diff options
Diffstat (limited to 'drivers/clk/meson/gxbb-aoclk-32k.c')
| -rw-r--r-- | drivers/clk/meson/gxbb-aoclk-32k.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/drivers/clk/meson/gxbb-aoclk-32k.c b/drivers/clk/meson/gxbb-aoclk-32k.c new file mode 100644 index 000000000000..491634dbc985 --- /dev/null +++ b/drivers/clk/meson/gxbb-aoclk-32k.c @@ -0,0 +1,194 @@ +/* + * Copyright (c) 2017 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <linux/clk-provider.h> +#include <linux/bitfield.h> +#include <linux/regmap.h> +#include "gxbb-aoclk.h" + +/* + * The AO Domain embeds a dual/divider to generate a more precise + * 32,768KHz clock for low-power suspend mode and CEC. + * ______ ______ + * | | | | + * ______ | Div1 |-| Cnt1 | ______ + * | | /|______| |______|\ | | + * Xtal-->| Gate |---| ______ ______ X-X--| Gate |--> + * |______| | \| | | |/ | |______| + * | | Div2 |-| Cnt2 | | + * | |______| |______| | + * |_______________________| + * + * The dividing can be switched to single or dual, with a counter + * for each divider to set when the switching is done. + * The entire dividing mechanism can be also bypassed. + */ + +#define CLK_CNTL0_N1_MASK GENMASK(11, 0) +#define CLK_CNTL0_N2_MASK GENMASK(23, 12) +#define CLK_CNTL0_DUALDIV_EN BIT(28) +#define CLK_CNTL0_OUT_GATE_EN BIT(30) +#define CLK_CNTL0_IN_GATE_EN BIT(31) + +#define CLK_CNTL1_M1_MASK GENMASK(11, 0) +#define CLK_CNTL1_M2_MASK GENMASK(23, 12) +#define CLK_CNTL1_BYPASS_EN BIT(24) +#define CLK_CNTL1_SELECT_OSC BIT(27) + +#define PWR_CNTL_ALT_32K_SEL GENMASK(13, 10) + +struct cec_32k_freq_table { + unsigned long parent_rate; + unsigned long target_rate; + bool dualdiv; + unsigned int n1; + unsigned int n2; + unsigned int m1; + unsigned int m2; +}; + +static const struct cec_32k_freq_table aoclk_cec_32k_table[] = { + [0] = { + .parent_rate = 24000000, + .target_rate = 32768, + .dualdiv = true, + .n1 = 733, + .n2 = 732, + .m1 = 8, + .m2 = 11, + }, +}; + +/* + * If CLK_CNTL0_DUALDIV_EN == 0 + * - will use N1 divider only + * If CLK_CNTL0_DUALDIV_EN == 1 + * - hold M1 cycles of N1 divider then changes to N2 + * - hold M2 cycles of N2 divider then changes to N1 + * Then we can get more accurate division. + */ +static unsigned long aoclk_cec_32k_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw); + unsigned long n1; + u32 reg0, reg1; + + regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, ®0); + regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, ®1); + + if (reg1 & CLK_CNTL1_BYPASS_EN) + return parent_rate; + + if (reg0 & CLK_CNTL0_DUALDIV_EN) { + unsigned long n2, m1, m2, f1, f2, p1, p2; + + n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1; + n2 = FIELD_GET(CLK_CNTL0_N2_MASK, reg0) + 1; + + m1 = FIELD_GET(CLK_CNTL1_M1_MASK, reg1) + 1; + m2 = FIELD_GET(CLK_CNTL1_M2_MASK, reg1) + 1; + + f1 = DIV_ROUND_CLOSEST(parent_rate, n1); + f2 = DIV_ROUND_CLOSEST(parent_rate, n2); + + p1 = DIV_ROUND_CLOSEST(100000000 * m1, f1 * (m1 + m2)); + p2 = DIV_ROUND_CLOSEST(100000000 * m2, f2 * (m1 + m2)); + + return DIV_ROUND_UP(100000000, p1 + p2); + } + + n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1; + + return DIV_ROUND_CLOSEST(parent_rate, n1); +} + +static const struct cec_32k_freq_table *find_cec_32k_freq(unsigned long rate, + unsigned long prate) +{ + int i; + + for (i = 0 ; i < ARRAY_SIZE(aoclk_cec_32k_table) ; ++i) + if (aoclk_cec_32k_table[i].parent_rate == prate && + aoclk_cec_32k_table[i].target_rate == rate) + return &aoclk_cec_32k_table[i]; + + return NULL; +} + +static long aoclk_cec_32k_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate, + *prate); + + /* If invalid return first one */ + if (!freq) + return aoclk_cec_32k_table[0].target_rate; + + return freq->target_rate; +} + +/* + * From the Amlogic init procedure, the IN and OUT gates needs to be handled + * in the init procedure to avoid any glitches. + */ + +static int aoclk_cec_32k_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate, + parent_rate); + struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw); + u32 reg = 0; + + if (!freq) + return -EINVAL; + + /* Disable clock */ + regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, + CLK_CNTL0_IN_GATE_EN | CLK_CNTL0_OUT_GATE_EN, 0); + + reg = FIELD_PREP(CLK_CNTL0_N1_MASK, freq->n1 - 1); + if (freq->dualdiv) + reg |= CLK_CNTL0_DUALDIV_EN | + FIELD_PREP(CLK_CNTL0_N2_MASK, freq->n2 - 1); + + regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, reg); + + reg = FIELD_PREP(CLK_CNTL1_M1_MASK, freq->m1 - 1); + if (freq->dualdiv) + reg |= FIELD_PREP(CLK_CNTL1_M2_MASK, freq->m2 - 1); + + regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, reg); + + /* Enable clock */ + regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, + CLK_CNTL0_IN_GATE_EN, CLK_CNTL0_IN_GATE_EN); + + udelay(200); + + regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, + CLK_CNTL0_OUT_GATE_EN, CLK_CNTL0_OUT_GATE_EN); + + regmap_update_bits(cec_32k->regmap, AO_CRT_CLK_CNTL1, + CLK_CNTL1_SELECT_OSC, CLK_CNTL1_SELECT_OSC); + + /* Select 32k from XTAL */ + regmap_update_bits(cec_32k->regmap, + AO_RTI_PWR_CNTL_REG0, + PWR_CNTL_ALT_32K_SEL, + FIELD_PREP(PWR_CNTL_ALT_32K_SEL, 4)); + + return 0; +} + +const struct clk_ops meson_aoclk_cec_32k_ops = { + .recalc_rate = aoclk_cec_32k_recalc_rate, + .round_rate = aoclk_cec_32k_round_rate, + .set_rate = aoclk_cec_32k_set_rate, +}; |