MSB 9 +#define RX_DELAY_MAP_LSB 8 +#define RX_DELAY_MAP_VALUE_DIRECT 0x0 +#define RX_DELAY_MAP_VALUE 0x1 +#define RX_DELAY_MAP_VALUE_STRETCH 0x2 +// Field : RX_DELAY_FIXED +#define RX_DELAY_FIXED_RESET 0x00 +#define RX_DELAY_FIXED_BITS 0x0000001f +#define RX_DELAY_FIXED_MSB 4 +#define RX_DELAY_FIXED_LSB 0 +// Register : NDIV +#define NDIV 0x00000018 +#define NDIV_BITS 0x1fff0000 +#define NDIV_RESET 0x00110000 +// Field : NDIV_DIVB +#define NDIV_DIVB_RESET 0x001 +#define NDIV_DIVB_BITS 0x1ff00000 +#define NDIV_DIVB_MSB 28 +#define NDIV_DIVB_LSB 20 +// Field : NDIV_DIVA +#define NDIV_DIVA_RESET 0x1 +#define NDIV_DIVA_BITS 0x000f0000 +#define NDIV_DIVA_MSB 19 +#define NDIV_DIVA_LSB 16 +// Register : CS +#define CS 0x0000001c +#define CS_BITS 0x00111101 +#define CS_RESET 0x00000001 +// Field : CS_RX_DEL_UPDATED +#define CS_RX_DEL_UPDATED_RESET 0x0 +#define CS_RX_DEL_UPDATED_BITS 0x00100000 +#define CS_RX_DEL_UPDATED_MSB 20 +#define CS_RX_DEL_UPDATED_LSB 20 +// Field : CS_RX_CLK_RUNNING +#define CS_RX_CLK_RUNNING_RESET 0x0 +#define CS_RX_CLK_RUNNING_BITS 0x00010000 +#define CS_RX_CLK_RUNNING_MSB 16 +#define CS_RX_CLK_RUNNING_LSB 16 +// Field : CS_SD_CLK_RUNNING +#define CS_SD_CLK_RUNNING_RESET 0x0 +#define CS_SD_CLK_RUNNING_BITS 0x00001000 +#define CS_SD_CLK_RUNNING_MSB 12 +#define CS_SD_CLK_RUNNING_LSB 12 +// Field : CS_TX_CLK_RUNNING +#define CS_TX_CLK_RUNNING_RESET 0x0 +#define CS_TX_CLK_RUNNING_BITS 0x00000100 +#define CS_TX_CLK_RUNNING_MSB 8 +#define CS_TX_CLK_RUNNING_LSB 8 +// Field : CS_RESET +#define CS_RESET_RESET 0x1 +#define CS_RESET_BITS 0x00000001 +#define CS_RESET_MSB 0 +#define CS_RESET_LSB 0 + +#define FPGA_SRC_RATE 400000000 + +/* Base number of steps to delay in relation to tx clk. + * The relationship of the 3 clocks are as follows: + * tx_clk: This clock is provided to the controller. Data is sent out + * to the pads using this clock. + * sd_clk: This clock is sent out to the card. + * rx_clk: This clock is used to sample the data coming back from the card. + * This may need to be several steps ahead of the tx_clk. The default rx delay + * is used as a base delay, and can be further adjusted by the sd host + * controller during the tuning process if using a DDR50 or faster SD card + */ +/* + * PRJY-1813 - the default SD clock delay needs to be set to ~60% of the total + * number of steps to meet tISU (>6ns) and tIH (>2ns) in high-speed mode. + * On FPGA this means delay SDCLK by 5, and sample RX with a delay of 6. + */ +#define DEFAULT_RX_DELAY 6 +#define DEFAULT_SD_DELAY 5 + +struct rp1_sdio_clkgen { + struct device *dev; + + /* Source clock. Either PLL VCO or fixed freq on FPGA */ + struct clk *src_clk; + /* Desired base frequency. Max freq card can go */ + struct clk *base_clk; + + struct clk_hw hw; + void __iomem *regs; + + /* Starting value of local register before changing freq */ + u32 local_base; +}; + +static inline void clkgen_write(struct rp1_sdio_clkgen *clkgen, u32 reg, u32 val) +{ + dev_dbg(clkgen->dev, "%s: write reg 0x%x: 0x%x\n", __func__, reg, val); + writel(val, clkgen->regs + reg); +} + +static inline u32 clkgen_read(struct rp1_sdio_clkgen *clkgen, u32 reg) +{ + u32 val = readl(clkgen->regs + reg); + + dev_dbg(clkgen->dev, "%s: read reg 0x%x: 0x%x\n", __func__, reg, val); + return val; +} + +static int get_steps(unsigned int steps) +{ + int ret = -1; + + if (steps == 4) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_4; + else if (steps == 5) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_5; + else if (steps == 6) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_6; + else if (steps == 8) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_8; + else if (steps == 10) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_10; + else if (steps == 12) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_12; + else if (steps == 16) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_16; + else if (steps == 20) + ret = MODE_STEPS_PER_CYCLE_VALUE_STEPS_20; + return ret; +} + +static int rp1_sdio_clk_init(struct rp1_sdio_clkgen *clkgen) +{ + unsigned long src_rate = clk_get_rate(clkgen->src_clk); + unsigned long base_rate = clk_get_rate(clkgen->base_clk); + unsigned int steps = src_rate / base_rate; + u32 reg = 0; + int steps_value = 0; + + dev_dbg(clkgen->dev, "init: src_rate %lu, base_rate %lu, steps %d\n", + src_rate, base_rate, steps); + + /* Assert reset while we set up clkgen */ + clkgen_write(clkgen, CS, CS_RESET_BITS); + + /* Pick clock source */ + if (src_rate == FPGA_SRC_RATE) { + /* Using ALT SRC */ + reg |= MODE_SRC_SEL_VALUE_CLK_ALT_SRC << MODE_SRC_SEL_LSB; + } else { + /* Assume we are using PLL SYS VCO */ + reg |= MODE_SRC_SEL_VALUE_PLL_SYS_VCO << MODE_SRC_SEL_LSB; + } + + /* How many delay steps are available in one cycle for this source */ + steps_value = get_steps(steps); + if (steps_value < 0) { + dev_err(clkgen->dev, "Invalid step value: %d\n", steps); + return -EINVAL; + } + reg |= steps_value << MODE_STEPS_PER_CYCLE_LSB; + + /* Mode register is done now*/ + clkgen_write(clkgen, MODE, reg); + + /* Now set delay mode */ + /* Clamp value if out of range rx delay is used */ + reg = RX_DELAY_OVERFLOW_VALUE_CLAMP << RX_DELAY_OVERFLOW_LSB; + /* SD tuning bus goes from 0x0 to 0xf but we don't necessarily have that + * many steps available depending on the source so map 0x0 -> 0xf to one + * cycle of rx delay + */ + reg |= RX_DELAY_MAP_VALUE_STRETCH << RX_DELAY_MAP_LSB; + + /* Default RX delay */ + dev_dbg(clkgen->dev, "default rx delay %d\n", DEFAULT_RX_DELAY); + reg |= (DEFAULT_RX_DELAY & RX_DELAY_FIXED_BITS) << RX_DELAY_FIXED_LSB; + clkgen_write(clkgen, RX_DELAY, reg); + + /* Default SD delay */ + dev_dbg(clkgen->dev, "default sd delay %d\n", DEFAULT_SD_DELAY); + reg = (DEFAULT_SD_DELAY & SD_DELAY_STEPS_BITS) << SD_DELAY_STEPS_LSB; + clkgen_write(clkgen, SD_DELAY, reg); + + /* We select freq, we turn on tx clock, we turn on sd clk, + * we pick clock generator mode + */ + reg = USE_LOCAL_FREQ_SEL_BITS | USE_LOCAL_CARD_CLK_EN_BITS | + USE_LOCAL_CLK2CARD_ON_BITS | USE_LOCAL_CLK_GEN_SEL_BITS; + clkgen_write(clkgen, USE_LOCAL, reg); + + /* Deassert reset. Reset bit is only writable bit of CS + * reg so fine to write a 0. + */ + clkgen_write(clkgen, CS, 0); + + return 0; +} + +#define RUNNING \ + (CS_TX_CLK_RUNNING_BITS | CS_RX_CLK_RUNNING_BITS | \ + CS_SD_CLK_RUNNING_BITS) +static int rp1_sdio_clk_is_prepared(struct clk_hw *hw) +{ + struct rp1_sdio_clkgen *clkgen = + container_of(hw, struct rp1_sdio_clkgen, hw); + u32 status; + + dev_dbg(clkgen->dev, "is_prepared\n"); + status = clkgen_read(clkgen, CS); + return ((status & RUNNING) == RUNNING); +} + +/* Can define an additional divider if an sd card isn't working at full speed */ +/* #define SLOWDOWN 3 */ + +static unsigned long rp1_sdio_clk_get_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + /* Get the current rate */ + struct rp1_sdio_clkgen *clkgen = + container_of(hw, struct rp1_sdio_clkgen, hw); + unsigned long actual_rate = 0; + u32 ndiv_diva; + u32 ndiv_divb; + u32 tmp; + u32 div; + + tmp = clkgen_read(clkgen, LOCAL); + if ((tmp & LOCAL_CLK2CARD_ON_BITS) == 0) { + dev_dbg(clkgen->dev, "get_rate 0\n"); + return 0; + } + + tmp = clkgen_read(clkgen, NDIV); + ndiv_diva = (tmp & NDIV_DIVA_BITS) >> NDIV_DIVA_LSB; + ndiv_divb = (tmp & NDIV_DIVB_BITS) >> NDIV_DIVB_LSB; + div = ndiv_diva * ndiv_divb; + actual_rate = (clk_get_rate(clkgen->base_clk) / div); + +#ifdef SLOWDOWN + actual_rate *= SLOWDOWN; +#endif + + dev_dbg(clkgen->dev, "get_rate. ndiv_diva %d, ndiv_divb %d = %lu\n", + ndiv_diva, ndiv_divb, actual_rate); + + return actual_rate; +} + +static int rp1_sdio_clk_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct rp1_sdio_clkgen *clkgen = + container_of(hw, struct rp1_sdio_clkgen, hw); + u32 div; + u32 reg; + + dev_dbg(clkgen->dev, "set_rate %lu\n", rate); + + if (rate == 0) { + /* Keep tx clock running */ + clkgen_write(clkgen, LOCAL, LOCAL_CARD_CLK_EN_BITS); + return 0; + } + +#ifdef SLOWDOWN + rate /= SLOWDOWN; +#endif + + div = (clk_get_rate(clkgen->base_clk) / rate) - 1; + reg = LOCAL_CLK_GEN_SEL_BITS | LOCAL_CARD_CLK_EN_BITS | + LOCAL_CLK2CARD_ON_BITS | (div << LOCAL_FREQ_SEL_LSB); + clkgen_write(clkgen, LOCAL, reg); + + return 0; +} + +#define MAX_NDIV (256 * 8) +static int rp1_sdio_clk_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + unsigned long rate; + struct rp1_sdio_clkgen *clkgen = + container_of(hw, struct rp1_sdio_clkgen, hw); + unsigned long base_rate = clk_get_rate(clkgen->base_clk); + u32 div; + + /* What is the actual rate I can get if I request xyz */ + if (req->rate) { + div = min((u32)(base_rate / req->rate), (u32)MAX_NDIV); + rate = base_rate / div; + req->rate = rate; + dev_dbg(clkgen->dev, "determine_rate %lu: %lu / %d = %lu\n", + req->rate, base_rate, div, rate); + } else { + rate = 0; + dev_dbg(clkgen->dev, "determine_rate %lu: %lu\n", req->rate, + rate); + } + + return 0; +} + +static const struct clk_ops rp1_sdio_clk_ops = { + .is_prepared = rp1_sdio_clk_is_prepared, + .recalc_rate = rp1_sdio_clk_get_rate, + .set_rate = rp1_sdio_clk_set_rate, + .determine_rate = rp1_sdio_clk_determine_rate, +}; + +static int rp1_sdio_clk_probe(struct platform_device *pdev) +{ + struct device_node *node = pdev->dev.of_node; + struct rp1_sdio_clkgen *clkgen; + void __iomem *regs; + struct clk_init_data init = {}; + int ret; + + clkgen = devm_kzalloc(&pdev->dev, sizeof(*clkgen), GFP_KERNEL); + if (!clkgen) + return -ENOMEM; + platform_set_drvdata(pdev, clkgen); + + clkgen->dev = &pdev->dev; + + /* Source freq */ + clkgen->src_clk = devm_clk_get(&pdev->dev, "src"); + if (IS_ERR(clkgen->src_clk)) { + int err = PTR_ERR(clkgen->src_clk); + + dev_err(&pdev->dev, "failed to get src clk: %d\n", err); + return err; + } + + /* Desired maximum output freq (i.e. base freq) */ + clkgen->base_clk = devm_clk_get(&pdev->dev, "base"); + if (IS_ERR(clkgen->base_clk)) { + int err = PTR_ERR(clkgen->base_clk); + + dev_err(&pdev->dev, "failed to get base clk: %d\n", err); + return err; + } + + regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(regs)) + return PTR_ERR(regs); + + init.name = node->name; + init.ops = &rp1_sdio_clk_ops; + init.flags = CLK_GET_RATE_NOCACHE; + + clkgen->hw.init = &init; + clkgen->regs = regs; + + dev_info(&pdev->dev, "loaded %s\n", init.name); + + ret = devm_clk_hw_register(&pdev->dev, &clkgen->hw); + if (ret) + return ret; + + ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &clkgen->hw); + if (ret) + return ret; + + ret = rp1_sdio_clk_init(clkgen); + return ret; +} + +static int rp1_sdio_clk_remove(struct platform_device *pdev) +{ + return 0; +} + +static const struct of_device_id rp1_sdio_clk_dt_ids[] = { + { .compatible = "raspberrypi,rp1-sdio-clk", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rp1_sdio_clk_dt_ids); + +static struct platform_driver rp1_sdio_clk_driver = { + .probe = rp1_sdio_clk_probe, + .remove = rp1_sdio_clk_remove, + .driver = { + .name = "rp1-sdio-clk", + .of_match_table = rp1_sdio_clk_dt_ids, + }, +}; +module_platform_driver(rp1_sdio_clk_driver); + +MODULE_AUTHOR("Liam Fraser "); +MODULE_DESCRIPTION("RP1 SDIO clock driver"); +MODULE_LICENSE("GPL"); -- 2.7.4