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[203.254.224.25]) by mx.google.com with ESMTP id kc9si5175975pbc.175.2012.08.01.02.27.19; Wed, 01 Aug 2012 02:27:20 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of rajeshwari.s@samsung.com designates 203.254.224.25 as permitted sender) client-ip=203.254.224.25; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of rajeshwari.s@samsung.com designates 203.254.224.25 as permitted sender) smtp.mail=rajeshwari.s@samsung.com Received: from epcpsbgm2.samsung.com (mailout2.samsung.com [203.254.224.25]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M8200M47KWLFKH0@mailout2.samsung.com>; Wed, 01 Aug 2012 18:27:19 +0900 (KST) X-AuditID: cbfee61b-b7f566d000005c8a-e5-5018f676b330 Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm2.samsung.com (EPCPMTA) with SMTP id 6F.D2.23690.676F8105; Wed, 01 Aug 2012 18:27:18 +0900 (KST) Received: from rajeshwari-linux.sisodomain.com ([107.108.215.115]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0M820029AKX8FS00@mmp2.samsung.com>; Wed, 01 Aug 2012 18:27:18 +0900 (KST) From: Rajeshwari Shinde To: u-boot@lists.denx.de Cc: patches@linaro.org, alim.akhtar@samsung.com, sjg@chromium.org, mk7.kang@samsung.com, chander.kashyap@linaro.org Subject: [PATCH 3/7 V3] EXYNOS: Add clock for SPI. Date: Wed, 01 Aug 2012 15:03:28 +0530 Message-id: <1343813612-1587-4-git-send-email-rajeshwari.s@samsung.com> X-Mailer: git-send-email 1.7.4.4 In-reply-to: <1343813612-1587-1-git-send-email-rajeshwari.s@samsung.com> References: <1343813612-1587-1-git-send-email-rajeshwari.s@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrGJMWRmVeSWpSXmKPExsVy+t9jQd2ybxIBBv+/WVs8XH+TxWLK4S8s Dkwed67tYQtgjOKySUnNySxLLdK3S+DKmDfhPFvBcvWKtxeusDcwbpXvYuTkkBAwkfhw8gcb hC0mceHeeiCbi0NIYDqjxIvjN1kgnIlMEr9+H2EFqWITMJLYenIaI4gtIiAh8av/KpDNwcEs UCoxZWIeSFgYqOTAhzvMIDaLgKrEuTOPwGxeAXeJm3e+QS1TkDg29SsrSCungIfE951gYSGg kltvd7FOYORdwMiwilE0tSC5oDgpPddIrzgxt7g0L10vOT93EyPY98+kdzCuarA4xCjAwajE w/vCTCJAiDWxrLgy9xCjBAezkghvwU2gEG9KYmVValF+fFFpTmrxIUZpDhYlcV4T76/+QgLp iSWp2ampBalFMFkmDk6pBsbaHbtvbBBZHKihzH11A/O6N3Wbn2j1/tsqc5Q7XPEs2zmLBzm1 fBMuPD1Vw3O/a+vaI+/lfDplGRferdw+vYfL4cnmSXGPNrlOdTxZlLTyL5/NXSVG0YyVpuUH pMp8imJvbVHVmGWQsn/51Jsht8ufcG0+52US/MtMcGpluN0cL9eObVqHZPOVWIozEg21mIuK EwEWLjj4+QEAAA== X-TM-AS-MML: No X-Gm-Message-State: ALoCoQnviy3yNn/MZuZPp0rsfPiiiZUACNq/eRbkd40H5neBHTS8WQpxXKyHnCu4IA0cjYyXyxv5 This patch adds api to calculate and set the clock for SPI channels Signed-off-by: Simon Glass Signed-off-by: Rajeshwari Shinde --- Changes in V2: - None Changes in V3: - Corrected Warning messages. arch/arm/cpu/armv7/exynos/clock.c | 124 ++++++++++++++++++++++++++++++++ arch/arm/include/asm/arch-exynos/clk.h | 4 +- 2 files changed, 127 insertions(+), 1 deletions(-) diff --git a/arch/arm/cpu/armv7/exynos/clock.c b/arch/arm/cpu/armv7/exynos/clock.c index de3db8e..2aa511e 100644 --- a/arch/arm/cpu/armv7/exynos/clock.c +++ b/arch/arm/cpu/armv7/exynos/clock.c @@ -628,6 +628,122 @@ static unsigned long exynos5_get_i2c_clk(void) return aclk_66; } +/** + * Linearly searches for the most accurate main and fine stage clock scalars + * (divisors) for a specified target frequency and scalar bit sizes by checking + * all multiples of main_scalar_bits values. Will always return scalars up to or + * slower than target. + * + * @param main_scalar_bits Number of main scalar bits, must be > 0 and < 32 + * @param fine_scalar_bits Number of fine scalar bits, must be > 0 and < 32 + * @param input_freq Clock frequency to be scaled in Hz + * @param target_freq Desired clock frequency in Hz + * @param best_fine_scalar Pointer to store the fine stage divisor + * + * @return best_main_scalar Main scalar for desired frequency or -1 if none + * found + */ +static int clock_calc_best_scalar(unsigned int main_scaler_bits, + unsigned int fine_scalar_bits, unsigned int input_rate, + unsigned int target_rate, unsigned int *best_fine_scalar) +{ + int i; + int best_main_scalar = -1; + unsigned int best_error = target_rate; + const unsigned int cap = (1 << fine_scalar_bits) - 1; + const unsigned int loops = 1 << main_scaler_bits; + + debug("Input Rate is %u, Target is %u, Cap is %u\n", input_rate, + target_rate, cap); + + assert(best_fine_scalar != NULL); + assert(main_scaler_bits <= fine_scalar_bits); + + *best_fine_scalar = 1; + + if (input_rate == 0 || target_rate == 0) + return -1; + + if (target_rate >= input_rate) + return 1; + + for (i = 1; i <= loops; i++) { + const unsigned int effective_div = max(min(input_rate / i / + target_rate, cap), 1); + const unsigned int effective_rate = input_rate / i / + effective_div; + const int error = target_rate - effective_rate; + + debug("%d|effdiv:%u, effrate:%u, error:%d\n", i, effective_div, + effective_rate, error); + + if (error >= 0 && error <= best_error) { + best_error = error; + best_main_scalar = i; + *best_fine_scalar = effective_div; + } + } + + return best_main_scalar; +} + +static int exynos5_spi_set_clock_rate(enum periph_id periph_id, + unsigned int rate) +{ + struct exynos5_clock *clk = + (struct exynos5_clock *)samsung_get_base_clock(); + int main; + unsigned int fine; + unsigned shift, pre_shift; + unsigned mask = 0xff; + u32 *reg; + + main = clock_calc_best_scalar(4, 8, 400000000, rate, &fine); + if (main < 0) { + debug("%s: Cannot set clock rate for periph %d", + __func__, periph_id); + return -1; + } + main = main - 1; + fine = fine - 1; + + switch (periph_id) { + case PERIPH_ID_SPI0: + reg = &clk->div_peric1; + shift = 0; + pre_shift = 8; + break; + case PERIPH_ID_SPI1: + reg = &clk->div_peric1; + shift = 16; + pre_shift = 24; + break; + case PERIPH_ID_SPI2: + reg = &clk->div_peric2; + shift = 0; + pre_shift = 8; + break; + case PERIPH_ID_SPI3: + reg = &clk->sclk_div_isp; + shift = 0; + pre_shift = 4; + break; + case PERIPH_ID_SPI4: + reg = &clk->sclk_div_isp; + shift = 12; + pre_shift = 16; + break; + default: + debug("%s: Unsupported peripheral ID %d\n", __func__, + periph_id); + return -1; + } + clrsetbits_le32(reg, mask << shift, (main & mask) << shift); + clrsetbits_le32(reg, mask << pre_shift, (fine & mask) << pre_shift); + + return 0; +} + unsigned long get_pll_clk(int pllreg) { if (cpu_is_exynos5()) @@ -697,3 +813,11 @@ void set_mipi_clk(void) if (cpu_is_exynos4()) exynos4_set_mipi_clk(); } + +int spi_set_clock_rate(enum periph_id periph_id, unsigned int rate) +{ + if (cpu_is_exynos5()) + return exynos5_spi_set_clock_rate(periph_id, rate); + else + return 0; +} diff --git a/arch/arm/include/asm/arch-exynos/clk.h b/arch/arm/include/asm/arch-exynos/clk.h index 5529025..4e51402 100644 --- a/arch/arm/include/asm/arch-exynos/clk.h +++ b/arch/arm/include/asm/arch-exynos/clk.h @@ -22,6 +22,8 @@ #ifndef __ASM_ARM_ARCH_CLK_H_ #define __ASM_ARM_ARCH_CLK_H_ +#include + #define APLL 0 #define MPLL 1 #define EPLL 2 @@ -38,5 +40,5 @@ void set_mmc_clk(int dev_index, unsigned int div); unsigned long get_lcd_clk(void); void set_lcd_clk(void); void set_mipi_clk(void); - +int spi_set_clock_rate(enum periph_id periph_id, unsigned int rate); #endif